task_name
string | initial_board
string | solution
string | puzzle_id
string | title
string | rules
string | initial_observation
string | rows
int64 | cols
int64 | visual_elements
string | description
string | task_type
string | data_source
string | difficulty
string | hint
string |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
normal_sudoku_1787
|
..46.........8...686...51....274......1....3.48...12..59.....122....9..8..85..9..
|
314697825725184396869235147932746581651928734487351269596873412273419658148562973
|
Basic 9x9 Sudoku 1787
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 4 6 . . . . .
. . . . 8 . . . 6
8 6 . . . 5 1 . .
. . 2 7 4 . . . .
. . 1 . . . . 3 .
4 8 . . . 1 2 . .
5 9 . . . . . 1 2
2 . . . . 9 . . 8
. . 8 5 . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
314697825725184396869235147932746581651928734487351269596873412273419658148562973 #1 Extreme (29004) bf
Brute Force: r5c3=1
Hidden Single: r4c9=1
Finned Swordfish: 5 r148 c278 fr1c9 => r2c78<>5
Locked Candidates Type 1 (Pointing): 5 in b3 => r1c2<>5
Brute Force: r5c4=9
Naked Single: r6c4=3
Hidden Single: r7c4=8
Locked Candidates Type 2 (Claiming): 2 in c4 => r1c56,r2c6,r3c5<>2
Finned X-Wing: 9 r24 c18 fr2c3 => r1c1<>9
Discontinuous Nice Loop: 3 r1c2 -3- r4c2 =3= r4c1 =9= r4c8 =8= r1c8 =2= r1c2 => r1c2<>3
Grouped Discontinuous Nice Loop: 5 r1c8 =8= r4c8 =9= r4c1 =3= r4c2 =5= r4c78 -5- r56c9 =5= r1c9 -5- r1c8 => r1c8<>5
Forcing Chain Contradiction in r2 => r1c8<>9
r1c8=9 r4c8<>9 r4c1=9 r2c1<>9
r1c8=9 r1c8<>8 r4c8=8 r4c6<>8 r4c6=6 r6c5<>6 r6c5=5 r6c3<>5 r2c3=5 r2c3<>9
r1c8=9 r2c8<>9
Discontinuous Nice Loop: 4 r8c8 -4- r8c4 -1- r2c4 =1= r1c5 =9= r1c9 =5= r1c7 -5- r8c7 =5= r8c8 => r8c8<>4
Grouped Discontinuous Nice Loop: 1 r2c1 -1- r2c4 =1= r1c5 =9= r1c9 =5= r56c9 -5- r4c78 =5= r4c2 =3= r4c1 =9= r2c1 => r2c1<>1
Discontinuous Nice Loop: 1 r9c2 -1- r2c2 =1= r2c4 -1- r8c4 -4- r8c2 =4= r9c2 => r9c2<>1
Grouped Discontinuous Nice Loop: 7 r5c9 -7- r5c2 -5- r4c2 =5= r4c78 -5- r56c9 =5= r1c9 =9= r1c5 =1= r2c4 -1- r8c4 -4- r7c6 =4= r7c7 -4- r5c7 =4= r5c9 => r5c9<>7
Grouped Discontinuous Nice Loop: 7 r9c2 -7- r5c2 -5- r4c2 =5= r4c78 -5- r56c9 =5= r1c9 =9= r1c5 =1= r2c4 -1- r8c4 -4- r8c2 =4= r9c2 => r9c2<>7
Almost Locked Set XZ-Rule: A=r2c167 {3479}, B=r378c3 {3679}, X=9, Z=3,7 => r2c3<>3, r2c3<>7
Almost Locked Set XY-Wing: A=r3c359 {3479}, B=r4c678 {5689}, C=r5c9 {45}, X,Y=4,5, Z=9 => r3c8<>9
Almost Locked Set XY-Wing: A=r136789c5 {1235679}, B=r12c1,r23c3 {13579}, C=r9c12689 {123467}, X,Y=1,2, Z=5 => r6c3<>5
Hidden Single: r2c3=5
X-Wing: 9 r24 c18 => r6c8<>9
Almost Locked Set XZ-Rule: A=r49c2 {345}, B=r689c8 {4567}, X=4, Z=5 => r4c8<>5
Almost Locked Set XY-Wing: A=r1c16 {137}, B=r689c8 {4567}, C=r12459c2 {123457}, X,Y=1,4, Z=7 => r1c8<>7
Almost Locked Set XY-Wing: A=r4c267 {3568}, B=r689c8 {4567}, C=r9c2 {34}, X,Y=3,4, Z=6 => r4c8<>6
Forcing Chain Contradiction in c9 => r5c9=4
r5c9<>4 r5c7=4 r7c7<>4 r7c6=4 r8c4<>4 r8c4=1 r2c4<>1 r1c5=1 r1c5<>9 r1c9=9 r1c9<>3
r5c9<>4 r5c7=4 r78c7<>4 r9c89=4 r9c2<>4 r9c2=3 r78c3<>3 r3c3=3 r3c9<>3
r5c9<>4 r5c7=4 r78c7<>4 r9c89=4 r9c2<>4 r9c2=3 r9c9<>3
Naked Triple: 3,7,9 in r3c359 => r3c8<>7
Grouped Discontinuous Nice Loop: 6 r7c7 -6- r45c7 =6= r6c8 -6- r6c5 -5- r6c9 =5= r1c9 =9= r1c5 =1= r2c4 -1- r8c4 -4- r7c6 =4= r7c7 => r7c7<>6
Almost Locked Set Chain: 37- r1c16 {137} -1- r9c12689 {123467} -2- r136789c5 {1235679} -5- r369c9 {3579} -37 => r1c9<>3, r1c9<>7
Sashimi X-Wing: 3 c39 r39 fr7c3 fr8c3 => r9c12<>3
Naked Single: r9c2=4
Locked Candidates Type 1 (Pointing): 4 in b9 => r2c7<>4
Naked Triple: 5,6,7 in r689c8 => r2c8<>7
Finned Franken Swordfish: 3 r39b7 c359 fr8c2 fr9c6 => r8c5<>3
Finned Franken Swordfish: 6 r67b9 c358 fr7c6 fr8c7 => r8c5<>6
Forcing Chain Contradiction in r1 => r8c8=5
r8c8<>5 r6c8=5 r6c5<>5 r5c5=5 r5c5<>2 r9c5=2 r9c5<>1 r9c1=1 r1c1<>1
r8c8<>5 r6c8=5 r6c5<>5 r6c5=6 r4c6<>6 r4c6=8 r4c8<>8 r1c8=8 r1c8<>2 r1c2=2 r1c2<>1
r8c8<>5 r8c7=5 r8c7<>4 r8c4=4 r8c4<>1 r2c4=1 r1c5<>1
2-String Kite: 6 in r6c8,r8c3 (connected by r8c7,r9c8) => r6c3<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r9c1<>6
Finned X-Wing: 6 r69 c58 fr9c6 => r7c5<>6
Hidden Triple: 2,5,6 in r569c5 => r9c5<>1, r9c5<>3, r9c5<>7
Hidden Single: r9c1=1
Naked Pair: 3,7 in r1c16 => r1c257<>7, r1c57<>3
Naked Triple: 3,7,9 in r12c1,r3c3 => r2c2<>3, r2c2<>7
Hidden Pair: 3,7 in r2c7,r3c9 => r3c9<>9
Naked Pair: 3,7 in r39c9 => r6c9<>7
Skyscraper: 3 in r7c5,r9c9 (connected by r3c59) => r7c7,r9c6<>3
Hidden Single: r9c9=3
Naked Single: r3c9=7
Naked Single: r2c7=3
Locked Candidates Type 1 (Pointing): 7 in b1 => r5c1<>7
Naked Single: r5c1=6
Locked Candidates Type 1 (Pointing): 7 in b2 => r79c6<>7
Hidden Single: r9c8=7
Naked Single: r6c8=6
Naked Single: r7c7=4
Full House: r8c7=6
Naked Single: r6c5=5
Naked Single: r5c5=2
Naked Single: r6c9=9
Full House: r1c9=5
Full House: r6c3=7
Naked Single: r5c6=8
Full House: r4c6=6
Naked Single: r9c5=6
Full House: r9c6=2
Naked Single: r4c8=8
Naked Single: r1c7=8
Naked Single: r5c2=5
Full House: r5c7=7
Full House: r4c7=5
Naked Single: r8c3=3
Naked Single: r7c6=3
Naked Single: r1c8=2
Naked Single: r4c2=3
Full House: r4c1=9
Naked Single: r3c3=9
Full House: r7c3=6
Full House: r8c2=7
Full House: r7c5=7
Naked Single: r1c6=7
Full House: r2c6=4
Naked Single: r1c2=1
Full House: r2c2=2
Naked Single: r3c8=4
Full House: r2c8=9
Naked Single: r2c1=7
Full House: r1c1=3
Full House: r1c5=9
Full House: r2c4=1
Naked Single: r3c5=3
Full House: r8c5=1
Full House: r3c4=2
Full House: r8c4=4
|
normal_sudoku_6136
|
2.38....1.59.21..3.1..........23....7..1.8..4....472........7.8...3...42...7.413.
|
263875491459621873817493526584239617792168354631547289345912768178356942926784135
|
Basic 9x9 Sudoku 6136
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . 3 8 . . . . 1
. 5 9 . 2 1 . . 3
. 1 . . . . . . .
. . . 2 3 . . . .
7 . . 1 . 8 . . 4
. . . . 4 7 2 . .
. . . . . . 7 . 8
. . . 3 . . . 4 2
. . . 7 . 4 1 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
263875491459621873817493526584239617792168354631547289345912768178356942926784135 #1 Extreme (12808) bf
Hidden Single: r2c6=1
Hidden Single: r3c6=3
Hidden Single: r3c8=2
Hidden Single: r2c8=7
Hidden Single: r7c6=2
Hidden Single: r5c7=3
Hidden Single: r4c9=7
Locked Candidates Type 1 (Pointing): 8 in b3 => r4c7<>8
Naked Triple: 5,6,9 in r4c7,r5c8,r6c9 => r46c8<>5, r46c8<>6, r46c8<>9
Brute Force: r5c8=5
Hidden Rectangle: 2/6 in r5c23,r9c23 => r9c2<>6
Finned Franken Swordfish: 9 c48b6 r367 fr1c8 fr4c7 => r3c7<>9
Forcing Net Verity => r6c4=5
r1c6=5 r4c6<>5 r6c4=5
r1c6=6 (r1c6<>9) (r2c4<>6) (r3c4<>6) r1c8<>6 r7c8=6 (r8c7<>6) (r9c9<>6) r7c4<>6 r6c4=6 r6c9<>6 r3c9=6 r3c9<>5 r9c9=5 r8c7<>5 r8c7=9 r8c6<>9 r4c6=9 r4c6<>5 r6c4=5
r1c6=9 (r1c6<>6) (r1c8<>9 r7c8=9 r8c7<>9) (r3c4<>9) r3c5<>9 r3c9=9 r3c9<>5 r9c9=5 r8c7<>5 r8c7=6 r8c6<>6 r4c6=6 r4c6<>5 r6c4=5
Naked Pair: 6,9 in r4c67 => r4c123<>6, r4c12<>9
Naked Pair: 6,9 in r7c48 => r7c1235<>6, r7c125<>9
Skyscraper: 9 in r1c8,r3c4 (connected by r7c48) => r1c56,r3c9<>9
2-String Kite: 9 in r5c2,r8c6 (connected by r4c6,r5c5) => r8c2<>9
Empty Rectangle: 9 in b4 (r69c9) => r9c2<>9
Locked Candidates Type 1 (Pointing): 9 in b7 => r6c1<>9
W-Wing: 6/9 in r4c7,r7c8 connected by 9 in r1c78 => r8c7<>6
W-Wing: 6/9 in r5c5,r7c4 connected by 9 in r3c45 => r89c5<>6
Turbot Fish: 6 r1c8 =6= r7c8 -6- r7c4 =6= r8c6 => r1c6<>6
Naked Single: r1c6=5
Naked Pair: 6,9 in r7c4,r8c6 => r89c5<>9
Remote Pair: 6/9 r1c8 -9- r7c8 -6- r7c4 -9- r8c6 -6- r4c6 -9- r4c7 => r123c7<>6, r1c7<>9
Naked Single: r1c7=4
Naked Single: r2c7=8
Naked Single: r3c7=5
Naked Single: r3c9=6
Full House: r1c8=9
Naked Single: r8c7=9
Full House: r4c7=6
Naked Single: r6c9=9
Full House: r9c9=5
Full House: r7c8=6
Naked Single: r8c6=6
Full House: r4c6=9
Full House: r5c5=6
Naked Single: r9c5=8
Naked Single: r7c4=9
Naked Single: r1c5=7
Full House: r1c2=6
Naked Single: r5c3=2
Full House: r5c2=9
Naked Single: r9c2=2
Naked Single: r3c4=4
Full House: r2c4=6
Full House: r3c5=9
Full House: r2c1=4
Naked Single: r9c3=6
Full House: r9c1=9
Naked Single: r3c1=8
Full House: r3c3=7
Hidden Single: r8c2=7
Hidden Single: r6c1=6
Hidden Single: r8c3=8
Naked Single: r6c3=1
Naked Single: r4c1=5
Naked Single: r6c8=8
Full House: r4c8=1
Full House: r6c2=3
Naked Single: r4c3=4
Full House: r4c2=8
Full House: r7c2=4
Full House: r7c3=5
Naked Single: r8c1=1
Full House: r7c1=3
Full House: r7c5=1
Full House: r8c5=5
|
normal_sudoku_2263
|
.326478.....92...7...38.5..9.4....6.7.............4.2...1...9..4....2......7.3...
|
532647891148925637697381542914278365726539418385164729271456983453892176869713254
|
Basic 9x9 Sudoku 2263
|
puzzles2_17_clue
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 2 6 4 7 8 . .
. . . 9 2 . . . 7
. . . 3 8 . 5 . .
9 . 4 . . . . 6 .
7 . . . . . . . .
. . . . . 4 . 2 .
. . 1 . . . 9 . .
4 . . . . 2 . . .
. . . 7 . 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
532647891148925637697381542914278365726539418385164729271456983453892176869713254 #1 Easy (272)
Hidden Single: r1c6=7
Naked Single: r3c6=1
Full House: r2c6=5
Naked Single: r3c1=6
Naked Single: r4c6=8
Naked Single: r2c3=8
Naked Single: r7c6=6
Full House: r5c6=9
Naked Single: r2c1=1
Naked Single: r7c5=5
Naked Single: r1c1=5
Naked Single: r2c2=4
Naked Single: r2c8=3
Full House: r2c7=6
Hidden Single: r3c9=2
Hidden Single: r9c7=2
Naked Single: r9c1=8
Naked Single: r6c1=3
Full House: r7c1=2
Naked Single: r7c2=7
Naked Single: r3c2=9
Full House: r3c3=7
Full House: r3c8=4
Naked Single: r7c8=8
Naked Single: r7c4=4
Full House: r7c9=3
Hidden Single: r6c9=9
Naked Single: r1c9=1
Full House: r1c8=9
Naked Single: r4c9=5
Naked Single: r5c8=1
Naked Single: r8c9=6
Naked Single: r6c7=7
Naked Single: r9c8=5
Full House: r8c8=7
Naked Single: r8c2=5
Naked Single: r9c9=4
Full House: r8c7=1
Full House: r5c9=8
Naked Single: r4c7=3
Full House: r5c7=4
Naked Single: r9c2=6
Naked Single: r8c4=8
Naked Single: r8c5=9
Full House: r8c3=3
Full House: r9c3=9
Full House: r9c5=1
Naked Single: r5c2=2
Naked Single: r4c5=7
Naked Single: r6c5=6
Full House: r5c5=3
Naked Single: r4c2=1
Full House: r4c4=2
Full House: r6c2=8
Naked Single: r5c4=5
Full House: r5c3=6
Full House: r6c3=5
Full House: r6c4=1
|
normal_sudoku_49
|
.3957....7....8.9..68.2........8.567.2....8..8..91..2....76.93..1.2.......4...6..
|
139576248752438196468129753941382567523647819876915324285764931617293485394851672
|
Basic 9x9 Sudoku 49
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 9 5 7 . . . .
7 . . . . 8 . 9 .
. 6 8 . 2 . . . .
. . . . 8 . 5 6 7
. 2 . . . . 8 . .
8 . . 9 1 . . 2 .
. . . 7 6 . 9 3 .
. 1 . 2 . . . . .
. . 4 . . . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
139576248752438196468129753941382567523647819876915324285764931617293485394851672 #1 Hard (776)
Hidden Single: r3c3=8
Hidden Single: r3c6=9
Hidden Single: r5c9=9
Hidden Single: r4c6=2
Hidden Single: r9c4=8
Hidden Single: r5c8=1
Hidden Single: r7c2=8
Locked Pair: 2,5 in r7c13 => r7c69,r8c13,r9c12<>5, r7c9,r9c1<>2
Hidden Single: r9c9=2
Hidden Single: r9c6=1
Naked Single: r7c6=4
Naked Single: r1c6=6
Naked Single: r7c9=1
Hidden Single: r2c9=6
Hidden Single: r5c4=6
Hidden Single: r6c3=6
Hidden Single: r8c1=6
Hidden Single: r8c5=9
Locked Pair: 4,8 in r1c89 => r1c17,r23c7,r3c89<>4
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c1<>5
Locked Candidates Type 1 (Pointing): 3 in b6 => r6c6<>3
Locked Candidates Type 1 (Pointing): 4 in b6 => r6c2<>4
Naked Pair: 5,7 in r39c8 => r8c8<>5, r8c8<>7
Skyscraper: 4 in r3c4,r5c5 (connected by r35c1) => r2c5,r4c4<>4
Naked Single: r2c5=3
Naked Single: r4c4=3
Naked Single: r9c5=5
Full House: r5c5=4
Full House: r8c6=3
Naked Single: r4c3=1
Naked Single: r9c8=7
Naked Single: r8c3=7
Naked Single: r3c8=5
Naked Single: r8c7=4
Naked Single: r9c2=9
Full House: r9c1=3
Naked Single: r3c9=3
Naked Single: r6c7=3
Full House: r6c9=4
Naked Single: r8c8=8
Full House: r1c8=4
Full House: r8c9=5
Full House: r1c9=8
Naked Single: r4c2=4
Full House: r4c1=9
Naked Single: r5c1=5
Naked Single: r2c2=5
Full House: r6c2=7
Full House: r5c3=3
Full House: r5c6=7
Full House: r6c6=5
Naked Single: r7c1=2
Full House: r7c3=5
Full House: r2c3=2
Naked Single: r1c1=1
Full House: r1c7=2
Full House: r3c1=4
Naked Single: r2c7=1
Full House: r2c4=4
Full House: r3c4=1
Full House: r3c7=7
|
normal_sudoku_1945
|
.685..3..31.489.....7.........7........631..7.....846..8.1....2629.7.1...5.8...4.
|
968517324312489576547263891836742915495631287271958463784195632629374158153826749
|
Basic 9x9 Sudoku 1945
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 8 5 . . 3 . .
3 1 . 4 8 9 . . .
. . 7 . . . . . .
. . . 7 . . . . .
. . . 6 3 1 . . 7
. . . . . 8 4 6 .
. 8 . 1 . . . . 2
6 2 9 . 7 . 1 . .
. 5 . 8 . . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
968517324312489576547263891836742915495631287271958463784195632629374158153826749 #1 Unfair (972)
Naked Single: r2c2=1
Naked Single: r8c4=3
Naked Single: r3c4=2
Full House: r6c4=9
Naked Single: r1c5=1
Naked Single: r1c6=7
Naked Single: r3c5=6
Full House: r3c6=3
Hidden Single: r4c3=6
Hidden Single: r6c2=7
Hidden Single: r8c6=4
Hidden Single: r4c2=3
Hidden Single: r4c5=4
Hidden Single: r7c8=3
Naked Single: r7c3=4
Naked Single: r7c1=7
Naked Single: r9c1=1
Full House: r9c3=3
Hidden Single: r6c9=3
Hidden Single: r2c8=7
Hidden Single: r9c7=7
Hidden Single: r6c3=1
Locked Candidates Type 1 (Pointing): 5 in b8 => r7c7<>5
Naked Pair: 2,5 in r5c3,r6c1 => r45c1<>2, r45c1<>5
2-String Kite: 2 in r1c8,r5c3 (connected by r1c1,r2c3) => r5c8<>2
X-Wing: 2 r25 c37 => r4c7<>2
XY-Chain: 2 2- r2c3 -5- r2c9 -6- r9c9 -9- r9c5 -2- r6c5 -5- r6c1 -2 => r1c1,r5c3<>2
Naked Single: r5c3=5
Full House: r2c3=2
Naked Single: r6c1=2
Full House: r6c5=5
Full House: r4c6=2
Naked Single: r7c5=9
Full House: r9c5=2
Naked Single: r9c6=6
Full House: r7c6=5
Full House: r7c7=6
Full House: r9c9=9
Naked Single: r2c7=5
Full House: r2c9=6
Naked Single: r1c9=4
Naked Single: r1c1=9
Full House: r1c8=2
Naked Single: r3c2=4
Full House: r3c1=5
Full House: r5c2=9
Naked Single: r4c1=8
Full House: r5c1=4
Naked Single: r5c8=8
Full House: r5c7=2
Naked Single: r4c7=9
Full House: r3c7=8
Naked Single: r8c8=5
Full House: r8c9=8
Naked Single: r3c9=1
Full House: r3c8=9
Full House: r4c8=1
Full House: r4c9=5
|
normal_sudoku_1462
|
74....19..16...4.2.....1.6.9...1.6....29....1...5.87..4......7.6.7...9...91...2.4
|
745326198816759432239481567984217653572963841163548729458192376627834915391675284
|
Basic 9x9 Sudoku 1462
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 4 . . . . 1 9 .
. 1 6 . . . 4 . 2
. . . . . 1 . 6 .
9 . . . 1 . 6 . .
. . 2 9 . . . . 1
. . . 5 . 8 7 . .
4 . . . . . . 7 .
6 . 7 . . . 9 . .
. 9 1 . . . 2 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
745326198816759432239481567984217653572963841163548729458192376627834915391675284 #1 Extreme (35276) bf
Hidden Single: r1c7=1
Hidden Single: r6c9=9
Hidden Single: r3c9=7
Hidden Single: r3c3=9
Hidden Single: r6c1=1
Hidden Single: r8c8=1
Hidden Single: r3c1=2
Hidden Single: r7c9=6
Hidden Single: r7c4=1
Brute Force: r5c5=6
Hidden Single: r6c2=6
Brute Force: r5c2=7
Brute Force: r5c6=3
Hidden Single: r5c8=4
Forcing Net Verity => r1c9<>3
r3c7=3 r1c9<>3
r3c7=5 (r3c7<>3 r7c7=3 r7c3<>3) (r3c2<>5) r5c7<>5 r5c1=5 r2c1<>5 r1c3=5 r7c3<>5 r7c3=8 r9c1<>8 r2c1=8 (r2c8<>8) r5c1<>8 r5c7=8 (r5c1<>8) r3c7<>8 r1c9=8 r1c9<>3
r3c7=8 (r3c7<>3 r7c7=3 r7c3<>3) (r3c2<>8) r5c7<>8 r5c1=8 r2c1<>8 r1c3=8 (r1c3<>5) r7c3<>8 r7c3=5 (r4c3<>5 r4c2=5 r3c2<>5) r9c1<>5 r2c1=5 r5c1<>5 r5c7=5 (r5c1<>5) r3c7<>5 r3c5=5 (r1c5<>5) r1c6<>5 r1c9=5 r1c9<>3
Discontinuous Nice Loop: 3 r3c4 -3- r3c7 =3= r2c8 -3- r6c8 -2- r6c5 -4- r3c5 =4= r3c4 => r3c4<>3
Grouped Discontinuous Nice Loop: 3 r3c5 -3- r3c7 =3= r2c8 -3- r6c8 =3= r6c3 -3- r1c3 =3= r1c45 -3- r3c5 => r3c5<>3
Almost Locked Set XY-Wing: A=r1c39 {358}, B=r123c5,r2c46,r3c4 {2345789}, C=r6c35 {234}, X,Y=2,3, Z=5,8 => r1c6<>5, r1c4<>8
Grouped Discontinuous Nice Loop: 5 r9c5 =7= r2c5 =9= r2c6 =5= r123c5 -5- r9c5 => r9c5<>5
Forcing Chain Contradiction in r7 => r2c5<>3
r2c5=3 r2c1<>3 r9c1=3 r7c2<>3
r2c5=3 r2c1<>3 r9c1=3 r7c3<>3
r2c5=3 r7c5<>3
r2c5=3 r2c8<>3 r3c7=3 r7c7<>3
Forcing Net Verity => r3c4=4
r4c9=3 r6c8<>3 r6c8=2 r6c5<>2 r6c5=4 r3c5<>4 r3c4=4
r4c9=5 (r4c3<>5) (r5c7<>5 r5c7=8 r7c7<>8) r4c9<>3 r8c9=3 r7c7<>3 r7c7=5 (r3c7<>5) r7c3<>5 r1c3=5 r3c2<>5 r3c5=5 r3c5<>4 r3c4=4
r4c9=8 (r1c9<>8 r1c9=5 r1c5<>5) (r1c9<>8 r1c9=5 r2c8<>5) r5c7<>8 r5c7=5 (r5c1<>5) r4c8<>5 r9c8=5 r9c1<>5 r2c1=5 (r2c5<>5) r2c6<>5 r3c5=5 r3c5<>4 r3c4=4
Forcing Net Verity => r4c3=4
r7c7=3 r3c7<>3 r2c8=3 r6c8<>3 r6c8=2 r6c5<>2 r6c5=4 r4c6<>4 r4c3=4
r7c7=5 (r7c7<>3 r3c7=3 r3c2<>3) (r7c3<>5) r5c7<>5 r5c1=5 (r4c3<>5) (r9c1<>5 r9c6=5 r8c6<>5 r8c2=5 r8c2<>8) (r9c1<>5) r4c3<>5 r1c3=5 (r3c2<>5 r3c2=8 r7c2<>8) r1c3<>3 r2c1=3 r9c1<>3 r9c1=8 (r7c3<>8) r5c1<>8 r5c7=8 (r4c8<>8 r9c8=8 r9c1<>8 r9c1=3 r7c3<>3 r7c3=8 r4c3<>8) r7c7<>8 r7c5=8 (r8c4<>8) r8c5<>8 r8c9=8 r8c9<>3 r4c9=3 r4c3<>3 r4c3=4
r7c7=8 (r7c7<>3 r3c7=3 r3c2<>3) (r7c3<>8) r5c7<>8 r5c1=8 r4c3<>8 r1c3=8 (r1c9<>8 r4c9=8 r4c8<>8 r2c8=8 r2c4<>8) r1c3<>3 r2c1=3 r2c4<>3 r2c4=7 r4c4<>7 r4c6=7 r4c6<>4 r4c3=4
Naked Single: r6c3=3
Naked Single: r6c8=2
Full House: r6c5=4
Hidden Single: r8c6=4
Locked Candidates Type 2 (Claiming): 3 in r1 => r2c4<>3
Naked Pair: 5,8 in r1c39 => r1c5<>5, r1c5<>8
Avoidable Rectangle Type 2: 6/3 in r1c56,r5c56 => r1c4<>2
Finned Franken Swordfish: 5 c37b4 r357 fr1c3 fr4c2 => r3c2<>5
W-Wing: 8/5 in r5c1,r7c3 connected by 5 in r1c3,r2c1 => r9c1<>8
Sashimi Swordfish: 8 c137 r357 fr1c3 fr2c1 => r3c2<>8
Naked Single: r3c2=3
Hidden Single: r2c8=3
Hidden Single: r9c1=3
Hidden Single: r7c7=3
Hidden Single: r4c9=3
Remote Pair: 5/8 r3c5 -8- r3c7 -5- r5c7 -8- r5c1 -5- r4c2 -8- r4c8 -5- r9c8 -8- r8c9 => r8c25<>5, r8c25<>8
Naked Single: r8c2=2
Naked Single: r8c5=3
Naked Single: r1c5=2
Naked Single: r8c4=8
Full House: r8c9=5
Full House: r1c9=8
Full House: r9c8=8
Full House: r3c7=5
Full House: r4c8=5
Full House: r3c5=8
Full House: r5c7=8
Full House: r5c1=5
Full House: r4c2=8
Full House: r2c1=8
Full House: r1c3=5
Full House: r7c2=5
Full House: r7c3=8
Naked Single: r1c6=6
Full House: r1c4=3
Naked Single: r2c4=7
Naked Single: r9c5=7
Naked Single: r7c5=9
Full House: r2c5=5
Full House: r7c6=2
Full House: r2c6=9
Naked Single: r4c4=2
Full House: r9c4=6
Full House: r9c6=5
Full House: r4c6=7
|
normal_sudoku_1365
|
.798...5..3....6.88..3...9......1..2.............2.48..16..3....4..1.7...5867...3
|
179862354534197628862345197685431972421789536397526481716253849243918765958674213
|
Basic 9x9 Sudoku 1365
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 9 8 . . . 5 .
. 3 . . . . 6 . 8
8 . . 3 . . . 9 .
. . . . . 1 . . 2
. . . . . . . . .
. . . . 2 . 4 8 .
. 1 6 . . 3 . . .
. 4 . . 1 . 7 . .
. 5 8 6 7 . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
179862354534197628862345197685431972421789536397526481716253849243918765958674213 #1 Extreme (1924)
Hidden Single: r2c9=8
Hidden Single: r2c4=1
Hidden Single: r7c7=8
Hidden Single: r7c1=7
Hidden Single: r1c7=3
Hidden Single: r8c6=8
Locked Candidates Type 1 (Pointing): 2 in b2 => r9c6<>2
Locked Candidates Type 1 (Pointing): 7 in b2 => r56c6<>7
Locked Candidates Type 1 (Pointing): 9 in b7 => r456c1<>9
Locked Candidates Type 1 (Pointing): 5 in b9 => r56c9<>5
Locked Candidates Type 2 (Claiming): 3 in r6 => r4c13,r5c13<>3
Hidden Pair: 3,8 in r45c5 => r45c5<>4, r45c5<>5, r45c5<>6, r45c5<>9
Locked Candidates Type 1 (Pointing): 6 in b5 => r13c6<>6
Empty Rectangle: 1 in b6 (r1c19) => r5c1<>1
XY-Wing: 1/4/2 in r1c69,r3c7 => r3c6<>2
XY-Wing: 4/9/2 in r19c6,r9c1 => r1c1<>2
Hidden Single: r1c6=2
XY-Chain: 6 6- r1c5 -4- r1c9 -1- r3c7 -2- r3c2 -6 => r1c1,r3c5<>6
Hidden Single: r1c5=6
Hidden Single: r3c2=6
Naked Single: r6c2=9
Naked Single: r4c2=8
Full House: r5c2=2
Naked Single: r4c5=3
Naked Single: r5c5=8
Hidden Single: r5c8=3
Hidden Single: r9c8=1
Hidden Single: r9c6=4
Skyscraper: 2 in r3c3,r9c1 (connected by r39c7) => r2c1,r8c3<>2
Naked Single: r8c3=3
Hidden Single: r6c1=3
Hidden Single: r1c1=1
Full House: r1c9=4
Hidden Single: r7c8=4
Hidden Single: r7c4=2
XYZ-Wing: 1/6/7 in r36c9,r4c8 => r5c9<>7
W-Wing: 5/7 in r3c6,r6c4 connected by 7 in r36c9 => r56c6<>5
Naked Single: r6c6=6
Naked Single: r5c6=9
Hidden Single: r2c5=9
Naked Single: r7c5=5
Full House: r3c5=4
Full House: r7c9=9
Full House: r8c4=9
Naked Single: r9c7=2
Full House: r9c1=9
Full House: r8c1=2
Naked Single: r3c7=1
Naked Single: r8c8=6
Full House: r8c9=5
Naked Single: r3c9=7
Full House: r2c8=2
Full House: r4c8=7
Naked Single: r5c7=5
Full House: r4c7=9
Naked Single: r3c6=5
Full House: r2c6=7
Full House: r3c3=2
Naked Single: r6c9=1
Full House: r5c9=6
Naked Single: r5c1=4
Naked Single: r2c1=5
Full House: r2c3=4
Full House: r4c1=6
Naked Single: r4c3=5
Full House: r4c4=4
Naked Single: r5c4=7
Full House: r5c3=1
Full House: r6c3=7
Full House: r6c4=5
|
normal_sudoku_757
|
..2.69..8....259.....8.......92.78....65..2.......6.1..7......3..86..5...4......2
|
452169378837425961961873425319247856786591234524386719275914683198632547643758192
|
Basic 9x9 Sudoku 757
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . 6 9 . . 8
. . . . 2 5 9 . .
. . . 8 . . . . .
. . 9 2 . 7 8 . .
. . 6 5 . . 2 . .
. . . . . 6 . 1 .
. 7 . . . . . . 3
. . 8 6 . . 5 . .
. 4 . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
452169378837425961961873425319247856786591234524386719275914683198632547643758192 #1 Extreme (29806) bf
Hidden Single: r6c6=6
Hidden Single: r3c8=2
Locked Candidates Type 1 (Pointing): 6 in b7 => r23c1<>6
Brute Force: r5c9=4
2-String Kite: 9 in r5c5,r8c9 (connected by r5c8,r6c9) => r8c5<>9
Forcing Chain Contradiction in c2 => r2c9<>6
r2c9=6 r4c9<>6 r4c9=5 r4c8<>5 r1c8=5 r1c2<>5
r2c9=6 r2c2<>6 r3c2=6 r3c2<>5
r2c9=6 r4c9<>6 r4c9=5 r4c2<>5
r2c9=6 r2c2<>6 r3c2=6 r3c2<>9 r8c2=9 r8c2<>2 r6c2=2 r6c2<>5
Forcing Chain Contradiction in c2 => r4c1<>5
r4c1=5 r4c8<>5 r1c8=5 r1c2<>5
r4c1=5 r4c89<>5 r6c9=5 r6c9<>9 r8c9=9 r8c2<>9 r3c2=9 r3c2<>5
r4c1=5 r4c2<>5
r4c1=5 r6c2<>5
Brute Force: r5c8=3
Naked Single: r6c7=7
Hidden Single: r5c1=7
Hidden Single: r5c5=9
Hidden Single: r6c9=9
Locked Candidates Type 1 (Pointing): 5 in b6 => r4c2<>5
Naked Pair: 1,7 in r28c9 => r3c9<>1, r3c9<>7
Discontinuous Nice Loop: 4 r2c1 -4- r4c1 =4= r4c5 =1= r5c6 =8= r5c2 -8- r2c2 =8= r2c1 => r2c1<>4
Discontinuous Nice Loop: 5 r3c3 -5- r3c9 =5= r1c8 =7= r1c4 -7- r3c5 =7= r3c3 => r3c3<>5
Almost Locked Set XY-Wing: A=r3c3567 {13467}, B=r124568c2 {1235689}, C=r79c7,r8c89 {14679}, X,Y=6,9, Z=1,3 => r3c2<>1, r3c2<>3
Almost Locked Set XY-Wing: A=r5c6 {18}, B=r7c3 {15}, C=r6c345 {3458}, X,Y=5,8, Z=1 => r7c6<>1
Almost Locked Set Chain: 1- r5c6 {18} -8- r6c345 {3458} -5- r79c3 {135} -3- r59c6 {138} -1 => r38c6<>1
Forcing Chain Verity => r2c1<>1
r1c4=1 r1c4<>7 r1c8=7 r2c9<>7 r2c9=1 r2c1<>1
r2c4=1 r2c1<>1
r3c5=1 r4c5<>1 r5c6=1 r5c6<>8 r5c2=8 r2c2<>8 r2c1=8 r2c1<>1
Forcing Chain Contradiction in r1 => r2c2<>1
r2c2=1 r1c1<>1
r2c2=1 r1c2<>1
r2c2=1 r2c9<>1 r2c9=7 r1c8<>7 r1c4=7 r1c4<>1
r2c2=1 r45c2<>1 r4c1=1 r4c1<>4 r4c5=4 r6c4<>4 r6c4=3 r12c4<>3 r3c56=3 r3c7<>3 r1c7=3 r1c7<>1
Forcing Chain Contradiction in c3 => r3c3<>3
r3c3=3 r3c3<>7 r2c3=7 r2c3<>4
r3c3=3 r3c3<>4
r3c3=3 r2c123<>3 r2c4=3 r6c4<>3 r6c4=4 r6c3<>4
Forcing Chain Contradiction in c7 => r7c4<>4
r7c4=4 r6c4<>4 r6c4=3 r12c4<>3 r3c56=3 r3c7<>3 r1c7=3 r1c7<>4
r7c4=4 r12c4<>4 r3c56=4 r3c7<>4
r7c4=4 r7c7<>4
Grouped Discontinuous Nice Loop: 3 r3c5 -3- r3c6 -4- r12c4 =4= r6c4 =3= r46c5 -3- r3c5 => r3c5<>3
Forcing Chain Contradiction in r9 => r7c1<>9
r7c1=9 r7c4<>9 r9c4=9 r9c4<>7
r7c1=9 r7c4<>9 r7c4=1 r7c3<>1 r7c3=5 r7c5<>5 r9c5=5 r9c5<>7
r7c1=9 r7c1<>6 r9c1=6 r9c7<>6 r9c7=1 r8c9<>1 r8c9=7 r9c8<>7
Almost Locked Set XZ-Rule: A=r1248c8 {45679}, B=r7c13,r8c12,r9c3 {123569}, X=9, Z=6 => r7c8<>6
Hidden Rectangle: 1/6 in r7c17,r9c17 => r7c1<>1
Forcing Chain Contradiction in r9 => r7c4=9
r7c4<>9 r9c4=9 r9c4<>7
r7c4<>9 r7c4=1 r7c3<>1 r7c3=5 r7c5<>5 r9c5=5 r9c5<>7
r7c4<>9 r7c8=9 r7c8<>8 r9c8=8 r9c8<>7
Discontinuous Nice Loop: 8 r7c6 -8- r7c8 =8= r9c8 =9= r9c1 =6= r7c1 =2= r7c6 => r7c6<>8
Naked Triple: 2,3,4 in r378c6 => r9c6<>3
Almost Locked Set XY-Wing: A=r6c345 {3458}, B=r12478c8 {456789}, C=r79c3,r8c12 {12359}, X,Y=5,9, Z=8 => r7c5<>8
Hidden Single: r7c8=8
Forcing Net Verity => r1c7=3
r1c4=3 (r3c6<>3 r8c6=3 r8c1<>3) (r3c6<>3 r8c6=3 r8c2<>3) (r3c6<>3 r3c6=4 r3c3<>4) (r3c6<>3 r3c6=4 r3c3<>4) (r1c7<>3 r3c7=3 r3c7<>1) (r1c4<>1) r1c4<>7 r1c8=7 r2c9<>7 (r8c9=7 r8c5<>7) r2c9=1 (r1c7<>1) r2c4<>1 r9c4=1 (r8c5<>1 r8c5=4 r7c6<>4 r7c7=4 r1c7<>4 r1c8=4 r1c8<>7 r1c4=7 r1c4<>3) r9c7<>1 r7c7=1 r7c3<>1 r7c3=5 r9c3<>5 r9c5=5 (r9c1<>5) r9c5<>7 r3c5=7 r3c3<>7 r3c3=1 r3c3<>7 r2c3=7 r2c3<>4 r6c3=4 r6c4<>4 r6c4=3 r2c4<>3 r3c6=3 r8c6<>3 r8c5=3 r8c6<>3 r3c6=3 r3c7<>3 r1c7=3
r2c4=3 (r2c4<>1) (r2c1<>3 r2c1=8 r2c2<>8 r2c2=6 r2c8<>6) (r3c6<>3 r3c6=4 r3c3<>4) r6c4<>3 r6c4=4 r6c3<>4 r2c3=4 r2c8<>4 r2c8=7 r1c8<>7 r1c4=7 (r9c4<>7 r9c5=7 r9c5<>5 r7c5=5 r7c5<>4) r1c4<>1 r9c4=1 r7c5<>1 r7c7=1 r7c7<>4 r7c6=4 r3c6<>4 r3c6=3 r3c7<>3 r1c7=3
r3c6=3 r3c7<>3 r1c7=3
Finned X-Wing: 4 c67 r37 fr8c6 => r7c5<>4
Naked Pair: 1,5 in r7c35 => r7c1<>5, r7c7<>1
Empty Rectangle: 1 in b2 (r39c7) => r9c4<>1
Locked Candidates Type 2 (Claiming): 1 in c4 => r3c5<>1
Continuous Nice Loop: 1/4/7 7= r1c4 =1= r2c4 -1- r2c9 -7- r1c8 =7= r1c4 =1 => r2c3<>1, r1c4<>4, r2c8<>7
Finned X-Wing: 1 c37 r39 fr7c3 => r9c1<>1
X-Chain: 4 r1c8 =4= r1c1 -4- r4c1 =4= r4c5 -4- r6c4 =4= r2c4 => r2c8<>4
Naked Single: r2c8=6
Naked Single: r3c9=5
Naked Single: r4c8=5
Full House: r4c9=6
Hidden Single: r3c2=6
Hidden Single: r3c1=9
Hidden Single: r8c2=9
Hidden Single: r9c8=9
Hidden Single: r3c6=3
Hidden Single: r6c2=2
Hidden Single: r1c2=5
Locked Candidates Type 1 (Pointing): 7 in b9 => r8c5<>7
Locked Candidates Type 2 (Claiming): 1 in c2 => r4c1<>1
Locked Candidates Type 2 (Claiming): 4 in c6 => r8c5<>4
Naked Pair: 3,8 in r2c12 => r2c3<>3
X-Wing: 3 c34 r69 => r6c15,r9c15<>3
Swordfish: 1 c149 r128 => r8c5<>1
Naked Single: r8c5=3
Naked Single: r9c4=7
Naked Single: r1c4=1
Naked Single: r1c1=4
Full House: r1c8=7
Full House: r8c8=4
Naked Single: r2c4=4
Full House: r3c5=7
Full House: r6c4=3
Naked Single: r2c3=7
Naked Single: r4c1=3
Naked Single: r2c9=1
Full House: r3c7=4
Full House: r3c3=1
Full House: r8c9=7
Naked Single: r7c7=6
Full House: r9c7=1
Naked Single: r8c6=2
Full House: r8c1=1
Naked Single: r2c1=8
Full House: r2c2=3
Naked Single: r4c2=1
Full House: r4c5=4
Full House: r5c2=8
Full House: r5c6=1
Full House: r6c5=8
Naked Single: r7c3=5
Naked Single: r7c1=2
Naked Single: r9c6=8
Full House: r7c6=4
Full House: r7c5=1
Full House: r9c5=5
Naked Single: r6c1=5
Full House: r6c3=4
Full House: r9c1=6
Full House: r9c3=3
|
normal_sudoku_1514
|
.9...1..74..7..2....7.4..1...6.5.9...8...934....4....1..5.6....8..2....3.2...47..
|
693821457418795236257346819746153982182679345539482671375968124864217593921534768
|
Basic 9x9 Sudoku 1514
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . . . 1 . . 7
4 . . 7 . . 2 . .
. . 7 . 4 . . 1 .
. . 6 . 5 . 9 . .
. 8 . . . 9 3 4 .
. . . 4 . . . . 1
. . 5 . 6 . . . .
8 . . 2 . . . . 3
. 2 . . . 4 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
693821457418795236257346819746153982182679345539482671375968124864217593921534768 #1 Extreme (17828) bf
Brute Force: r5c8=4
Hidden Single: r1c7=4
Hidden Single: r4c2=4
Hidden Single: r8c3=4
Hidden Single: r7c9=4
Hidden Single: r7c8=2
Forcing Net Verity => r2c8<>9
r8c8=5 (r1c8<>5) (r9c8<>5) r9c9<>5 r9c4=5 r1c4<>5 r1c1=5 (r1c1<>6) r5c1<>5 r5c9=5 r5c9<>6 r5c4=6 r1c4<>6 r1c8=6 r1c8<>3 r2c8=3 r2c8<>9
r8c8=6 (r1c8<>6) (r9c8<>6) r9c9<>6 r9c1=6 r1c1<>6 r1c4=6 (r1c4<>5) r5c4<>6 r5c9=6 r5c9<>5 r5c1=5 r1c1<>5 r1c8=5 r1c8<>3 r2c8=3 r2c8<>9
r8c8=9 r2c8<>9
Locked Candidates Type 1 (Pointing): 9 in b3 => r9c9<>9
Forcing Net Contradiction in c2 => r2c9<>5
r2c9=5 (r2c9<>9 r2c5=9 r8c5<>9) r5c9<>5 r5c1=5 r5c1<>7 r5c5=7 r8c5<>7 r8c5=1 (r8c2<>1) r8c7<>1 r7c7=1 r7c2<>1 r2c2=1 r2c2<>6
r2c9=5 (r3c7<>5) (r3c9<>5) (r1c8<>5) r5c9<>5 r5c1=5 (r3c1<>5) r1c1<>5 r1c4=5 (r3c4<>5) r3c6<>5 r3c2=5 r3c2<>6
r2c9=5 (r2c6<>5) (r1c8<>5) r5c9<>5 r5c1=5 (r5c1<>7 r5c5=7 r8c5<>7 r8c5=1 r8c7<>1) r1c1<>5 r1c4=5 r3c6<>5 r8c6=5 r8c7<>5 r8c7=6 r8c2<>6
Forcing Net Contradiction in r8c2 => r4c9=2
r4c9<>2 r5c9=2 (r5c9<>5 r5c1=5 r6c2<>5) r5c3<>2 r5c3=1 r2c3<>1 r2c2=1 (r2c2<>6) r2c2<>5 r3c2=5 r3c2<>6 r8c2=6
r4c9<>2 r5c9=2 (r5c9<>5) r5c3<>2 r5c3=1 r2c3<>1 r2c2=1 r2c2<>5 r3c2=5 r3c9<>5 r9c9=5 (r8c8<>5 r8c6=5 r8c6<>7) r5c9<>5 r5c1=5 (r6c2<>5) r5c1<>7 r5c5=7 r8c5<>7 r8c2=7
Forcing Chain Contradiction in c5 => r1c8<>8
r1c8=8 r1c5<>8
r1c8=8 r1c3<>8 r2c3=8 r2c5<>8
r1c8=8 r4c8<>8 r4c46=8 r6c5<>8
r1c8=8 r23c9<>8 r9c9=8 r9c5<>8
Forcing Chain Contradiction in c5 => r2c8<>8
r2c8=8 r2c3<>8 r1c3=8 r1c5<>8
r2c8=8 r2c5<>8
r2c8=8 r4c8<>8 r4c46=8 r6c5<>8
r2c8=8 r23c9<>8 r9c9=8 r9c5<>8
Forcing Net Verity => r5c3=2
r6c6=2 (r5c5<>2) r3c6<>2 r3c1=2 r5c1<>2 r5c3=2
r6c6=3 (r6c6<>6 r5c4=6 r5c9<>6 r5c9=5 r9c9<>5) (r6c6<>6) r6c6<>2 r3c6=2 (r3c6<>5) r3c6<>6 r2c6=6 r2c6<>5 r8c6=5 (r8c7<>5 r3c7=5 r2c8<>5) (r8c7<>5) r9c4<>5 r9c8=5 r8c8<>5 r8c6=5 (r8c7<>5 r3c7=5 r2c8<>5) (r8c7<>5) r2c6<>5 r2c2=5 r2c2<>1 r2c3=1 r5c3<>1 r5c3=2
r6c6=6 r5c4<>6 r5c4=1 r5c3<>1 r5c3=2
r6c6=7 (r8c6<>7 r8c6=5 r2c6<>5) (r8c6<>7 r8c6=5 r8c7<>5) r6c6<>6 r5c4=6 r5c9<>6 r5c9=5 r6c7<>5 r3c7=5 r2c8<>5 r2c2=5 r2c2<>1 r2c3=1 r5c3<>1 r5c3=2
r6c6=8 (r6c6<>6 r5c4=6 r5c9<>6 r5c9=5 r9c9<>5) (r6c6<>6) r6c6<>2 r3c6=2 (r3c6<>5) r3c6<>6 r2c6=6 r2c6<>5 r8c6=5 (r8c7<>5 r3c7=5 r2c8<>5) (r8c7<>5) r9c4<>5 r9c8=5 r8c8<>5 r8c6=5 (r8c7<>5 r3c7=5 r2c8<>5) (r8c7<>5) r2c6<>5 r2c2=5 r2c2<>1 r2c3=1 r5c3<>1 r5c3=2
Locked Candidates Type 1 (Pointing): 1 in b4 => r79c1<>1
Forcing Net Verity => r8c8=9
r8c8=5 (r1c8<>5) (r9c8<>5) r9c9<>5 r9c4=5 r1c4<>5 r1c1=5 (r1c1<>2 r1c5=2 r3c6<>2 r3c1=2 r3c1<>6 r9c1=6 r9c9<>6 r9c9=8 r3c9<>8) (r1c1<>6) r5c1<>5 r5c9=5 (r3c9<>5) r5c9<>6 r5c4=6 r1c4<>6 r1c8=6 r3c9<>6 r3c9=9 r2c9<>9 r2c5=9 r8c5<>9 r8c8=9
r8c8=6 (r8c8<>5) (r9c9<>6 r9c1=6 r1c1<>6 r1c4=6 r2c6<>6) (r9c9<>6 r9c1=6 r1c1<>6 r1c4=6 r5c4<>6 r5c9=6 r5c9<>5) (r9c9<>6 r9c1=6 r1c1<>6 r1c4=6 r1c4<>5) r8c8<>9 r8c5=9 r2c5<>9 r2c9=9 (r2c9<>6) r3c9<>9 r3c4=9 r3c4<>5 r9c4=5 r9c9<>5 r3c9=5 (r2c8<>5) (r1c8<>5) r5c9<>5 r5c1=5 r1c1<>5 r1c4=5 r2c6<>5 r2c2=5 r2c2<>6 r2c8=6 r8c8<>6 r8c8=9
r8c8=9 r8c8=9
Naked Pair: 1,7 in r58c5 => r6c5<>7, r9c5<>1
Forcing Chain Contradiction in b1 => r3c4<>6
r3c4=6 r5c4<>6 r6c6=6 r6c6<>2 r6c5=2 r1c5<>2 r1c1=2 r1c1<>6
r3c4=6 r5c4<>6 r5c4=1 r9c4<>1 r9c3=1 r2c3<>1 r2c2=1 r2c2<>6
r3c4=6 r3c1<>6
r3c4=6 r3c2<>6
Forcing Chain Contradiction in r1 => r3c9<>5
r3c9=5 r5c9<>5 r5c1=5 r1c1<>5
r3c9=5 r5c9<>5 r5c9=6 r5c4<>6 r1c4=6 r1c4<>5
r3c9=5 r1c8<>5
Forcing Chain Contradiction in c7 => r6c7<>5
r6c7=5 r5c9<>5 r9c9=5 r9c9<>8 r23c9=8 r3c7<>8
r6c7=5 r6c7<>8
r6c7=5 r5c9<>5 r5c9=6 r5c4<>6 r5c4=1 r5c5<>1 r8c5=1 r8c7<>1 r7c7=1 r7c7<>8
Turbot Fish: 5 r3c7 =5= r8c7 -5- r8c6 =5= r9c4 => r3c4<>5
Discontinuous Nice Loop: 6 r1c4 -6- r5c4 =6= r5c9 =5= r9c9 -5- r9c4 =5= r1c4 => r1c4<>6
Hidden Single: r5c4=6
Naked Single: r5c9=5
Finned Swordfish: 6 r169 c178 fr9c9 => r8c7<>6
Hidden Single: r8c2=6
Locked Candidates Type 1 (Pointing): 7 in b7 => r7c6<>7
Hidden Pair: 2,6 in r13c1 => r13c1<>3, r13c1<>5
Hidden Single: r6c1=5
Hidden Single: r6c3=9
X-Wing: 5 r19 c48 => r2c8<>5
XYZ-Wing: 3/8/9 in r7c6,r9c15 => r9c4<>3
XY-Chain: 5 5- r3c2 -3- r6c2 -7- r5c1 -1- r5c5 -7- r8c5 -1- r8c7 -5 => r3c7<>5
Hidden Single: r8c7=5
Naked Single: r8c6=7
Full House: r8c5=1
Naked Single: r5c5=7
Full House: r5c1=1
Hidden Single: r1c8=5
Hidden Single: r9c4=5
Hidden Single: r7c7=1
Hidden Single: r4c4=1
Hidden Single: r9c3=1
Hidden Single: r2c8=3
Naked Single: r2c3=8
Full House: r1c3=3
Naked Single: r2c5=9
Naked Single: r1c4=8
Naked Single: r3c2=5
Naked Single: r2c9=6
Naked Single: r1c5=2
Full House: r1c1=6
Naked Single: r3c4=3
Full House: r7c4=9
Naked Single: r2c2=1
Full House: r2c6=5
Full House: r3c1=2
Full House: r3c6=6
Naked Single: r3c7=8
Full House: r3c9=9
Full House: r9c9=8
Full House: r6c7=6
Full House: r9c8=6
Naked Single: r9c5=3
Full House: r6c5=8
Full House: r7c6=8
Full House: r9c1=9
Naked Single: r4c6=3
Full House: r6c6=2
Naked Single: r6c8=7
Full House: r4c8=8
Full House: r4c1=7
Full House: r6c2=3
Full House: r7c1=3
Full House: r7c2=7
|
normal_sudoku_6952
|
.3.....8.9.....7....2.4...53.4..6..17......9..8....34..237.......1.5........61..2
|
137529684945618723862347915354896271716432598289175346623784159491253867578961432
|
Basic 9x9 Sudoku 6952
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . . . . 8 .
9 . . . . . 7 . .
. . 2 . 4 . . . 5
3 . 4 . . 6 . . 1
7 . . . . . . 9 .
. 8 . . . . 3 4 .
. 2 3 7 . . . . .
. . 1 . 5 . . . .
. . . . 6 1 . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
137529684945618723862347915354896271716432598289175346623784159491253867578961432 #1 Extreme (2998)
Hidden Single: r4c1=3
Hidden Single: r6c1=2
Hidden Single: r5c2=1
Locked Candidates Type 1 (Pointing): 6 in b4 => r12c3<>6
2-String Kite: 3 in r2c9,r9c4 (connected by r8c9,r9c8) => r2c4<>3
X-Chain: 3 r5c5 =3= r2c5 -3- r2c9 =3= r8c9 -3- r9c8 =3= r9c4 => r5c4<>3
Discontinuous Nice Loop: 6 r2c2 -6- r3c2 -7- r1c3 -5- r5c3 -6- r6c3 =6= r6c9 =7= r8c9 =3= r2c9 =4= r2c2 => r2c2<>6
Forcing Chain Contradiction in c5 => r1c5<>7
r1c5=7 r1c5<>2
r1c5=7 r4c5<>7 r4c8=7 r4c8<>2 r2c8=2 r2c5<>2
r1c5=7 r1c3<>7 r1c3=5 r56c3<>5 r4c2=5 r4c78<>5 r5c7=5 r5c7<>2 r4c78=2 r4c5<>2
r1c5=7 r4c5<>7 r4c8=7 r6c9<>7 r8c9=7 r8c9<>3 r2c9=3 r2c5<>3 r5c5=3 r5c5<>2
Locked Candidates Type 1 (Pointing): 7 in b2 => r6c6<>7
Almost Locked Set XY-Wing: A=r6c346 {1569}, B=r12c3,r3c12 {15678}, C=r5c3 {56}, X,Y=5,6, Z=1 => r3c4<>1
Forcing Chain Contradiction in r2c6 => r1c3=7
r1c3<>7 r1c3=5 r5c3<>5 r5c3=6 r6c3<>6 r6c9=6 r6c9<>7 r4c8=7 r4c8<>2 r2c8=2 r2c6<>2
r1c3<>7 r1c3=5 r5c3<>5 r5c3=6 r6c3<>6 r6c9=6 r6c9<>7 r8c9=7 r8c9<>3 r2c9=3 r2c6<>3
r1c3<>7 r9c3=7 r9c3<>9 r6c3=9 r6c6<>9 r6c6=5 r2c6<>5
r1c3<>7 r1c3=5 r2c3<>5 r2c3=8 r2c6<>8
Naked Single: r3c2=6
Hidden Single: r3c6=7
X-Wing: 3 r39 c48 => r28c8,r8c4<>3
2-String Kite: 8 in r3c4,r9c3 (connected by r2c3,r3c1) => r9c4<>8
Continuous Nice Loop: 4/5/6/8/9 8= r3c4 =3= r3c8 -3- r9c8 =3= r8c9 =7= r6c9 =6= r6c3 =9= r9c3 =8= r2c3 -8- r3c1 =8= r3c4 =3 => r8c9<>4, r69c3<>5, r8c9<>6, r8c9<>8, r3c4,r8c9<>9
Hidden Single: r3c7=9
Hidden Single: r7c9=9
Naked Single: r7c5=8
Naked Single: r7c6=4
Hidden Single: r5c9=8
Hidden Single: r5c4=4
Hidden Single: r4c4=8
Naked Single: r3c4=3
Naked Single: r3c8=1
Full House: r3c1=8
Naked Single: r9c4=9
Naked Single: r2c3=5
Naked Single: r8c4=2
Full House: r8c6=3
Naked Single: r9c3=8
Naked Single: r2c2=4
Full House: r1c1=1
Naked Single: r5c3=6
Full House: r6c3=9
Full House: r4c2=5
Naked Single: r8c9=7
Naked Single: r6c6=5
Naked Single: r4c7=2
Naked Single: r9c2=7
Full House: r8c2=9
Naked Single: r6c9=6
Naked Single: r8c8=6
Naked Single: r5c6=2
Naked Single: r6c4=1
Full House: r6c5=7
Naked Single: r4c8=7
Full House: r5c7=5
Full House: r5c5=3
Full House: r4c5=9
Naked Single: r1c9=4
Full House: r2c9=3
Naked Single: r2c8=2
Full House: r1c7=6
Naked Single: r7c8=5
Full House: r9c8=3
Naked Single: r8c1=4
Full House: r8c7=8
Naked Single: r1c6=9
Full House: r2c6=8
Naked Single: r2c4=6
Full House: r2c5=1
Full House: r1c5=2
Full House: r1c4=5
Naked Single: r7c7=1
Full House: r9c7=4
Full House: r7c1=6
Full House: r9c1=5
|
normal_sudoku_2070
|
....7..4.4.........953..2863..9.7.24...4.2.....61..3.7.81.9....6...15.......8.53.
|
812576943463829715795341286358967124179432658246158397581793462634215879927684531
|
Basic 9x9 Sudoku 2070
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 7 . . 4 .
4 . . . . . . . .
. 9 5 3 . . 2 8 6
3 . . 9 . 7 . 2 4
. . . 4 . 2 . . .
. . 6 1 . . 3 . 7
. 8 1 . 9 . . . .
6 . . . 1 5 . . .
. . . . 8 . 5 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
812576943463829715795341286358967124179432658246158397581793462634215879927684531 #1 Easy (212)
Naked Single: r3c4=3
Naked Single: r4c3=8
Naked Single: r6c6=8
Naked Single: r6c5=5
Naked Single: r7c9=2
Naked Single: r3c5=4
Naked Single: r4c5=6
Full House: r5c5=3
Full House: r2c5=2
Naked Single: r6c8=9
Naked Single: r3c6=1
Full House: r3c1=7
Naked Single: r4c7=1
Full House: r4c2=5
Naked Single: r6c1=2
Full House: r6c2=4
Naked Single: r8c8=7
Naked Single: r2c3=3
Naked Single: r7c1=5
Naked Single: r1c7=9
Naked Single: r9c1=9
Naked Single: r7c8=6
Naked Single: r8c4=2
Naked Single: r1c3=2
Naked Single: r1c6=6
Naked Single: r2c7=7
Naked Single: r5c1=1
Full House: r1c1=8
Naked Single: r9c9=1
Naked Single: r5c8=5
Full House: r2c8=1
Naked Single: r7c4=7
Naked Single: r7c7=4
Full House: r7c6=3
Naked Single: r8c2=3
Naked Single: r8c3=4
Naked Single: r1c2=1
Full House: r2c2=6
Naked Single: r2c6=9
Full House: r9c6=4
Full House: r9c4=6
Naked Single: r5c2=7
Full House: r5c3=9
Full House: r9c3=7
Full House: r9c2=2
Naked Single: r1c4=5
Full House: r1c9=3
Full House: r2c9=5
Full House: r2c4=8
Naked Single: r5c9=8
Full House: r5c7=6
Full House: r8c7=8
Full House: r8c9=9
|
normal_sudoku_4872
|
93..2.4....1..4...24.3...1.61.......4...568....3.4..2...9.1..8....7....5.5...87..
|
935821467871564239246379518617283954492156873583947621729415386368792145154638792
|
Basic 9x9 Sudoku 4872
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 3 . . 2 . 4 . .
. . 1 . . 4 . . .
2 4 . 3 . . . 1 .
6 1 . . . . . . .
4 . . . 5 6 8 . .
. . 3 . 4 . . 2 .
. . 9 . 1 . . 8 .
. . . 7 . . . . 5
. 5 . . . 8 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
935821467871564239246379518617283954492156873583947621729415386368792145154638792 #1 Extreme (25652) bf
Brute Force: r5c5=5
Locked Candidates Type 1 (Pointing): 3 in b5 => r4c789<>3
Almost Locked Set XZ-Rule: A=r5c234 {1279}, B=r6c246 {1789}, X=1, Z=7 => r6c1<>7
Forcing Net Contradiction in c8 => r2c7<>5
r2c7=5 (r1c8<>5) (r3c7<>5) r4c7<>5 r4c7=9 r3c7<>9 r3c7=6 r1c8<>6 r1c8=7
r2c7=5 (r4c7<>5 r4c7=9 r5c8<>9) (r2c7<>3) r2c7<>2 r2c9=2 r2c9<>3 r2c8=3 r5c8<>3 r5c8=7
Brute Force: r5c8=7
Naked Single: r5c3=2
Naked Single: r5c2=9
Naked Single: r5c4=1
Full House: r5c9=3
Hidden Single: r1c6=1
Locked Triple: 4,5,9 in r4c789 => r4c3,r6c7<>5, r4c456,r6c79<>9
Hidden Single: r6c1=5
W-Wing: 8/7 in r2c1,r6c2 connected by 7 in r7c12 => r2c2<>8
AIC: 5 5- r2c4 =5= r2c8 =3= r2c7 =2= r2c9 -2- r9c9 =2= r9c4 =4= r7c4 =5= r7c6 -5 => r3c6,r7c4<>5
Hidden Single: r7c6=5
Naked Pair: 7,9 in r36c6 => r4c6<>7, r8c6<>9
2-String Kite: 7 in r3c6,r4c3 (connected by r4c5,r6c6) => r3c3<>7
Empty Rectangle: 7 in b1 (r4c35) => r2c5<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r3c9<>7
Hidden Rectangle: 5/6 in r1c48,r2c48 => r2c4<>6
AIC: 3 3- r7c7 =3= r7c1 =7= r7c2 =2= r8c2 -2- r8c6 -3 => r8c78<>3
Discontinuous Nice Loop: 8 r2c4 -8- r4c4 -2- r9c4 =2= r9c9 -2- r2c9 =2= r2c7 =3= r2c8 =5= r2c4 => r2c4<>8
Discontinuous Nice Loop: 9 r2c4 -9- r6c4 -8- r6c2 -7- r7c2 =7= r7c1 =3= r7c7 -3- r2c7 =3= r2c8 =5= r2c4 => r2c4<>9
Naked Single: r2c4=5
Discontinuous Nice Loop: 6 r1c9 -6- r1c4 -8- r6c4 =8= r6c2 =7= r4c3 -7- r1c3 =7= r1c9 => r1c9<>6
Discontinuous Nice Loop: 6 r2c8 -6- r2c2 -7- r2c1 =7= r7c1 =3= r7c7 -3- r2c7 =3= r2c8 => r2c8<>6
Discontinuous Nice Loop: 8 r2c9 -8- r2c1 -7- r7c1 -3- r7c7 =3= r2c7 =2= r2c9 => r2c9<>8
Discontinuous Nice Loop: 8 r3c3 -8- r3c9 =8= r1c9 =7= r1c3 =5= r3c3 => r3c3<>8
Continuous Nice Loop: 6/9 8= r3c5 =7= r4c5 -7- r4c3 =7= r1c3 -7- r1c9 -8- r3c9 =8= r3c5 =7 => r3c5<>6, r3c5<>9
Sue de Coq: r3c79 - {5689} (r3c56 - {789}, r1c8 - {56}) => r2c79<>6
Discontinuous Nice Loop: 6 r7c2 -6- r2c2 =6= r2c5 -6- r1c4 -8- r4c4 -2- r4c6 =2= r8c6 -2- r8c2 =2= r7c2 => r7c2<>6
Discontinuous Nice Loop: 2 r7c4 -2- r7c2 -7- r7c1 -3- r7c7 =3= r2c7 =2= r2c9 -2- r9c9 =2= r9c4 -2- r7c4 => r7c4<>2
Discontinuous Nice Loop: 6 r7c4 -6- r1c4 =6= r2c5 -6- r2c2 =6= r8c2 -6- r9c3 -4- r9c4 =4= r7c4 => r7c4<>6
Naked Single: r7c4=4
Locked Candidates Type 2 (Claiming): 6 in r7 => r8c78,r9c89<>6
Hidden Single: r1c8=6
Naked Single: r1c4=8
Naked Single: r1c9=7
Full House: r1c3=5
Naked Single: r3c5=7
Naked Single: r4c4=2
Naked Single: r6c4=9
Full House: r9c4=6
Naked Single: r3c3=6
Naked Single: r3c6=9
Full House: r2c5=6
Naked Single: r4c6=3
Naked Single: r6c6=7
Full House: r4c5=8
Full House: r8c6=2
Naked Single: r9c3=4
Naked Single: r2c2=7
Full House: r2c1=8
Naked Single: r3c7=5
Full House: r3c9=8
Naked Single: r6c2=8
Full House: r4c3=7
Full House: r8c3=8
Naked Single: r7c2=2
Full House: r8c2=6
Naked Single: r4c7=9
Naked Single: r7c9=6
Naked Single: r4c9=4
Full House: r4c8=5
Naked Single: r8c7=1
Naked Single: r6c9=1
Full House: r6c7=6
Naked Single: r7c7=3
Full House: r2c7=2
Full House: r7c1=7
Naked Single: r8c1=3
Full House: r9c1=1
Naked Single: r9c8=9
Naked Single: r2c9=9
Full House: r2c8=3
Full House: r8c8=4
Full House: r8c5=9
Full House: r9c5=3
Full House: r9c9=2
|
normal_sudoku_6218
|
...7...5.1....28....6.3...44....96....1.6...9.9.5...7.3...8...2.89..63...1.......
|
938714256145692837726835914473129685851367429692548173367481592589276341214953768
|
Basic 9x9 Sudoku 6218
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 7 . . . 5 .
1 . . . . 2 8 . .
. . 6 . 3 . . . 4
4 . . . . 9 6 . .
. . 1 . 6 . . . 9
. 9 . 5 . . . 7 .
3 . . . 8 . . . 2
. 8 9 . . 6 3 . .
. 1 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
938714256145692837726835914473129685851367429692548173367481592589276341214953768 #1 Extreme (11910) bf
Brute Force: r5c5=6
Hidden Single: r1c9=6
Hidden Single: r2c4=6
Hidden Single: r7c2=6
Hidden Single: r6c1=6
Hidden Single: r9c8=6
Hidden Single: r9c9=8
Locked Candidates Type 1 (Pointing): 3 in b3 => r2c23<>3
Locked Candidates Type 1 (Pointing): 4 in b7 => r12c3<>4
Discontinuous Nice Loop: 5 r4c3 -5- r4c9 =5= r8c9 =7= r2c9 -7- r2c3 -5- r4c3 => r4c3<>5
Almost Locked Set XY-Wing: A=r2c89 {379}, B=r2c3,r3c2 {257}, C=r378c8 {1249}, X,Y=2,9, Z=7 => r2c2<>7
Almost Locked Set Chain: 45- r2c23 {457} -7- r2c89 {379} -9- r378c8 {1249} -2- r2c23,r3c2 {2457} -45 => r1c2,r2c5<>4, r3c1<>5
Hidden Single: r2c2=4
Forcing Chain Contradiction in r8 => r2c3=5
r2c3<>5 r79c3=5 r8c1<>5
r2c3<>5 r2c5=5 r8c5<>5
r2c3<>5 r2c3=7 r2c9<>7 r8c9=7 r8c9<>5
Naked Single: r2c5=9
Naked Single: r2c8=3
Full House: r2c9=7
Hidden Single: r3c6=5
Hidden Single: r7c7=5
Naked Single: r8c9=1
Naked Single: r6c9=3
Full House: r4c9=5
Naked Single: r8c8=4
Naked Single: r7c8=9
Full House: r9c7=7
Naked Single: r8c4=2
Hidden Single: r5c2=5
Hidden Single: r9c4=9
Hidden Single: r9c6=3
Hidden Single: r5c4=3
Hidden Single: r7c4=4
Naked Single: r7c3=7
Full House: r7c6=1
Naked Single: r9c5=5
Full House: r8c5=7
Full House: r8c1=5
Naked Single: r9c1=2
Full House: r9c3=4
Hidden Single: r5c6=7
Naked Single: r5c1=8
Naked Single: r1c1=9
Full House: r3c1=7
Naked Single: r5c8=2
Full House: r5c7=4
Naked Single: r6c3=2
Naked Single: r3c2=2
Naked Single: r3c8=1
Full House: r4c8=8
Full House: r6c7=1
Naked Single: r4c3=3
Full House: r1c3=8
Full House: r1c2=3
Full House: r4c2=7
Naked Single: r1c7=2
Full House: r3c7=9
Full House: r3c4=8
Full House: r4c4=1
Full House: r4c5=2
Naked Single: r6c5=4
Full House: r1c5=1
Full House: r1c6=4
Full House: r6c6=8
|
normal_sudoku_3434
|
.7.....4.5.......99.8.4.7..6....1....8.49...7...2...6..5..1...41.35..2..8....3..5
|
372189546546327819918645723695731482281496357437258961759812634163574298824963175
|
Basic 9x9 Sudoku 3434
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . . . . 4 .
5 . . . . . . . 9
9 . 8 . 4 . 7 . .
6 . . . . 1 . . .
. 8 . 4 9 . . . 7
. . . 2 . . . 6 .
. 5 . . 1 . . . 4
1 . 3 5 . . 2 . .
8 . . . . 3 . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
372189546546327819918645723695731482281496357437258961759812634163574298824963175 #1 Extreme (17750) bf
Locked Candidates Type 2 (Claiming): 4 in c1 => r4c23,r56c3,r6c2<>4
Brute Force: r5c4=4
Hidden Single: r4c7=4
Hidden Single: r6c1=4
Hidden Single: r8c6=4
Hidden Single: r5c6=6
Hidden Single: r7c1=7
Turbot Fish: 9 r6c7 =9= r4c8 -9- r8c8 =9= r8c2 => r6c2<>9
Almost Locked Set XZ-Rule: A=r46c2,r5c1 {1239}, B=r4c89,r5c78,r6c9 {123589}, X=9, Z=1 => r6c7<>1
Almost Locked Set XY-Wing: A=r6c29 {138}, B=r12579c3 {124569}, C=r8c29 {689}, X,Y=8,9, Z=1 => r6c3<>1
Almost Locked Set XY-Wing: A=r8c29 {689}, B=r46c9,r5c78 {12358}, C=r12579c3 {124569}, X,Y=5,9, Z=8 => r1c9<>8
Almost Locked Set XY-Wing: A=r8c29 {689}, B=r12579c3 {124569}, C=r46c9,r5c78 {12358}, X,Y=5,8, Z=9 => r9c2<>9
Almost Locked Set Chain: 3- r6c29 {138} -8- r8c29 {689} -9- r46c2,r5c13 {12359} -5- r46c9,r5c78 {12358} -3 => r6c7<>3
Forcing Chain Contradiction in r4c2 => r1c7<>1
r1c7=1 r13c9<>1 r6c9=1 r6c2<>1 r6c2=3 r5c1<>3 r5c1=2 r4c2<>2
r1c7=1 r13c9<>1 r6c9=1 r6c2<>1 r6c2=3 r4c2<>3
r1c7=1 r9c7<>1 r9c8=1 r9c8<>7 r8c8=7 r8c8<>9 r8c2=9 r4c2<>9
Forcing Chain Contradiction in r4c2 => r2c7<>1
r2c7=1 r13c9<>1 r6c9=1 r6c2<>1 r6c2=3 r5c1<>3 r5c1=2 r4c2<>2
r2c7=1 r13c9<>1 r6c9=1 r6c2<>1 r6c2=3 r4c2<>3
r2c7=1 r9c7<>1 r9c8=1 r9c8<>7 r8c8=7 r8c8<>9 r8c2=9 r4c2<>9
Forcing Net Verity => r1c4<>3
r5c1=2 r1c1<>2 r1c1=3 r1c4<>3
r5c3=2 (r5c1<>2 r5c1=3 r4c2<>3 r4c2=9 r4c3<>9) (r5c1<>2 r5c1=3 r4c2<>3 r4c2=9 r6c3<>9) (r9c3<>2) r7c3<>2 r7c6=2 (r3c6<>2 r3c6=5 r1c6<>5 r1c7=5 r5c7<>5) r9c5<>2 r9c2=2 r9c2<>4 r9c3=4 r9c3<>9 r7c3=9 r8c2<>9 r8c8=9 (r9c8<>9 r9c4=9 r9c4<>7) r8c8<>7 r8c5=7 r9c5<>7 r9c8=7 r9c8<>1 r9c7=1 r5c7<>1 r5c7=3 r5c1<>3 r1c1=3 r1c4<>3
r5c8=2 (r5c8<>3) (r3c8<>2) (r4c9<>2) r5c1<>2 r1c1=2 r1c9<>2 r3c9=2 (r3c6<>2 r3c6=5 r3c8<>5) r3c9<>1 r1c9=1 r3c8<>1 (r3c4=1 r3c4<>6) r3c8=3 (r3c2<>3) r7c8<>3 r7c7=3 r5c7<>3 r5c1=3 (r4c2<>3) r6c2<>3 (r6c2=1 r6c9<>1) (r6c2=1 r5c3<>1) (r6c2=1 r6c9<>1) r2c2=3 r2c2<>4 r2c3=4 r2c3<>1 r1c3=1 r1c9<>1 r3c9=1 r3c4<>1 r3c4=3 r1c4<>3
Forcing Net Verity => r1c5<>2
r4c3=9 (r6c3<>9 r6c7=9 r6c7<>5) (r4c3<>5) r4c3<>7 r6c3=7 r6c3<>5 r5c3=5 (r5c7<>5) (r5c8<>5) r5c7<>5 r1c7=5 r3c8<>5 (r3c6=5 r6c6<>5 r6c5=5 r6c5<>3) r4c8=5 r5c8<>5 r5c3=5 (r5c7<>5) (r5c8<>5) r5c3<>1 r6c2=1 r6c2<>3 r6c9=3 (r5c7<>3) r5c8<>3 r5c1=3 r1c1<>3 r1c1=2 r1c5<>2
r6c3=9 (r4c3<>9 r4c8=9 r4c8<>5) (r6c3<>5) r6c3<>7 r4c3=7 r4c3<>5 r5c3=5 r5c8<>5 r3c8=5 r3c6<>5 r3c6=2 r1c5<>2
r7c3=9 (r7c6<>9 r1c6=9 r1c6<>8) (r8c2<>9 r8c2=6 r8c9<>6 r8c9=8 r7c8<>8 r7c4=8 r1c4<>8) (r7c6<>9 r1c6=9 r1c6<>5) r7c3<>2 r7c6=2 r3c6<>2 r3c6=5 r1c5<>5 r1c7=5 r1c7<>8 r1c5=8 r1c5<>2
r9c3=9 (r9c3<>2) r9c3<>4 r9c2=4 r9c2<>2 r9c5=2 r1c5<>2
2-String Kite: 2 in r2c5,r7c3 (connected by r7c6,r9c5) => r2c3<>2
Forcing Net Verity => r1c5<>3
r5c1=2 r1c1<>2 r1c1=3 r1c5<>3
r5c3=2 (r5c1<>2 r5c1=3 r4c2<>3 r4c2=9 r4c3<>9) (r5c1<>2 r5c1=3 r4c2<>3 r4c2=9 r6c3<>9) (r9c3<>2) r7c3<>2 r7c6=2 (r7c6<>9 r1c6=9 r1c6<>8) r9c5<>2 r9c2=2 r9c2<>4 r9c3=4 r9c3<>9 r7c3=9 (r8c2<>9 r8c2=6 r8c9<>6 r8c9=8 r7c8<>8 r7c4=8 r1c4<>8) r7c3<>2 r7c6=2 (r7c6<>9 r1c6=9 r1c6<>8) r3c6<>2 r3c6=5 (r1c6<>5) r1c5<>5 r1c7=5 r1c7<>8 r1c5=8 r1c5<>3
r5c8=2 (r5c8<>3) (r3c8<>2) (r4c9<>2) r5c1<>2 r1c1=2 r1c9<>2 r3c9=2 (r3c6<>2 r3c6=5 r3c8<>5) r3c9<>1 r1c9=1 (r1c9<>3) r3c8<>1 (r3c4=1 r3c4<>6) r3c8=3 (r2c7<>3) (r2c8<>3) (r1c7<>3) r7c8<>3 r7c7=3 r5c7<>3 r5c1=3 (r6c2<>3 r6c2=1 r6c9<>1) (r6c2<>3 r6c2=1 r5c3<>1) (r6c2<>3 r6c2=1 r6c9<>1) r1c1<>3 r1c5=3 (r2c4<>3) r2c5<>3 r2c2=3 r2c2<>4 r2c3=4 r2c3<>1 r1c3=1 r1c9<>1 r3c9=1 r3c4<>1 r3c4=3 r1c5<>3
Finned Swordfish: 3 r157 c178 fr1c9 => r2c78,r3c8<>3
Grouped Discontinuous Nice Loop: 8 r6c7 -8- r2c7 -6- r79c7 =6= r8c9 =8= r46c9 -8- r6c7 => r6c7<>8
Forcing Chain Contradiction in r3c8 => r3c9<>2
r3c9=2 r3c9<>3 r1c79=3 r1c1<>3 r5c1=3 r6c2<>3 r6c2=1 r6c9<>1 r13c9=1 r3c8<>1
r3c9=2 r3c8<>2
r3c9=2 r3c6<>2 r3c6=5 r3c8<>5
Skyscraper: 2 in r4c9,r5c1 (connected by r1c19) => r4c23,r5c8<>2
Discontinuous Nice Loop: 3 r1c7 -3- r1c1 -2- r5c1 =2= r5c3 -2- r7c3 =2= r7c6 -2- r3c6 -5- r3c8 =5= r1c7 => r1c7<>3
Locked Candidates Type 1 (Pointing): 3 in b3 => r46c9<>3
XY-Chain: 3 3- r4c2 -9- r8c2 -6- r8c9 -8- r6c9 -1- r6c2 -3 => r23c2,r5c1<>3
Naked Single: r5c1=2
Full House: r1c1=3
Hidden Single: r3c9=3
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c8<>3
Turbot Fish: 1 r1c9 =1= r6c9 -1- r6c2 =1= r5c3 => r1c3<>1
XYZ-Wing: 2/6/9 in r17c3,r8c2 => r9c3<>6
Empty Rectangle: 6 in b7 (r3c24) => r7c4<>6
2-String Kite: 6 in r1c9,r7c3 (connected by r7c7,r8c9) => r1c3<>6
Naked Single: r1c3=2
Hidden Single: r4c9=2
Hidden Single: r9c2=2
Hidden Single: r7c6=2
Naked Single: r3c6=5
Hidden Single: r2c5=2
Hidden Single: r9c3=4
Hidden Single: r2c2=4
Hidden Single: r3c8=2
Hidden Single: r1c6=9
Hidden Single: r1c7=5
Naked Single: r6c7=9
Hidden Single: r2c4=3
Hidden Single: r2c6=7
Full House: r6c6=8
Naked Single: r4c4=7
Naked Single: r6c9=1
Naked Single: r1c9=6
Full House: r8c9=8
Naked Single: r5c7=3
Naked Single: r6c2=3
Naked Single: r1c5=8
Full House: r1c4=1
Full House: r3c4=6
Full House: r3c2=1
Full House: r2c3=6
Naked Single: r2c7=8
Full House: r2c8=1
Naked Single: r5c8=5
Full House: r4c8=8
Full House: r5c3=1
Naked Single: r7c7=6
Full House: r9c7=1
Naked Single: r4c2=9
Full House: r8c2=6
Full House: r7c3=9
Naked Single: r6c5=5
Full House: r4c5=3
Full House: r4c3=5
Full House: r6c3=7
Naked Single: r9c4=9
Full House: r7c4=8
Full House: r7c8=3
Naked Single: r8c5=7
Full House: r8c8=9
Full House: r9c8=7
Full House: r9c5=6
|
normal_sudoku_654
|
..9...2..1....2..6.4..5..3.8...3.....5.8.7..3...5.4.8.......9.16.81..3...1..4..7.
|
739461258185372496246958137897236514451897623362514789524783961678129345913645872
|
Basic 9x9 Sudoku 654
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . . . 2 . .
1 . . . . 2 . . 6
. 4 . . 5 . . 3 .
8 . . . 3 . . . .
. 5 . 8 . 7 . . 3
. . . 5 . 4 . 8 .
. . . . . . 9 . 1
6 . 8 1 . . 3 . .
. 1 . . 4 . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
739461258185372496246958137897236514451897623362514789524783961678129345913645872 #1 Extreme (24076) bf
Locked Candidates Type 1 (Pointing): 4 in b7 => r7c8<>4
Locked Candidates Type 1 (Pointing): 8 in b9 => r9c46<>8
Brute Force: r5c4=8
Brute Force: r5c3=1
Skyscraper: 1 in r3c6,r6c5 (connected by r36c7) => r1c5,r4c6<>1
Hidden Single: r6c5=1
Grouped Discontinuous Nice Loop: 6 r4c3 -6- r4c46 =6= r5c5 -6- r5c7 -4- r5c1 =4= r4c3 => r4c3<>6
Forcing Chain Contradiction in r9 => r5c1<>2
r5c1=2 r9c1<>2
r5c1=2 r3c1<>2 r3c3=2 r9c3<>2
r5c1=2 r5c5<>2 r4c4=2 r9c4<>2
r5c1=2 r6c123<>2 r6c9=2 r9c9<>2
Grouped Discontinuous Nice Loop: 7 r6c9 -7- r6c7 -6- r5c7 -4- r5c1 -9- r6c12 =9= r6c9 => r6c9<>7
Grouped Discontinuous Nice Loop: 9 r4c8 -9- r6c9 -2- r5c8 =2= r5c5 =9= r4c46 -9- r4c8 => r4c8<>9
Sashimi Swordfish: 9 c258 r258 fr4c2 fr6c2 => r5c1<>9
Naked Single: r5c1=4
Naked Single: r5c7=6
Naked Single: r6c7=7
Hidden Single: r7c3=4
Hidden Single: r7c8=6
Hidden Single: r1c5=6
Hidden Single: r3c3=6
Hidden Single: r6c2=6
Hidden Single: r3c1=2
Naked Pair: 2,9 in r5c8,r6c9 => r4c89<>2, r4c9<>9
Empty Rectangle: 9 in b5 (r48c2) => r8c5<>9
X-Wing: 9 c58 r25 => r2c4<>9
Hidden Rectangle: 6/9 in r4c46,r9c46 => r9c4<>9
Locked Candidates Type 1 (Pointing): 9 in b8 => r34c6<>9
Naked Single: r4c6=6
Hidden Single: r9c4=6
Naked Pair: 1,8 in r3c67 => r3c9<>8
X-Wing: 2 r69 c39 => r4c3,r8c9<>2
Naked Single: r4c3=7
Naked Pair: 4,5 in r48c9 => r1c9<>4, r19c9<>5
Sue de Coq: r1c12 - {3578} (r1c9 - {78}, r2c3 - {35}) => r2c2<>3, r1c4<>7, r1c6<>8
2-String Kite: 3 in r2c4,r7c2 (connected by r1c2,r2c3) => r7c4<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r1c6<>3
Naked Single: r1c6=1
Naked Single: r3c6=8
Naked Single: r3c7=1
Hidden Single: r4c8=1
Hidden Single: r7c5=8
Naked Pair: 7,9 in r2c5,r3c4 => r2c4<>7
X-Wing: 2 r47 c24 => r8c2<>2
X-Wing: 7 r28 c25 => r17c2<>7
XY-Wing: 2/9/3 in r47c2,r6c1 => r79c1<>3
Naked Triple: 5,7,9 in r79c1,r8c2 => r9c3<>5
Hidden Single: r2c3=5
Hidden Single: r1c8=5
Hidden Single: r2c4=3
Naked Single: r1c4=4
Bivalue Universal Grave + 1 => r9c6<>3, r9c6<>9
Naked Single: r9c6=5
Naked Single: r7c6=3
Full House: r8c6=9
Naked Single: r9c1=9
Naked Single: r9c7=8
Naked Single: r7c2=2
Naked Single: r8c2=7
Naked Single: r6c1=3
Naked Single: r2c7=4
Full House: r4c7=5
Naked Single: r9c9=2
Full House: r9c3=3
Full House: r7c1=5
Full House: r7c4=7
Full House: r8c5=2
Full House: r1c1=7
Full House: r6c3=2
Full House: r4c2=9
Full House: r6c9=9
Naked Single: r2c2=8
Full House: r1c2=3
Full House: r1c9=8
Naked Single: r2c8=9
Full House: r3c9=7
Full House: r3c4=9
Full House: r4c4=2
Full House: r4c9=4
Full House: r5c5=9
Full House: r5c8=2
Full House: r8c8=4
Full House: r2c5=7
Full House: r8c9=5
|
normal_sudoku_522
|
...7.6..3....5.72...7..286.......2..2......4...6..1..77..6.39.2.6..97....315.....
|
528716493649358721317942865185479236273865149496231587754683912862197354931524678
|
Basic 9x9 Sudoku 522
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 7 . 6 . . 3
. . . . 5 . 7 2 .
. . 7 . . 2 8 6 .
. . . . . . 2 . .
2 . . . . . . 4 .
. . 6 . . 1 . . 7
7 . . 6 . 3 9 . 2
. 6 . . 9 7 . . .
. 3 1 5 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
528716493649358721317942865185479236273865149496231587754683912862197354931524678 #1 Extreme (14430)
Hidden Single: r2c7=7
Hidden Single: r2c1=6
Hidden Single: r9c8=7
Hidden Single: r1c2=2
Hidden Single: r8c3=2
Hidden Single: r9c1=9
Hidden Single: r9c5=2
Hidden Single: r6c4=2
Hidden Pair: 6,7 in r45c5 => r45c5<>3, r4c5<>4, r45c5<>8
Skyscraper: 9 in r1c3,r6c2 (connected by r16c8) => r23c2,r45c3<>9
Forcing Net Contradiction in r8 => r1c3<>4
r1c3=4 r1c3<>9 (r1c8=9 r6c8<>9 r6c2=9 r6c2<>4) r2c3=9 r2c3<>3 r2c4=3 r3c5<>3 r6c5=3 r6c5<>4 r6c1=4 r8c1<>4
r1c3=4 r1c3<>9 (r1c8=9 r3c9<>9 r3c4=9 r3c4<>1) r2c3=9 r2c3<>3 r2c4=3 r2c4<>1 r8c4=1 r8c4<>4
r1c3=4 r1c3<>9 (r1c8=9 r1c8<>5) (r1c8=9 r3c9<>9 r3c4=9 r3c4<>1) r2c3=9 r2c3<>3 r2c4=3 (r3c5<>3 r6c5=3 r6c7<>3 r6c7=5 r4c8<>5) (r3c5<>3 r6c5=3 r6c7<>3 r6c7=5 r6c8<>5) r2c4<>1 r8c4=1 r7c5<>1 r7c8=1 r7c8<>5 r8c8=5 r8c8<>3 r8c7=3 r8c7<>4
r1c3=4 r1c7<>4 r89c7=4 r8c9<>4
Forcing Net Contradiction in r4c6 => r4c8<>1
r4c8=1 (r4c8<>9) (r5c7<>1) r5c9<>1 r5c2=1 (r5c2<>9) r5c2<>7 r5c5=7 r4c5<>7 r4c2=7 r4c2<>9 r6c2=9 r6c8<>9 r1c8=9 (r3c9<>9 r3c4=9 r3c4<>1) r1c3<>9 r2c3=9 r2c3<>3 r2c4=3 r2c4<>1 r8c4=1 r7c5<>1 r7c8=1 r4c8<>1
Forcing Net Contradiction in r2 => r3c4<>3
r3c4=3 (r4c4<>3) (r5c4<>3) r2c4<>3 r2c3=3 (r4c3<>3) r5c3<>3 r5c7=3 r4c8<>3 r4c1=3 r4c1<>1 r13c1=1 r2c2<>1
r3c4=3 (r3c5<>3 r6c5=3 r6c7<>3 r6c7=5 r1c7<>5 r1c8=5 r1c8<>1) (r5c4<>3) r2c4<>3 r2c3=3 r5c3<>3 r5c7=3 r8c7<>3 r8c8=3 (r8c8<>1) r8c8<>1 r7c8=1 (r8c7<>1) r8c9<>1 r8c4=1 r2c4<>1
r3c4=3 (r5c4<>3) r2c4<>3 r2c3=3 r5c3<>3 r5c7=3 r5c7<>1 r45c9=1 r2c9<>1
Forcing Net Contradiction in b4 => r4c9<>5
r4c9=5 r6c7<>5 r6c7=3 (r6c1<>3) r6c5<>3 r3c5=3 r3c1<>3 r4c1=3 r4c1<>1
r4c9=5 r4c9<>6 r4c5=6 r4c5<>7 r4c2=7 r4c2<>1
r4c9=5 r4c9<>1 r4c12=1 r5c2<>1
Forcing Net Contradiction in r6c1 => r6c2<>5
r6c2=5 r6c7<>5 r6c7=3 r6c1<>3
r6c2=5 (r6c7<>5 r6c7=3 r6c5<>3 r3c5=3 r2c4<>3 r2c3=3 r2c3<>4) (r4c3<>5) (r5c3<>5) r6c2<>9 r6c8=9 r1c8<>9 r1c3=9 r1c3<>5 r7c3=5 r7c3<>4 r4c3=4 r6c1<>4
r6c2=5 r6c1<>5
r6c2=5 (r5c3<>5) r6c7<>5 r6c7=3 r6c5<>3 r3c5=3 r2c4<>3 r2c3=3 r5c3<>3 r5c3=8 r6c1<>8
Forcing Net Verity => r4c6<>8
r7c5=8 (r9c6<>8 r9c6=4 r2c6<>4) (r1c5<>8) (r7c2<>8) r7c3<>8 r8c1=8 r1c1<>8 r1c3=8 r1c3<>9 r2c3=9 r2c6<>9 r2c6=8 r4c6<>8
r8c4=8 (r9c6<>8 r9c9=8 r7c8<>8) r8c4<>1 r7c5=1 r7c8<>1 r7c8=5 (r1c8<>5) (r6c8<>5) (r8c7<>5) (r8c8<>5) r8c9<>5 r8c1=5 (r1c1<>5) r6c1<>5 r6c7=5 r1c7<>5 r1c3=5 (r3c2<>5 r3c9=5 r3c9<>9 r3c4=9 r5c4<>9) r1c3<>9 r2c3=9 r2c3<>3 r2c4=3 r5c4<>3 r5c4=8 r4c6<>8
r9c6=8 r4c6<>8
Forcing Net Verity => r5c6<>8
r7c5=8 (r9c6<>8 r9c6=4 r2c6<>4) (r1c5<>8) (r7c2<>8) r7c3<>8 r8c1=8 r1c1<>8 r1c3=8 r1c3<>9 r2c3=9 r2c6<>9 r2c6=8 r5c6<>8
r8c4=8 (r9c6<>8 r9c9=8 r7c8<>8) r8c4<>1 r7c5=1 r7c8<>1 r7c8=5 (r1c8<>5) (r6c8<>5) (r8c7<>5) (r8c8<>5) r8c9<>5 r8c1=5 (r1c1<>5) r6c1<>5 r6c7=5 r1c7<>5 r1c3=5 (r3c2<>5 r3c9=5 r3c9<>9 r3c4=9 r5c4<>9) r1c3<>9 r2c3=9 r2c3<>3 r2c4=3 r5c4<>3 r5c4=8 r5c6<>8
r9c6=8 r5c6<>8
Forcing Net Contradiction in r7c8 => r7c8<>5
r7c8=5 (r1c8<>5) (r6c8<>5) (r8c7<>5) (r8c8<>5) r8c9<>5 r8c1=5 (r1c1<>5) r6c1<>5 r6c7=5 r1c7<>5 r1c3=5 (r3c2<>5 r3c9=5 r3c9<>9 r3c4=9 r3c4<>1) r1c3<>9 r2c3=9 r2c3<>3 r2c4=3 r2c4<>1 r8c4=1 r7c5<>1 r7c8=1
r7c8=5 r7c8=5
Locked Candidates Type 1 (Pointing): 5 in b9 => r8c1<>5
Discontinuous Nice Loop: 8 r8c4 -8- r9c6 =8= r9c9 -8- r7c8 -1- r7c5 =1= r8c4 => r8c4<>8
Forcing Net Contradiction in b2 => r1c1<>8
r1c1=8 r1c5<>8
r1c1=8 r8c1<>8 r8c1=4 (r3c1<>4) (r6c1<>4) (r7c2<>4) r7c3<>4 r7c5=4 (r9c6<>4 r9c6=8 r2c6<>8 r2c4=8 r2c4<>4) (r1c5<>4 r1c7=4 r2c9<>4) (r3c5<>4) (r1c5<>4 r1c7=4 r3c9<>4) r6c5<>4 r6c2=4 (r2c2<>4) r3c2<>4 r3c4=4 r2c6<>4 r2c3=4 r2c3<>3 r2c4=3 r2c4<>8
r1c1=8 r8c1<>8 r8c1=4 (r7c2<>4) r7c3<>4 r7c5=4 r9c6<>4 r9c6=8 r2c6<>8
Discontinuous Nice Loop: 8 r2c4 -8- r1c5 =8= r1c3 =9= r2c3 =3= r2c4 => r2c4<>8
Locked Candidates Type 2 (Claiming): 8 in c4 => r6c5<>8
Forcing Chain Contradiction in c3 => r2c4<>1
r2c4=1 r2c4<>3 r2c3=3 r2c3<>9 r1c3=9 r1c3<>8
r2c4=1 r2c4<>3 r2c3=3 r2c3<>8
r2c4=1 r8c4<>1 r7c5=1 r7c8<>1 r7c8=8 r6c8<>8 r6c12=8 r4c3<>8
r2c4=1 r8c4<>1 r7c5=1 r7c8<>1 r7c8=8 r6c8<>8 r6c12=8 r5c3<>8
r2c4=1 r8c4<>1 r8c4=4 r8c1<>4 r8c1=8 r7c3<>8
Empty Rectangle: 1 in b4 (r2c29) => r4c9<>1
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c2<>1
Grouped Discontinuous Nice Loop: 1 r3c1 -1- r3c45 =1= r1c5 =8= r1c3 =9= r2c3 =3= r3c1 => r3c1<>1
Forcing Chain Contradiction in c5 => r2c4<>4
r2c4=4 r2c4<>3 r2c3=3 r2c3<>9 r1c3=9 r1c3<>8 r1c5=8 r1c5<>1
r2c4=4 r2c4<>3 r3c5=3 r3c5<>1
r2c4=4 r8c4<>4 r8c4=1 r7c5<>1
Forcing Chain Contradiction in b3 => r3c9<>1
r3c9=1 r3c9<>9 r3c4=9 r2c4<>9 r2c4=3 r3c5<>3 r6c5=3 r6c7<>3 r6c7=5 r1c7<>5
r3c9=1 r3c45<>1 r1c5=1 r1c5<>8 r1c3=8 r1c3<>9 r1c8=9 r1c8<>5
r3c9=1 r3c9<>5
Forcing Chain Contradiction in r6 => r4c1<>8
r4c1=8 r8c1<>8 r8c1=4 r6c1<>4
r4c1=8 r6c12<>8 r6c8=8 r6c8<>9 r6c2=9 r6c2<>4
r4c1=8 r8c1<>8 r8c1=4 r7c23<>4 r7c5=4 r6c5<>4
Forcing Chain Contradiction in r7 => r4c3<>8
r4c3=8 r6c1<>8 r8c1=8 r7c2<>8
r4c3=8 r7c3<>8
r4c3=8 r1c3<>8 r1c5=8 r7c5<>8
r4c3=8 r6c12<>8 r6c8=8 r7c8<>8
Forcing Chain Verity => r4c4<>3
r1c3=8 r1c3<>9 r2c3=9 r2c3<>3 r2c4=3 r4c4<>3
r2c3=8 r2c3<>3 r2c4=3 r4c4<>3
r5c3=8 r5c4<>8 r4c4=8 r4c4<>3
r7c3=8 r8c1<>8 r8c1=4 r7c23<>4 r7c5=4 r6c5<>4 r6c5=3 r4c4<>3
Forcing Chain Contradiction in r7 => r5c3<>8
r5c3=8 r6c1<>8 r8c1=8 r7c2<>8
r5c3=8 r7c3<>8
r5c3=8 r1c3<>8 r1c5=8 r7c5<>8
r5c3=8 r6c12<>8 r6c8=8 r7c8<>8
W-Wing: 5/3 in r5c3,r6c7 connected by 3 in r5c4,r6c5 => r5c79,r6c1<>5
Locked Candidates Type 2 (Claiming): 5 in r6 => r4c8<>5
Discontinuous Nice Loop: 1 r8c9 -1- r8c4 =1= r3c4 =9= r3c9 =5= r8c9 => r8c9<>1
Discontinuous Nice Loop: 5 r8c7 -5- r8c9 =5= r3c9 =9= r3c4 -9- r2c4 -3- r5c4 =3= r6c5 -3- r6c7 -5- r8c7 => r8c7<>5
Almost Locked Set XZ-Rule: A=r6c15 {348}, B=r8c147 {1348}, X=8, Z=3 => r6c7<>3
Naked Single: r6c7=5
Discontinuous Nice Loop: 1 r1c8 -1- r7c8 =1= r7c5 -1- r8c4 =1= r3c4 =9= r3c9 =5= r1c8 => r1c8<>1
Locked Candidates Type 2 (Claiming): 1 in c8 => r8c7<>1
Grouped Discontinuous Nice Loop: 4 r8c7 -4- r9c79 =4= r9c6 =8= r2c6 -8- r1c5 =8= r1c3 =9= r1c8 =5= r8c8 =3= r8c7 => r8c7<>4
Naked Single: r8c7=3
X-Wing: 3 r25 c34 => r4c3<>3
Discontinuous Nice Loop: 4 r1c5 -4- r1c7 =4= r9c7 -4- r9c6 -8- r2c6 =8= r1c5 => r1c5<>4
Discontinuous Nice Loop: 8 r4c8 -8- r4c4 =8= r5c4 =3= r5c3 -3- r4c1 =3= r4c8 => r4c8<>8
Empty Rectangle: 8 in b6 (r68c1) => r8c9<>8
Grouped AIC: 5 5- r4c3 -4- r4c46 =4= r6c5 =3= r5c4 -3- r5c3 -5 => r17c3,r4c12,r5c2<>5
Hidden Single: r7c2=5
Empty Rectangle: 4 in b5 (r7c35) => r4c3<>4
Naked Single: r4c3=5
Naked Single: r5c3=3
Hidden Single: r5c6=5
Hidden Single: r2c4=3
Hidden Single: r3c1=3
Hidden Single: r4c8=3
Hidden Single: r6c5=3
Hidden Single: r3c9=5
Naked Single: r1c8=9
Naked Single: r8c9=4
Naked Single: r1c3=8
Naked Single: r6c8=8
Naked Single: r2c9=1
Full House: r1c7=4
Naked Single: r8c1=8
Full House: r7c3=4
Full House: r2c3=9
Naked Single: r8c4=1
Full House: r8c8=5
Full House: r7c8=1
Full House: r7c5=8
Full House: r9c6=4
Naked Single: r9c7=6
Full House: r5c7=1
Full House: r9c9=8
Naked Single: r1c5=1
Full House: r1c1=5
Naked Single: r6c1=4
Full House: r4c1=1
Full House: r6c2=9
Naked Single: r2c2=4
Full House: r2c6=8
Full House: r4c6=9
Full House: r3c2=1
Naked Single: r3c5=4
Full House: r3c4=9
Naked Single: r4c9=6
Full House: r5c9=9
Naked Single: r5c4=8
Full House: r4c4=4
Naked Single: r4c5=7
Full House: r4c2=8
Full House: r5c2=7
Full House: r5c5=6
|
normal_sudoku_3011
|
2.....98.9.43......6...9..4.41..67.9..7.......9...1..6.5.16.4..4....5.....6.9...5
|
275614983984357162163829574341586729627943851598271346859162437412735698736498215
|
Basic 9x9 Sudoku 3011
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . . . 9 8 .
9 . 4 3 . . . . .
. 6 . . . 9 . . 4
. 4 1 . . 6 7 . 9
. . 7 . . . . . .
. 9 . . . 1 . . 6
. 5 . 1 6 . 4 . .
4 . . . . 5 . . .
. . 6 . 9 . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
275614983984357162163829574341586729627943851598271346859162437412735698736498215 #1 Extreme (25912) bf
Hidden Single: r2c1=9
Hidden Single: r5c1=6
Hidden Single: r1c4=6
Hidden Single: r5c4=9
Brute Force: r5c8=5
Hidden Single: r6c8=4
Hidden Single: r9c4=4
Brute Force: r5c7=8
Hidden Single: r5c9=1
Grouped Discontinuous Nice Loop: 3 r6c5 -3- r6c7 -2- r6c3 =2= r5c2 =3= r5c56 -3- r6c5 => r6c5<>3
Forcing Net Contradiction in r9 => r2c7<>2
r2c7=2 (r2c7<>1) (r2c7<>5 r2c5=5 r2c5<>1) r2c7<>6 r2c8=6 r2c8<>1 r2c2=1 r3c1<>1 r9c1=1
r2c7=2 (r9c7<>2) r6c7<>2 r6c7=3 r9c7<>3 r9c7=1
Forcing Net Contradiction in c5 => r2c8<>2
r2c8=2 (r2c6<>2) r2c9<>2 r2c9=7 (r2c2<>7) r2c6<>7 r2c6=8 r2c2<>8 r2c2=1 r1c2<>1 r1c5=1 r1c5<>4
r2c8=2 (r2c9<>2 r2c9=7 r1c9<>7 r1c9=3 r7c9<>3) (r2c9<>2 r2c9=7 r1c9<>7 r1c9=3 r1c2<>3) (r3c8<>2) (r2c9<>2 r2c9=7 r3c8<>7) r4c8<>2 r4c8=3 (r7c8<>3) r3c8<>3 r3c8=1 r3c1<>1 r9c1=1 r9c7<>1 r9c7=3 (r9c2<>3) r6c7<>3 r6c7=2 (r9c7<>2) r6c3<>2 r5c2=2 (r5c2<>3) r5c2<>3 r8c2=3 (r7c1<>3) r7c3<>3 r7c6=3 r5c6<>3 r5c5=3 r5c5<>4
Forcing Net Verity => r2c6<>2
r3c8=1 (r2c8<>1) (r8c8<>1) r3c1<>1 r9c1=1 r8c2<>1 r8c7=1 r8c7<>6 r8c8=6 r2c8<>6 r2c8=7 r2c9<>7 r2c9=2 r2c6<>2
r3c8=2 (r9c8<>2) r4c8<>2 r6c7=2 (r9c7<>2) r6c3<>2 r5c2=2 r9c2<>2 r9c6=2 r2c6<>2
r3c8=3 r1c9<>3 r1c9=7 r2c9<>7 r2c9=2 r2c6<>2
r3c8=7 r2c9<>7 r2c9=2 r2c6<>2
Grouped Discontinuous Nice Loop: 2 r7c9 -2- r2c9 -7- r2c6 -8- r79c6 =8= r8c45 -8- r8c9 =8= r7c9 => r7c9<>2
Finned Franken Swordfish: 2 r47b4 c368 fr4c4 fr4c5 fr5c2 => r5c6<>2
Locked Candidates Type 2 (Claiming): 2 in c6 => r8c45<>2
Grouped Discontinuous Nice Loop: 3 r8c9 -3- r8c5 =3= r45c5 -3- r5c6 -4- r1c6 -7- r1c9 -3- r8c9 => r8c9<>3
Almost Locked Set XY-Wing: A=r8c459 {2378}, B=r369c7 {1235}, C=r2c26789 {125678}, X,Y=2,5, Z=3 => r8c7<>3
Almost Locked Set XY-Wing: A=r8c459 {2378}, B=r1589c2 {12378}, C=r2c269 {1278}, X,Y=1,2, Z=8 => r8c3<>8
Almost Locked Set XY-Wing: A=r5c26 {234}, B=r8c459 {2378}, C=r1279c6 {23478}, X,Y=3,4, Z=2 => r8c2<>2
Almost Locked Set XZ-Rule: A=r2c269 {1278}, B=r8c2459 {12378}, X=1,2 => r19c2<>1, r2c58,r8c8<>7, r2c5<>8, r8c38<>3
Hidden Single: r1c5=1
Hidden Single: r1c6=4
Naked Single: r5c6=3
Naked Single: r5c2=2
Full House: r5c5=4
Hidden Single: r1c3=5
Hidden Single: r8c5=3
Naked Pair: 3,8 in r36c3 => r7c3<>3, r7c3<>8
Skyscraper: 3 in r7c9,r9c2 (connected by r1c29) => r7c1,r9c78<>3
X-Wing: 3 c37 r36 => r3c18,r6c1<>3
Empty Rectangle: 8 in b8 (r2c26) => r8c2<>8
W-Wing: 7/8 in r2c6,r7c1 connected by 8 in r29c2 => r7c6<>7
W-Wing: 7/8 in r7c1,r8c4 connected by 8 in r78c9 => r8c2<>7
Naked Single: r8c2=1
Hidden Single: r3c1=1
Locked Candidates Type 1 (Pointing): 7 in b1 => r9c2<>7
Naked Pair: 2,7 in r2c9,r3c8 => r1c9<>7, r3c7<>2
Naked Single: r1c9=3
Full House: r1c2=7
Naked Single: r3c7=5
Naked Single: r2c2=8
Full House: r3c3=3
Full House: r9c2=3
Naked Single: r2c6=7
Naked Single: r6c3=8
Naked Single: r2c9=2
Naked Single: r6c1=5
Full House: r4c1=3
Naked Single: r2c5=5
Naked Single: r3c8=7
Naked Single: r4c8=2
Full House: r6c7=3
Naked Single: r4c5=8
Full House: r4c4=5
Naked Single: r9c8=1
Naked Single: r3c5=2
Full House: r3c4=8
Full House: r6c5=7
Full House: r6c4=2
Full House: r8c4=7
Naked Single: r2c8=6
Full House: r2c7=1
Naked Single: r9c7=2
Full House: r8c7=6
Naked Single: r8c9=8
Full House: r7c9=7
Naked Single: r8c8=9
Full House: r7c8=3
Full House: r8c3=2
Full House: r7c3=9
Naked Single: r9c6=8
Full House: r7c6=2
Full House: r7c1=8
Full House: r9c1=7
|
normal_sudoku_2978
|
173.6....9.......3.6.35..74...4.....7......383..51.2.....24.7....7.....2.....15..
|
173864925954172863268359174829437651715926438346518297591243786487695312632781549
|
Basic 9x9 Sudoku 2978
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 7 3 . 6 . . . .
9 . . . . . . . 3
. 6 . 3 5 . . 7 4
. . . 4 . . . . .
7 . . . . . . 3 8
3 . . 5 1 . 2 . .
. . . 2 4 . 7 . .
. . 7 . . . . . 2
. . . . . 1 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
173864925954172863268359174829437651715926438346518297591243786487695312632781549 #1 Medium (424)
Hidden Single: r1c3=3
Hidden Single: r3c7=1
Hidden Single: r2c4=1
Hidden Single: r8c7=3
Hidden Single: r1c6=4
Hidden Single: r3c6=9
Naked Single: r1c4=8
Naked Single: r1c7=9
Naked Single: r1c9=5
Full House: r1c8=2
Naked Single: r4c7=6
Naked Single: r2c7=8
Full House: r5c7=4
Full House: r2c8=6
Naked Single: r6c8=9
Naked Single: r6c9=7
Naked Single: r4c9=1
Full House: r4c8=5
Hidden Single: r9c4=7
Locked Triple: 2,8,9 in r4c123 => r4c56,r5c23<>2, r4c56,r6c23<>8, r4c5,r5c23<>9
Naked Single: r6c2=4
Naked Single: r6c3=6
Full House: r6c6=8
Hidden Single: r2c3=4
Hidden Single: r2c2=5
Naked Single: r5c2=1
Naked Single: r5c3=5
Hidden Single: r7c3=1
Naked Single: r7c8=8
Naked Single: r9c8=4
Full House: r8c8=1
Hidden Single: r8c1=4
Hidden Single: r8c6=5
Hidden Single: r7c1=5
Hidden Single: r8c4=6
Full House: r5c4=9
Naked Single: r7c6=3
Naked Single: r5c5=2
Full House: r5c6=6
Naked Single: r4c6=7
Full House: r2c6=2
Full House: r2c5=7
Full House: r4c5=3
Naked Single: r7c2=9
Full House: r7c9=6
Full House: r9c9=9
Naked Single: r8c2=8
Full House: r8c5=9
Full House: r9c5=8
Naked Single: r4c2=2
Full House: r9c2=3
Naked Single: r9c3=2
Full House: r9c1=6
Naked Single: r4c1=8
Full House: r3c1=2
Full House: r3c3=8
Full House: r4c3=9
|
normal_sudoku_1060
|
4...1.98.......7.....2...1.9.....4..638..1.9...4.3.87....3.6.5...9.5......31826..
|
426517983591843762387269514975628431638471295214935876842396157169754328753182649
|
Basic 9x9 Sudoku 1060
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . . 1 . 9 8 .
. . . . . . 7 . .
. . . 2 . . . 1 .
9 . . . . . 4 . .
6 3 8 . . 1 . 9 .
. . 4 . 3 . 8 7 .
. . . 3 . 6 . 5 .
. . 9 . 5 . . . .
. . 3 1 8 2 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
426517983591843762387269514975628431638471295214935876842396157169754328753182649 #1 Extreme (2096)
Naked Single: r9c7=6
Naked Single: r9c8=4
Hidden Single: r9c9=9
Hidden Single: r7c5=9
Hidden Single: r8c2=6
Hidden Single: r7c2=4
Locked Pair: 2,5 in r5c79 => r46c9,r5c4<>5, r4c89,r5c5,r6c9<>2
Hidden Single: r4c5=2
Locked Candidates Type 1 (Pointing): 7 in b4 => r4c46<>7
Locked Candidates Type 1 (Pointing): 6 in b5 => r12c4<>6
Locked Candidates Type 1 (Pointing): 1 in b6 => r78c9<>1
Locked Candidates Type 1 (Pointing): 8 in b7 => r23c1<>8
Locked Candidates Type 1 (Pointing): 7 in b8 => r8c19<>7
Hidden Single: r7c9=7
Hidden Single: r7c1=8
Hidden Single: r8c9=8
Naked Pair: 4,7 in r58c4 => r1c4<>7, r2c4<>4
Naked Single: r1c4=5
Hidden Pair: 8,9 in r23c2 => r2c2<>1, r2c2<>2, r23c2<>5, r3c2<>7
Locked Candidates Type 2 (Claiming): 1 in c2 => r4c3,r6c1<>1
Naked Pair: 8,9 in r2c24 => r2c6<>8, r2c6<>9
Naked Triple: 3,4,7 in r128c6 => r3c6<>3, r3c6<>4, r3c6<>7
2-String Kite: 2 in r2c8,r7c3 (connected by r7c7,r8c8) => r2c3<>2
Hidden Rectangle: 4/6 in r2c59,r3c59 => r3c9<>6
Sue de Coq: r3c123 - {356789} (r3c67 - {3589}, r1c23 - {267}) => r2c1<>2, r2c3<>6, r3c9<>3, r3c9<>5
Naked Single: r3c9=4
Locked Candidates Type 1 (Pointing): 2 in b1 => r1c9<>2
Naked Triple: 1,3,6 in r146c9 => r2c9<>3, r2c9<>6
XY-Chain: 1 1- r2c3 -5- r2c9 -2- r5c9 -5- r5c7 -2- r7c7 -1- r7c3 -2- r8c1 -1 => r2c1,r7c3<>1
Naked Single: r7c3=2
Full House: r7c7=1
Naked Single: r8c1=1
Hidden Single: r2c3=1
Hidden Single: r1c2=2
Hidden Single: r6c1=2
XY-Chain: 3 3- r1c9 -6- r1c3 -7- r4c3 -5- r4c6 -8- r4c4 -6- r4c8 -3 => r2c8,r4c9<>3
Hidden Single: r4c8=3
Naked Single: r8c8=2
Full House: r2c8=6
Full House: r8c7=3
Naked Single: r1c9=3
Naked Single: r2c5=4
Naked Single: r3c7=5
Full House: r2c9=2
Full House: r5c7=2
Naked Single: r1c6=7
Full House: r1c3=6
Naked Single: r2c6=3
Naked Single: r5c5=7
Full House: r3c5=6
Naked Single: r5c9=5
Full House: r5c4=4
Naked Single: r8c6=4
Full House: r8c4=7
Naked Single: r3c3=7
Full House: r4c3=5
Naked Single: r2c1=5
Naked Single: r3c1=3
Full House: r9c1=7
Full House: r9c2=5
Naked Single: r4c6=8
Naked Single: r6c2=1
Full House: r4c2=7
Naked Single: r3c6=9
Full House: r2c4=8
Full House: r3c2=8
Full House: r6c6=5
Full House: r2c2=9
Naked Single: r4c4=6
Full House: r4c9=1
Full House: r6c9=6
Full House: r6c4=9
|
normal_sudoku_6663
|
.7..3.8....69.....1....4.3...41...2..2..4.9.8..9..6....5..7..8....4..2.5......7..
|
975632814346918572182754639864195327521347968739826451453279186617483295298561743
|
Basic 9x9 Sudoku 6663
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . 3 . 8 . .
. . 6 9 . . . . .
1 . . . . 4 . 3 .
. . 4 1 . . . 2 .
. 2 . . 4 . 9 . 8
. . 9 . . 6 . . .
. 5 . . 7 . . 8 .
. . . 4 . . 2 . 5
. . . . . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
975632814346918572182754639864195327521347968739826451453279186617483295298561743 #1 Extreme (19940) bf
Brute Force: r5c7=9
Forcing Net Verity => r1c8<>9
r8c8=1 (r1c8<>1) (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 (r6c2<>1 r9c2=1 r9c2<>4 r2c2=4 r1c1<>4) r7c3<>1 r7c6=1 r1c6<>1 r1c9=1 r1c9<>4 r1c8=4 r1c8<>9
r8c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 (r4c2<>6 r9c2=6 r9c2<>4 r2c2=4 r1c1<>4) r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>4 r1c8=4 r1c8<>9
r8c8=9 r1c8<>9
Locked Candidates Type 1 (Pointing): 9 in b3 => r79c9<>9
Forcing Net Contradiction in b4 => r7c1<>3
r7c1=3 (r2c1<>3 r2c2=3 r4c2<>3) (r7c3<>3) (r8c3<>3) r9c3<>3 r5c3=3 r5c3<>1 r5c8=1 r5c8<>6 r5c1=6 r4c2<>6 r4c2=8
r7c1=3 (r9c3<>3 r5c3=3 r5c3<>1 r5c8=1 r6c9<>1 r6c2=1 r6c2<>8) (r6c1<>3) (r2c1<>3 r2c2=3 r6c2<>3) (r7c9<>3 r9c9=3 r6c9<>3) (r4c1<>3) (r2c1<>3 r2c2=3 r4c2<>3) (r7c9<>3 r9c9=3 r4c9<>3) (r8c1<>3) (r8c2<>3) r8c3<>3 r8c6=3 r4c6<>3 r4c7=3 r6c7<>3 r6c4=3 (r6c4<>8) r6c4<>2 r6c5=2 r6c5<>8 r6c1=8
Forcing Net Verity => r8c1<>9
r8c8=1 (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 r7c3<>1 r7c6=1 r7c6<>9 r7c1=9 r8c1<>9
r8c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>9 r1c1=9 r8c1<>9
r8c8=9 r8c1<>9
Forcing Net Verity => r8c5<>9
r8c8=1 (r1c8<>1) (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 r7c3<>1 r7c6=1 r1c6<>1 r1c9=1 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r8c5<>9
r8c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r8c5<>9
r8c8=9 r8c5<>9
Forcing Net Verity => r4c5=9
r9c8=1 (r1c8<>1) (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 r7c3<>1 r7c6=1 r1c6<>1 r1c9=1 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r4c6<>9 r4c5=9
r9c8=4 (r7c7<>4) r7c9<>4 r7c1=4 r7c1<>9 r7c6=9 r4c6<>9 r4c5=9
r9c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r4c6<>9 r4c5=9
r9c8=9 r9c5<>9 r4c5=9
Forcing Net Contradiction in r8 => r3c4<>6
r3c4=6 (r3c7<>6 r3c7=5 r4c7<>5) r3c4<>7 r3c9=7 (r4c9<>7) (r2c8<>7) r2c9<>7 r2c6=7 (r5c6<>7) r4c6<>7 r4c1=7 r4c1<>5 r4c6=5 r5c6<>5 r5c6=3 r5c3<>3 r789c3=3 r8c1<>3
r3c4=6 (r3c7<>6 r3c7=5 r4c7<>5) r3c4<>7 r3c9=7 (r4c9<>7) (r2c8<>7) r2c9<>7 r2c6=7 (r5c6<>7) r4c6<>7 r4c1=7 r4c1<>5 r4c6=5 r5c6<>5 r5c6=3 r5c3<>3 r789c3=3 r8c2<>3
r3c4=6 r3c4<>7 r3c9=7 (r4c9<>7) (r2c8<>7) r2c9<>7 r2c6=7 r4c6<>7 r4c1=7 r8c1<>7 r8c3=7 r8c3<>3
r3c4=6 (r3c7<>6 r3c7=5 r4c7<>5) r3c4<>7 r3c9=7 (r4c9<>7) (r2c8<>7) r2c9<>7 r2c6=7 (r5c6<>7) r4c6<>7 r4c1=7 r4c1<>5 r4c6=5 r5c6<>5 r5c6=3 r8c6<>3
Forcing Net Contradiction in r7 => r6c4<>7
r6c4=7 (r6c8<>7) r3c4<>7 r3c9=7 r2c8<>7 r5c8=7 r5c8<>6 r5c1=6 r7c1<>6
r6c4=7 (r3c4<>7 r3c9=7 r4c9<>7 r4c1=7 r4c1<>5) (r6c4<>8) r6c4<>2 r6c5=2 r6c5<>8 r4c6=8 r4c6<>5 r4c7=5 r3c7<>5 r3c7=6 (r1c8<>6) r1c9<>6 r1c4=6 r7c4<>6
r6c4=7 (r3c4<>7 r3c9=7 r4c9<>7 r4c1=7 r4c1<>5) (r6c4<>8) r6c4<>2 r6c5=2 r6c5<>8 r4c6=8 r4c6<>5 r4c7=5 r3c7<>5 r3c7=6 r7c7<>6
r6c4=7 (r3c4<>7 r3c9=7 r4c9<>7 r4c1=7 r4c1<>6) (r3c4<>7 r3c9=7 r2c8<>7 r5c8=7 r5c8<>6 r5c1=6 r4c2<>6) (r3c4<>7 r3c9=7 r4c9<>7 r4c1=7 r4c1<>5) (r6c4<>8) r6c4<>2 r6c5=2 r6c5<>8 r4c6=8 r4c6<>5 r4c7=5 r4c7<>6 r4c9=6 r7c9<>6
Forcing Net Contradiction in r7c4 => r5c1<>7
r5c1=7 (r5c4<>7 r3c4=7 r2c6<>7 r4c6=7 r4c9<>7) r5c1<>6 r5c8=6 (r5c8<>1 r5c3=1 r7c3<>1) r4c9<>6 r4c9=3 (r4c7<>3) r6c7<>3 r7c7=3 r7c3<>3 r7c3=2 r7c4<>2
r5c1=7 (r5c4<>7 r3c4=7 r2c6<>7 r4c6=7 r4c9<>7) r5c1<>6 r5c8=6 r4c9<>6 r4c9=3 (r4c7<>3) r6c7<>3 r7c7=3 r7c4<>3
r5c1=7 (r5c4<>7 r3c4=7 r2c6<>7 r4c6=7 r4c9<>7) r5c1<>6 r5c8=6 (r1c8<>6) (r4c7<>6) r4c9<>6 r4c9=3 r4c7<>3 r4c7=5 r3c7<>5 r3c7=6 r1c9<>6 r1c4=6 r7c4<>6
Forcing Net Verity => r8c6<>9
r8c8=1 (r1c8<>1) (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 r7c3<>1 r7c6=1 r1c6<>1 r1c9=1 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r8c6<>9
r8c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>9 r1c1=9 r7c1<>9 r7c6=9 r8c6<>9
r8c8=9 r8c6<>9
Forcing Chain Contradiction in r7 => r8c8<>1
r8c8=1 r5c8<>1 r5c3=1 r7c3<>1
r8c8=1 r8c8<>9 r8c2=9 r7c1<>9 r7c6=9 r7c6<>1
r8c8=1 r7c7<>1
r8c8=1 r7c9<>1
Forcing Net Verity => r1c1=9
r9c8=1 (r1c8<>1) (r7c7<>1) (r7c9<>1) r5c8<>1 r5c3=1 r7c3<>1 r7c6=1 r1c6<>1 r1c9=1 r1c9<>9 r1c1=9
r9c8=4 (r1c8<>4) (r7c7<>4) r7c9<>4 r7c1=4 r1c1<>4 r1c9=4 r1c9<>9 r1c1=9
r9c8=6 (r1c8<>6) (r7c7<>6) (r7c9<>6) r5c8<>6 r5c1=6 r7c1<>6 r7c4=6 r1c4<>6 r1c9=6 r1c9<>9 r1c1=9
r9c8=9 r8c8<>9 r8c2=9 r3c2<>9 r3c9=9 r1c9<>9 r1c1=9
Naked Single: r3c2=8
Hidden Single: r3c9=9
Hidden Single: r7c6=9
Hidden Single: r3c4=7
Locked Pair: 2,5 in r13c3 => r2c1,r5c3<>5, r2c1,r79c3<>2
Locked Candidates Type 1 (Pointing): 4 in b1 => r2c789<>4
Locked Candidates Type 1 (Pointing): 8 in b4 => r89c1<>8
XYZ-Wing: 3/5/6 in r4c2,r5c14 => r5c3<>3
Locked Candidates Type 2 (Claiming): 3 in c3 => r8c12,r9c12<>3
Hidden Rectangle: 6/9 in r8c28,r9c28 => r9c2<>6
2-String Kite: 6 in r5c8,r8c2 (connected by r4c2,r5c1) => r8c8<>6
Naked Single: r8c8=9
Hidden Single: r9c2=9
Hidden Single: r2c2=4
Naked Single: r2c1=3
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c6,r6c4<>3
Hidden Pair: 2,4 in r79c1 => r79c1<>6
Locked Candidates Type 1 (Pointing): 6 in b7 => r8c5<>6
Sashimi X-Wing: 1 r57 c38 fr7c7 fr7c9 => r9c8<>1
Sue de Coq: r5c13 - {1567} (r5c46 - {357}, r46c2 - {136}) => r4c1<>6, r5c8<>5, r5c8<>7
Sue de Coq: r7c79 - {1346} (r7c3 - {13}, r9c8 - {46}) => r9c9<>4, r9c9<>6, r7c4<>3
Discontinuous Nice Loop: 5/7 r4c1 =8= r4c6 =7= r5c6 -7- r5c3 =7= r8c3 =8= r9c3 -8- r9c4 =8= r6c4 -8- r6c1 =8= r4c1 => r4c1<>5, r4c1<>7
Naked Single: r4c1=8
Naked Triple: 3,5,7 in r45c6,r5c4 => r6c45<>5
AIC: 2 2- r7c4 -6- r1c4 =6= r3c5 -6- r3c7 -5- r4c7 =5= r4c6 =7= r5c6 -7- r5c3 -1- r5c8 -6- r9c8 -4- r9c1 -2 => r7c1,r9c456<>2
Naked Single: r7c1=4
Naked Single: r9c1=2
Hidden Single: r7c4=2
Naked Single: r6c4=8
Naked Single: r6c5=2
Hidden Single: r6c7=4
Hidden Single: r9c8=4
Hidden Single: r3c3=2
Full House: r1c3=5
Naked Single: r1c4=6
Naked Single: r1c8=1
Naked Single: r3c5=5
Full House: r3c7=6
Naked Single: r1c6=2
Full House: r1c9=4
Naked Single: r2c7=5
Naked Single: r5c8=6
Naked Single: r2c8=7
Full House: r2c9=2
Full House: r6c8=5
Naked Single: r4c7=3
Full House: r7c7=1
Naked Single: r5c1=5
Naked Single: r6c1=7
Full House: r8c1=6
Naked Single: r4c2=6
Naked Single: r4c9=7
Full House: r6c9=1
Full House: r4c6=5
Full House: r6c2=3
Full House: r5c3=1
Full House: r8c2=1
Naked Single: r7c3=3
Full House: r7c9=6
Full House: r9c9=3
Naked Single: r5c4=3
Full House: r9c4=5
Full House: r5c6=7
Naked Single: r8c5=8
Naked Single: r9c3=8
Full House: r8c3=7
Full House: r8c6=3
Naked Single: r2c5=1
Full House: r2c6=8
Full House: r9c6=1
Full House: r9c5=6
|
normal_sudoku_628
|
.7..28.5.......2688..........743..92...7..8..3.9.......9.2..7.....84....2.4.9...3
|
476328159931574268825916347187435692542769831369182475698253714753841926214697583
|
Basic 9x9 Sudoku 628
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . 2 8 . 5 .
. . . . . . 2 6 8
8 . . . . . . . .
. . 7 4 3 . . 9 2
. . . 7 . . 8 . .
3 . 9 . . . . . .
. 9 . 2 . . 7 . .
. . . 8 4 . . . .
2 . 4 . 9 . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
476328159931574268825916347187435692542769831369182475698253714753841926214697583 #1 Extreme (14202) bf
Hidden Single: r1c6=8
Hidden Single: r6c5=8
Hidden Single: r8c8=2
Hidden Single: r8c1=7
Hidden Single: r7c3=8
Hidden Single: r5c6=9
Hidden Single: r9c6=7
Hidden Single: r5c8=3
Hidden Single: r4c2=8
Hidden Single: r9c8=8
Hidden Single: r7c6=3
Hidden Single: r6c6=2
Hidden Single: r2c5=7
Brute Force: r5c1=5
Locked Candidates Type 1 (Pointing): 4 in b4 => r23c2<>4
Naked Pair: 1,6 in r47c1 => r12c1<>1, r1c1<>6
Finned Franken Swordfish: 6 c15b1 r357 fr1c3 fr4c1 => r5c3<>6
Hidden Rectangle: 1/2 in r3c23,r5c23 => r3c2<>1
Finned Franken Swordfish: 6 c16b1 r348 fr1c3 fr7c1 => r8c3<>6
Locked Candidates Type 2 (Claiming): 6 in c3 => r3c2<>6
Forcing Net Contradiction in r9 => r3c2=2
r3c2<>2 r3c3=2 r5c3<>2 r5c3=1 (r2c3<>1 r2c2=1 r2c4<>1) (r5c5<>1) r4c1<>1 r7c1=1 (r7c8<>1) r7c5<>1 r3c5=1 (r1c4<>1) (r3c4<>1) r3c8<>1 r6c8=1 r6c4<>1 r9c4=1
r3c2<>2 r3c3=2 r5c3<>2 r5c3=1 (r4c1<>1) (r5c5<>1) r4c1<>1 (r4c1=6 r7c1<>6) r7c1=1 (r7c8<>1) r7c5<>1 r3c5=1 r3c8<>1 r6c8=1 r4c7<>1 r4c6=1 (r4c6<>5 r4c7=5 r9c7<>5) r5c5<>1 r5c5=6 r7c5<>6 r7c9=6 r9c7<>6 r9c7=1
Hidden Single: r5c3=2
Forcing Net Verity => r7c5=5
r7c5=1 (r5c5<>1 r5c5=6 r4c6<>6) r7c1<>1 (r4c1=1 r4c6<>1 r4c6=5 r8c6<>5) r7c1=6 r4c1<>6 r4c7=6 (r9c7<>6) r4c1<>6 r7c1=6 r9c2<>6 r9c4=6 r9c4<>5 r7c5=5
r7c5=5 r7c5=5
r7c5=6 (r5c5<>6 r5c5=1 r4c6<>1) r7c1<>6 (r4c1=6 r4c6<>6 r4c6=5 r8c6<>5) r7c1=1 r4c1<>1 r4c7=1 (r9c7<>1) r4c1<>1 r7c1=1 r9c2<>1 r9c4=1 r9c4<>5 r7c5=5
Grouped Discontinuous Nice Loop: 1 r1c3 -1- r1c79 =1= r3c789 -1- r3c5 -6- r3c3 =6= r1c3 => r1c3<>1
Finned Franken Swordfish: 1 r47b8 c167 fr7c8 fr7c9 fr9c4 => r9c7<>1
W-Wing: 6/1 in r7c1,r8c6 connected by 1 in r9c24 => r8c2<>6
Sashimi Swordfish: 6 r478 c167 fr7c9 fr8c9 => r9c7<>6
Naked Single: r9c7=5
Hidden Single: r4c6=5
Hidden Single: r6c9=5
Hidden Single: r6c8=7
Hidden Single: r3c9=7
Naked Pair: 1,6 in r7c1,r9c2 => r8c23<>1
Locked Candidates Type 2 (Claiming): 1 in c3 => r2c2<>1
Naked Pair: 1,6 in r69c4 => r123c4<>1, r13c4<>6
Hidden Single: r1c3=6
Locked Candidates Type 2 (Claiming): 1 in r1 => r3c78<>1
Naked Single: r3c8=4
Full House: r7c8=1
Naked Single: r7c1=6
Full House: r7c9=4
Naked Single: r4c1=1
Full House: r4c7=6
Naked Single: r9c2=1
Full House: r9c4=6
Full House: r8c6=1
Naked Single: r5c9=1
Full House: r6c7=4
Naked Single: r8c7=9
Full House: r8c9=6
Full House: r1c9=9
Naked Single: r6c4=1
Full House: r5c5=6
Full House: r6c2=6
Full House: r3c5=1
Full House: r5c2=4
Naked Single: r2c6=4
Full House: r3c6=6
Naked Single: r3c7=3
Full House: r1c7=1
Naked Single: r1c1=4
Full House: r1c4=3
Full House: r2c1=9
Naked Single: r3c3=5
Full House: r3c4=9
Full House: r2c4=5
Naked Single: r2c2=3
Full House: r2c3=1
Full House: r8c3=3
Full House: r8c2=5
|
normal_sudoku_5674
|
.7..3......2..736....8....7.6...3..2.............6.5....941..2..2...8..3.8.3..196
|
576231849812947365943856217164583972357129684298764531639415728721698453485372196
|
Basic 9x9 Sudoku 5674
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . 3 . . . .
. . 2 . . 7 3 6 .
. . . 8 . . . . 7
. 6 . . . 3 . . 2
. . . . . . . . .
. . . . 6 . 5 . .
. . 9 4 1 . . 2 .
. 2 . . . 8 . . 3
. 8 . 3 . . 1 9 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
576231849812947365943856217164583972357129684298764531639415728721698453485372196 #1 Extreme (34508) bf
Hidden Single: r9c4=3
Hidden Single: r5c7=6
Locked Candidates Type 1 (Pointing): 4 in b9 => r8c13<>4
2-String Kite: 6 in r1c4,r7c1 (connected by r7c6,r8c4) => r1c1<>6
Grouped Discontinuous Nice Loop: 2 r5c6 -2- r9c6 -5- r7c6 -6- r8c4 =6= r1c4 =2= r56c4 -2- r5c6 => r5c6<>2
Grouped Discontinuous Nice Loop: 2 r6c6 -2- r9c6 -5- r7c6 -6- r8c4 =6= r1c4 =2= r56c4 -2- r6c6 => r6c6<>2
Almost Locked Set XY-Wing: A=r9c13 {457}, B=r78c7,r8c8 {4578}, C=r7c1269 {35678}, X,Y=7,8, Z=5 => r8c13<>5
Forcing Chain Contradiction in r1 => r1c7<>4
r1c7=4 r8c7<>4 r8c7=7 r7c7<>7 r7c1=7 r7c1<>6 r7c6=6 r8c4<>6 r1c4=6 r1c4<>2
r1c7=4 r8c7<>4 r8c7=7 r8c45<>7 r9c5=7 r9c5<>2 r9c6=2 r1c6<>2
r1c7=4 r1c7<>2
Brute Force: r5c3=7
Brute Force: r5c4=1
AIC: 7 7- r6c8 =7= r6c4 =2= r1c4 =6= r8c4 -6- r7c6 =6= r7c1 =7= r7c7 -7 => r4c7,r8c8<>7
Discontinuous Nice Loop: 3 r5c2 -3- r5c8 =3= r6c8 =7= r6c4 =2= r1c4 =6= r8c4 -6- r7c6 -5- r7c2 -3- r5c2 => r5c2<>3
Discontinuous Nice Loop: 8 r5c1 -8- r2c1 =8= r2c9 -8- r7c9 -5- r7c6 -6- r8c4 =6= r1c4 =2= r6c4 -2- r6c1 =2= r5c1 => r5c1<>8
Grouped Discontinuous Nice Loop: 8 r6c8 -8- r5c89 =8= r5c5 =2= r6c4 =7= r6c8 => r6c8<>8
Finned X-Wing: 8 r26 c19 fr6c3 => r4c1<>8
Almost Locked Set XZ-Rule: A=r5c269 {4589}, B=r7c9,r8c8 {458}, X=8, Z=4 => r5c8<>4
Almost Locked Set XZ-Rule: A=r248c4 {5679}, B=r567c6 {4569}, X=6, Z=9 => r6c4<>9
Almost Locked Set Chain: 459- r5c269 {4589} -8- r7c69 {568} -6- r2468c4 {25679} -2- r4c13,r56c2,r6c13 {1234589} -459 => r5c1<>4, r5c1<>5, r5c1<>9
Sue de Coq: r6c123 - {123489} (r6c69 - {1489}, r5c1 - {23}) => r6c8<>1, r6c8<>4
Forcing Chain Verity => r2c1<>1
r1c8=8 r2c9<>8 r2c1=8 r2c1<>1
r4c8=8 r4c8<>1 r6c9=1 r6c2<>1 r23c2=1 r2c1<>1
r5c8=8 r5c8<>3 r6c8=3 r6c8<>7 r4c8=7 r4c8<>1 r6c9=1 r6c2<>1 r23c2=1 r2c1<>1
Forcing Chain Verity => r3c2<>3
r6c1=8 r2c1<>8 r2c9=8 r7c9<>8 r7c9=5 r7c2<>5 r7c2=3 r3c2<>3
r6c3=8 r6c3<>3 r3c3=3 r3c2<>3
r6c9=8 r7c9<>8 r7c9=5 r7c2<>5 r7c2=3 r3c2<>3
Grouped Discontinuous Nice Loop: 1 r3c3 -1- r8c3 -6- r78c1 =6= r3c1 =3= r3c3 => r3c3<>1
Forcing Net Contradiction in r3 => r7c2=3
r7c2<>3 (r7c2=5 r7c6<>5 r7c6=6 r3c6<>6) r7c1=3 r3c1<>3 r3c3=3 r3c3<>6 r3c1=6 r3c1<>5
r7c2<>3 r7c2=5 r3c2<>5
r7c2<>3 r7c1=3 r3c1<>3 r3c3=3 r3c3<>5
r7c2<>3 (r7c2=5 r5c2<>5) (r7c2=5 r7c9<>5 r7c9=8 r5c9<>8) r7c1=3 r5c1<>3 r5c8=3 r5c8<>8 r5c5=8 r5c5<>5 r5c6=5 (r9c6<>5 r9c6=2 r3c6<>2) (r9c6<>5 r9c6=2 r1c6<>2) r7c6<>5 r7c6=6 r8c4<>6 r1c4=6 r1c4<>2 r1c7=2 r3c7<>2 r3c5=2 r3c5<>5
r7c2<>3 (r7c2=5 r5c2<>5) (r7c2=5 r7c9<>5 r7c9=8 r5c9<>8) r7c1=3 r5c1<>3 r5c8=3 r5c8<>8 r5c5=8 r5c5<>5 r5c6=5 r3c6<>5
r7c2<>3 r7c2=5 r7c9<>5 r8c8=5 r3c8<>5
Forcing Net Contradiction in r4 => r1c6<>2
r1c6=2 (r1c6<>4) (r1c6<>1 r3c6=1 r3c8<>1) r9c6<>2 r9c6=5 (r9c3<>5 r9c3=4 r1c3<>4) (r8c4<>5) r8c5<>5 r8c8=5 r3c8<>5 r3c8=4 (r1c8<>4) r1c9<>4 r1c1=4 r4c1<>4
r1c6=2 r9c6<>2 r9c6=5 r9c3<>5 r9c3=4 r4c3<>4
r1c6=2 (r1c6<>4) (r1c6<>1 r3c6=1 r3c8<>1) r9c6<>2 r9c6=5 (r9c3<>5 r9c3=4 r1c3<>4) (r8c4<>5) r8c5<>5 r8c8=5 r3c8<>5 r3c8=4 (r2c9<>4) (r1c8<>4) r1c9<>4 r1c1=4 (r2c1<>4) r2c2<>4 r2c5=4 r4c5<>4
r1c6=2 r9c6<>2 r9c6=5 (r8c4<>5) r8c5<>5 r8c8=5 r8c8<>4 r8c7=4 r4c7<>4
r1c6=2 (r1c6<>1 r3c6=1 r3c8<>1) r9c6<>2 r9c6=5 (r8c4<>5) r8c5<>5 r8c8=5 r3c8<>5 r3c8=4 r4c8<>4
Forcing Chain Contradiction in c7 => r1c7<>9
r1c7=9 r1c7<>8
r1c7=9 r1c7<>2 r1c4=2 r6c4<>2 r5c5=2 r5c5<>8 r4c5=8 r4c7<>8
r1c7=9 r1c7<>2 r1c4=2 r1c4<>6 r8c4=6 r7c6<>6 r7c6=5 r7c9<>5 r7c9=8 r7c7<>8
Forcing Net Contradiction in r3c3 => r1c6<>6
r1c6=6 r7c6<>6 r7c6=5 r7c9<>5 r7c9=8 (r6c9<>8) r2c9<>8 r2c1=8 r6c1<>8 r6c3=8 r6c3<>3 r3c3=3
r1c6=6 (r3c6<>6) r7c6<>6 r7c1=6 r3c1<>6 r3c3=6
Forcing Net Contradiction in c9 => r1c6<>9
r1c6=9 (r1c6<>1 r3c6=1 r3c8<>1) (r2c4<>9 r2c4=5 r2c2<>5) (r5c6<>9) r6c6<>9 r6c6=4 r5c6<>4 r5c6=5 r5c2<>5 r3c2=5 r3c8<>5 r3c8=4 r1c9<>4
r1c6=9 (r2c5<>9) r2c4<>9 r2c4=5 r2c5<>5 r2c5=4 r2c9<>4
r1c6=9 (r2c4<>9 r2c4=5 r2c5<>5 r2c5=4 r2c2<>4) (r2c4<>9 r2c4=5 r2c2<>5) (r5c6<>9) r6c6<>9 r6c6=4 (r6c2<>4) r5c6<>4 r5c6=5 r5c2<>5 r3c2=5 r3c2<>4 r5c2=4 r5c9<>4
r1c6=9 r6c6<>9 r6c6=4 r6c9<>4
Sashimi X-Wing: 9 c67 r34 fr5c6 fr6c6 => r4c45<>9
Forcing Chain Verity => r4c7<>4
r1c1=9 r4c1<>9 r4c7=9 r4c7<>4
r1c4=9 r1c4<>6 r8c4=6 r7c6<>6 r7c6=5 r7c9<>5 r8c8=5 r8c8<>4 r8c7=4 r4c7<>4
r1c9=9 r3c7<>9 r4c7=9 r4c7<>4
Forcing Chain Verity => r3c3<>4
r6c1=8 r2c1<>8 r2c9=8 r7c9<>8 r7c9=5 r8c8<>5 r8c8=4 r8c7<>4 r3c7=4 r3c3<>4
r6c3=8 r6c3<>3 r3c3=3 r3c3<>4
r6c9=8 r7c9<>8 r7c9=5 r8c8<>5 r8c8=4 r8c7<>4 r3c7=4 r3c3<>4
Forcing Net Verity => r2c1=8
r3c1=9 (r3c1<>6) r3c1<>3 r3c3=3 r3c3<>6 r3c6=6 r7c6<>6 r7c6=5 r7c9<>5 r7c9=8 r2c9<>8 r2c1=8
r3c2=9 (r1c1<>9) (r2c1<>9) (r3c1<>9) r3c7<>9 r4c7=9 r4c1<>9 r6c1=9 (r6c1<>8) (r6c1<>8) (r6c1<>3) r6c1<>2 r6c4=2 r6c4<>7 r6c8=7 r6c8<>3 r6c3=3 r6c3<>8 r4c3=8 r6c3<>8 r6c9=8 r2c9<>8 r2c1=8
r3c5=9 (r2c4<>9 r2c4=5 r8c4<>5) (r3c5<>2) r8c5<>9 r8c4=9 r8c4<>6 r1c4=6 r1c4<>2 r1c7=2 r3c7<>2 r3c6=2 r9c6<>2 r9c6=5 r8c5<>5 r8c8=5 r7c9<>5 r7c9=8 r2c9<>8 r2c1=8
r3c6=9 (r2c5<>9) (r3c5<>9) (r1c4<>9) r2c4<>9 r8c4=9 r8c5<>9 r5c5=9 (r5c5<>8) r5c5<>2 r5c1=2 r5c1<>3 r5c8=3 r5c8<>8 r5c9=8 r2c9<>8 r2c1=8
r3c7=9 r4c7<>9 r4c7=8 (r4c8<>8) r5c8<>8 r1c8=8 r2c9<>8 r2c1=8
Forcing Chain Contradiction in r3 => r3c3<>5
r3c3=5 r3c3<>3 r3c1=3 r3c1<>6
r3c3=5 r3c3<>6
r3c3=5 r3c3<>3 r6c3=3 r6c3<>8 r6c9=8 r7c9<>8 r7c9=5 r7c6<>5 r7c6=6 r3c6<>6
Forcing Net Verity => r8c3=1
r3c1=9 (r3c1<>6) r3c1<>3 r3c3=3 r3c3<>6 r3c6=6 r1c4<>6 r1c3=6 r8c3<>6 r8c3=1
r3c2=9 (r1c1<>9) (r3c1<>9) r3c7<>9 r4c7=9 r4c1<>9 r6c1=9 (r6c1<>3) r6c1<>2 r6c4=2 r6c4<>7 r6c8=7 r6c8<>3 r6c3=3 r3c3<>3 r3c3=6 r8c3<>6 r8c3=1
r3c5=9 (r2c4<>9 r2c4=5 r8c4<>5) (r3c5<>2) r8c5<>9 r8c4=9 r8c4<>6 r1c4=6 r1c4<>2 r1c7=2 (r3c7<>2) r3c7<>2 r3c6=2 r9c6<>2 r9c6=5 r8c5<>5 r8c8=5 r8c8<>4 r8c7=4 r3c7<>4 r3c7=9 (r1c9<>9) r4c7<>9 r4c1=9 r1c1<>9 r1c4=9 r1c4<>6 r1c3=6 r8c3<>6 r8c3=1
r3c6=9 (r2c4<>9 r8c4=9 r8c5<>9 r5c5=9 r5c5<>8 r4c5=8 r4c3<>8 r6c3=8 r6c9<>8 r6c9=1 r2c9<>1 r2c9=9 r1c9<>9 r1c1=9 r1c9<>9) (r2c4<>9 r8c4=9 r8c5<>9 r5c5=9 r5c2<>9) (r5c6<>9) r6c6<>9 r6c6=4 (r4c5<>4) r5c6<>4 r5c6=5 r5c2<>5 r5c2=4 (r5c9<>4) (r4c1<>4) r4c3<>4 r4c8=4 r8c8<>4 r8c8=5 r7c9<>5 r7c9=8 r5c9<>8 r5c9=9 r4c7<>9 r4c1=9 r1c1<>9 r1c4=9 r1c4<>6 r1c3=6 r8c3<>6 r8c3=1
r3c7=9 (r1c9<>9) r4c7<>9 r4c1=9 r1c1<>9 r1c4=9 r1c4<>6 r1c3=6 r8c3<>6 r8c3=1
Locked Candidates Type 1 (Pointing): 6 in b7 => r3c1<>6
Continuous Nice Loop: 4/5/8 8= r6c3 =3= r3c3 =6= r3c6 -6- r7c6 -5- r7c9 -8- r6c9 =8= r6c3 =3 => r6c3<>4, r7c1<>5, r15c9<>8
Locked Candidates Type 1 (Pointing): 5 in b7 => r9c56<>5
Naked Single: r9c6=2
Naked Single: r9c5=7
Naked Triple: 4,5,9 in r5c269 => r5c5<>4, r5c5<>5, r5c5<>9
Locked Candidates Type 1 (Pointing): 9 in b5 => r3c6<>9
Finned Swordfish: 5 r257 c269 fr2c4 fr2c5 => r13c6<>5
Discontinuous Nice Loop: 1 r1c8 -1- r1c6 =1= r3c6 =6= r1c4 =2= r1c7 =8= r1c8 => r1c8<>1
Discontinuous Nice Loop: 5 r1c8 -5- r8c8 =5= r7c9 =8= r7c7 -8- r1c7 =8= r1c8 => r1c8<>5
Simple Colors Trap: 5 (r3c8,r5c6,r7c9) / (r5c2,r7c6,r8c8) => r3c2<>5
AIC: 9 9- r2c4 -5- r2c2 =5= r5c2 -5- r5c6 =5= r7c6 -5- r8c5 -9 => r23c5,r8c4<>9
Hidden Single: r8c5=9
Finned X-Wing: 9 r34 c17 fr3c2 => r1c1<>9
Discontinuous Nice Loop: 5 r1c3 -5- r2c2 =5= r5c2 -5- r5c6 =5= r7c6 =6= r3c6 -6- r3c3 =6= r1c3 => r1c3<>5
AIC: 4 4- r1c3 -6- r1c4 =6= r8c4 =5= r7c6 -5- r5c6 =5= r5c2 -5- r4c3 =5= r9c3 =4= r9c1 -4 => r13c1,r9c3<>4
Naked Single: r9c3=5
Full House: r9c1=4
Empty Rectangle: 4 in b5 (r14c3) => r1c6<>4
Naked Single: r1c6=1
Naked Single: r1c1=5
Hidden Single: r5c2=5
Hidden Single: r7c6=5
Full House: r8c4=6
Naked Single: r7c9=8
Naked Single: r8c1=7
Full House: r7c1=6
Full House: r7c7=7
Naked Single: r8c7=4
Full House: r8c8=5
Hidden Single: r2c9=5
Naked Single: r2c4=9
Naked Single: r2c5=4
Full House: r2c2=1
Naked Single: r1c4=2
Naked Single: r3c6=6
Full House: r3c5=5
Naked Single: r1c7=8
Naked Single: r6c4=7
Full House: r4c4=5
Naked Single: r3c3=3
Naked Single: r4c5=8
Full House: r5c5=2
Naked Single: r1c8=4
Naked Single: r4c7=9
Full House: r3c7=2
Naked Single: r6c8=3
Naked Single: r3c1=9
Naked Single: r6c3=8
Naked Single: r4c3=4
Full House: r1c3=6
Full House: r1c9=9
Full House: r3c8=1
Full House: r3c2=4
Full House: r6c2=9
Naked Single: r5c1=3
Naked Single: r4c1=1
Full House: r4c8=7
Full House: r5c8=8
Full House: r6c1=2
Naked Single: r5c9=4
Full House: r5c6=9
Full House: r6c6=4
Full House: r6c9=1
|
normal_sudoku_1952
|
..2..43.943.....82....6.1....83....1.......3..2.478..521.7.5...5768.2..3..91.....
|
162584379435917682987263154658329741794651238321478965213745896576892413849136527
|
Basic 9x9 Sudoku 1952
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . . 4 3 . 9
4 3 . . . . . 8 2
. . . . 6 . 1 . .
. . 8 3 . . . . 1
. . . . . . . 3 .
. 2 . 4 7 8 . . 5
2 1 . 7 . 5 . . .
5 7 6 8 . 2 . . 3
. . 9 1 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
162584379435917682987263154658329741794651238321478965213745896576892413849136527 #1 Easy (204)
Naked Single: r8c1=5
Naked Single: r1c4=5
Naked Single: r2c4=9
Naked Single: r2c5=1
Naked Single: r3c4=2
Full House: r5c4=6
Naked Single: r1c5=8
Naked Single: r2c6=7
Full House: r3c6=3
Naked Single: r4c6=9
Naked Single: r1c2=6
Naked Single: r2c3=5
Full House: r2c7=6
Naked Single: r9c6=6
Full House: r5c6=1
Naked Single: r1c8=7
Full House: r1c1=1
Naked Single: r3c3=7
Naked Single: r6c7=9
Naked Single: r3c9=4
Full House: r3c8=5
Naked Single: r5c3=4
Naked Single: r6c8=6
Naked Single: r8c7=4
Naked Single: r4c2=5
Naked Single: r7c3=3
Full House: r6c3=1
Full House: r6c1=3
Naked Single: r7c7=8
Naked Single: r7c8=9
Naked Single: r8c5=9
Full House: r8c8=1
Naked Single: r9c8=2
Full House: r4c8=4
Naked Single: r4c5=2
Full House: r5c5=5
Naked Single: r5c2=9
Naked Single: r9c1=8
Full House: r9c2=4
Full House: r3c2=8
Full House: r3c1=9
Naked Single: r7c9=6
Full House: r7c5=4
Full House: r9c5=3
Naked Single: r9c9=7
Full House: r5c9=8
Full House: r9c7=5
Naked Single: r4c7=7
Full House: r4c1=6
Full House: r5c1=7
Full House: r5c7=2
|
normal_sudoku_2431
|
...6...7.9.6.....237..92.6121.37.69..6.....177.....2.3.2..3.....9..8..3....1.4..9
|
142653978986741352375892461218375694463928517759416283821539746694287135537164829
|
Basic 9x9 Sudoku 2431
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 6 . . . 7 .
9 . 6 . . . . . 2
3 7 . . 9 2 . 6 1
2 1 . 3 7 . 6 9 .
. 6 . . . . . 1 7
7 . . . . . 2 . 3
. 2 . . 3 . . . .
. 9 . . 8 . . 3 .
. . . 1 . 4 . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
142653978986741352375892461218375694463928517759416283821539746694287135537164829 #1 Extreme (2644)
Hidden Single: r2c3=6
Hidden Single: r5c3=3
Hidden Single: r1c3=2
Hidden Single: r9c2=3
Hidden Single: r8c4=2
Hidden Single: r9c8=2
Hidden Single: r1c7=9
Hidden Single: r6c3=9
Hidden Single: r1c1=1
Hidden Single: r5c5=2
Hidden Single: r1c6=3
Hidden Single: r2c7=3
Naked Triple: 4,5,8 in r6c248 => r6c5<>4, r6c56<>5, r6c6<>8
Locked Candidates Type 1 (Pointing): 4 in b5 => r23c4<>4
Skyscraper: 4 in r3c7,r4c9 (connected by r34c3) => r1c9,r5c7<>4
Finned Swordfish: 4 r348 c379 fr8c1 => r7c3<>4
Finned Franken Swordfish: 8 r16b2 c248 fr1c9 fr2c6 => r2c8<>8
Discontinuous Nice Loop: 8 r4c9 -8- r1c9 -5- r2c8 -4- r6c8 =4= r4c9 => r4c9<>8
Sashimi Jellyfish: 8 r3459 c1347 fr4c6 fr5c6 => r6c4<>8
Grouped AIC: 5 5- r3c4 -8- r3c3 =8= r12c2 -8- r6c2 =8= r6c8 -8- r5c7 -5 => r3c7,r5c4<>5
XY-Wing: 4/8/5 in r2c8,r3c47 => r2c456<>5
2-String Kite: 5 in r3c3,r9c5 (connected by r1c5,r3c4) => r9c3<>5
XY-Wing: 4/8/5 in r2c8,r35c7 => r6c8<>5
Skyscraper: 5 in r3c3,r6c2 (connected by r36c4) => r12c2,r4c3<>5
Hidden Single: r2c8=5
Naked Single: r1c9=8
Full House: r3c7=4
Naked Single: r1c2=4
Full House: r1c5=5
Naked Single: r2c2=8
Full House: r3c3=5
Full House: r3c4=8
Full House: r6c2=5
Naked Single: r9c5=6
Naked Single: r2c4=7
Naked Single: r6c4=4
Naked Single: r6c5=1
Full House: r2c5=4
Full House: r2c6=1
Naked Single: r5c4=9
Full House: r7c4=5
Naked Single: r6c8=8
Full House: r6c6=6
Full House: r7c8=4
Naked Single: r8c6=7
Full House: r7c6=9
Naked Single: r5c7=5
Full House: r4c9=4
Naked Single: r7c9=6
Full House: r8c9=5
Naked Single: r5c6=8
Full House: r4c6=5
Full House: r4c3=8
Full House: r5c1=4
Naked Single: r8c7=1
Naked Single: r7c1=8
Naked Single: r9c3=7
Naked Single: r8c1=6
Full House: r8c3=4
Full House: r9c1=5
Full House: r7c3=1
Full House: r7c7=7
Full House: r9c7=8
|
normal_sudoku_3178
|
..29..........3.8.85.1.239.7.3..5...........342..........3.12....952.8......98.51
|
362987514941653782857142396793215468185476923426839175578361249619524837234798651
|
Basic 9x9 Sudoku 3178
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 9 . . . . .
. . . . . 3 . 8 .
8 5 . 1 . 2 3 9 .
7 . 3 . . 5 . . .
. . . . . . . . 3
4 2 . . . . . . .
. . . 3 . 1 2 . .
. . 9 5 2 . 8 . .
. . . . 9 8 . 5 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
362987514941653782857142396793215468185476923426839175578361249619524837234798651 #1 Extreme (16456) bf
Hidden Single: r3c7=3
Hidden Single: r6c5=3
Hidden Single: r2c9=2
Hidden Single: r9c1=2
Hidden Single: r7c9=9
Hidden Single: r1c5=8
Hidden Single: r8c8=3
Hidden Single: r9c2=3
Hidden Single: r2c5=5
Hidden Single: r1c1=3
Brute Force: r5c4=4
Hidden Single: r5c8=2
Hidden Single: r4c4=2
Hidden Single: r6c4=8
Hidden Single: r4c9=8
Finned X-Wing: 4 r29 c37 fr2c2 => r3c3<>4
2-String Kite: 4 in r3c9,r8c6 (connected by r1c6,r3c5) => r8c9<>4
Locked Candidates Type 2 (Claiming): 4 in c9 => r1c78,r2c7<>4
Locked Candidates Type 2 (Claiming): 4 in r2 => r1c2<>4
Forcing Chain Contradiction in r9c3 => r2c1<>6
r2c1=6 r2c1<>9 r2c2=9 r2c2<>4 r2c3=4 r9c3<>4
r2c1=6 r2c4<>6 r9c4=6 r9c3<>6
r2c1=6 r3c3<>6 r3c3=7 r9c3<>7
Forcing Chain Contradiction in r9c3 => r2c2<>6
r2c2=6 r2c2<>4 r2c3=4 r9c3<>4
r2c2=6 r2c4<>6 r9c4=6 r9c3<>6
r2c2=6 r3c3<>6 r3c3=7 r9c3<>7
Forcing Chain Contradiction in r9c3 => r2c2<>7
r2c2=7 r2c2<>4 r2c3=4 r9c3<>4
r2c2=7 r3c3<>7 r3c3=6 r9c3<>6
r2c2=7 r2c4<>7 r9c4=7 r9c3<>7
Forcing Chain Contradiction in r9c3 => r3c5<>6
r3c5=6 r3c5<>4 r7c5=4 r7c8<>4 r9c7=4 r9c3<>4
r3c5=6 r2c4<>6 r9c4=6 r9c3<>6
r3c5=6 r3c3<>6 r3c3=7 r9c3<>7
Sashimi Swordfish: 6 r239 c347 fr3c9 => r1c7<>6
Discontinuous Nice Loop: 7 r8c6 -7- r9c4 -6- r2c4 =6= r1c6 =4= r8c6 => r8c6<>7
Discontinuous Nice Loop: 7 r1c9 -7- r8c9 -6- r8c6 -4- r1c6 =4= r1c9 => r1c9<>7
Discontinuous Nice Loop: 7 r6c9 -7- r8c9 -6- r8c6 -4- r1c6 =4= r1c9 =5= r6c9 => r6c9<>7
Almost Locked Set Chain: 6- r3c3 {67} -7- r3c59 {467} -6- r6c9 {56} -5- r2369c3 {14567} -6 => r57c3<>6
Finned Franken Swordfish: 7 r38b8 c359 fr8c2 fr9c4 => r9c3<>7
AIC: 5 5- r1c7 =5= r1c9 =4= r1c6 -4- r8c6 =4= r8c2 -4- r9c3 -6- r3c3 =6= r3c9 -6- r6c9 -5 => r1c9,r56c7<>5
Hidden Single: r1c7=5
Hidden Single: r6c9=5
Hidden Pair: 5,8 in r57c3 => r5c3<>1, r7c3<>4, r7c3<>7
Locked Candidates Type 1 (Pointing): 7 in b7 => r1c2<>7
2-String Kite: 1 in r1c8,r6c3 (connected by r1c2,r2c3) => r6c8<>1
W-Wing: 6/1 in r1c2,r4c5 connected by 1 in r14c8 => r4c2<>6
W-Wing: 9/1 in r2c1,r4c2 connected by 1 in r8c12 => r2c2,r5c1<>9
Hidden Single: r2c1=9
Sashimi Swordfish: 7 c349 r239 fr8c9 => r9c7<>7
Hidden Single: r9c4=7
Full House: r2c4=6
Skyscraper: 6 in r3c9,r9c7 (connected by r39c3) => r8c9<>6
Naked Single: r8c9=7
Hidden Single: r7c2=7
Hidden Single: r7c3=8
Naked Single: r5c3=5
Hidden Single: r5c2=8
Hidden Single: r7c1=5
Hidden Single: r4c2=9
Locked Candidates Type 2 (Claiming): 6 in c9 => r1c8<>6
2-String Kite: 6 in r5c1,r9c7 (connected by r8c1,r9c3) => r5c7<>6
Turbot Fish: 6 r5c1 =6= r8c1 -6- r8c6 =6= r7c5 => r5c5<>6
Turbot Fish: 6 r4c5 =6= r7c5 -6- r7c8 =6= r9c7 => r4c7<>6
X-Wing: 6 r47 c58 => r6c8<>6
Naked Single: r6c8=7
Naked Single: r1c8=1
Naked Single: r1c2=6
Naked Single: r2c7=7
Naked Single: r1c9=4
Full House: r1c6=7
Full House: r3c9=6
Full House: r3c5=4
Full House: r3c3=7
Naked Single: r7c5=6
Full House: r7c8=4
Full House: r8c6=4
Full House: r4c8=6
Full House: r9c7=6
Full House: r9c3=4
Naked Single: r4c5=1
Full House: r4c7=4
Full House: r5c5=7
Naked Single: r8c2=1
Full House: r2c2=4
Full House: r2c3=1
Full House: r8c1=6
Full House: r6c3=6
Full House: r5c1=1
Naked Single: r6c6=9
Full House: r5c6=6
Full House: r5c7=9
Full House: r6c7=1
|
normal_sudoku_6970
|
4..7...3......8..2....2.1....34...7..5..37..974..6......1..9....7.1...5.3.....8..
|
492716538137548962568923147813495276256837419749261385681359724974182653325674891
|
Basic 9x9 Sudoku 6970
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . 7 . . . 3 .
. . . . . 8 . . 2
. . . . 2 . 1 . .
. . 3 4 . . . 7 .
. 5 . . 3 7 . . 9
7 4 . . 6 . . . .
. . 1 . . 9 . . .
. 7 . 1 . . . 5 .
3 . . . . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
492716538137548962568923147813495276256837419749261385681359724974182653325674891 #1 Extreme (55624) bf
Finned Swordfish: 4 r257 c578 fr7c9 => r8c7,r9c8<>4
Brute Force: r5c5=3
Forcing Net Contradiction in r8c7 => r7c5<>8
r7c5=8 r8c5<>8 r8c5=4 (r9c6<>4 r3c6=4 r3c6<>3 r8c6=3 r7c4<>3) (r8c9<>4) (r9c6<>4 r3c6=4 r3c9<>4) r8c3<>4 r9c3=4 r9c9<>4 r7c9=4 (r7c9<>7) r7c9<>3 r7c7=3 r7c7<>7 r7c5=7 r7c5<>8
Forcing Net Contradiction in r4 => r8c1<>8
r8c1=8 (r7c2<>8 r7c4=8 r5c4<>8 r5c4=2 r5c1<>2) (r8c1<>2) r8c5<>8 r8c5=4 r8c3<>4 r9c3=4 r9c3<>5 r7c1=5 r7c1<>2 r4c1=2 r4c1<>9
r8c1=8 (r8c5<>8 r8c5=4 r9c6<>4 r3c6=4 r3c6<>6) (r7c1<>8) r7c2<>8 r7c4=8 (r7c4<>6) (r5c4<>8 r5c4=2 r4c6<>2) (r5c4<>8 r5c4=2 r6c6<>2) r7c4<>3 r8c6=3 (r8c6<>6) r8c6<>2 r9c6=2 (r9c2<>2) r9c6<>6 r1c6=6 (r2c4<>6) r3c4<>6 r9c4=6 r9c2<>6 r9c2=9 r4c2<>9
r8c1=8 r8c5<>8 r4c5=8 r4c5<>9
Forcing Net Contradiction in r9c9 => r8c5=8
r8c5<>8 r4c5=8 (r4c1<>8) (r4c2<>8) r8c5<>8 r8c3=8 (r5c3<>8) r6c3<>8 r5c1=8 r5c1<>1 r5c8=1 r9c8<>1 r9c9=1
r8c5<>8 r8c5=4 (r7c5<>4) r8c3<>4 r9c3=4 r9c3<>5 r7c1=5 r7c5<>5 r7c5=7 r9c5<>7 r9c9=7
Finned Swordfish: 8 r147 c129 fr1c3 => r3c12<>8
Forcing Net Contradiction in r9c9 => r8c6<>4
r8c6=4 r8c6<>3 r3c6=3 (r2c4<>3 r2c2=3 r2c2<>1) r3c6<>4 r2c5=4 r2c5<>1 r2c1=1 r5c1<>1 r5c8=1 r9c8<>1 r9c9=1
r8c6=4 (r7c5<>4) r8c3<>4 r9c3=4 r9c3<>5 r7c1=5 r7c5<>5 r7c5=7 r9c5<>7 r9c9=7
Brute Force: r5c4=8
Forcing Net Contradiction in r1 => r4c1<>6
r4c1=6 r5c3<>6 r5c3=2 r1c3<>2 r1c2=2 r1c2<>9
r4c1=6 (r4c1<>8 r7c1=8 r7c2<>8) r5c3<>6 r5c3=2 (r6c3<>2) r1c3<>2 r1c2=2 r1c2<>8 r4c2=8 r6c3<>8 r6c3=9 r1c3<>9
r4c1=6 (r4c1<>9) (r4c1<>8 r7c1=8 r7c2<>8) r5c3<>6 r5c3=2 r1c3<>2 r1c2=2 r1c2<>8 r4c2=8 r4c2<>9 r4c5=9 r1c5<>9
r4c1=6 r4c1<>8 r7c1=8 (r7c1<>2 r8c1=2 r8c1<>9) r7c1<>5 r9c3=5 r9c3<>4 r8c3=4 r8c3<>9 r8c7=9 r1c7<>9
Forcing Net Contradiction in r1 => r8c3<>6
r8c3=6 r5c3<>6 r5c3=2 r1c3<>2 r1c2=2 r1c2<>9
r8c3=6 (r5c3<>6 r5c3=2 r6c3<>2) r8c3<>4 r9c3=4 r9c3<>5 r7c1=5 r7c1<>8 r4c1=8 r6c3<>8 r6c3=9 r1c3<>9
r8c3=6 (r5c3<>6 r5c3=2 r1c3<>2 r1c2=2 r9c2<>2 r9c2=9 r4c2<>9) r8c3<>4 r9c3=4 r9c3<>5 r7c1=5 r7c1<>8 r4c1=8 r4c1<>9 r4c5=9 r1c5<>9
r8c3=6 (r8c7<>6) (r5c3<>6 r5c3=2 r4c1<>2) (r5c3<>6 r5c3=2 r5c1<>2) r8c3<>4 r9c3=4 (r9c6<>4 r3c6=4 r3c6<>3 r8c6=3 r8c7<>3) r9c3<>5 r7c1=5 r7c1<>2 r8c1=2 r8c7<>2 r8c7=9 r1c7<>9
Forcing Net Contradiction in b5 => r9c3<>6
r9c3=6 (r5c3<>6 r5c3=2 r1c3<>2 r1c2=2 r1c2<>9) (r9c3<>4 r8c3=4 r8c3<>9) (r5c3<>6 r5c3=2 r4c1<>2) (r5c3<>6 r5c3=2 r5c1<>2) r9c3<>5 r7c1=5 (r7c1<>8 r4c1=8 r6c3<>8 r6c3=9 r1c3<>9) r7c1<>2 r8c1=2 r8c1<>9 r8c7=9 r1c7<>9 r1c5=9 r4c5<>9
r9c3=6 (r5c3<>6 r5c3=2 r6c3<>2) r9c3<>5 r7c1=5 r7c1<>8 r4c1=8 r6c3<>8 r6c3=9 r6c4<>9
Brute Force: r5c3=6
Forcing Net Contradiction in c8 => r9c5<>4
r9c5=4 (r2c5<>4) r9c5<>7 r9c9=7 (r9c9<>1 r9c8=1 r5c8<>1) r3c9<>7 r3c3=7 r2c3<>7 r2c7=7 r2c7<>4 r2c8=4 r5c8<>4 r5c8=2
r9c5=4 (r9c3<>4 r8c3=4 r8c9<>4 r7c9=4 r7c8<>4) (r9c3<>4 r8c3=4 r8c9<>4) r9c6<>4 r3c6=4 r3c6<>3 r8c6=3 r8c9<>3 r8c9=6 r7c8<>6 r7c8=2
Brute Force: r5c7=4
Forcing Net Contradiction in c7 => r1c3<>9
r1c3=9 (r6c3<>9) (r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r3c8<>8) (r1c3<>8) r1c3<>2 r1c2=2 r1c2<>8 r1c9=8 r3c9<>8 r3c3=8 r6c3<>8 r6c3=2 r5c1<>2 r5c8=2 r4c7<>2
r1c3=9 (r6c3<>9) (r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r3c8<>8) (r1c3<>8) r1c3<>2 r1c2=2 r1c2<>8 r1c9=8 r3c9<>8 r3c3=8 r6c3<>8 r6c3=2 r6c7<>2
r1c3=9 (r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r2c7<>9 r2c5=9 r2c5<>4 r7c5=4 r7c5<>7) (r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r3c8<>8) (r1c3<>8) r1c3<>2 r1c2=2 r1c2<>8 r1c9=8 r3c9<>8 r3c3=8 r3c3<>7 r3c9=7 r7c9<>7 r7c7=7 r7c7<>2
r1c3=9 (r1c7<>9) (r3c1<>9) (r3c2<>9) (r3c3<>9) r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r2c7<>9 r8c7=9 r8c7<>2
Forcing Net Contradiction in r1c9 => r4c9<>1
r4c9=1 (r4c9<>6 r4c7=6 r1c7<>6) r9c9<>1 r9c8=1 r9c8<>9 r8c7=9 r1c7<>9 r1c7=5 r1c9<>5
r4c9=1 (r6c9<>1 r6c6=1 r1c6<>1) (r4c9<>6 r4c7=6 r1c7<>6) r9c9<>1 r9c8=1 r9c8<>9 r8c7=9 r1c7<>9 r1c7=5 r1c6<>5 r1c6=6 r1c9<>6
r4c9=1 (r5c8<>1 r5c8=2 r4c7<>2) (r5c8<>1 r5c8=2 r6c7<>2) r9c9<>1 r9c8=1 r9c8<>9 r8c7=9 r8c7<>2 r7c7=2 r7c7<>7 r2c7=7 r3c9<>7 r3c3=7 r3c3<>8 r1c23=8 r1c9<>8
Forcing Net Contradiction in r8c9 => r3c9<>5
r3c9=5 (r3c9<>4) (r3c9<>8) r3c9<>7 r3c3=7 r3c3<>8 r3c8=8 r3c8<>4 r3c6=4 r3c6<>3 r8c6=3 r8c9<>3
r3c9=5 (r4c9<>5) (r1c9<>5) (r3c9<>8) r3c9<>7 r3c3=7 r3c3<>8 r3c8=8 r1c9<>8 r1c9=6 r4c9<>6 r4c9=8 r4c1<>8 r7c1=8 r7c1<>5 r9c3=5 r9c3<>4 r8c3=4 r8c9<>4
r3c9=5 (r1c9<>5) (r3c9<>8) r3c9<>7 r3c3=7 r3c3<>8 r3c8=8 r1c9<>8 r1c9=6 r8c9<>6
Forcing Net Contradiction in r8c9 => r3c9<>6
r3c9=6 (r3c9<>4) (r3c9<>8) r3c9<>7 r3c3=7 r3c3<>8 r3c8=8 r3c8<>4 r3c6=4 r3c6<>3 r8c6=3 r8c9<>3
r3c9=6 (r4c9<>6) (r1c9<>6) (r3c9<>8) r3c9<>7 r3c3=7 r3c3<>8 r3c8=8 r1c9<>8 r1c9=5 r4c9<>5 r4c9=8 r4c1<>8 r7c1=8 r7c1<>5 r9c3=5 r9c3<>4 r8c3=4 r8c9<>4
r3c9=6 r8c9<>6
Forcing Net Contradiction in b9 => r7c4<>5
r7c4=5 (r9c6<>5 r9c3=5 r9c3<>4) (r7c5<>5) r9c5<>5 r9c5=7 r7c5<>7 r7c5=4 (r7c8<>4) r9c6<>4 r9c9=4 r9c9<>1 r9c8=1 r5c8<>1 r5c8=2 r7c8<>2 r7c8=6
r7c4=5 (r7c4<>3 r8c6=3 r8c9<>3) (r9c4<>5) (r9c5<>5) r9c6<>5 r9c3=5 r9c3<>4 r8c3=4 r8c9<>4 r8c9=6
Almost Locked Set XY-Wing: A=r1479c5 {14579}, B=r2c12,r3c12 {13569}, C=r7c124789 {2345678}, X,Y=4,5, Z=1 => r2c5<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r1c2<>1
Forcing Net Contradiction in r7 => r9c5=7
r9c5<>7 r9c9=7 (r7c7<>7) r7c9<>7 r7c5=7 r7c5<>4
r9c5<>7 (r9c9=7 r3c9<>7 r3c3=7 r3c3<>8) (r9c9=7 r9c9<>1 r6c9=1 r6c9<>8) r9c5=5 r7c5<>5 r7c1=5 r7c1<>8 r4c1=8 r6c3<>8 r6c8=8 r3c8<>8 r3c9=8 r3c9<>4 r23c8=4 r7c8<>4
r9c5<>7 r9c9=7 r9c9<>1 (r6c9=1 r6c9<>3 r6c7=3 r7c7<>3) r9c8=1 r5c8<>1 r5c1=1 r2c1<>1 r2c2=1 r2c2<>3 r2c4=3 r7c4<>3 r7c9=3 r7c9<>4
Forcing Net Verity => r4c1=8
r7c5=4 r7c5<>5 r7c1=5 r7c1<>8 r4c1=8
r7c8=4 (r3c8<>4) (r7c5<>4 r7c5=5 r9c6<>5 r9c3=5 r2c3<>5) (r3c8<>4) r2c8<>4 r2c5=4 r3c6<>4 r3c9=4 r3c9<>7 r3c3=7 (r3c3<>8) (r3c3<>9) r2c3<>7 r2c3=9 (r3c1<>9) (r3c2<>9) r6c3<>9 r6c4=9 r3c4<>9 r3c8=9 r3c8<>8 r3c9=8 r3c9<>4 r3c6=4 r2c5<>4 r7c5=4 r7c5<>5 r7c1=5 r7c1<>8 r4c1=8
r7c9=4 (r7c5<>4 r7c5=5 r4c5<>5) (r7c9<>3) r7c9<>7 r7c7=7 r7c7<>3 r7c4=3 (r3c4<>3) r2c4<>3 r2c2=3 r3c2<>3 r3c6=3 r2c4<>3 r2c2=3 r2c2<>1 (r2c1=1 r4c1<>1) (r2c1=1 r5c1<>1 r5c1=2 r4c1<>2) r4c2=1 r4c5<>1 r4c5=9 r4c1<>9 r4c1=8
Hidden Single: r7c2=8
Sashimi Swordfish: 9 r148 c257 fr8c1 fr8c3 => r9c2<>9
Finned Swordfish: 9 r369 c348 fr3c1 fr3c2 => r2c3<>9
Sue de Coq: r9c46 - {2456} (r9c2 - {26}, r7c5 - {45}) => r9c38<>2, r9c89<>6
Discontinuous Nice Loop: 9 r2c8 -9- r9c8 -1- r9c9 -4- r9c6 =4= r3c6 -4- r2c5 =4= r2c8 => r2c8<>9
Discontinuous Nice Loop: 4 r3c9 -4- r3c6 =4= r9c6 -4- r7c5 -5- r7c1 =5= r9c3 -5- r2c3 -7- r2c7 =7= r3c9 => r3c9<>4
Locked Candidates Type 1 (Pointing): 4 in b3 => r7c8<>4
Discontinuous Nice Loop: 5 r2c1 -5- r7c1 =5= r7c5 =4= r2c5 -4- r2c8 -6- r7c8 -2- r5c8 -1- r5c1 =1= r2c1 => r2c1<>5
Discontinuous Nice Loop: 5 r3c6 -5- r3c1 =5= r7c1 -5- r7c5 -4- r2c5 =4= r3c6 => r3c6<>5
Discontinuous Nice Loop: 2 r7c1 -2- r7c8 -6- r2c8 -4- r2c5 =4= r7c5 =5= r7c1 => r7c1<>2
Grouped Continuous Nice Loop: 2/6/9 9= r8c1 =2= r5c1 -2- r6c3 -9- r89c3 =9= r8c1 =2 => r4c2<>2, r8c1<>6, r3c3<>9
Discontinuous Nice Loop: 6 r2c2 -6- r2c8 -4- r2c5 =4= r7c5 =5= r7c1 =6= r9c2 -6- r2c2 => r2c2<>6
Discontinuous Nice Loop: 1 r4c6 -1- r4c2 =1= r5c1 =2= r5c8 -2- r4c7 =2= r4c6 => r4c6<>1
Naked Triple: 2,5,6 in r4c679 => r4c5<>5
XYZ-Wing: 2/5/9 in r4c6,r6c34 => r6c6<>2
Sashimi X-Wing: 5 c15 r37 fr1c5 fr2c5 => r3c4<>5
Locked Candidates Type 2 (Claiming): 5 in r3 => r12c3<>5
Naked Single: r2c3=7
Hidden Single: r7c7=7
Hidden Single: r3c9=7
Turbot Fish: 2 r5c1 =2= r8c1 -2- r8c7 =2= r7c8 => r5c8<>2
Naked Single: r5c8=1
Full House: r5c1=2
Naked Single: r9c8=9
Naked Single: r6c3=9
Full House: r4c2=1
Naked Single: r8c1=9
Naked Single: r4c5=9
Hidden Single: r2c1=1
Hidden Single: r6c6=1
Hidden Single: r9c9=1
Hidden Single: r1c5=1
XY-Wing: 4/5/6 in r1c6,r2c58 => r1c79,r2c4<>6
Locked Candidates Type 2 (Claiming): 6 in r2 => r3c8<>6
Hidden Rectangle: 3/9 in r2c24,r3c24 => r3c4<>3
Finned X-Wing: 6 r19 c26 fr9c4 => r8c6<>6
Locked Candidates Type 2 (Claiming): 6 in r8 => r7c89<>6
Naked Single: r7c8=2
Naked Single: r6c8=8
Naked Single: r3c8=4
Full House: r2c8=6
Hidden Single: r3c3=8
Naked Single: r1c3=2
Naked Single: r8c3=4
Full House: r9c3=5
Naked Single: r7c1=6
Full House: r3c1=5
Full House: r9c2=2
Naked Single: r7c4=3
Naked Single: r9c4=6
Full House: r9c6=4
Naked Single: r7c9=4
Full House: r7c5=5
Full House: r8c6=2
Full House: r2c5=4
Naked Single: r3c4=9
Naked Single: r4c6=5
Full House: r6c4=2
Full House: r2c4=5
Naked Single: r1c6=6
Full House: r3c6=3
Full House: r3c2=6
Naked Single: r4c9=6
Full House: r4c7=2
Naked Single: r2c7=9
Full House: r2c2=3
Full House: r1c2=9
Naked Single: r8c9=3
Full House: r8c7=6
Naked Single: r1c7=5
Full House: r1c9=8
Full House: r6c9=5
Full House: r6c7=3
|
normal_sudoku_1491
|
..4.6.5.78..1.....9....7.....3.5.6.9..52....1728.19..4......41...6....38.4..8..65
|
134862597867195243952347186413758629695234871728619354389576412576421938241983765
|
Basic 9x9 Sudoku 1491
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 4 . 6 . 5 . 7
8 . . 1 . . . . .
9 . . . . 7 . . .
. . 3 . 5 . 6 . 9
. . 5 2 . . . . 1
7 2 8 . 1 9 . . 4
. . . . . . 4 1 .
. . 6 . . . . 3 8
. 4 . . 8 . . 6 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
134862597867195243952347186413758629695234871728619354389576412576421938241983765 #1 Easy (208)
Naked Single: r6c3=8
Naked Single: r7c9=2
Naked Single: r4c2=1
Naked Single: r6c7=3
Naked Single: r6c8=5
Full House: r6c4=6
Naked Single: r1c2=3
Naked Single: r4c1=4
Naked Single: r4c6=8
Naked Single: r5c1=6
Full House: r5c2=9
Naked Single: r1c6=2
Naked Single: r4c4=7
Full House: r4c8=2
Naked Single: r1c1=1
Naked Single: r3c3=2
Naked Single: r2c3=7
Naked Single: r7c3=9
Full House: r9c3=1
Naked Single: r9c6=3
Naked Single: r5c6=4
Full House: r5c5=3
Naked Single: r7c4=5
Naked Single: r7c5=7
Naked Single: r9c1=2
Naked Single: r9c4=9
Full House: r9c7=7
Full House: r8c7=9
Naked Single: r2c6=5
Naked Single: r3c5=4
Naked Single: r7c1=3
Full House: r8c1=5
Naked Single: r7c6=6
Full House: r8c6=1
Full House: r7c2=8
Full House: r8c2=7
Naked Single: r1c4=8
Full House: r1c8=9
Naked Single: r8c4=4
Full House: r8c5=2
Full House: r2c5=9
Full House: r3c4=3
Naked Single: r5c7=8
Full House: r5c8=7
Naked Single: r2c7=2
Full House: r3c7=1
Naked Single: r2c2=6
Full House: r3c2=5
Naked Single: r3c8=8
Full House: r2c8=4
Full House: r3c9=6
Full House: r2c9=3
|
normal_sudoku_5282
|
.2...3..4..56...1....45...7.6.9.4..2...7..9..9...1.7..2.439...83.6..8....8.......
|
621873594475629813893451627167984352542736981938215746254397168316548279789162435
|
Basic 9x9 Sudoku 5282
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . . 3 . . 4
. . 5 6 . . . 1 .
. . . 4 5 . . . 7
. 6 . 9 . 4 . . 2
. . . 7 . . 9 . .
9 . . . 1 . 7 . .
2 . 4 3 9 . . . 8
3 . 6 . . 8 . . .
. 8 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
621873594475629813893451627167984352542736981938215746254397168316548279789162435 #1 Extreme (10622)
Hidden Single: r4c4=9
Locked Candidates Type 1 (Pointing): 4 in b6 => r89c8<>4
Turbot Fish: 9 r1c8 =9= r1c3 -9- r9c3 =9= r8c2 => r8c8<>9
Finned X-Wing: 6 c59 r59 fr6c9 => r5c8<>6
Almost Locked Set XZ-Rule: A=r189c4 {1258}, B=r12c5 {278}, X=8, Z=2 => r89c5<>2
Forcing Chain Contradiction in c7 => r1c3<>8
r1c3=8 r1c3<>9 r1c8=9 r2c9<>9 r2c9=3 r2c7<>3
r1c3=8 r1c3<>9 r1c8=9 r2c9<>9 r2c9=3 r3c7<>3
r1c3=8 r1c4<>8 r6c4=8 r4c5<>8 r4c5=3 r4c7<>3
r1c3=8 r1c5<>8 r1c5=7 r8c5<>7 r8c5=4 r8c7<>4 r9c7=4 r9c7<>3
Forcing Chain Contradiction in c7 => r2c7<>2
r2c7=2 r2c7<>3
r2c7=2 r2c56<>2 r3c6=2 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r3c7<>3
r2c7=2 r2c5<>2 r5c5=2 r5c5<>3 r4c5=3 r4c7<>3
r2c7=2 r2c5<>2 r5c5=2 r5c5<>6 r9c5=6 r9c5<>4 r9c7=4 r9c7<>3
Locked Candidates Type 1 (Pointing): 2 in b3 => r3c6<>2
Forcing Chain Contradiction in c7 => r4c3<>3
r4c3=3 r4c5<>3 r4c5=8 r6c4<>8 r1c4=8 r1c4<>1 r3c6=1 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r2c7<>3
r4c3=3 r4c5<>3 r4c5=8 r6c4<>8 r1c4=8 r1c4<>1 r3c6=1 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r3c7<>3
r4c3=3 r4c7<>3
r4c3=3 r4c5<>3 r5c5=3 r5c5<>6 r9c5=6 r9c5<>4 r9c7=4 r9c7<>3
Forcing Chain Contradiction in r9 => r4c8<>3
r4c8=3 r4c5<>3 r5c5=3 r5c5<>6 r9c5=6 r9c5<>4 r9c7=4 r9c7<>3
r4c8=3 r9c8<>3
r4c8=3 r4c5<>3 r4c5=8 r6c4<>8 r1c4=8 r1c4<>1 r3c6=1 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r9c9<>3
Forcing Chain Contradiction in c7 => r5c5<>8
r5c5=8 r6c4<>8 r1c4=8 r1c4<>1 r3c6=1 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r2c7<>3
r5c5=8 r6c4<>8 r1c4=8 r1c4<>1 r3c6=1 r3c6<>9 r2c6=9 r2c9<>9 r2c9=3 r3c7<>3
r5c5=8 r5c5<>3 r4c5=3 r4c7<>3
r5c5=8 r5c5<>6 r9c5=6 r9c5<>4 r9c7=4 r9c7<>3
Forcing Chain Contradiction in r7 => r6c2<>5
r6c2=5 r7c2<>5
r6c2=5 r6c4<>5 r89c4=5 r7c6<>5
r6c2=5 r4c1<>5 r4c78=5 r56c9<>5 r89c9=5 r7c7<>5
r6c2=5 r4c1<>5 r4c78=5 r56c9<>5 r89c9=5 r7c8<>5
Grouped Discontinuous Nice Loop: 8 r4c1 -8- r5c13 =8= r5c8 =4= r6c8 -4- r6c2 -3- r23c2 =3= r3c3 =8= r123c1 -8- r4c1 => r4c1<>8
Forcing Chain Contradiction in b7 => r7c7<>5
r7c7=5 r7c2<>5
r7c7=5 r1c7<>5 r1c8=5 r1c8<>9 r1c3=9 r9c3<>9 r8c2=9 r8c2<>5
r7c7=5 r89c9<>5 r56c9=5 r4c78<>5 r4c1=5 r9c1<>5
Forcing Chain Contradiction in r8 => r1c7<>6
r1c7=6 r1c7<>5 r1c8=5 r1c8<>9 r1c3=9 r9c3<>9 r8c2=9 r8c2<>1
r1c7=6 r1c7<>5 r1c8=5 r4c8<>5 r4c8=8 r4c5<>8 r6c4=8 r1c4<>8 r1c4=1 r8c4<>1
r1c7=6 r7c7<>6 r7c7=1 r8c7<>1
r1c7=6 r7c7<>6 r7c7=1 r8c9<>1
Discontinuous Nice Loop: 5 r9c7 -5- r1c7 -8- r1c5 -7- r8c5 -4- r8c7 =4= r9c7 => r9c7<>5
Forcing Chain Contradiction in r4c7 => r9c8<>6
r9c8=6 r7c7<>6 r7c7=1 r4c7<>1
r9c8=6 r9c5<>6 r5c5=6 r5c5<>3 r4c5=3 r4c7<>3
r9c8=6 r9c8<>9 r13c8=9 r2c9<>9 r2c9=3 r2c7<>3 r2c7=8 r1c7<>8 r1c7=5 r4c7<>5
r9c8=6 r9c8<>9 r13c8=9 r2c9<>9 r2c9=3 r2c7<>3 r2c7=8 r4c7<>8
Forcing Net Contradiction in r8 => r1c7=5
r1c7<>5 r1c7=8 r2c7<>8 r2c7=3 r2c9<>3 r2c9=9 r8c9<>9 r8c2=9 r8c2<>1
r1c7<>5 r1c7=8 r1c4<>8 r1c4=1 r8c4<>1
r1c7<>5 (r1c7=8 r1c5<>8 r1c5=7 r8c5<>7) r1c8=5 (r7c8<>5) r1c8<>9 r1c3=9 (r2c2<>9) r3c2<>9 r8c2=9 r8c2<>7 r8c8=7 r7c8<>7 r7c8=6 r7c7<>6 r7c7=1 r8c7<>1
r1c7<>5 (r1c7=8 r1c5<>8 r1c5=7 r8c5<>7) r1c8=5 (r7c8<>5) r1c8<>9 r1c3=9 (r2c2<>9) r3c2<>9 r8c2=9 r8c2<>7 r8c8=7 r7c8<>7 r7c8=6 r7c7<>6 r7c7=1 r8c9<>1
Forcing Net Verity => r1c5=7
r1c1=7 (r9c1<>7) (r4c1<>7 r4c3=7 r9c3<>7) r1c1<>6 r1c8=6 r1c8<>9 r1c3=9 r9c3<>9 r9c3=1 r9c1<>1 r9c1=5 (r7c2<>5) r4c1<>5 r4c8=5 r7c8<>5 r7c6=5 (r8c4<>5) r9c4<>5 r6c4=5 r6c4<>8 r1c4=8 r1c5<>8 r1c5=7
r1c3=7 (r1c5<>7 r1c5=8 r1c4<>8 r1c4=1 r3c6<>1 r3c6=9 r3c3<>9 r9c3=9 r9c9<>9) (r1c5<>7 r1c5=8 r4c5<>8) r1c3<>9 r1c8=9 r2c9<>9 r2c9=3 (r3c7<>3 r9c7=3 r9c7<>4 r9c5=4 r8c5<>4 r8c5=7 r9c6<>7 r2c6=7 r2c2<>7 r7c2=7 r7c2<>5) r2c7<>3 r2c7=8 r4c7<>8 (r4c7=1 r5c9<>1) r4c3=8 r5c3<>8 r5c8=8 (r5c8<>3) (r5c1<>8) r5c8<>4 r6c8=4 (r6c2<>4 r6c2=3 r5c2<>3) (r6c2<>4 r6c2=3 r3c2<>3) (r6c8<>3) r6c8<>6 r6c9=6 (r6c6<>6) r5c9<>6 r5c9=3 r2c9<>3 (r2c2=3 r6c2<>3 r6c2=4 r5c2<>4) r2c9=9 r1c8<>9 r1c3=9 r9c3<>9 r9c8=9 r9c8<>3 r3c8=3 r2c9<>3 (r2c2=3 r6c2<>3 r6c2=4 r5c2<>4) r2c9=9 r1c8<>9 r1c3=9 r3c2<>9 r3c2=1 r5c2<>1 r5c2=5 r4c1<>5 r4c8=5 (r5c9<>5) (r4c8<>8) r7c8<>5 r7c6=5 (r8c4<>5) r9c4<>5 r6c4=5 r6c4<>8 r1c4=8 r1c5<>8 r1c5=7
r1c5=7 r1c5=7
Naked Single: r8c5=4
Naked Single: r9c5=6
Hidden Single: r9c7=4
Locked Candidates Type 2 (Claiming): 6 in c9 => r6c8<>6
Hidden Pair: 4,7 in r2c12 => r2c1<>8, r2c2<>3, r2c2<>9
Locked Candidates Type 1 (Pointing): 3 in b1 => r3c78<>3
Sue de Coq: r89c9 - {1359} (r2c9 - {39}, r7c78,r8c78 - {12567}) => r9c8<>2, r9c8<>5, r9c8<>7, r56c9<>3
Locked Candidates Type 1 (Pointing): 2 in b9 => r8c4<>2
Hidden Rectangle: 5/6 in r5c69,r6c69 => r5c6<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r6c89<>5
Naked Single: r6c9=6
Hidden Single: r5c6=6
Hidden Rectangle: 2/5 in r6c46,r9c46 => r9c4<>5
Sue de Coq: r4c78 - {1358} (r4c5 - {38}, r5c9 - {15}) => r5c8<>5, r4c3<>8
Naked Triple: 1,7,9 in r149c3 => r35c3<>1, r3c3<>9
XY-Chain: 5 5- r4c8 -8- r4c5 -3- r5c5 -2- r2c5 -8- r1c4 -1- r8c4 -5 => r8c8<>5
Discontinuous Nice Loop: 8 r3c8 -8- r2c7 -3- r2c9 -9- r8c9 =9= r8c2 =7= r8c8 =2= r3c8 => r3c8<>8
Discontinuous Nice Loop: 9 r3c8 -9- r3c2 =9= r8c2 =7= r8c8 =2= r3c8 => r3c8<>9
X-Wing: 9 c38 r19 => r9c9<>9
Sue de Coq: r3c12 - {13689} (r3c378 - {2368}, r1c3 - {19}) => r1c1<>1
Discontinuous Nice Loop: 3 r6c3 -3- r3c3 =3= r3c2 =9= r3c6 -9- r2c6 -2- r2c5 =2= r5c5 -2- r5c3 =2= r6c3 => r6c3<>3
Naked Triple: 2,5,8 in r6c346 => r6c8<>8
Discontinuous Nice Loop: 5 r8c9 -5- r8c4 -1- r1c4 =1= r1c3 =9= r1c8 -9- r9c8 =9= r8c9 => r8c9<>5
2-String Kite: 5 in r4c1,r9c9 (connected by r4c8,r5c9) => r9c1<>5
Locked Candidates Type 1 (Pointing): 5 in b7 => r5c2<>5
W-Wing: 1/5 in r5c9,r8c4 connected by 5 in r9c69 => r8c9<>1
Naked Single: r8c9=9
Naked Single: r2c9=3
Naked Single: r9c8=3
Naked Single: r2c7=8
Naked Single: r6c8=4
Naked Single: r2c5=2
Naked Single: r5c8=8
Naked Single: r6c2=3
Naked Single: r2c6=9
Naked Single: r5c5=3
Full House: r4c5=8
Naked Single: r4c8=5
Naked Single: r5c3=2
Naked Single: r3c6=1
Full House: r1c4=8
Naked Single: r5c9=1
Full House: r4c7=3
Full House: r9c9=5
Naked Single: r6c3=8
Naked Single: r3c2=9
Naked Single: r1c1=6
Naked Single: r5c2=4
Full House: r5c1=5
Naked Single: r3c3=3
Naked Single: r1c3=1
Full House: r1c8=9
Naked Single: r3c1=8
Naked Single: r2c2=7
Full House: r2c1=4
Naked Single: r4c3=7
Full House: r4c1=1
Full House: r9c3=9
Full House: r9c1=7
Naked Single: r9c6=2
Full House: r9c4=1
Naked Single: r6c6=5
Full House: r6c4=2
Full House: r8c4=5
Full House: r7c6=7
Naked Single: r8c2=1
Full House: r7c2=5
Naked Single: r7c8=6
Full House: r7c7=1
Naked Single: r8c7=2
Full House: r3c7=6
Full House: r3c8=2
Full House: r8c8=7
|
normal_sudoku_4743
|
.2..86..1..7..438.9..3..62.7..41...28..6...7...9..7....3..51..85.....4....684..3.
|
324986751657124389981375624763418592845692173219537846432751968598263417176849235
|
Basic 9x9 Sudoku 4743
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . 8 6 . . 1
. . 7 . . 4 3 8 .
9 . . 3 . . 6 2 .
7 . . 4 1 . . . 2
8 . . 6 . . . 7 .
. . 9 . . 7 . . .
. 3 . . 5 1 . . 8
5 . . . . . 4 . .
. . 6 8 4 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
324986751657124389981375624763418592845692173219537846432751968598263417176849235 #1 Easy (214)
Hidden Single: r3c8=2
Naked Single: r3c5=7
Naked Single: r3c6=5
Naked Single: r1c4=9
Naked Single: r3c9=4
Naked Single: r2c5=2
Full House: r2c4=1
Naked Single: r1c8=5
Naked Single: r6c5=3
Naked Single: r2c1=6
Naked Single: r1c7=7
Full House: r2c9=9
Full House: r2c2=5
Naked Single: r5c5=9
Full House: r8c5=6
Naked Single: r4c2=6
Naked Single: r4c6=8
Naked Single: r5c6=2
Full House: r6c4=5
Naked Single: r8c9=7
Naked Single: r4c8=9
Naked Single: r9c6=9
Full House: r8c6=3
Naked Single: r6c9=6
Naked Single: r8c4=2
Full House: r7c4=7
Naked Single: r9c9=5
Full House: r5c9=3
Naked Single: r4c7=5
Full House: r4c3=3
Naked Single: r7c8=6
Naked Single: r8c8=1
Full House: r6c8=4
Naked Single: r5c7=1
Full House: r6c7=8
Naked Single: r1c3=4
Full House: r1c1=3
Naked Single: r8c3=8
Full House: r8c2=9
Naked Single: r9c7=2
Full House: r7c7=9
Naked Single: r6c2=1
Full House: r6c1=2
Naked Single: r5c2=4
Full House: r5c3=5
Naked Single: r7c3=2
Full House: r3c3=1
Full House: r3c2=8
Full House: r9c2=7
Full House: r9c1=1
Full House: r7c1=4
|
normal_sudoku_1745
|
...59........2.9....746..........1.5......37..5.6.9...1.3..2..8.......46.9.......
|
314598627685327914927461853839274165246185379751639482163742598578913246492856731
|
Basic 9x9 Sudoku 1745
|
puzzles2_17_clue
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 5 9 . . . .
. . . . 2 . 9 . .
. . 7 4 6 . . . .
. . . . . . 1 . 5
. . . . . . 3 7 .
. 5 . 6 . 9 . . .
1 . 3 . . 2 . . 8
. . . . . . . 4 6
. 9 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
314598627685327914927461853839274165246185379751639482163742598578913246492856731 #1 Medium (754)
Hidden Single: r1c5=9
Hidden Single: r4c8=6
Hidden Single: r7c2=6
Hidden Single: r9c6=6
Hidden Single: r1c7=6
Hidden Single: r3c1=9
Hidden Single: r5c9=9
Hidden Single: r7c8=9
Naked Single: r7c4=7
Naked Single: r7c7=5
Full House: r7c5=4
Hidden Single: r8c4=9
Hidden Single: r6c7=4
Naked Single: r6c9=2
Full House: r6c8=8
Naked Single: r6c3=1
Hidden Single: r4c3=9
Hidden Single: r3c8=5
Hidden Single: r3c7=8
Hidden Single: r3c2=2
Hidden Single: r1c8=2
Locked Candidates Type 1 (Pointing): 7 in b2 => r4c6<>7
Locked Candidates Type 1 (Pointing): 7 in b3 => r9c9<>7
Locked Candidates Type 1 (Pointing): 1 in b9 => r9c45<>1
Locked Candidates Type 1 (Pointing): 3 in b9 => r9c45<>3
Naked Single: r9c4=8
Naked Single: r9c5=5
Hidden Single: r5c6=5
Hidden Single: r4c6=4
Naked Pair: 1,3 in r2c4,r3c6 => r12c6<>1, r12c6<>3
Naked Pair: 1,3 in r2c8,r3c9 => r12c9<>1, r12c9<>3
Hidden Single: r1c2=1
Hidden Single: r1c1=3
Naked Single: r6c1=7
Full House: r6c5=3
Naked Single: r4c4=2
Naked Single: r8c5=1
Full House: r8c6=3
Naked Single: r4c1=8
Naked Single: r5c4=1
Full House: r2c4=3
Naked Single: r5c5=8
Full House: r4c5=7
Full House: r4c2=3
Naked Single: r3c6=1
Full House: r3c9=3
Naked Single: r5c2=4
Naked Single: r2c8=1
Full House: r9c8=3
Naked Single: r9c9=1
Naked Single: r2c2=8
Full House: r8c2=7
Naked Single: r1c3=4
Naked Single: r2c6=7
Full House: r1c6=8
Full House: r1c9=7
Full House: r2c9=4
Naked Single: r8c7=2
Full House: r9c7=7
Naked Single: r9c3=2
Full House: r9c1=4
Naked Single: r8c1=5
Full House: r8c3=8
Naked Single: r5c3=6
Full House: r2c3=5
Full House: r2c1=6
Full House: r5c1=2
|
normal_sudoku_3221
|
.4......99....3.....68...5..3..8..1...4..2.7...76....84...56.8..6..2...5..59..1..
|
741265839958473621326891457632789514894512376517634298473156982169328745285947163
|
Basic 9x9 Sudoku 3221
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . . . . . . 9
9 . . . . 3 . . .
. . 6 8 . . . 5 .
. 3 . . 8 . . 1 .
. . 4 . . 2 . 7 .
. . 7 6 . . . . 8
4 . . . 5 6 . 8 .
. 6 . . 2 . . . 5
. . 5 9 . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
741265839958473621326891457632789514894512376517634298473156982169328745285947163 #1 Extreme (22486) bf
Brute Force: r5c3=4
Brute Force: r5c2=9
Naked Single: r4c3=2
Hidden Single: r5c1=8
Hidden Single: r4c1=6
Naked Single: r4c9=4
Locked Candidates Type 1 (Pointing): 1 in b4 => r6c56<>1
Locked Candidates Type 1 (Pointing): 5 in b4 => r6c67<>5
Empty Rectangle: 4 in b3 (r28c4) => r8c7<>4
Locked Candidates Type 1 (Pointing): 4 in b9 => r2c8<>4
Hidden Rectangle: 4/9 in r3c56,r6c56 => r3c5<>4
Discontinuous Nice Loop: 2/3/7 r3c7 =4= r3c6 -4- r6c6 -9- r4c6 =9= r4c7 =5= r5c7 =6= r5c9 -6- r9c9 =6= r9c8 =4= r8c8 -4- r8c4 =4= r2c4 -4- r2c7 =4= r3c7 => r3c7<>2, r3c7<>3, r3c7<>7
Naked Single: r3c7=4
AIC: 5 5- r1c6 =5= r4c6 =9= r4c7 -9- r6c8 =9= r8c8 =4= r9c8 =6= r9c9 -6- r5c9 =6= r5c7 =5= r5c4 -5 => r12c4,r4c6<>5
Hidden Single: r2c2=5
Naked Single: r6c2=1
Full House: r6c1=5
Hidden Single: r1c6=5
Hidden Single: r9c2=8
Hidden Single: r8c6=8
Hidden Single: r3c6=1
Hidden Single: r5c5=1
Hidden Single: r2c9=1
Naked Single: r2c3=8
Hidden Single: r3c5=9
Hidden Single: r1c7=8
Turbot Fish: 7 r2c7 =7= r3c9 -7- r3c2 =7= r7c2 => r7c7<>7
Finned X-Wing: 2 c29 r37 fr9c9 => r7c7<>2
XY-Chain: 3 3- r6c5 -4- r6c6 -9- r4c6 -7- r4c4 -5- r4c7 -9- r7c7 -3 => r6c7<>3
AIC: 7 7- r4c4 -5- r4c7 -9- r6c8 =9= r8c8 =4= r8c4 -4- r9c6 -7 => r4c6,r78c4<>7
Naked Single: r4c6=9
Naked Single: r4c7=5
Full House: r4c4=7
Naked Single: r6c6=4
Full House: r9c6=7
Naked Single: r1c4=2
Naked Single: r6c5=3
Full House: r5c4=5
Naked Single: r2c4=4
Naked Single: r9c5=4
Hidden Single: r8c8=4
Hidden Single: r6c8=9
Full House: r6c7=2
Hidden Single: r2c8=2
Naked Triple: 1,3,9 in r7c347 => r7c9<>3
X-Wing: 7 c29 r37 => r3c1<>7
Naked Pair: 2,3 in r39c1 => r18c1<>3
Skyscraper: 3 in r1c8,r3c1 (connected by r9c18) => r1c3,r3c9<>3
Naked Single: r1c3=1
Naked Single: r3c9=7
Naked Single: r1c1=7
Naked Single: r2c7=6
Full House: r1c8=3
Full House: r1c5=6
Full House: r2c5=7
Full House: r9c8=6
Naked Single: r3c2=2
Full House: r3c1=3
Full House: r7c2=7
Naked Single: r7c9=2
Naked Single: r8c1=1
Full House: r9c1=2
Full House: r9c9=3
Full House: r5c9=6
Full House: r5c7=3
Naked Single: r8c4=3
Full House: r7c4=1
Naked Single: r7c7=9
Full House: r7c3=3
Full House: r8c3=9
Full House: r8c7=7
|
normal_sudoku_629
|
.4..3....835......6.1.....51..9..4.6...62..8.5..1..972.18....3..9.......2...6...8
|
947532861835416297621897345182973456479625183563148972718254639396781524254369718
|
Basic 9x9 Sudoku 629
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . . 3 . . . .
8 3 5 . . . . . .
6 . 1 . . . . . 5
1 . . 9 . . 4 . 6
. . . 6 2 . . 8 .
5 . . 1 . . 9 7 2
. 1 8 . . . . 3 .
. 9 . . . . . . .
2 . . . 6 . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
947532861835416297621897345182973456479625183563148972718254639396781524254369718 #1 Easy (270)
Naked Single: r6c8=7
Naked Single: r5c2=7
Naked Single: r4c8=5
Naked Single: r3c2=2
Naked Single: r9c2=5
Naked Single: r4c2=8
Full House: r6c2=6
Naked Single: r4c5=7
Naked Single: r4c6=3
Full House: r4c3=2
Hidden Single: r3c7=3
Naked Single: r5c7=1
Full House: r5c9=3
Naked Single: r9c7=7
Hidden Single: r7c7=6
Naked Single: r2c7=2
Naked Single: r1c7=8
Full House: r8c7=5
Hidden Single: r8c3=6
Hidden Single: r5c6=5
Hidden Single: r6c3=3
Naked Single: r9c3=4
Naked Single: r5c3=9
Full House: r1c3=7
Full House: r5c1=4
Full House: r1c1=9
Naked Single: r7c1=7
Full House: r8c1=3
Naked Single: r9c4=3
Naked Single: r1c9=1
Naked Single: r1c8=6
Naked Single: r8c9=4
Naked Single: r1c6=2
Full House: r1c4=5
Naked Single: r7c9=9
Full House: r2c9=7
Naked Single: r7c6=4
Naked Single: r9c8=1
Full House: r8c8=2
Full House: r9c6=9
Naked Single: r2c4=4
Naked Single: r6c6=8
Full House: r6c5=4
Naked Single: r7c4=2
Full House: r7c5=5
Naked Single: r2c8=9
Full House: r3c8=4
Naked Single: r3c6=7
Naked Single: r2c5=1
Full House: r2c6=6
Full House: r8c6=1
Naked Single: r3c4=8
Full House: r3c5=9
Full House: r8c5=8
Full House: r8c4=7
|
normal_sudoku_1720
|
35.....21.1.....9.7..12....6.....1.......9.....97..635.3.94..56.6....8..2.4.3....
|
356894721412657398798123564623485179571369482849712635137948256965271843284536917
|
Basic 9x9 Sudoku 1720
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 5 . . . . . 2 1
. 1 . . . . . 9 .
7 . . 1 2 . . . .
6 . . . . . 1 . .
. . . . . 9 . . .
. . 9 7 . . 6 3 5
. 3 . 9 4 . . 5 6
. 6 . . . . 8 . .
2 . 4 . 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
356894721412657398798123564623485179571369482849712635137948256965271843284536917 #1 Easy (270)
Hidden Single: r1c9=1
Hidden Single: r3c2=9
Hidden Single: r4c9=9
Naked Single: r9c9=7
Naked Single: r7c7=2
Naked Single: r9c2=8
Naked Single: r9c7=9
Naked Single: r9c8=1
Naked Single: r7c1=1
Naked Single: r8c8=4
Full House: r8c9=3
Naked Single: r7c3=7
Full House: r7c6=8
Naked Single: r8c3=5
Full House: r8c1=9
Naked Single: r8c4=2
Hidden Single: r1c5=9
Hidden Single: r3c8=6
Naked Single: r3c3=8
Naked Single: r1c3=6
Naked Single: r2c1=4
Full House: r2c3=2
Naked Single: r3c9=4
Naked Single: r2c9=8
Full House: r5c9=2
Naked Single: r6c1=8
Full House: r5c1=5
Naked Single: r4c3=3
Full House: r5c3=1
Naked Single: r1c7=7
Naked Single: r6c5=1
Naked Single: r1c6=4
Full House: r1c4=8
Naked Single: r5c7=4
Naked Single: r8c5=7
Full House: r8c6=1
Naked Single: r6c6=2
Full House: r6c2=4
Naked Single: r5c2=7
Full House: r4c2=2
Naked Single: r4c6=5
Naked Single: r5c8=8
Full House: r4c8=7
Naked Single: r3c6=3
Full House: r3c7=5
Full House: r2c7=3
Naked Single: r4c4=4
Full House: r4c5=8
Naked Single: r9c6=6
Full House: r2c6=7
Full House: r9c4=5
Naked Single: r5c5=6
Full House: r2c5=5
Full House: r2c4=6
Full House: r5c4=3
|
normal_sudoku_387
|
.81.92.45...3...1...6..129..5..2.4816...4.95.........6.4..5...9..3..7....6.2...7.
|
381792645925364718476581293759623481632148957814975326247856139593417862168239574
|
Basic 9x9 Sudoku 387
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 1 . 9 2 . 4 5
. . . 3 . . . 1 .
. . 6 . . 1 2 9 .
. 5 . . 2 . 4 8 1
6 . . . 4 . 9 5 .
. . . . . . . . 6
. 4 . . 5 . . . 9
. . 3 . . 7 . . .
. 6 . 2 . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
381792645925364718476581293759623481632148957814975326247856139593417862168239574 #1 Hard (1108)
Locked Candidates Type 1 (Pointing): 6 in b3 => r78c7<>6
Naked Pair: 3,7 in r1c1,r3c2 => r2c123,r3c13<>7, r3c1<>3
Naked Triple: 6,7,8 in r1c4,r23c5 => r2c6,r3c4<>6, r2c6,r3c4<>8, r3c4<>7
Locked Candidates Type 1 (Pointing): 8 in b2 => r689c5<>8
Naked Pair: 4,5 in r3c14 => r3c3<>4, r3c3<>5
Naked Single: r3c3=6
Hidden Pair: 4,9 in r8c4,r9c6 => r8c4<>1, r8c4<>6, r8c4,r9c6<>8, r9c6<>3
Locked Candidates Type 1 (Pointing): 8 in b8 => r7c137<>8
Skyscraper: 3 in r7c8,r9c5 (connected by r6c58) => r7c6,r9c79<>3
Hidden Single: r9c5=3
2-String Kite: 1 in r5c2,r8c5 (connected by r5c4,r6c5) => r8c2<>1
Locked Candidates Type 1 (Pointing): 1 in b7 => r6c1<>1
Naked Pair: 2,9 in r28c2 => r56c2<>2, r6c2<>9
Naked Triple: 1,3,7 in r6c257 => r6c168<>3, r6c134<>7, r6c4<>1
Naked Single: r6c8=2
Naked Single: r8c8=6
Full House: r7c8=3
Naked Single: r8c5=1
Naked Single: r7c7=1
Naked Single: r6c5=7
Naked Single: r3c5=8
Full House: r2c5=6
Naked Single: r6c7=3
Full House: r5c9=7
Naked Single: r1c4=7
Naked Single: r6c2=1
Naked Single: r2c9=8
Naked Single: r3c9=3
Naked Single: r1c1=3
Full House: r1c7=6
Full House: r2c7=7
Naked Single: r5c2=3
Naked Single: r9c9=4
Full House: r8c9=2
Naked Single: r3c2=7
Naked Single: r5c6=8
Naked Single: r9c6=9
Naked Single: r8c2=9
Full House: r2c2=2
Naked Single: r5c3=2
Full House: r5c4=1
Naked Single: r7c6=6
Naked Single: r6c6=5
Naked Single: r8c4=4
Full House: r7c4=8
Naked Single: r7c3=7
Full House: r7c1=2
Naked Single: r4c6=3
Full House: r2c6=4
Full House: r3c4=5
Full House: r3c1=4
Naked Single: r6c4=9
Full House: r4c4=6
Naked Single: r4c3=9
Full House: r4c1=7
Naked Single: r6c1=8
Full House: r6c3=4
Naked Single: r2c3=5
Full House: r2c1=9
Full House: r9c3=8
Naked Single: r8c1=5
Full House: r8c7=8
Full House: r9c7=5
Full House: r9c1=1
|
normal_sudoku_3612
|
..1..3.6.63.4.....5...2.....1...7.5...5.6...97..8..2....8.4.6.71......8..6.9..5.1
|
471583962632419875589726143916237458825164739743895216258341697197652384364978521
|
Basic 9x9 Sudoku 3612
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 . . 3 . 6 .
6 3 . 4 . . . . .
5 . . . 2 . . . .
. 1 . . . 7 . 5 .
. . 5 . 6 . . . 9
7 . . 8 . . 2 . .
. . 8 . 4 . 6 . 7
1 . . . . . . 8 .
. 6 . 9 . . 5 . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
471583962632419875589726143916237458825164739743895216258341697197652384364978521 #1 Extreme (28578) bf
Brute Force: r5c3=5
Grouped Discontinuous Nice Loop: 9 r2c5 =1= r6c5 =5= r6c6 =9= r46c5 -9- r2c5 => r2c5<>9
Forcing Net Contradiction in r1 => r4c3<>2
r4c3=2 (r4c4<>2 r4c4=3 r4c5<>3 r4c5=9 r6c6<>9 r6c2=9 r7c2<>9) (r4c4<>2 r4c4=3 r7c4<>3) (r4c3<>3) (r4c4<>2 r4c4=3 r4c1<>3) r4c3<>6 r4c9=6 r6c9<>6 r6c3=6 r6c3<>3 r5c1=3 r7c1<>3 r7c8=3 r7c8<>9 r7c1=9 r1c1<>9
r4c3=2 (r4c3<>6 r4c9=6 r6c9<>6 r6c3=6 r6c3<>9) r4c4<>2 r4c4=3 r4c5<>3 r4c5=9 (r6c5<>9) r6c6<>9 r6c2=9 r1c2<>9
r4c3=2 r4c4<>2 r4c4=3 r4c5<>3 r4c5=9 r1c5<>9
r4c3=2 (r4c4<>2 r4c4=3 r4c5<>3 r4c5=9 r6c6<>9 r6c2=9 r8c2<>9) (r4c4<>2 r4c4=3 r4c5<>3 r4c5=9 r6c6<>9 r6c2=9 r7c2<>9) (r4c4<>2 r4c4=3 r7c4<>3) (r4c3<>3) (r4c4<>2 r4c4=3 r4c1<>3) r4c3<>6 r4c9=6 r6c9<>6 r6c3=6 r6c3<>3 r5c1=3 r7c1<>3 r7c8=3 r7c8<>9 r7c1=9 r8c3<>9 r8c7=9 r1c7<>9
Forcing Net Contradiction in c5 => r8c4<>2
r8c4=2 (r8c4<>6 r8c6=6 r3c6<>6 r3c4=6 r3c4<>7 r1c4=7 r1c2<>7) (r8c4<>5) (r7c4<>2) (r5c4<>2) r4c4<>2 r4c4=3 (r7c4<>3) r5c4<>3 r5c4=1 (r6c5<>1 r6c5=5 r8c5<>5) r7c4<>1 r7c4=5 r8c6<>5 r8c2=5 r8c2<>7 r3c2=7 r3c2<>8 r1c12=8 r1c5<>8
r8c4=2 (r5c4<>2) r4c4<>2 r4c4=3 r5c4<>3 r5c4=1 r6c5<>1 r2c5=1 r2c5<>8
r8c4=2 r9c6<>2 r9c6=8 r9c5<>8
Brute Force: r5c4=1
Hidden Single: r6c8=1
Hidden Single: r2c5=1
Hidden Single: r7c6=1
Hidden Single: r3c7=1
Forcing Chain Contradiction in r5c2 => r5c1<>4
r5c1=4 r5c6<>4 r5c6=2 r5c2<>2
r5c1=4 r5c2<>4
r5c1=4 r5c6<>4 r5c6=2 r9c6<>2 r9c6=8 r9c5<>8 r1c5=8 r1c1<>8 r45c1=8 r5c2<>8
Forcing Chain Contradiction in r5c2 => r5c7<>4
r5c7=4 r5c6<>4 r5c6=2 r5c2<>2
r5c7=4 r5c2<>4
r5c7=4 r5c6<>4 r5c6=2 r9c6<>2 r9c6=8 r9c5<>8 r1c5=8 r1c1<>8 r45c1=8 r5c2<>8
Forcing Chain Contradiction in r5c2 => r5c8<>4
r5c8=4 r5c6<>4 r5c6=2 r5c2<>2
r5c8=4 r5c2<>4
r5c8=4 r5c6<>4 r5c6=2 r9c6<>2 r9c6=8 r9c5<>8 r1c5=8 r1c1<>8 r45c1=8 r5c2<>8
Finned Franken Swordfish: 4 c18b6 r149 fr3c8 fr6c9 => r1c9<>4
Forcing Chain Contradiction in r1c9 => r1c7<>7
r1c7=7 r2c78<>7 r2c3=7 r2c3<>2 r1c12=2 r1c9<>2
r1c7=7 r1c4<>7 r1c4=5 r1c9<>5
r1c7=7 r2c78<>7 r2c3=7 r9c3<>7 r9c5=7 r9c5<>8 r1c5=8 r1c9<>8
Forcing Chain Verity => r7c2<>2
r8c2=2 r7c2<>2
r8c3=2 r7c2<>2
r8c6=2 r8c6<>6 r8c4=6 r3c4<>6 r3c4=7 r1c4<>7 r1c4=5 r7c4<>5 r7c2=5 r7c2<>2
r8c9=2 r1c9<>2 r1c12=2 r2c3<>2 r89c3=2 r7c2<>2
Forcing Net Verity => r2c9=5
r1c7=4 (r3c9<>4) (r1c1<>4) r3c8<>4 r9c8=4 (r8c9<>4) r9c1<>4 r4c1=4 r4c9<>4 r6c9=4 (r6c6<>4) r6c2<>4 r6c2=9 r6c6<>9 r6c6=5 r2c6<>5 r2c9=5
r1c7=8 (r2c7<>8) r2c9<>8 r2c6=8 r2c6<>5 r2c9=5
r1c7=9 (r1c5<>9) (r1c1<>9) (r2c8<>9) r3c8<>9 r7c8=9 r7c1<>9 r4c1=9 r4c5<>9 r6c5=9 r6c5<>5 r6c6=5 r2c6<>5 r2c9=5
2-String Kite: 2 in r2c3,r8c9 (connected by r1c9,r2c8) => r8c3<>2
Sashimi Swordfish: 2 r247 c148 fr2c3 => r1c1<>2
Discontinuous Nice Loop: 7/9 r2c3 =2= r2c8 -2- r1c9 -8- r1c5 =8= r9c5 =7= r9c3 =2= r2c3 => r2c3<>7, r2c3<>9
Naked Single: r2c3=2
Hidden Single: r1c9=2
Locked Candidates Type 2 (Claiming): 7 in r2 => r3c8<>7
Continuous Nice Loop: 3/4/9 4= r3c8 =3= r3c9 -3- r8c9 -4- r9c8 =4= r3c8 =3 => r46c9<>3, r8c7<>4, r3c8<>9
Hidden Rectangle: 4/6 in r4c39,r6c39 => r4c3<>4
Continuous Nice Loop: 2/3/8/9 9= r7c8 =2= r9c8 -2- r9c6 -8- r2c6 -9- r2c8 =9= r7c8 =2 => r9c1<>2, r7c8<>3, r3c6<>8, r2c7<>9
Discontinuous Nice Loop: 7 r3c3 -7- r3c4 -6- r3c6 -9- r2c6 -8- r9c6 =8= r9c5 =7= r9c3 -7- r3c3 => r3c3<>7
Locked Candidates Type 1 (Pointing): 7 in b1 => r8c2<>7
Discontinuous Nice Loop: 4 r1c2 -4- r3c3 -9- r3c6 -6- r3c4 -7- r3c2 =7= r1c2 => r1c2<>4
2-String Kite: 4 in r1c1,r9c8 (connected by r1c7,r3c8) => r9c1<>4
Naked Single: r9c1=3
Hidden Single: r7c4=3
Naked Single: r4c4=2
Naked Single: r5c6=4
Hidden Single: r7c2=5
Locked Pair: 2,8 in r5c12 => r4c1,r5c7<>8
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c7<>3
Naked Pair: 4,9 in r4c1,r6c2 => r46c3<>9, r6c3<>4
X-Wing: 4 c17 r14 => r4c9<>4
Skyscraper: 9 in r1c7,r3c3 (connected by r8c37) => r1c12<>9
Locked Candidates Type 1 (Pointing): 9 in b1 => r3c6<>9
Naked Single: r3c6=6
Naked Single: r3c4=7
Naked Single: r1c4=5
Full House: r8c4=6
Hidden Single: r1c2=7
W-Wing: 9/4 in r3c3,r6c2 connected by 4 in r14c1 => r3c2<>9
Hidden Single: r3c3=9
Locked Candidates Type 2 (Claiming): 4 in c3 => r8c2<>4
XY-Wing: 4/8/9 in r1c15,r4c1 => r4c5<>9
Naked Single: r4c5=3
Naked Single: r4c3=6
Naked Single: r4c9=8
Naked Single: r6c3=3
Naked Single: r4c7=4
Full House: r4c1=9
Naked Single: r6c9=6
Naked Single: r6c2=4
Naked Single: r7c1=2
Full House: r7c8=9
Naked Single: r3c2=8
Full House: r1c1=4
Full House: r5c1=8
Full House: r5c2=2
Full House: r8c2=9
Naked Single: r2c8=7
Naked Single: r8c7=3
Naked Single: r2c7=8
Full House: r2c6=9
Full House: r1c5=8
Full House: r1c7=9
Full House: r5c7=7
Full House: r5c8=3
Naked Single: r8c9=4
Full House: r3c9=3
Full House: r3c8=4
Full House: r9c8=2
Naked Single: r6c6=5
Full House: r6c5=9
Naked Single: r9c5=7
Full House: r8c5=5
Naked Single: r8c3=7
Full House: r8c6=2
Full House: r9c6=8
Full House: r9c3=4
|
normal_sudoku_6537
|
.39...7.8.2.98..1......72...463.8.......1..3.3.1..9......1.23.......3.29.1...5..7
|
539241768427986513168537294746328951952714836381659472694172385875463129213895647
|
Basic 9x9 Sudoku 6537
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 9 . . . 7 . 8
. 2 . 9 8 . . 1 .
. . . . . 7 2 . .
. 4 6 3 . 8 . . .
. . . . 1 . . 3 .
3 . 1 . . 9 . . .
. . . 1 . 2 3 . .
. . . . . 3 . 2 9
. 1 . . . 5 . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
539241768427986513168537294746328951952714836381659472694172385875463129213895647 #1 Extreme (1896)
Hidden Single: r6c1=3
Hidden Single: r1c6=1
Hidden Single: r2c9=3
Hidden Single: r3c5=3
Hidden Single: r9c3=3
Hidden Single: r3c8=9
Hidden Single: r3c1=1
Hidden Single: r8c7=1
Hidden Single: r4c9=1
Hidden Single: r9c1=2
Hidden Single: r5c3=2
Hidden Single: r4c5=2
Hidden Single: r9c5=9
Hidden Single: r6c9=2
Hidden Single: r1c4=2
Locked Candidates Type 1 (Pointing): 5 in b9 => r7c123<>5
Forcing Chain Contradiction in c9 => r3c4<>4
r3c4=4 r3c9<>4
r3c4=4 r2c6<>4 r5c6=4 r5c9<>4
r3c4=4 r9c4<>4 r9c78=4 r7c9<>4
Discontinuous Nice Loop: 6 r6c5 -6- r5c6 -4- r2c6 =4= r1c5 =5= r6c5 => r6c5<>6
Finned Jellyfish: 6 r1269 c1478 fr1c5 fr2c6 => r3c4<>6
Naked Single: r3c4=5
Hidden Single: r6c5=5
Locked Candidates Type 1 (Pointing): 7 in b5 => r8c4<>7
Finned Swordfish: 5 r147 c189 fr4c7 => r5c9<>5
Hidden Single: r7c9=5
Naked Pair: 4,6 in r5c69 => r5c47<>4, r5c47<>6
Naked Single: r5c4=7
Remote Pair: 4/6 r2c6 -6- r5c6 -4- r5c9 -6- r3c9 => r2c7<>4, r2c7<>6
Naked Single: r2c7=5
Naked Single: r4c7=9
Naked Single: r5c7=8
Hidden Single: r1c1=5
Naked Single: r4c1=7
Full House: r4c8=5
Naked Single: r5c1=9
Naked Single: r6c2=8
Full House: r5c2=5
Naked Single: r3c2=6
Naked Single: r2c1=4
Naked Single: r3c9=4
Full House: r3c3=8
Full House: r2c3=7
Full House: r2c6=6
Full House: r1c8=6
Full House: r5c9=6
Full House: r1c5=4
Full House: r5c6=4
Full House: r6c4=6
Naked Single: r8c2=7
Full House: r7c2=9
Naked Single: r7c3=4
Full House: r8c3=5
Naked Single: r6c7=4
Full House: r6c8=7
Full House: r9c7=6
Naked Single: r8c5=6
Full House: r7c5=7
Naked Single: r7c8=8
Full House: r7c1=6
Full House: r8c1=8
Full House: r9c8=4
Full House: r8c4=4
Full House: r9c4=8
|
normal_sudoku_1347
|
1..........67..31..5.32...4..3.....6785......4.2...185..157.....7948.....2.1...9.
|
134896572296745318857321964913258746785614239462937185641579823379482651528163497
|
Basic 9x9 Sudoku 1347
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . . . . . . . .
. . 6 7 . . 3 1 .
. 5 . 3 2 . . . 4
. . 3 . . . . . 6
7 8 5 . . . . . .
4 . 2 . . . 1 8 5
. . 1 5 7 . . . .
. 7 9 4 8 . . . .
. 2 . 1 . . . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
134896572296745318857321964913258746785614239462937185641579823379482651528163497 #1 Easy (212)
Naked Single: r4c3=3
Naked Single: r4c1=9
Naked Single: r3c1=8
Naked Single: r4c2=1
Full House: r6c2=6
Naked Single: r2c1=2
Naked Single: r3c3=7
Naked Single: r6c4=9
Naked Single: r1c3=4
Full House: r9c3=8
Naked Single: r3c8=6
Naked Single: r6c5=3
Full House: r6c6=7
Naked Single: r2c2=9
Full House: r1c2=3
Full House: r7c2=4
Naked Single: r3c7=9
Full House: r3c6=1
Naked Single: r9c5=6
Naked Single: r2c9=8
Naked Single: r9c6=3
Naked Single: r8c6=2
Full House: r7c6=9
Naked Single: r9c1=5
Naked Single: r9c9=7
Full House: r9c7=4
Naked Single: r1c9=2
Naked Single: r5c7=2
Naked Single: r7c9=3
Naked Single: r4c7=7
Naked Single: r5c4=6
Naked Single: r5c9=9
Full House: r8c9=1
Naked Single: r7c1=6
Full House: r8c1=3
Naked Single: r7c8=2
Full House: r7c7=8
Naked Single: r8c8=5
Full House: r8c7=6
Full House: r1c7=5
Full House: r1c8=7
Naked Single: r4c8=4
Full House: r5c8=3
Naked Single: r1c4=8
Full House: r4c4=2
Naked Single: r5c6=4
Full House: r5c5=1
Naked Single: r1c5=9
Full House: r1c6=6
Naked Single: r4c5=5
Full House: r2c5=4
Full House: r2c6=5
Full House: r4c6=8
|
normal_sudoku_1453
|
..63.......7.5.2........841.4.26.....29....5.5.34........9.7....84.13..27.......4
|
416382597897154263352679841148265739629731458573498126261947385984513672735826914
|
Basic 9x9 Sudoku 1453
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 3 . . . . .
. . 7 . 5 . 2 . .
. . . . . . 8 4 1
. 4 . 2 6 . . . .
. 2 9 . . . . 5 .
5 . 3 4 . . . . .
. . . 9 . 7 . . .
. 8 4 . 1 3 . . 2
7 . . . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
416382597897154263352679841148265739629731458573498126261947385984513672735826914 #1 Easy (364)
Naked Single: r8c5=1
Hidden Single: r4c6=5
Hidden Single: r4c3=8
Naked Single: r4c1=1
Naked Single: r5c1=6
Full House: r6c2=7
Naked Single: r8c1=9
Hidden Single: r5c5=3
Hidden Single: r6c8=2
Hidden Single: r5c7=4
Hidden Single: r7c5=4
Hidden Single: r5c4=7
Naked Single: r3c4=6
Naked Single: r5c9=8
Full House: r5c6=1
Naked Single: r8c4=5
Naked Single: r9c4=8
Full House: r2c4=1
Naked Single: r9c5=2
Full House: r9c6=6
Hidden Single: r6c7=1
Hidden Single: r3c5=7
Hidden Single: r7c8=8
Hidden Single: r1c2=1
Hidden Single: r7c2=6
Hidden Single: r6c9=6
Hidden Single: r9c8=1
Naked Single: r9c3=5
Naked Single: r3c3=2
Full House: r7c3=1
Naked Single: r9c2=3
Full House: r7c1=2
Full House: r9c7=9
Naked Single: r3c1=3
Naked Single: r3c6=9
Full House: r3c2=5
Full House: r2c2=9
Naked Single: r1c5=8
Full House: r6c5=9
Full House: r6c6=8
Naked Single: r2c9=3
Naked Single: r1c1=4
Full House: r2c1=8
Naked Single: r2c6=4
Full House: r2c8=6
Full House: r1c6=2
Naked Single: r7c9=5
Full House: r7c7=3
Naked Single: r8c8=7
Full House: r8c7=6
Naked Single: r4c7=7
Full House: r1c7=5
Naked Single: r1c8=9
Full House: r1c9=7
Full House: r4c9=9
Full House: r4c8=3
|
normal_sudoku_3209
|
2.58........51.....7...4...5....3..76.7.5..3..3....4.5.63..584...9...5.......6.7.
|
215837694496512783378694251581463927647259138932781465163975842729348516854126379
|
Basic 9x9 Sudoku 3209
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . 5 8 . . . . .
. . . 5 1 . . . .
. 7 . . . 4 . . .
5 . . . . 3 . . 7
6 . 7 . 5 . . 3 .
. 3 . . . . 4 . 5
. 6 3 . . 5 8 4 .
. . 9 . . . 5 . .
. . . . . 6 . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
215837694496512783378694251581463927647259138932781465163975842729348516854126379 #1 Extreme (13160) bf
Hidden Single: r5c5=5
Hidden Single: r3c8=5
Hidden Single: r9c2=5
Hidden Rectangle: 7/9 in r1c67,r2c67 => r2c7<>9
Forcing Net Contradiction in c8 => r2c7<>6
r2c7=6 (r2c7<>2) (r1c9<>6 r1c5=6 r1c5<>3) (r1c9<>6 r1c5=6 r1c5<>7) r2c7<>7 r2c6=7 (r2c6<>2) r1c6<>7 r1c7=7 r1c7<>3 r1c9=3 (r2c9<>3 r2c1=3 r2c1<>4) r1c9<>4 r1c2=4 (r2c2<>4) r2c3<>4 r2c9=4 r2c9<>2 r2c8=2
r2c7=6 (r3c9<>6 r8c9=6 r8c8<>6) (r1c8<>6) r2c7<>7 r2c6=7 r1c6<>7 r1c6=9 r1c8<>9 r1c8=1 r8c8<>1 r8c8=2
Brute Force: r5c4=2
Hidden Single: r5c2=4
Hidden Single: r1c9=4
2-String Kite: 2 in r6c8,r8c2 (connected by r4c2,r6c3) => r8c8<>2
2-String Kite: 2 in r2c6,r7c9 (connected by r7c5,r8c6) => r2c9<>2
Finned Swordfish: 2 c268 r248 fr6c8 => r4c7<>2
Locked Candidates Type 1 (Pointing): 2 in b6 => r2c8<>2
Hidden Pair: 2,7 in r2c67 => r2c6<>9, r2c7<>3
Grouped Continuous Nice Loop: 3/6/7/8/9 6= r1c5 =3= r1c7 -3- r2c9 =3= r2c1 =4= r2c3 =6= r3c3 -6- r3c45 =6= r1c5 =3 => r3c79<>3, r3c79<>6, r1c5<>7, r2c13<>8, r1c5,r2c1<>9
Locked Candidates Type 1 (Pointing): 7 in b2 => r68c6<>7
Empty Rectangle: 9 in b2 (r36c1) => r6c6<>9
W-Wing: 1/9 in r1c2,r5c7 connected by 9 in r15c6 => r1c7<>1
AIC: 1 1- r5c7 -9- r5c6 =9= r1c6 =7= r1c7 =3= r2c9 =6= r8c9 -6- r8c8 -1 => r46c8,r9c7<>1
Sashimi Swordfish: 1 c268 r148 fr5c6 fr6c6 => r4c4<>1
AIC: 7 7- r1c6 =7= r1c7 =3= r2c9 -3- r2c1 -4- r2c3 =4= r9c3 =2= r8c2 -2- r8c6 =2= r2c6 =7= r2c7 -7 => r1c7,r2c6<>7
Naked Single: r2c6=2
Naked Single: r2c7=7
Hidden Single: r1c6=7
Hidden Single: r5c6=9
Naked Single: r5c7=1
Full House: r5c9=8
Hidden Single: r2c8=8
Naked Single: r2c2=9
Naked Single: r1c2=1
Hidden Single: r6c1=9
Hidden Single: r8c8=1
Naked Single: r8c6=8
Full House: r6c6=1
Naked Single: r8c2=2
Full House: r4c2=8
Naked Single: r6c3=2
Full House: r4c3=1
Naked Single: r6c8=6
Naked Single: r1c8=9
Full House: r4c8=2
Full House: r4c7=9
Naked Single: r6c4=7
Full House: r6c5=8
Naked Single: r3c7=2
Naked Single: r3c9=1
Naked Single: r9c7=3
Full House: r1c7=6
Full House: r1c5=3
Full House: r2c9=3
Naked Single: r8c9=6
Naked Single: r2c1=4
Full House: r2c3=6
Naked Single: r8c1=7
Naked Single: r3c3=8
Full House: r3c1=3
Full House: r9c3=4
Naked Single: r7c1=1
Full House: r9c1=8
Naked Single: r8c5=4
Full House: r8c4=3
Naked Single: r7c4=9
Naked Single: r4c5=6
Full House: r4c4=4
Naked Single: r3c4=6
Full House: r9c4=1
Full House: r3c5=9
Naked Single: r7c9=2
Full House: r7c5=7
Full House: r9c5=2
Full House: r9c9=9
|
normal_sudoku_6744
|
......9..48.23..61..58974..25....1...31....48...1......9.........84..2..3.257.8..
|
723641985489235761615897423254983176931762548876154392197328654568419237342576819
|
Basic 9x9 Sudoku 6744
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . 9 . .
4 8 . 2 3 . . 6 1
. . 5 8 9 7 4 . .
2 5 . . . . 1 . .
. 3 1 . . . . 4 8
. . . 1 . . . . .
. 9 . . . . . . .
. . 8 4 . . 2 . .
3 . 2 5 7 . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
723641985489235761615897423254983176931762548876154392197328654568419237342576819 #1 Easy (272)
Naked Single: r2c4=2
Naked Single: r1c4=6
Naked Single: r2c6=5
Naked Single: r7c4=3
Naked Single: r2c7=7
Full House: r2c3=9
Hidden Single: r1c8=8
Hidden Single: r6c1=8
Hidden Single: r1c3=3
Hidden Single: r6c7=3
Hidden Single: r1c9=5
Hidden Single: r5c1=9
Naked Single: r5c4=7
Full House: r4c4=9
Naked Single: r4c8=7
Naked Single: r4c9=6
Naked Single: r4c3=4
Naked Single: r5c7=5
Full House: r7c7=6
Naked Single: r4c5=8
Full House: r4c6=3
Naked Single: r7c3=7
Full House: r6c3=6
Full House: r6c2=7
Naked Single: r7c9=4
Naked Single: r9c9=9
Naked Single: r6c9=2
Full House: r6c8=9
Naked Single: r9c8=1
Naked Single: r3c9=3
Full House: r3c8=2
Full House: r8c9=7
Naked Single: r6c6=4
Full House: r6c5=5
Naked Single: r7c8=5
Full House: r8c8=3
Naked Single: r9c6=6
Full House: r9c2=4
Naked Single: r1c6=1
Full House: r1c5=4
Naked Single: r7c1=1
Naked Single: r5c6=2
Full House: r5c5=6
Naked Single: r8c5=1
Full House: r7c5=2
Full House: r7c6=8
Full House: r8c6=9
Naked Single: r1c1=7
Full House: r1c2=2
Naked Single: r3c1=6
Full House: r3c2=1
Full House: r8c2=6
Full House: r8c1=5
|
normal_sudoku_2421
|
.6.3.9....5.28....87.......416.......2...83.998.7..24........8.7..1.24......3..7.
|
164379528359281764872456931416923857527648319983715246241597683738162495695834172
|
Basic 9x9 Sudoku 2421
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . 3 . 9 . . .
. 5 . 2 8 . . . .
8 7 . . . . . . .
4 1 6 . . . . . .
. 2 . . . 8 3 . 9
9 8 . 7 . . 2 4 .
. . . . . . . 8 .
7 . . 1 . 2 4 . .
. . . . 3 . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
164379528359281764872456931416923857527648319983715246241597683738162495695834172 #1 Extreme (2330)
Naked Single: r5c2=2
Naked Single: r4c8=5
Naked Single: r5c1=5
Naked Single: r4c4=9
Naked Single: r4c6=3
Naked Single: r5c3=7
Full House: r6c3=3
Naked Single: r4c5=2
Hidden Single: r8c3=8
Hidden Single: r9c4=8
Hidden Single: r2c1=3
Locked Candidates Type 1 (Pointing): 4 in b1 => r79c3<>4
Locked Candidates Type 1 (Pointing): 9 in b1 => r79c3<>9
Locked Candidates Type 1 (Pointing): 2 in b9 => r13c9<>2
Naked Pair: 1,2 in r1c18 => r1c3579<>1, r1c3<>2
Naked Single: r1c3=4
2-String Kite: 5 in r3c4,r8c9 (connected by r7c4,r8c5) => r3c9<>5
Uniqueness Test 2: 7/8 in r1c79,r4c79 => r1c5,r3c7<>5
Naked Single: r1c5=7
Hidden Single: r7c6=7
Discontinuous Nice Loop: 9 r2c7 -9- r9c7 =9= r9c2 =4= r9c6 -4- r2c6 =4= r2c9 =7= r2c7 => r2c7<>9
Discontinuous Nice Loop: 5 r9c7 -5- r1c7 -8- r1c9 =8= r4c9 =7= r2c9 =4= r2c6 -4- r9c6 =4= r9c2 =9= r9c7 => r9c7<>5
Almost Locked Set XZ-Rule: A=r3c4567 {14569}, B=r9c13679 {124569}, X=9, Z=4 => r2c6<>4
Hidden Single: r2c9=4
Hidden Single: r2c7=7
Naked Single: r4c7=8
Full House: r4c9=7
Naked Single: r1c7=5
Naked Single: r1c9=8
Turbot Fish: 6 r2c6 =6= r2c8 -6- r5c8 =6= r6c9 => r6c6<>6
Empty Rectangle: 1 in b3 (r5c58) => r3c5<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r6c6<>1
Naked Single: r6c6=5
Finned X-Wing: 6 r68 c59 fr8c8 => r79c9<>6
Finned Swordfish: 6 c167 r379 fr2c6 => r3c45<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r9c6<>6
Naked Single: r9c6=4
Naked Single: r9c2=9
Naked Single: r8c2=3
Full House: r7c2=4
Hidden Single: r7c9=3
Hidden Single: r3c8=3
Hidden Single: r9c9=2
Hidden Single: r3c3=2
Naked Single: r1c1=1
Full House: r1c8=2
Full House: r2c3=9
Naked Single: r9c1=6
Full House: r7c1=2
Naked Single: r9c7=1
Full House: r9c3=5
Full House: r7c3=1
Hidden Single: r8c9=5
Hidden Single: r3c7=9
Full House: r7c7=6
Full House: r8c8=9
Full House: r8c5=6
Naked Single: r7c4=5
Full House: r7c5=9
Naked Single: r6c5=1
Full House: r6c9=6
Full House: r3c9=1
Full House: r5c8=1
Full House: r2c8=6
Full House: r2c6=1
Full House: r3c6=6
Naked Single: r3c4=4
Full House: r3c5=5
Full House: r5c5=4
Full House: r5c4=6
|
normal_sudoku_6616
|
9.37..481....4...2.46....97........54...8.976.3........1.87...98....472....29....
|
953762481187945362246138597691427835425381976738659214512873649869514723374296158
|
Basic 9x9 Sudoku 6616
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . 3 7 . . 4 8 1
. . . . 4 . . . 2
. 4 6 . . . . 9 7
. . . . . . . . 5
4 . . . 8 . 9 7 6
. 3 . . . . . . .
. 1 . 8 7 . . . 9
8 . . . . 4 7 2 .
. . . 2 9 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
953762481187945362246138597691427835425381976738659214512873649869514723374296158 #1 Medium (382)
Naked Single: r1c9=1
Naked Single: r8c9=3
Hidden Single: r3c6=8
Locked Candidates Type 1 (Pointing): 6 in b3 => r2c46<>6
Locked Candidates Type 1 (Pointing): 3 in b6 => r4c456<>3
Hidden Single: r3c5=3
Naked Single: r3c7=5
Naked Single: r3c4=1
Full House: r3c1=2
Naked Single: r7c7=6
Naked Single: r1c2=5
Naked Single: r2c7=3
Full House: r2c8=6
Naked Single: r5c2=2
Hidden Single: r5c4=3
Hidden Single: r8c5=1
Hidden Single: r7c3=2
Hidden Single: r4c8=3
Hidden Single: r6c5=5
Naked Single: r5c6=1
Full House: r5c3=5
Naked Single: r8c3=9
Naked Single: r8c2=6
Full House: r8c4=5
Naked Single: r9c2=7
Naked Single: r2c4=9
Naked Single: r7c6=3
Full House: r9c6=6
Naked Single: r2c2=8
Full House: r4c2=9
Naked Single: r9c3=4
Naked Single: r2c6=5
Naked Single: r7c1=5
Full House: r7c8=4
Full House: r9c1=3
Naked Single: r1c6=2
Full House: r1c5=6
Full House: r4c5=2
Naked Single: r9c9=8
Full House: r6c9=4
Naked Single: r6c8=1
Full House: r9c8=5
Full House: r9c7=1
Naked Single: r4c6=7
Full House: r6c6=9
Naked Single: r6c4=6
Full House: r4c4=4
Naked Single: r4c7=8
Full House: r6c7=2
Naked Single: r6c1=7
Full House: r6c3=8
Naked Single: r4c3=1
Full House: r2c3=7
Full House: r2c1=1
Full House: r4c1=6
|
normal_sudoku_192
|
.8.2..3.1.7...9......3..9.8..4..1.....57.6.89.9..4....4....58....3.6..2...7..3...
|
986254371371689542542317968634891257215736489798542613429175836153968724867423195
|
Basic 9x9 Sudoku 192
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 . 2 . . 3 . 1
. 7 . . . 9 . . .
. . . 3 . . 9 . 8
. . 4 . . 1 . . .
. . 5 7 . 6 . 8 9
. 9 . . 4 . . . .
4 . . . . 5 8 . .
. . 3 . 6 . . 2 .
. . 7 . . 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
986254371371689542542317968634891257215736489798542613429175836153968724867423195 #1 Easy (324)
Naked Single: r5c4=7
Hidden Single: r5c7=4
Hidden Single: r3c2=4
Naked Single: r3c6=7
Naked Single: r1c5=5
Naked Single: r1c6=4
Naked Single: r3c5=1
Naked Single: r8c6=8
Full House: r6c6=2
Naked Single: r2c5=8
Full House: r2c4=6
Naked Single: r5c5=3
Naked Single: r4c5=9
Naked Single: r9c5=2
Full House: r7c5=7
Hidden Single: r2c1=3
Hidden Single: r6c3=8
Naked Single: r6c4=5
Full House: r4c4=8
Hidden Single: r1c8=7
Hidden Single: r9c1=8
Hidden Single: r4c2=3
Hidden Single: r2c3=1
Hidden Single: r3c1=5
Naked Single: r3c8=6
Full House: r3c3=2
Naked Single: r4c8=5
Naked Single: r2c8=4
Hidden Single: r7c2=2
Naked Single: r5c2=1
Full House: r5c1=2
Naked Single: r8c2=5
Full House: r9c2=6
Naked Single: r7c3=9
Full House: r1c3=6
Full House: r8c1=1
Full House: r1c1=9
Naked Single: r7c4=1
Naked Single: r8c7=7
Naked Single: r7c8=3
Full House: r7c9=6
Naked Single: r8c9=4
Full House: r8c4=9
Full House: r9c4=4
Naked Single: r6c8=1
Full House: r9c8=9
Naked Single: r9c9=5
Full House: r9c7=1
Naked Single: r6c7=6
Naked Single: r2c9=2
Full House: r2c7=5
Full House: r4c7=2
Naked Single: r6c1=7
Full House: r4c1=6
Full House: r4c9=7
Full House: r6c9=3
|
normal_sudoku_5281
|
.....2..9..91..8..3..8...7..1.9....5..7.854..2...14.....84..6..7......3..6...1..8
|
871342569649157823352896174416923785937685412285714396128439657794568231563271948
|
Basic 9x9 Sudoku 5281
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 2 . . 9
. . 9 1 . . 8 . .
3 . . 8 . . . 7 .
. 1 . 9 . . . . 5
. . 7 . 8 5 4 . .
2 . . . 1 4 . . .
. . 8 4 . . 6 . .
7 . . . . . . 3 .
. 6 . . . 1 . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
871342569649157823352896174416923785937685412285714396128439657794568231563271948 #1 Extreme (25246) bf
Brute Force: r5c5=8
Hidden Single: r8c6=8
Forcing Net Contradiction in c2 => r1c3<>4
r1c3=4 (r1c3<>6) r4c3<>4 r4c1=4 r4c1<>8 (r1c1=8 r1c1<>1 r7c1=1 r8c3<>1 r3c3=1 r3c3<>6) r4c8=8 r6c8<>8 r6c2=8 r6c2<>5 r6c3=5 r6c3<>6 r4c3=6 r5c1<>6 r5c1=9 r5c2<>9
r1c3=4 r4c3<>4 r4c1=4 r4c1<>8 r4c8=8 r6c8<>8 r6c2=8 r6c2<>9
r1c3=4 (r2c1<>4) (r1c3<>6) r4c3<>4 r4c1=4 r4c1<>8 (r1c1=8 r1c1<>1 r7c1=1 r8c3<>1 r3c3=1 r3c3<>6) r4c8=8 r6c8<>8 r6c2=8 r6c2<>5 r6c3=5 r6c3<>6 r4c3=6 (r4c6<>6) (r5c1<>6 r5c1=9 r9c1<>9) r4c3<>4 r4c1=4 r9c1<>4 r9c1=5 r2c1<>5 r2c1=6 r2c6<>6 r3c6=6 r3c6<>9 r7c6=9 r7c2<>9
r1c3=4 (r1c2<>4) (r2c2<>4) r3c2<>4 r8c2=4 r8c2<>9
Forcing Net Contradiction in c2 => r3c3<>4
r3c3=4 (r3c3<>6) r4c3<>4 r4c1=4 r4c1<>8 (r1c1=8 r1c1<>1 r7c1=1 r8c3<>1 r1c3=1 r1c3<>6) r4c8=8 r6c8<>8 r6c2=8 r6c2<>5 r6c3=5 r6c3<>6 r4c3=6 r5c1<>6 r5c1=9 r5c2<>9
r3c3=4 r4c3<>4 r4c1=4 r4c1<>8 r4c8=8 r6c8<>8 r6c2=8 r6c2<>9
r3c3=4 (r2c1<>4) (r3c3<>6) r4c3<>4 r4c1=4 r4c1<>8 (r1c1=8 r1c1<>1 r7c1=1 r8c3<>1 r1c3=1 r1c3<>6) r4c8=8 r6c8<>8 r6c2=8 r6c2<>5 r6c3=5 r6c3<>6 r4c3=6 (r4c6<>6) (r5c1<>6 r5c1=9 r9c1<>9) r4c3<>4 r4c1=4 r9c1<>4 r9c1=5 r2c1<>5 r2c1=6 r2c6<>6 r3c6=6 r3c6<>9 r7c6=9 r7c2<>9
r3c3=4 (r1c2<>4) (r2c2<>4) r3c2<>4 r8c2=4 r8c2<>9
Brute Force: r5c4=6
Naked Single: r5c1=9
Naked Single: r5c2=3
Hidden Single: r8c5=6
Hidden Single: r4c5=2
Hidden Single: r9c3=3
Swordfish: 2 r257 c289 => r3c29,r8c29,r9c8<>2
Skyscraper: 3 in r1c4,r2c9 (connected by r6c49) => r1c7,r2c56<>3
Hidden Single: r2c9=3
2-String Kite: 7 in r4c6,r7c9 (connected by r4c7,r6c9) => r7c6<>7
Discontinuous Nice Loop: 4 r1c1 -4- r3c2 -5- r6c2 -8- r1c2 =8= r1c1 => r1c1<>4
Discontinuous Nice Loop: 7 r1c5 -7- r2c6 =7= r4c6 =3= r7c6 -3- r7c5 =3= r1c5 => r1c5<>7
Discontinuous Nice Loop: 5 r3c3 -5- r6c3 =5= r6c2 =8= r1c2 =7= r2c2 =2= r3c3 => r3c3<>5
Discontinuous Nice Loop: 1 r7c8 -1- r7c1 =1= r8c3 =2= r3c3 -2- r3c7 =2= r2c8 -2- r5c8 -1- r7c8 => r7c8<>1
Discontinuous Nice Loop: 5 r8c2 -5- r8c4 -2- r8c3 =2= r7c2 =9= r8c2 => r8c2<>5
Discontinuous Nice Loop: 5 r8c3 -5- r8c4 -2- r9c4 =2= r9c7 =7= r7c9 -7- r6c9 -6- r6c3 -5- r8c3 => r8c3<>5
Discontinuous Nice Loop: 1 r1c1 -1- r1c7 -5- r1c3 =5= r6c3 -5- r6c2 -8- r1c2 =8= r1c1 => r1c1<>1
Hidden Single: r7c1=1
XY-Wing: 2/4/5 in r8c34,r9c1 => r9c45<>5
AIC: 5 5- r1c7 -1- r8c7 =1= r8c9 =4= r3c9 -4- r3c2 -5 => r1c123,r3c7<>5
Hidden Single: r6c3=5
Naked Single: r6c2=8
Hidden Single: r1c1=8
Hidden Single: r4c8=8
Avoidable Rectangle Type 1: 2/8 in r4c58,r5c58 => r5c8<>2
Naked Single: r5c8=1
Full House: r5c9=2
Naked Single: r7c9=7
Naked Single: r6c9=6
Naked Single: r6c8=9
Naked Pair: 4,5 in r9c18 => r9c7<>5
X-Wing: 5 c47 r18 => r1c58<>5
W-Wing: 5/2 in r7c8,r8c4 connected by 2 in r9c47 => r7c5,r8c7<>5
Hidden Single: r8c4=5
Hidden Single: r1c7=5
Hidden Single: r9c4=2
Naked Single: r9c7=9
Naked Single: r9c5=7
Hidden Single: r1c3=1
Hidden Single: r8c2=9
Hidden Single: r1c8=6
Locked Candidates Type 2 (Claiming): 4 in c2 => r2c1<>4
W-Wing: 5/4 in r2c5,r3c2 connected by 4 in r1c25 => r2c12,r3c5<>5
Naked Single: r2c1=6
Naked Single: r2c6=7
Naked Single: r3c3=2
Naked Single: r4c1=4
Full House: r4c3=6
Full House: r8c3=4
Full House: r9c1=5
Full House: r7c2=2
Full House: r9c8=4
Naked Single: r1c4=3
Full House: r6c4=7
Full House: r4c6=3
Full House: r6c7=3
Full House: r4c7=7
Naked Single: r2c2=4
Naked Single: r3c7=1
Full House: r8c7=2
Full House: r8c9=1
Full House: r7c8=5
Full House: r2c8=2
Full House: r2c5=5
Full House: r3c9=4
Naked Single: r1c5=4
Full House: r1c2=7
Full House: r3c2=5
Naked Single: r7c6=9
Full House: r3c6=6
Full House: r3c5=9
Full House: r7c5=3
|
normal_sudoku_2825
|
2...3..9...1....6.4....6..26.71..8.....375.16.......5..1.6...74...4..93...4....28
|
286531497791248365435796182657129843948375216123864759319682574862457931574913628
|
Basic 9x9 Sudoku 2825
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . 3 . . 9 .
. . 1 . . . . 6 .
4 . . . . 6 . . 2
6 . 7 1 . . 8 . .
. . . 3 7 5 . 1 6
. . . . . . . 5 .
. 1 . 6 . . . 7 4
. . . 4 . . 9 3 .
. . 4 . . . . 2 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
286531497791248365435796182657129843948375216123864759319682574862457931574913628 #1 Medium (606)
Naked Single: r8c8=3
Naked Single: r3c8=8
Full House: r4c8=4
Naked Single: r7c7=5
Naked Single: r5c7=2
Naked Single: r8c9=1
Full House: r9c7=6
Hidden Single: r4c2=5
Hidden Single: r6c1=1
Hidden Single: r6c5=6
Hidden Single: r5c2=4
Hidden Single: r4c9=3
Naked Single: r6c7=7
Full House: r6c9=9
Hidden Single: r2c5=4
Naked Single: r2c7=3
Naked Single: r3c7=1
Full House: r1c7=4
Hidden Single: r6c6=4
Hidden Single: r1c6=1
Hidden Single: r9c5=1
Hidden Single: r6c4=8
Hidden Single: r2c6=8
Hidden Single: r2c4=2
Locked Candidates Type 1 (Pointing): 7 in b2 => r9c4<>7
Locked Candidates Type 1 (Pointing): 9 in b2 => r3c23<>9
Locked Candidates Type 2 (Claiming): 3 in c1 => r7c3,r9c2<>3
Naked Pair: 5,7 in r1c49 => r1c2<>7, r1c3<>5
Naked Pair: 7,9 in r29c2 => r38c2<>7
Naked Single: r3c2=3
Naked Single: r3c3=5
Naked Single: r6c2=2
Full House: r6c3=3
Naked Single: r3c5=9
Full House: r3c4=7
Full House: r1c4=5
Full House: r9c4=9
Naked Single: r4c5=2
Full House: r4c6=9
Naked Single: r1c9=7
Full House: r2c9=5
Naked Single: r9c2=7
Naked Single: r7c5=8
Full House: r8c5=5
Naked Single: r2c2=9
Full House: r2c1=7
Naked Single: r9c6=3
Full House: r9c1=5
Naked Single: r8c1=8
Naked Single: r7c6=2
Full House: r8c6=7
Naked Single: r5c1=9
Full House: r5c3=8
Full House: r7c1=3
Full House: r7c3=9
Naked Single: r8c2=6
Full House: r1c2=8
Full House: r1c3=6
Full House: r8c3=2
|
normal_sudoku_3903
|
.159..7......5.9.........56..638..7....67..4..37..98....18......78.9.1..25...1...
|
815946723764253918923718456596384271182675349437129865341867592678592134259431687
|
Basic 9x9 Sudoku 3903
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 5 9 . . 7 . .
. . . . 5 . 9 . .
. . . . . . . 5 6
. . 6 3 8 . . 7 .
. . . 6 7 . . 4 .
. 3 7 . . 9 8 . .
. . 1 8 . . . . .
. 7 8 . 9 . 1 . .
2 5 . . . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
815946723764253918923718456596384271182675349437129865341867592678592134259431687 #1 Extreme (17294) bf
Locked Candidates Type 1 (Pointing): 1 in b3 => r2c4<>1
Locked Candidates Type 1 (Pointing): 9 in b6 => r79c9<>9
Forcing Net Contradiction in r4c6 => r9c8<>6
r9c8=6 (r9c8<>8 r9c9=8 r9c9<>7 r9c4=7 r7c6<>7 r7c9=7 r7c9<>5) (r9c7<>6 r5c7=6 r5c6<>6) r9c8<>9 r9c3=9 r5c3<>9 r5c3=2 r5c6<>2 r5c6=5 r7c6<>5 r7c7=5 r4c7<>5 r4c7=2 r4c6<>2
r9c8=6 (r9c8<>9 r9c3=9 r5c3<>9 r5c3=2 r4c2<>2) (r7c7<>6) r9c7<>6 r5c7=6 r5c7<>3 r5c9=3 r5c9<>9 r4c9=9 r4c2<>9 r4c2=4 r4c6<>4
r9c8=6 (r9c7<>6 r5c7=6 r5c6<>6) r9c8<>9 r9c3=9 r5c3<>9 r5c3=2 r5c6<>2 r5c6=5 r4c6<>5
Brute Force: r5c4=6
Hidden Single: r6c8=6
Hidden Single: r2c8=1
Locked Candidates Type 1 (Pointing): 1 in b5 => r6c19<>1
Naked Pair: 2,5 in r4c7,r6c9 => r45c9,r5c7<>2, r45c9,r5c7<>5
Naked Single: r5c7=3
2-String Kite: 6 in r2c2,r8c6 (connected by r7c2,r8c1) => r2c6<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r1c1<>6
Uniqueness Test 4: 1/9 in r4c19,r5c19 => r45c1<>9
Discontinuous Nice Loop: 7 r2c4 -7- r2c1 =7= r3c1 =9= r7c1 -9- r7c8 =9= r9c8 =8= r9c9 =7= r9c4 -7- r2c4 => r2c4<>7
Grouped AIC: 4 4- r2c4 -2- r1c56 =2= r1c89 -2- r3c7 -4 => r2c9,r3c456<>4
Grouped Discontinuous Nice Loop: 5 r4c6 -5- r4c7 =5= r6c9 -5- r6c1 -4- r4c12 =4= r4c6 => r4c6<>5
Almost Locked Set XZ-Rule: A=r2c34 {234}, B=r1456c1 {13458}, X=3, Z=4 => r2c1<>4
Almost Locked Set XZ-Rule: A=r4c67 {245}, B=r7c12578 {234569}, X=5, Z=4 => r7c6<>4
Almost Locked Set XZ-Rule: A=r1456c1 {13458}, B=r235c3 {2349}, X=3, Z=4 => r3c1<>4
Almost Locked Set XY-Wing: A=r2c349 {2348}, B=r145678c1 {1345689}, C=r9c34579 {346789}, X,Y=8,9, Z=3 => r2c1<>3
Almost Locked Set Chain: 24- r2c349 {2348} -8- r9c34579 {346789} -9- r145678c1 {1345689} -6- r3457c2 {24689} -24 => r2c2<>2, r2c2<>4
Grouped Discontinuous Nice Loop: 2 r3c6 -2- r3c2 =2= r45c2 -2- r5c3 -9- r5c9 -1- r5c1 =1= r4c1 =5= r4c7 =2= r6c9 -2- r6c45 =2= r45c6 -2- r3c6 => r3c6<>2
Forcing Chain Contradiction in r7 => r2c2=6
r2c2<>6 r2c2=8 r5c2<>8 r5c1=8 r5c1<>5 r5c6=5 r7c6<>5
r2c2<>6 r2c2=8 r5c2<>8 r5c1=8 r5c1<>1 r4c1=1 r4c1<>5 r4c7=5 r7c7<>5
r2c2<>6 r2c1=6 r2c1<>7 r2c6=7 r7c6<>7 r7c9=7 r7c9<>5
XYZ-Wing: 2/4/9 in r47c2,r5c3 => r5c2<>9
Discontinuous Nice Loop: 4 r7c9 -4- r7c2 -9- r7c8 =9= r9c8 =8= r9c9 =7= r7c9 => r7c9<>4
Forcing Chain Contradiction in r7 => r5c2=8
r5c2<>8 r5c2=2 r5c6<>2 r5c6=5 r7c6<>5
r5c2<>8 r5c1=8 r5c1<>1 r4c1=1 r4c1<>5 r4c7=5 r7c7<>5
r5c2<>8 r5c2=2 r5c3<>2 r5c3=9 r9c3<>9 r9c8=9 r9c8<>8 r9c9=8 r9c9<>7 r7c9=7 r7c9<>5
Locked Triple: 1,4,5 in r456c1 => r178c1,r4c2<>4
Sue de Coq: r1c89 - {2348} (r1c1 - {38}, r3c7 - {24}) => r2c9<>2, r1c56<>3, r1c6<>8
Naked Triple: 2,4,6 in r1c56,r2c4 => r2c6,r3c45<>2, r2c6<>4
Naked Triple: 3,7,8 in r2c169 => r2c3<>3
Skyscraper: 2 in r2c4,r5c6 (connected by r25c3) => r1c6,r6c4<>2
Hidden Rectangle: 7/8 in r2c16,r3c16 => r3c6<>7
Finned Swordfish: 2 r168 c589 fr8c4 fr8c6 => r7c5<>2
W-Wing: 4/2 in r2c4,r4c6 connected by 2 in r16c5 => r1c6,r6c4<>4
Naked Single: r1c6=6
Hidden Single: r8c1=6
XYZ-Wing: 2/3/9 in r7c18,r8c8 => r7c9<>3
Hidden Rectangle: 4/6 in r7c57,r9c57 => r7c5<>4
Finned X-Wing: 3 r28 c69 fr8c8 => r9c9<>3
Sashimi X-Wing: 4 r18 c59 fr8c4 fr8c6 => r9c5<>4
Locked Pair: 3,6 in r79c5 => r3c5,r78c6<>3
Naked Single: r3c5=1
Naked Single: r3c4=7
Naked Single: r9c4=4
Naked Single: r2c4=2
Naked Single: r9c7=6
Naked Single: r1c5=4
Naked Single: r2c3=4
Naked Single: r8c4=5
Full House: r6c4=1
Naked Single: r9c5=3
Naked Single: r6c5=2
Full House: r7c5=6
Naked Single: r8c6=2
Full House: r7c6=7
Naked Single: r9c3=9
Naked Single: r4c6=4
Full House: r5c6=5
Naked Single: r6c9=5
Full House: r6c1=4
Naked Single: r8c8=3
Full House: r8c9=4
Naked Single: r5c3=2
Full House: r3c3=3
Naked Single: r7c1=3
Full House: r7c2=4
Naked Single: r9c8=8
Full House: r9c9=7
Naked Single: r5c1=1
Full House: r5c9=9
Naked Single: r4c7=2
Full House: r4c9=1
Naked Single: r7c9=2
Naked Single: r4c2=9
Full House: r4c1=5
Full House: r3c2=2
Naked Single: r1c1=8
Naked Single: r3c6=8
Full House: r2c6=3
Naked Single: r1c8=2
Full House: r7c8=9
Full House: r7c7=5
Full House: r3c7=4
Full House: r1c9=3
Full House: r3c1=9
Full House: r2c1=7
Full House: r2c9=8
|
normal_sudoku_6815
|
.1..9..6.6....8..4..3.7.....32.....9.74..96..9..8...4.7....2..63.....51....53...8
|
518493267627158394493276851132645789874319625965827143751982436389764512246531978
|
Basic 9x9 Sudoku 6815
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . . 9 . . 6 .
6 . . . . 8 . . 4
. . 3 . 7 . . . .
. 3 2 . . . . . 9
. 7 4 . . 9 6 . .
9 . . 8 . . . 4 .
7 . . . . 2 . . 6
3 . . . . . 5 1 .
. . . 5 3 . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
518493267627158394493276851132645789874319625965827143751982436389764512246531978 #1 Extreme (5102)
Hidden Single: r8c1=3
Locked Candidates Type 1 (Pointing): 6 in b4 => r6c56<>6
Locked Candidates Type 1 (Pointing): 8 in b4 => r13c1<>8
Naked Triple: 1,2,5 in r256c5 => r47c5<>1, r4c5<>5
Finned X-Wing: 3 c69 r16 fr5c9 => r6c7<>3
Almost Locked Set XZ-Rule: A=r5c45,r6c56 {12357}, B=r78c5,r89c6 {14678}, X=7, Z=1 => r4c6<>1
Forcing Net Contradiction in r7c7 => r1c3<>5
r1c3=5 (r6c3<>5) r7c3<>5 r7c2=5 r6c2<>5 r6c2=6 r6c3<>6 r6c3=1 (r6c6<>1) (r4c1<>1) r5c1<>1 r9c1=1 r9c6<>1 r3c6=1 (r2c5<>1 r2c7=1 r4c7<>1) r9c6<>1 r7c4=1 r7c4<>9 r8c4=9 r8c4<>7 r4c4=7 r4c7<>7 r4c7=8 r1c7<>8 r1c3=8 r1c3<>5
Forcing Net Contradiction in b1 => r1c9<>2
r1c9=2 r8c9<>2 r8c9=7 (r8c4<>7 r4c4=7 r4c4<>4) (r8c4<>7 r4c4=7 r4c4<>6) (r9c7<>7) r9c8<>7 r9c6=7 r9c6<>1 r7c4=1 (r7c4<>4) r7c4<>9 r8c4=9 (r8c4<>4) r8c4<>6 r3c4=6 r3c4<>4 r1c4=4 r1c1<>4
r1c9=2 (r1c1<>2) r8c9<>2 r8c2=2 r9c1<>2 r3c1=2 r3c1<>4
r1c9=2 (r1c7<>2) (r2c7<>2) (r3c7<>2) r8c9<>2 (r8c2=2 r8c2<>8) r8c9=7 (r6c9<>7) r8c4<>7 r4c4=7 r6c6<>7 r6c7=7 r6c7<>2 r9c7=2 r9c7<>4 r7c7=4 r7c5<>4 r7c5=8 r7c2<>8 r3c2=8 r3c2<>4
Forcing Net Contradiction in r3 => r2c2<>5
r2c2=5 r7c2<>5 r7c3=5 (r6c3<>5 r6c3=1 r6c6<>1) r7c3<>1 r7c4=1 r9c6<>1 r3c6=1
r2c2=5 r7c2<>5 r7c3=5 (r6c3<>5 r6c3=1 r4c1<>1) r7c3<>1 r7c4=1 r4c4<>1 r4c7=1 (r5c9<>1) r6c9<>1 r3c9=1
Forcing Net Contradiction in r1c4 => r6c2=6
r6c2<>6 r6c2=5 r7c2<>5 r7c3=5 (r7c3<>9) r7c3<>1 (r9c3=1 r9c3<>9) r7c4=1 r7c4<>9 r8c4=9 r8c3<>9 r2c3=9 (r2c2<>9 r2c2=2 r1c1<>2) r2c3<>7 r1c3=7 r1c3<>8 r1c7=8 r1c7<>2 r1c4=2
r6c2<>6 r6c2=5 r7c2<>5 r7c3=5 r7c3<>1 r7c4=1 (r7c4<>4) r7c4<>9 r8c4=9 (r8c4<>4) (r8c4<>6) r8c4<>7 r4c4=7 (r4c4<>4) r4c4<>6 r3c4=6 r3c4<>4 r1c4=4
Grouped Discontinuous Nice Loop: 9 r7c2 =5= r3c2 =8= r1c3 =7= r2c3 =9= r23c2 -9- r7c2 => r7c2<>9
Forcing Net Contradiction in r7c7 => r6c3=5
r6c3<>5 r6c3=1 (r6c6<>1) (r4c1<>1) r5c1<>1 r9c1=1 r9c6<>1 r3c6=1 (r2c5<>1 r2c7=1 r4c7<>1) r9c6<>1 r7c4=1 r4c4<>1 r4c1=1 r6c3<>1 r6c3=5
Hidden Single: r7c2=5
Locked Candidates Type 1 (Pointing): 1 in b4 => r9c1<>1
Hidden Pair: 1,6 in r9c36 => r9c3<>9, r9c6<>4, r9c6<>7
Locked Candidates Type 1 (Pointing): 7 in b8 => r8c9<>7
Naked Single: r8c9=2
Skyscraper: 5 in r2c5,r4c6 (connected by r24c8) => r13c6,r5c5<>5
Hidden Single: r4c6=5
Hidden Single: r2c5=5
Locked Candidates Type 1 (Pointing): 2 in b2 => r5c4<>2
Locked Candidates Type 2 (Claiming): 1 in c5 => r45c4,r6c6<>1
Naked Single: r5c4=3
Naked Single: r6c6=7
Hidden Single: r1c6=3
Hidden Single: r6c9=3
Hidden Single: r8c4=7
Hidden Single: r1c9=7
Naked Single: r1c3=8
Naked Single: r1c7=2
Naked Single: r1c4=4
Full House: r1c1=5
Naked Single: r6c7=1
Full House: r6c5=2
Naked Single: r4c4=6
Naked Single: r5c9=5
Full House: r3c9=1
Naked Single: r5c5=1
Full House: r4c5=4
Naked Single: r3c4=2
Naked Single: r3c6=6
Full House: r2c4=1
Full House: r7c4=9
Naked Single: r5c1=8
Full House: r4c1=1
Full House: r5c8=2
Naked Single: r7c5=8
Full House: r8c5=6
Naked Single: r3c1=4
Full House: r9c1=2
Naked Single: r8c6=4
Full House: r9c6=1
Naked Single: r7c3=1
Naked Single: r7c8=3
Full House: r7c7=4
Naked Single: r8c3=9
Full House: r8c2=8
Naked Single: r3c2=9
Naked Single: r9c3=6
Full House: r2c3=7
Full House: r9c2=4
Full House: r2c2=2
Naked Single: r2c8=9
Full House: r2c7=3
Naked Single: r3c7=8
Full House: r3c8=5
Naked Single: r9c8=7
Full House: r4c8=8
Full House: r4c7=7
Full House: r9c7=9
|
normal_sudoku_6767
|
..9..8.5..6..4.9..5..9....3.....4.27..1..5...7..2..3...17..35.66..7...3..8.......
|
429368751163547982578912463895134627231675894746289315917823546654791238382456179
|
Basic 9x9 Sudoku 6767
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . . 8 . 5 .
. 6 . . 4 . 9 . .
5 . . 9 . . . . 3
. . . . . 4 . 2 7
. . 1 . . 5 . . .
7 . . 2 . . 3 . .
. 1 7 . . 3 5 . 6
6 . . 7 . . . 3 .
. 8 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
429368751163547982578912463895134627231675894746289315917823546654791238382456179 #1 Extreme (15446) bf
Brute Force: r5c6=5
Hidden Single: r2c4=5
Hidden Single: r6c9=5
Hidden Single: r5c5=7
Locked Candidates Type 1 (Pointing): 3 in b2 => r1c12<>3
Locked Candidates Type 2 (Claiming): 3 in c2 => r4c13,r5c1<>3
Discontinuous Nice Loop: 2 r1c5 -2- r7c5 =2= r7c1 -2- r5c1 =2= r5c2 =3= r5c4 -3- r1c4 =3= r1c5 => r1c5<>2
Discontinuous Nice Loop: 2 r9c5 -2- r7c5 =2= r7c1 -2- r5c1 =2= r5c2 =3= r4c2 =5= r4c3 -5- r9c3 =5= r9c5 => r9c5<>2
Grouped Discontinuous Nice Loop: 8 r5c1 -8- r4c1 -9- r79c1 =9= r8c2 =5= r4c2 =3= r5c2 =2= r5c1 => r5c1<>8
Grouped Discontinuous Nice Loop: 9 r5c1 -9- r79c1 =9= r8c2 =5= r4c2 =3= r5c2 =2= r5c1 => r5c1<>9
Grouped Discontinuous Nice Loop: 9 r7c5 -9- r4c5 =9= r4c12 -9- r6c2 -4- r5c1 -2- r7c1 =2= r7c5 => r7c5<>9
Forcing Chain Contradiction in r6 => r7c5=2
r7c5<>2 r7c1=2 r5c1<>2 r5c1=4 r6c2<>4 r6c2=9 r4c1<>9 r4c1=8 r6c3<>8
r7c5<>2 r7c5=8 r6c5<>8
r7c5<>2 r7c1=2 r5c1<>2 r5c1=4 r5c789<>4 r6c8=4 r6c8<>8
Naked Triple: 1,3,6 in r1c45,r3c5 => r23c6<>1, r3c6<>6
XY-Wing: 4/9/8 in r47c1,r7c4 => r4c4<>8
Finned X-Wing: 8 r57 c48 fr5c7 fr5c9 => r6c8<>8
AIC: 4 4- r7c1 -9- r4c1 -8- r6c3 =8= r6c5 -8- r8c5 =8= r7c4 =4= r9c4 -4 => r7c4,r9c13<>4
Naked Single: r7c4=8
Hidden Single: r9c4=4
Locked Candidates Type 2 (Claiming): 8 in r5 => r4c7<>8
Empty Rectangle: 4 in b6 (r7c18) => r5c1<>4
Naked Single: r5c1=2
W-Wing: 6/1 in r3c5,r4c7 connected by 1 in r14c4 => r3c7,r4c5<>6
W-Wing: 1/6 in r3c5,r4c7 connected by 6 in r1c7,r3c8 => r3c7,r4c5<>1
Hidden Pair: 1,6 in r3c58 => r3c8<>4, r3c8<>7, r3c8<>8
Finned Swordfish: 1 r368 c568 fr8c7 fr8c9 => r9c8<>1
Multi Colors 1: 1 (r1c1) / (r2c1), (r1c4,r4c7) / (r4c4,r6c8) => r2c8<>1
Sue de Coq: r56c8 - {14689} (r279c8 - {4789}, r4c7 - {16}) => r5c7<>6
Skyscraper: 6 in r3c5,r5c4 (connected by r35c8) => r1c4,r6c5<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r9c5<>6
Hidden Single: r9c6=6
2-String Kite: 1 in r4c7,r8c6 (connected by r4c4,r6c6) => r8c7<>1
Simple Colors Trap: 1 (r1c4,r3c8,r4c7) / (r3c5,r4c4,r6c8) => r1c5<>1
XY-Chain: 8 8- r2c8 -7- r9c8 -9- r7c8 -4- r7c1 -9- r4c1 -8 => r2c1<>8
Hidden Single: r4c1=8
Hidden Single: r6c5=8
Locked Candidates Type 1 (Pointing): 9 in b4 => r8c2<>9
AIC: 4 4- r1c1 -1- r1c4 =1= r4c4 -1- r6c6 -9- r6c2 -4 => r13c2<>4
Locked Pair: 2,7 in r13c2 => r23c3,r8c2<>2
Naked Pair: 2,7 in r3c26 => r3c7<>2, r3c7<>7
Naked Pair: 4,8 in r35c7 => r18c7<>4, r8c7<>8
Naked Single: r8c7=2
Hidden Single: r8c9=8
Hidden Single: r9c3=2
Hidden Single: r7c8=4
Full House: r7c1=9
Naked Single: r9c1=3
Naked Single: r2c1=1
Full House: r1c1=4
Naked Single: r2c9=2
Naked Single: r3c3=8
Naked Single: r1c9=1
Naked Single: r2c6=7
Naked Single: r2c3=3
Full House: r2c8=8
Naked Single: r3c7=4
Naked Single: r1c4=3
Naked Single: r3c8=6
Full House: r1c7=7
Naked Single: r9c9=9
Full House: r5c9=4
Naked Single: r3c6=2
Naked Single: r5c7=8
Naked Single: r1c5=6
Full House: r3c5=1
Full House: r1c2=2
Full House: r3c2=7
Naked Single: r5c4=6
Full House: r4c4=1
Naked Single: r5c8=9
Full House: r5c2=3
Naked Single: r9c7=1
Full House: r9c8=7
Full House: r9c5=5
Full House: r4c7=6
Full House: r6c8=1
Naked Single: r6c6=9
Full House: r4c5=3
Full House: r8c5=9
Full House: r8c6=1
Naked Single: r4c3=5
Full House: r4c2=9
Naked Single: r6c2=4
Full House: r6c3=6
Full House: r8c3=4
Full House: r8c2=5
|
normal_sudoku_3372
|
.3..1.4.8..19.4.3.4.........7...2...8...6..1.3.6.9..4.......5....8......96..4..8.
|
635217498721984635489356127174832956892465713356791842243178569518629374967543281
|
Basic 9x9 Sudoku 3372
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . 1 . 4 . 8
. . 1 9 . 4 . 3 .
4 . . . . . . . .
. 7 . . . 2 . . .
8 . . . 6 . . 1 .
3 . 6 . 9 . . 4 .
. . . . . . 5 . .
. . 8 . . . . . .
9 6 . . 4 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
635217498721984635489356127174832956892465713356791842243178569518629374967543281 #1 Extreme (37530) bf
Hidden Single: r2c6=4
Brute Force: r5c6=5
Brute Force: r5c7=7
Discontinuous Nice Loop: 8 r6c4 -8- r6c7 -2- r2c7 -6- r2c1 =6= r1c1 -6- r1c6 -7- r6c6 =7= r6c4 => r6c4<>8
Forcing Chain Contradiction in r9 => r9c4<>7
r9c4=7 r9c4<>5 r9c3=5 r9c3<>2
r9c4=7 r9c4<>2
r9c4=7 r6c4<>7 r6c6=7 r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r9c7<>2
r9c4=7 r6c4<>7 r6c6=7 r6c6<>8 r6c7=8 r6c7<>2 r56c9=2 r9c9<>2
Forcing Net Contradiction in r9 => r3c4<>7
r3c4=7 (r6c4<>7 r6c6=7 r9c6<>7) (r2c5<>7) r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c1<>7 r2c9=7 r9c9<>7 r9c3=7 r9c3<>2
r3c4=7 (r6c4<>7 r6c6=7 r9c6<>7) (r2c5<>7) r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c1<>7 r2c9=7 r9c9<>7 r9c3=7 r9c3<>5 r9c4=5 r9c4<>2
r3c4=7 r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r9c7<>2
r3c4=7 r6c4<>7 r6c6=7 r6c6<>8 r6c7=8 r6c7<>2 r56c9=2 r9c9<>2
Forcing Net Contradiction in r9 => r3c6<>7
r3c6=7 (r9c6<>7) (r2c5<>7) r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c1<>7 r2c9=7 r9c9<>7 r9c3=7 r9c3<>2
r3c6=7 (r9c6<>7) (r2c5<>7) r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c1<>7 r2c9=7 r9c9<>7 r9c3=7 r9c3<>5 r9c4=5 r9c4<>2
r3c6=7 r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r9c7<>2
r3c6=7 r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r6c7<>2 r56c9=2 r9c9<>2
Forcing Net Contradiction in r7c8 => r3c9<>2
r3c9=2 (r9c9<>2) (r6c9<>2 r6c9=5 r2c9<>5 r2c9=7 r9c9<>7) (r6c9<>2 r6c7=2 r9c7<>2) r3c9<>1 r3c7=1 r9c7<>1 r9c7=3 (r9c6<>3) r9c9<>3 r9c9=1 r9c6<>1 r9c6=7 r1c6<>7 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r3c9<>2
Forcing Net Contradiction in r9 => r7c5<>3
r7c5=3 r7c3<>3 r9c3=3 r9c3<>2
r7c5=3 r7c3<>3 r9c3=3 r9c3<>5 r9c4=5 r9c4<>2
r7c5=3 (r4c5<>3 r4c5=8 r6c6<>8) (r7c6<>3) (r8c6<>3) r9c6<>3 r3c6=3 (r3c6<>6) r3c6<>8 r7c6=8 (r7c6<>6) r7c6<>9 r8c6=9 r8c6<>6 r1c6=6 r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 r9c7<>2
r7c5=3 r4c5<>3 r4c5=8 r6c6<>8 r6c7=8 r6c7<>2 r56c9=2 r9c9<>2
Brute Force: r5c4=4
Hidden Single: r4c3=4
Hidden Single: r5c9=3
Locked Candidates Type 1 (Pointing): 2 in b6 => r6c2<>2
Forcing Net Verity => r1c3<>7
r1c1=5 (r1c1<>2) (r3c3<>5 r9c3=5 r9c3<>2) (r3c3<>5 r9c3=5 r8c2<>5 r6c2=5 r6c9<>5 r6c9=2 r9c9<>2) r1c1<>6 r2c1=6 r2c7<>6 r2c7=2 (r1c8<>2) r9c7<>2 r9c4=2 r1c4<>2 r1c3=2 r1c3<>7
r1c3=5 r1c3<>7
r2c1=5 r2c1<>6 r1c1=6 r1c6<>6 r1c6=7 r1c3<>7
r2c2=5 r6c2<>5 r6c9=5 r6c9<>2 r6c7=2 r2c7<>2 r2c7=6 r2c1<>6 r1c1=6 r1c6<>6 r1c6=7 r1c3<>7
r3c2=5 (r1c1<>5) (r1c3<>5) (r2c1<>5) (r2c2<>5) r6c2<>5 r6c9=5 r2c9<>5 r2c5=5 r1c4<>5 r1c8=5 r1c8<>9 r1c3=9 r1c3<>7
r3c3=5 (r1c1<>5) (r1c3<>5) r9c3<>5 r9c4=5 r1c4<>5 r1c8=5 r1c8<>9 r1c3=9 r1c3<>7
Forcing Net Verity => r1c1<>7
r9c3=2 (r9c3<>7) r9c3<>3 r7c3=3 r7c3<>7 r3c3=7 r1c1<>7
r9c4=2 r9c4<>5 r9c3=5 (r9c3<>7) r9c3<>3 r7c3=3 r7c3<>7 r3c3=7 r1c1<>7
r9c7=2 r2c7<>2 r2c7=6 r2c1<>6 r1c1=6 r1c1<>7
r9c9=2 r6c9<>2 r6c7=2 r2c7<>2 r2c7=6 r2c1<>6 r1c1=6 r1c1<>7
Discontinuous Nice Loop: 7 r3c5 -7- r3c3 =7= r2c1 =6= r1c1 -6- r1c6 -7- r3c5 => r3c5<>7
Finned Swordfish: 7 c158 r278 fr1c8 fr3c8 => r2c9<>7
Continuous Nice Loop: 2/5/6/7 7= r2c1 =6= r1c1 -6- r1c6 -7- r2c5 =7= r2c1 =6 => r2c1<>2, r2c1<>5, r1c48<>6, r1c4<>7
Grouped Discontinuous Nice Loop: 2 r7c3 -2- r78c1 =2= r1c1 -2- r1c4 -5- r9c4 =5= r9c3 =3= r7c3 => r7c3<>2
Grouped Discontinuous Nice Loop: 2 r9c3 -2- r78c1 =2= r1c1 -2- r1c4 -5- r9c4 =5= r9c3 => r9c3<>2
Grouped Discontinuous Nice Loop: 5 r1c1 -5- r1c4 -2- r9c4 =2= r9c79 -2- r78c8 =2= r13c8 -2- r2c7 -6- r2c1 =6= r1c1 => r1c1<>5
Discontinuous Nice Loop: 2 r1c1 -2- r1c4 -5- r9c4 =5= r9c3 -5- r8c1 =5= r4c1 -5- r6c2 =5= r6c9 =2= r6c7 -2- r2c7 -6- r2c1 =6= r1c1 => r1c1<>2
Naked Single: r1c1=6
Naked Single: r1c6=7
Naked Single: r2c1=7
Hidden Single: r6c4=7
Locked Candidates Type 1 (Pointing): 6 in b2 => r3c789<>6
Locked Candidates Type 2 (Claiming): 2 in c1 => r78c2<>2
Naked Triple: 1,4,5 in r678c2 => r23c2<>5
Locked Candidates Type 1 (Pointing): 5 in b1 => r9c3<>5
Hidden Single: r9c4=5
Naked Single: r1c4=2
Locked Candidates Type 2 (Claiming): 2 in r9 => r7c89,r8c789<>2
Hidden Single: r3c8=2
Naked Single: r2c7=6
Naked Single: r2c9=5
Naked Single: r1c8=9
Full House: r1c3=5
Naked Single: r2c5=8
Full House: r2c2=2
Naked Single: r6c9=2
Naked Single: r3c7=1
Full House: r3c9=7
Naked Single: r3c3=9
Full House: r3c2=8
Naked Single: r4c5=3
Naked Single: r5c2=9
Full House: r5c3=2
Naked Single: r6c7=8
Naked Single: r9c9=1
Naked Single: r3c5=5
Naked Single: r4c7=9
Naked Single: r6c6=1
Full House: r4c4=8
Full House: r6c2=5
Full House: r4c1=1
Naked Single: r9c6=3
Naked Single: r4c9=6
Full House: r4c8=5
Naked Single: r8c7=3
Full House: r9c7=2
Full House: r9c3=7
Full House: r7c3=3
Naked Single: r7c1=2
Full House: r8c1=5
Naked Single: r3c6=6
Full House: r3c4=3
Naked Single: r7c5=7
Full House: r8c5=2
Naked Single: r8c6=9
Full House: r7c6=8
Naked Single: r7c8=6
Full House: r8c8=7
Naked Single: r8c9=4
Full House: r7c9=9
Naked Single: r7c4=1
Full House: r7c2=4
Full House: r8c2=1
Full House: r8c4=6
|
normal_sudoku_1634
|
..9.4.8...7......13.8..1.7..235...9.8....93...9......79...6.....82....3.7.1..3..9
|
159742863276385941348691572623578194817429356594136287935264718482917635761853429
|
Basic 9x9 Sudoku 1634
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . 4 . 8 . .
. 7 . . . . . . 1
3 . 8 . . 1 . 7 .
. 2 3 5 . . . 9 .
8 . . . . 9 3 . .
. 9 . . . . . . 7
9 . . . 6 . . . .
. 8 2 . . . . 3 .
7 . 1 . . 3 . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
159742863276385941348691572623578194817429356594136287935264718482917635761853429 #1 Extreme (20088) bf
Hidden Single: r6c2=9
Hidden Single: r1c9=3
Hidden Single: r5c3=7
Hidden Single: r7c2=3
Brute Force: r5c8=5
Almost Locked Set XY-Wing: A=r235689c5 {1235789}, B=r4c79,r5c9,r6c7 {12468}, C=r8c1679 {14567}, X,Y=1,7, Z=8 => r4c5<>8
Forcing Net Contradiction in r6c8 => r1c1<>6
r1c1=6 (r8c1<>6) (r2c3<>6 r6c3=6 r6c3<>5) (r2c3<>6 r6c3=6 r5c2<>6 r9c2=6 r9c2<>5) r1c1<>1 r1c2=1 r1c2<>5 r3c2=5 (r3c9<>5) r2c3<>5 r7c3=5 r7c9<>5 r8c9=5 r8c9<>6 r8c7=6 (r8c7<>1) r8c7<>7 r7c7=7 r7c7<>1 r7c8=1 r6c8<>1
r1c1=6 r1c8<>6 r1c8=2 r6c8<>2
r1c1=6 (r1c1<>1 r1c2=1 r5c2<>1 r5c2=4 r4c1<>4 r4c1=1 r4c7<>1) (r1c6<>6) (r1c8<>6) (r1c2<>6) (r3c2<>6) r2c3<>6 r6c3=6 (r6c6<>6) (r6c8<>6) r5c2<>6 r9c2=6 r9c8<>6 r2c8=6 r2c6<>6 r4c6=6 r4c7<>6 r4c7=4 r6c8<>4
r1c1=6 r2c3<>6 r6c3=6 r6c8<>6
r1c1=6 (r1c1<>1 r1c2=1 r1c2<>5 r3c2=5 r3c9<>5 r3c9=4 r4c9<>4) (r1c6<>6) (r1c8<>6) (r1c2<>6) (r3c2<>6) r2c3<>6 r6c3=6 (r6c6<>6) (r6c8<>6) r5c2<>6 r9c2=6 r9c8<>6 r2c8=6 r2c6<>6 r4c6=6 r4c9<>6 r4c9=8 r6c8<>8
Forcing Net Contradiction in c6 => r1c2<>6
r1c2=6 r1c8<>6 r1c8=2 r1c6<>2
r1c2=6 r1c8<>6 r1c8=2 r1c1<>2 r2c1=2 r2c6<>2
r1c2=6 r1c2<>1 r5c2=1 r5c5<>1 r5c5=2 r6c6<>2
r1c2=6 (r1c8<>6 r1c8=2 r3c9<>2) r1c2<>1 r5c2=1 r5c5<>1 r5c5=2 r5c9<>2 r7c9=2 r7c6<>2
Almost Locked Set XZ-Rule: A=r1c128 {1256}, B=r2c138 {2456}, X=5, Z=6 => r2c7<>6
Forcing Net Contradiction in c4 => r2c1<>5
r2c1=5 (r3c2<>5 r9c2=5 r9c2<>6 r8c1=6 r8c9<>6 r8c9=4 r5c9<>4) (r3c2<>5) r6c1<>5 r6c3=5 r6c3<>6 r2c3=6 r3c2<>6 r3c2=4 r5c2<>4 r5c4=4
r2c1=5 (r1c2<>5) r3c2<>5 r9c2=5 (r9c2<>4) (r9c5<>5 r8c5=5 r8c9<>5) r9c2<>6 r8c1=6 r8c9<>6 r8c9=4 (r9c7<>4) r9c8<>4 r9c4=4
Forcing Net Contradiction in r6c8 => r2c1<>6
r2c1=6 (r2c3<>6 r6c3=6 r6c7<>6) (r2c3<>6 r6c3=6 r5c2<>6 r9c2=6 r9c7<>6) (r2c6<>6) (r2c3<>6 r6c3=6 r6c6<>6) r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 (r3c7<>6) r1c6<>6 r4c6=6 r4c7<>6 r8c7=6 (r8c7<>1) r8c7<>7 r7c7=7 r7c7<>1 r7c8=1 r6c8<>1
r2c1=6 (r2c8<>6) (r2c3<>6 r6c3=6 r6c3<>5 r6c1=5 r8c1<>5 r7c3=5 r2c3<>5) (r2c3<>6 r6c3=6 r5c2<>6 r9c2=6 r9c2<>5) r2c1<>2 r1c1=2 (r1c1<>5) r1c1<>1 r1c2=1 (r5c2<>1 r5c2=4 r3c2<>4) r1c2<>5 r3c2=5 r1c2<>5 r1c6=5 (r2c5<>5) r2c6<>5 r2c7=5 r2c7<>9 r3c7=9 r3c7<>4 r3c9=4 r2c8<>4 r2c8=2 r6c8<>2
r2c1=6 (r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 r1c6<>6 r4c6=6 r4c7<>6) (r2c1<>2 r1c1=2 r1c1<>1) r2c3<>6 r6c3=6 r6c3<>5 r6c1=5 r6c1<>1 r4c1=1 r4c7<>1 r4c7=4 r6c8<>4
r2c1=6 r2c3<>6 r6c3=6 r6c8<>6
r2c1=6 (r2c6<>6) (r2c3<>6 r6c3=6 r6c6<>6) r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 r1c6<>6 r4c6=6 r4c6<>8 r4c9=8 r6c8<>8
XYZ-Wing: 2/4/6 in r12c8,r2c1 => r2c7<>2
Forcing Chain Contradiction in r2c8 => r2c4<>2
r2c4=2 r2c8<>2
r2c4=2 r2c1<>2 r2c1=4 r2c8<>4
r2c4=2 r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 r2c8<>6
Forcing Chain Contradiction in r2c8 => r2c5<>2
r2c5=2 r2c8<>2
r2c5=2 r2c1<>2 r2c1=4 r2c8<>4
r2c5=2 r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 r2c8<>6
Forcing Chain Contradiction in r2c8 => r2c6<>2
r2c6=2 r2c8<>2
r2c6=2 r2c1<>2 r2c1=4 r2c8<>4
r2c6=2 r2c1<>2 r1c1=2 r1c8<>2 r1c8=6 r2c8<>6
Forcing Chain Contradiction in r2c8 => r2c7<>4
r2c7=4 r2c1<>4 r2c1=2 r2c8<>2
r2c7=4 r2c8<>4
r2c7=4 r2c13<>4 r3c2=4 r3c2<>6 r2c3=6 r2c8<>6
Forcing Net Contradiction in r6c8 => r2c3<>5
r2c3=5 (r2c5<>5) (r1c2<>5 r1c6=5 r3c5<>5) (r1c2<>5) r3c2<>5 r9c2=5 r9c5<>5 r8c5=5 (r8c5<>1) r8c5<>9 r8c4=9 r8c4<>1 r8c7=1 r7c8<>1 r6c8=1
r2c3=5 (r7c3<>5 r7c3=4 r7c8<>4) (r2c3<>6 r6c3=6 r5c2<>6 r5c2=4 r4c1<>4 r2c1=4 r2c8<>4) (r2c5<>5) (r1c2<>5 r1c6=5 r3c5<>5) (r1c2<>5) r3c2<>5 r9c2=5 (r8c1<>5 r8c1=6 r8c9<>6) r9c5<>5 r8c5=5 r8c9<>5 r8c9=4 r9c8<>4 r6c8=4
Naked Triple: 2,4,6 in r2c138 => r2c46<>6
Forcing Net Contradiction in r3 => r2c3=6
r2c3<>6 (r2c8=6 r1c8<>6 r1c8=2 r9c8<>2) (r2c8=6 r9c8<>6) (r2c3=4 r7c3<>4 r7c3=5 r9c2<>5) r3c2=6 r9c2<>6 r9c2=4 (r9c4<>4) r9c8<>4 r9c8=8 r9c4<>8 r9c4=2 r3c4<>2
r2c3<>6 (r6c3=6 r5c2<>6) (r2c3=4 r7c3<>4 r7c3=5 r9c2<>5) r3c2=6 r9c2<>6 r9c2=4 r5c2<>4 r5c2=1 r5c5<>1 r5c5=2 r3c5<>2
r2c3<>6 r2c8=6 r1c8<>6 r1c8=2 r3c7<>2
r2c3<>6 r2c8=6 r1c8<>6 r1c8=2 r3c9<>2
Grouped Discontinuous Nice Loop: 4 r3c7 -4- r3c2 -5- r3c79 =5= r2c7 =9= r3c7 => r3c7<>4
Finned Swordfish: 4 r359 c249 fr9c7 fr9c8 => r78c9<>4
Forcing Chain Contradiction in c9 => r9c2<>4
r9c2=4 r3c2<>4 r3c9=4 r3c9<>6
r9c2=4 r3c2<>4 r3c2=5 r1c12<>5 r1c6=5 r2c6<>5 r2c6=8 r4c6<>8 r4c9=8 r4c9<>6
r9c2=4 r9c2<>6 r5c2=6 r5c9<>6
r9c2=4 r9c2<>6 r8c1=6 r8c9<>6
Turbot Fish: 4 r2c8 =4= r2c1 -4- r8c1 =4= r7c3 => r7c8<>4
Forcing Net Contradiction in r2c8 => r2c1=2
r2c1<>2 r2c1=4 (r8c1<>4) r3c2<>4 r5c2=4 (r5c2<>6) r5c2<>6 r9c2=6 r8c1<>6 r8c1=5 r8c9<>5 r8c9=6 r5c9<>6 r5c4=6 (r4c6<>6) r6c6<>6 r1c6=6 r1c8<>6 r1c8=2 r2c8<>2 r2c1=2
Naked Single: r2c8=4
Hidden Single: r3c2=4
Locked Candidates Type 1 (Pointing): 5 in b1 => r1c6<>5
Locked Candidates Type 1 (Pointing): 4 in b9 => r46c7<>4
Forcing Chain Contradiction in r7 => r5c9<>2
r5c9=2 r5c5<>2 r5c5=1 r5c2<>1 r5c2=6 r9c2<>6 r9c2=5 r7c3<>5
r5c9=2 r5c9<>4 r4c9=4 r4c9<>8 r4c6=8 r2c6<>8 r2c6=5 r7c6<>5
r5c9=2 r5c5<>2 r5c5=1 r5c2<>1 r5c2=6 r9c2<>6 r8c1=6 r8c9<>6 r8c9=5 r7c7<>5
r5c9=2 r5c9<>4 r4c9=4 r4c9<>8 r7c9=8 r7c9<>5
Locked Candidates Type 1 (Pointing): 2 in b6 => r6c456<>2
Skyscraper: 2 in r1c6,r3c9 (connected by r7c69) => r1c8,r3c45<>2
Naked Single: r1c8=6
Hidden Single: r3c4=6
Skyscraper: 6 in r5c9,r9c7 (connected by r59c2) => r46c7,r8c9<>6
Naked Single: r4c7=1
Naked Single: r8c9=5
Naked Single: r4c5=7
Naked Single: r6c7=2
Naked Single: r3c9=2
Naked Single: r6c8=8
Naked Single: r7c9=8
Naked Single: r9c8=2
Full House: r7c8=1
Hidden Single: r4c6=8
Naked Single: r2c6=5
Naked Single: r2c7=9
Full House: r3c7=5
Full House: r3c5=9
Naked Single: r8c5=1
Naked Single: r5c5=2
Naked Single: r6c5=3
Naked Single: r2c5=8
Full House: r2c4=3
Full House: r9c5=5
Naked Single: r9c2=6
Naked Single: r5c2=1
Full House: r1c2=5
Full House: r1c1=1
Naked Single: r8c1=4
Full House: r7c3=5
Full House: r6c3=4
Naked Single: r9c7=4
Full House: r9c4=8
Naked Single: r5c4=4
Full House: r5c9=6
Full House: r4c9=4
Full House: r4c1=6
Full House: r6c1=5
Naked Single: r8c6=7
Naked Single: r6c4=1
Full House: r6c6=6
Naked Single: r7c7=7
Full House: r8c7=6
Full House: r8c4=9
Naked Single: r1c6=2
Full House: r1c4=7
Full House: r7c4=2
Full House: r7c6=4
|
normal_sudoku_285
|
46...9.8.728354...9....8..518.9.6.4...9.75..6......7..3..5..19.....8......1..32..
|
465719382728354961913268475187926543239475816654831729376542198592187634841693257
|
Basic 9x9 Sudoku 285
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 6 . . . 9 . 8 .
7 2 8 3 5 4 . . .
9 . . . . 8 . . 5
1 8 . 9 . 6 . 4 .
. . 9 . 7 5 . . 6
. . . . . . 7 . .
3 . . 5 . . 1 9 .
. . . . 8 . . . .
. . 1 . . 3 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
465719382728354961913268475187926543239475816654831729376542198592187634841693257 #1 Easy (284)
Naked Single: r3c1=9
Naked Single: r5c1=2
Naked Single: r3c3=3
Naked Single: r1c7=3
Naked Single: r1c3=5
Full House: r3c2=1
Naked Single: r4c7=5
Naked Single: r5c7=8
Naked Single: r4c3=7
Hidden Single: r3c7=4
Naked Single: r8c7=6
Full House: r2c7=9
Naked Single: r8c1=5
Naked Single: r2c9=1
Full House: r2c8=6
Naked Single: r6c1=6
Full House: r9c1=8
Naked Single: r6c3=4
Naked Single: r5c2=3
Full House: r6c2=5
Naked Single: r8c3=2
Full House: r7c3=6
Naked Single: r5c8=1
Full House: r5c4=4
Hidden Single: r6c9=9
Hidden Single: r7c9=8
Hidden Single: r9c5=9
Hidden Single: r8c2=9
Hidden Single: r6c4=8
Hidden Single: r9c8=5
Hidden Single: r7c5=4
Naked Single: r7c2=7
Full House: r7c6=2
Full House: r9c2=4
Naked Single: r6c6=1
Full House: r8c6=7
Naked Single: r9c9=7
Full House: r9c4=6
Full House: r8c4=1
Naked Single: r8c8=3
Full House: r8c9=4
Naked Single: r1c9=2
Full House: r3c8=7
Full House: r6c8=2
Full House: r4c9=3
Full House: r6c5=3
Full House: r4c5=2
Naked Single: r1c4=7
Full House: r1c5=1
Full House: r3c4=2
Full House: r3c5=6
|
normal_sudoku_4434
|
.9.8...7...4.....8....419..5.........3916.7....732.8.........2.3....6..9..14..3..
|
695832471714659238823741965582974613439168752167325894946583127378216549251497386
|
Basic 9x9 Sudoku 4434
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . 8 . . . 7 .
. . 4 . . . . . 8
. . . . 4 1 9 . .
5 . . . . . . . .
. 3 9 1 6 . 7 . .
. . 7 3 2 . 8 . .
. . . . . . . 2 .
3 . . . . 6 . . 9
. . 1 4 . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
695832471714659238823741965582974613439168752167325894946583127378216549251497386 #1 Extreme (19052) bf
Brute Force: r5c5=6
Locked Candidates Type 1 (Pointing): 5 in b5 => r1279c6<>5
Discontinuous Nice Loop: 4 r6c8 -4- r5c8 -5- r5c6 =5= r6c6 =9= r6c8 => r6c8<>4
Forcing Net Contradiction in c9 => r1c7<>5
r1c7=5 (r3c9<>5) (r3c8<>5) r1c5<>5 r1c5=3 r1c3<>3 r3c3=3 (r3c9<>3) r3c8<>3 r3c8=6 r3c9<>6 r3c9=2
r1c7=5 r1c5<>5 r1c5=3 (r1c3<>3 r3c3=3 r3c3<>2) r1c6<>3 r1c6=2 (r1c3<>2) (r2c4<>2) r3c4<>2 r8c4=2 r8c3<>2 r4c3=2 r5c1<>2 r5c9=2
Forcing Net Contradiction in r8 => r1c9<>2
r1c9=2 (r1c3<>2) (r2c7<>2 r4c7=2 r4c3<>2) r1c6<>2 r1c6=3 r1c3<>3 r3c3=3 r3c3<>2 r8c3=2
r1c9=2 (r5c9<>2 r5c1=2 r2c1<>2) (r1c9<>4 r1c7=4 r1c7<>1 r1c1=1 r2c1<>1) (r1c3<>2) r1c6<>2 r1c6=3 (r1c3<>3) r1c5<>3 r1c5=5 r1c3<>5 r1c3=6 r2c1<>6 r2c1=7 (r3c1<>7) r3c2<>7 r3c4=7 (r3c4<>2) r3c4<>6 r2c4=6 r2c4<>2 r8c4=2
Forcing Net Contradiction in b9 => r1c9<>3
r1c9=3 (r1c5<>3 r1c5=5 r2c4<>5) (r1c5<>3 r1c5=5 r3c4<>5) r1c6<>3 r1c6=2 (r2c4<>2) r3c4<>2 r8c4=2 r8c4<>5 r7c4=5 r7c7<>5
r1c9=3 (r1c5<>3 r1c5=5 r2c4<>5) (r1c5<>3 r1c5=5 r3c4<>5) r1c6<>3 r1c6=2 (r2c4<>2) r3c4<>2 r8c4=2 r8c4<>5 r7c4=5 r7c9<>5
r1c9=3 (r1c5<>3 r1c5=5 r1c3<>5) (r3c9<>3 r3c3=3 r3c3<>5) (r1c5<>3 r1c5=5 r2c4<>5) (r1c5<>3 r1c5=5 r3c4<>5) r1c6<>3 r1c6=2 (r2c4<>2) r3c4<>2 r8c4=2 r8c4<>5 r7c4=5 r7c3<>5 r8c3=5 r8c7<>5
r1c9=3 (r1c5<>3 r1c5=5 r1c3<>5) (r3c9<>3 r3c3=3 r3c3<>5) (r1c5<>3 r1c5=5 r2c4<>5) (r1c5<>3 r1c5=5 r3c4<>5) r1c6<>3 r1c6=2 (r2c4<>2) r3c4<>2 r8c4=2 r8c4<>5 r7c4=5 r7c3<>5 r8c3=5 r8c8<>5
r1c9=3 (r3c9<>3 r3c3=3 r3c3<>2) r1c6<>3 r1c6=2 (r1c7<>2) (r1c3<>2) (r2c4<>2) r3c4<>2 r8c4=2 r8c3<>2 r4c3=2 r4c7<>2 r2c7=2 r2c7<>5 r78c7=5 r9c8<>5
r1c9=3 (r3c9<>3 r3c3=3 r3c3<>2) r1c6<>3 r1c6=2 (r1c7<>2) (r1c3<>2) (r2c4<>2) r3c4<>2 r8c4=2 r8c3<>2 r4c3=2 r4c7<>2 r2c7=2 r2c7<>5 r78c7=5 r9c9<>5
Forcing Net Contradiction in c9 => r1c9<>5
r1c9=5 (r3c9<>5) (r3c8<>5) r1c5<>5 r1c5=3 r1c3<>3 r3c3=3 (r3c9<>3) r3c8<>3 r3c8=6 r3c9<>6 r3c9=2
r1c9=5 r1c5<>5 r1c5=3 (r1c3<>3 r3c3=3 r3c3<>2) r1c6<>3 r1c6=2 (r1c3<>2) (r2c4<>2) r3c4<>2 r8c4=2 r8c3<>2 r4c3=2 r5c1<>2 r5c9=2
Forcing Chain Verity => r2c2<>5
r9c2=5 r2c2<>5
r9c5=5 r1c5<>5 r1c3=5 r2c2<>5
r9c8=5 r78c7<>5 r2c7=5 r2c2<>5
r9c9=5 r78c7<>5 r2c7=5 r2c2<>5
Forcing Chain Contradiction in r3c8 => r2c4<>2
r2c4=2 r1c6<>2 r1c6=3 r1c3<>3 r3c3=3 r3c8<>3
r2c4=2 r1c6<>2 r1c6=3 r1c5<>3 r1c5=5 r1c3<>5 r3c23=5 r3c8<>5
r2c4=2 r2c4<>6 r3c4=6 r3c8<>6
Forcing Net Verity => r7c4=5
r2c4=5 (r8c4<>5) (r2c4<>6 r3c4=6 r3c9<>6) (r2c4<>6 r3c4=6 r3c8<>6) r1c5<>5 r1c5=3 r1c3<>3 r3c3=3 (r3c3<>2) (r3c9<>3) r3c8<>3 r3c8=5 r3c9<>5 r3c9=2 (r2c7<>2 r4c7=2 r4c3<>2) r3c4<>2 r8c4=2 r8c3<>2 r1c3=2 r1c3<>5 r1c5=5 (r2c4<>5) r3c4<>5 r7c4=5
r3c4=5 (r2c4<>5) (r8c4<>5) (r3c9<>5) (r3c8<>5) r1c5<>5 r1c5=3 r1c3<>3 r3c3=3 (r3c3<>2) (r3c9<>3) r3c8<>3 r3c8=6 r3c9<>6 r3c9=2 (r2c7<>2 r4c7=2 r4c3<>2) r3c4<>2 r8c4=2 r8c3<>2 r1c3=2 r1c3<>5 r1c5=5 r3c4<>5 r7c4=5
r7c4=5 r7c4=5
r8c4=5 (r2c4<>5) r8c4<>2 r3c4=2 (r3c3<>2) r1c6<>2 r1c6=3 r1c3<>3 r3c3=3 (r3c9<>3) (r3c8<>3) r3c3<>5 r3c2=5 (r3c9<>5) r3c8<>5 r3c8=6 r3c9<>6 r3c9=2 (r2c7<>2 r4c7=2 r4c3<>2) r3c4<>2 r8c4=2 (r8c4<>5) r8c3<>2 r1c3=2 r1c3<>5 r1c5=5 (r1c3<>5) r3c4<>5 r7c4=5
Forcing Chain Contradiction in c3 => r8c3<>2
r8c3=2 r8c4<>2 r3c4=2 r1c6<>2 r1c6=3 r1c5<>3 r1c5=5 r1c3<>5
r8c3=2 r8c4<>2 r3c4=2 r1c6<>2 r1c6=3 r1c3<>3 r3c3=3 r3c3<>5
r8c3=2 r8c3<>5
Almost Locked Set XZ-Rule: A=r7c12379 {146789}, B=r8c378 {1458}, X=1, Z=8 => r8c2<>8
Forcing Chain Contradiction in r3 => r2c2<>2
r2c2=2 r3c1<>2
r2c2=2 r3c2<>2
r2c2=2 r3c3<>2
r2c2=2 r8c2<>2 r8c4=2 r3c4<>2
r2c2=2 r89c2<>2 r9c1=2 r5c1<>2 r5c9=2 r3c9<>2
Forcing Net Verity => r2c4=6
r3c9=2 (r3c3<>2) (r1c7<>2) r2c7<>2 r4c7=2 r4c3<>2 r1c3=2 (r1c6<>2 r1c6=3 r2c5<>3 r2c8=3 r2c8<>6) (r1c3<>6) (r1c3<>5) r1c3<>3 r3c3=3 (r3c8<>3) r3c3<>5 r8c3=5 (r8c2<>5) r9c2<>5 r3c2=5 r3c8<>5 r3c8=6 (r2c7<>6) r1c9<>6 r1c1=6 (r2c1<>6) (r1c7<>6) r2c2<>6 r2c4=6
r3c9=3 (r3c9<>2) r3c3<>3 r1c3=3 (r1c5<>3 r1c5=5 r2c5<>5) r1c6<>3 r1c6=2 r1c7<>2 r2c7=2 r2c7<>5 r2c8=5 (r8c8<>5) (r5c8<>5 r5c8=4 r8c8<>4) r2c7<>5 r8c7=5 (r8c7<>4 r8c2=4 r8c2<>2 r8c4=2 r9c6<>2 r9c1=2 r3c1<>2) r8c3<>5 (r3c3=5 r3c3<>2) r8c3=8 r8c8<>8 (r9c8=8 r9c5<>8) (r9c8=8 r9c6<>8) r8c8=1 (r7c7<>1) r7c9<>1 r7c5=1 (r7c5<>8) r7c5<>3 r7c6=3 r7c6<>8 r8c5=8 (r8c3<>8 r8c3=5 r9c2<>5 r3c2=5 r3c2<>2) (r8c3<>8 r8c3=5 r8c7<>5 r2c7=5 r2c7<>2) r8c5<>1 r7c5=1 (r7c5<>8) r7c5<>3 r7c6=3 r1c6<>3 r1c6=2 r2c6<>2 r2c1=2 r5c1<>2 r5c9=2 r3c9<>2 r3c4=2 r3c4<>6 r2c4=6
r3c9=5 (r3c8<>5) (r2c7<>5) r2c8<>5 r2c5=5 r1c5<>5 r1c3=5 (r1c3<>6) r1c3<>3 r3c3=3 r3c8<>3 r3c8=6 (r2c7<>6) (r2c8<>6) (r1c7<>6) r1c9<>6 r1c1=6 (r2c1<>6) r2c2<>6 r2c4=6
r3c9=6 r3c4<>6 r2c4=6
Hidden Single: r4c4=9
Hidden Single: r6c8=9
Forcing Chain Verity => r3c2<>7
r1c3=5 r1c5<>5 r1c5=3 r1c6<>3 r1c6=2 r3c4<>2 r3c4=7 r3c2<>7
r3c2=5 r3c2<>7
r3c3=5 r3c3<>3 r1c3=3 r1c6<>3 r1c6=2 r3c4<>2 r3c4=7 r3c2<>7
Forcing Net Verity => r1c1=6
r1c1=1 r2c2<>1 r2c2=7 (r2c1<>7 r2c1=2 r3c3<>2 r4c3=2 r4c7<>2 r1c7=2 r1c7<>6) (r2c1<>7 r2c1=2 r5c1<>2 r5c9=2 r3c9<>2 r3c4=2 r8c4<>2 r8c2=2 r8c2<>5) (r2c1<>7 r2c1=2 r3c3<>2) (r2c1<>7 r2c1=2 r3c1<>2) (r2c1<>7 r2c1=2 r3c2<>2) (r2c1<>7 r2c1=2 r3c3<>2) r3c1<>7 r3c4=7 r3c4<>2 r3c9=2 (r1c7<>2) r2c7<>2 r4c7=2 r4c3<>2 r1c3=2 (r1c3<>6) (r1c3<>5) r1c3<>3 r3c3=3 (r3c8<>3) r3c3<>5 r8c3=5 r9c2<>5 r3c2=5 r3c8<>5 r3c8=6 r1c9<>6 r1c1=6
r1c1=2 (r1c1<>1) (r3c1<>2) (r3c2<>2) (r3c3<>2) r5c1<>2 r5c9=2 r3c9<>2 r3c4=2 r3c4<>7 r3c1=7 (r2c1<>7) r2c2<>7 r2c2=1 r2c1<>1 r2c1=2 r1c1<>2 r1c1=6
r1c1=6 r1c1=6
Locked Candidates Type 1 (Pointing): 1 in b1 => r2c78<>1
Naked Triple: 2,3,5 in r1c356 => r1c7<>2
X-Wing: 6 c37 r47 => r4c289,r7c29<>6
2-String Kite: 2 in r2c7,r5c1 (connected by r4c7,r5c9) => r2c1<>2
Locked Pair: 1,7 in r2c12 => r2c56,r3c1<>7
Hidden Single: r3c4=7
Full House: r8c4=2
Continuous Nice Loop: 1/4/5/8 6= r4c7 =2= r2c7 =5= r8c7 -5- r8c3 -8- r7c3 -6- r7c7 =6= r4c7 =2 => r4c7<>1, r4c7<>4, r8c28<>5, r34c3,r7c12,r9c12<>8
Locked Pair: 4,7 in r78c2 => r29c2,r79c1<>7, r46c2,r7c1<>4
Naked Single: r2c2=1
Naked Single: r7c1=9
Naked Single: r2c1=7
Naked Single: r6c2=6
Naked Single: r9c1=2
Naked Single: r4c3=2
Naked Single: r3c1=8
Naked Single: r9c2=5
Naked Single: r4c2=8
Naked Single: r4c7=6
Naked Single: r5c1=4
Full House: r6c1=1
Naked Single: r3c2=2
Naked Single: r8c3=8
Naked Single: r4c5=7
Naked Single: r5c8=5
Naked Single: r7c3=6
Naked Single: r4c6=4
Naked Single: r8c5=1
Naked Single: r2c8=3
Naked Single: r5c6=8
Full House: r5c9=2
Full House: r6c6=5
Full House: r6c9=4
Naked Single: r8c8=4
Naked Single: r3c8=6
Naked Single: r4c8=1
Full House: r9c8=8
Full House: r4c9=3
Naked Single: r1c9=1
Naked Single: r7c7=1
Naked Single: r8c2=7
Full House: r8c7=5
Full House: r7c2=4
Naked Single: r3c9=5
Full House: r3c3=3
Full House: r1c3=5
Naked Single: r9c5=9
Naked Single: r1c7=4
Full House: r2c7=2
Naked Single: r7c9=7
Full House: r9c9=6
Full House: r9c6=7
Naked Single: r1c5=3
Full House: r1c6=2
Naked Single: r2c5=5
Full House: r2c6=9
Full House: r7c6=3
Full House: r7c5=8
|
normal_sudoku_1497
|
.4..2.7..7251.9.8.36.....19.1...7.9.......4..2...86....8...3...9..2..1.........7.
|
149628753725139684368754219516347892893512467274986531681473925937265148452891376
|
Basic 9x9 Sudoku 1497
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . . 2 . 7 . .
7 2 5 1 . 9 . 8 .
3 6 . . . . . 1 9
. 1 . . . 7 . 9 .
. . . . . . 4 . .
2 . . . 8 6 . . .
. 8 . . . 3 . . .
9 . . 2 . . 1 . .
. . . . . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
149628753725139684368754219516347892893512467274986531681473925937265148452891376 #1 Medium (464)
Naked Single: r2c3=5
Naked Single: r3c3=8
Naked Single: r1c1=1
Full House: r1c3=9
Hidden Single: r3c7=2
Hidden Single: r2c9=4
Hidden Single: r5c6=2
Hidden Single: r6c9=1
Hidden Single: r4c9=2
Hidden Single: r7c8=2
Hidden Single: r9c6=1
Hidden Single: r5c5=1
Hidden Single: r5c9=7
Hidden Single: r9c3=2
Hidden Single: r8c8=4
Hidden Single: r7c3=1
Hidden Single: r5c1=8
Hidden Single: r4c7=8
Hidden Single: r3c6=4
Hidden Single: r5c8=6
Naked Single: r5c3=3
Locked Candidates Type 1 (Pointing): 5 in b3 => r1c46<>5
Naked Single: r1c6=8
Full House: r8c6=5
Hidden Single: r9c4=8
Hidden Single: r8c9=8
Hidden Single: r8c2=3
Naked Single: r9c2=5
Naked Single: r5c2=9
Full House: r5c4=5
Full House: r6c2=7
Naked Single: r3c4=7
Full House: r3c5=5
Naked Single: r6c3=4
Naked Single: r4c3=6
Full House: r4c1=5
Full House: r8c3=7
Full House: r8c5=6
Naked Single: r2c5=3
Full House: r1c4=6
Full House: r2c7=6
Naked Single: r4c5=4
Full House: r4c4=3
Full House: r6c4=9
Full House: r7c4=4
Naked Single: r9c5=9
Full House: r7c5=7
Naked Single: r7c1=6
Full House: r9c1=4
Naked Single: r9c7=3
Full House: r9c9=6
Naked Single: r7c9=5
Full House: r1c9=3
Full House: r7c7=9
Full House: r6c7=5
Full House: r1c8=5
Full House: r6c8=3
|
normal_sudoku_2179
|
.78.534..3..4718...426......1.....269.7.....3..3....7..2..6.......14...745...7.81
|
678253419395471862142689735514738926987526143263914578721865394839142657456397281
|
Basic 9x9 Sudoku 2179
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 8 . 5 3 4 . .
3 . . 4 7 1 8 . .
. 4 2 6 . . . . .
. 1 . . . . . 2 6
9 . 7 . . . . . 3
. . 3 . . . . 7 .
. 2 . . 6 . . . .
. . . 1 4 . . . 7
4 5 . . . 7 . 8 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
678253419395471862142689735514738926987526143263914578721865394839142657456397281 #1 Easy (284)
Hidden Single: r2c4=4
Hidden Single: r6c1=2
Hidden Single: r3c7=7
Hidden Single: r4c3=4
Hidden Single: r7c1=7
Hidden Single: r8c2=3
Hidden Single: r4c4=7
Hidden Single: r6c9=8
Naked Single: r6c2=6
Naked Single: r2c2=9
Full House: r5c2=8
Full House: r4c1=5
Naked Single: r3c1=1
Naked Single: r4c7=9
Naked Single: r1c1=6
Full House: r2c3=5
Full House: r8c1=8
Naked Single: r4c6=8
Full House: r4c5=3
Naked Single: r2c8=6
Full House: r2c9=2
Naked Single: r3c6=9
Naked Single: r1c9=9
Naked Single: r1c4=2
Full House: r3c5=8
Full House: r1c8=1
Naked Single: r3c9=5
Full House: r3c8=3
Full House: r7c9=4
Naked Single: r7c6=5
Naked Single: r5c4=5
Naked Single: r6c6=4
Naked Single: r7c7=3
Naked Single: r7c8=9
Naked Single: r8c6=2
Full House: r5c6=6
Naked Single: r5c7=1
Naked Single: r5c8=4
Full House: r8c8=5
Full House: r5c5=2
Full House: r6c7=5
Naked Single: r6c4=9
Full House: r6c5=1
Full House: r9c5=9
Naked Single: r7c3=1
Full House: r7c4=8
Full House: r9c4=3
Naked Single: r8c7=6
Full House: r8c3=9
Full House: r9c3=6
Full House: r9c7=2
|
normal_sudoku_1625
|
9.1.........2...7....8.....7.....16..3.17.9.419...4.3.3..4.6..16...3.7...49...6..
|
951647382863215479427893516784329165536178924192564837378456291615932748249781653
|
Basic 9x9 Sudoku 1625
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . 1 . . . . . .
. . . 2 . . . 7 .
. . . 8 . . . . .
7 . . . . . 1 6 .
. 3 . 1 7 . 9 . 4
1 9 . . . 4 . 3 .
3 . . 4 . 6 . . 1
6 . . . 3 . 7 . .
. 4 9 . . . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
951647382863215479427893516784329165536178924192564837378456291615932748249781653 #1 Extreme (14028) bf
Hidden Single: r6c1=1
Hidden Single: r3c8=1
Hidden Single: r5c3=6
Hidden Single: r6c9=7
Hidden Single: r4c3=4
Hidden Single: r8c8=4
Hidden Single: r8c2=1
Hidden Single: r9c9=3
Hidden Single: r7c8=9
Brute Force: r4c5=2
Locked Candidates Type 2 (Claiming): 9 in c5 => r23c6<>9
Naked Pair: 5,8 in r4c29 => r4c46<>5, r4c6<>8
Empty Rectangle: 8 in b1 (r4c29) => r2c9<>8
Finned X-Wing: 2 r67 c37 fr7c2 => r8c3<>2
Finned Swordfish: 2 r167 c237 fr1c8 fr1c9 => r3c7<>2
Finned Franken Swordfish: 8 r48b5 c369 fr4c2 fr6c5 => r6c3<>8
W-Wing: 5/8 in r4c9,r5c6 connected by 8 in r6c57 => r5c8<>5
Forcing Chain Contradiction in r9c1 => r4c4=3
r4c4<>3 r4c4=9 r4c6<>9 r8c6=9 r8c6<>2 r9c6=2 r9c1<>2
r4c4<>3 r4c4=9 r8c4<>9 r8c4=5 r7c5<>5 r7c5=8 r6c5<>8 r5c6=8 r5c6<>5 r5c1=5 r9c1<>5
r4c4<>3 r4c4=9 r8c4<>9 r8c4=5 r8c3<>5 r8c3=8 r9c1<>8
Naked Single: r4c6=9
Hidden Single: r8c4=9
Sashimi Swordfish: 5 r458 c369 fr4c2 fr5c1 => r6c3<>5
Naked Single: r6c3=2
Hidden Single: r5c8=2
Finned Franken Swordfish: 5 c48b6 r169 fr4c9 => r1c9<>5
Forcing Chain Contradiction in r8c9 => r9c4=7
r9c4<>7 r9c6=7 r9c6<>2 r8c6=2 r8c9<>2
r9c4<>7 r9c4=5 r7c5<>5 r7c5=8 r6c5<>8 r6c7=8 r6c7<>5 r4c9=5 r8c9<>5
r9c4<>7 r9c4=5 r9c8<>5 r9c8=8 r8c9<>8
W-Wing: 8/5 in r1c8,r6c7 connected by 5 in r16c4 => r12c7<>8
Locked Candidates Type 1 (Pointing): 8 in b3 => r1c2<>8
2-String Kite: 8 in r4c2,r7c7 (connected by r4c9,r6c7) => r7c2<>8
W-Wing: 5/8 in r4c9,r9c8 connected by 8 in r1c89 => r8c9<>5
Skyscraper: 5 in r5c1,r8c3 (connected by r58c6) => r9c1<>5
W-Wing: 8/2 in r8c9,r9c1 connected by 2 in r7c27 => r8c3,r9c8<>8
Naked Single: r8c3=5
Naked Single: r9c8=5
Full House: r1c8=8
Hidden Single: r7c5=5
2-String Kite: 8 in r5c1,r9c5 (connected by r5c6,r6c5) => r9c1<>8
Naked Single: r9c1=2
Naked Single: r7c2=7
Full House: r7c3=8
Full House: r7c7=2
Full House: r8c9=8
Full House: r8c6=2
Naked Single: r2c3=3
Full House: r3c3=7
Naked Single: r4c9=5
Full House: r4c2=8
Full House: r6c7=8
Full House: r5c1=5
Full House: r5c6=8
Naked Single: r6c5=6
Full House: r6c4=5
Full House: r1c4=6
Naked Single: r3c1=4
Full House: r2c1=8
Naked Single: r9c6=1
Full House: r9c5=8
Naked Single: r1c5=4
Naked Single: r1c9=2
Naked Single: r3c5=9
Full House: r2c5=1
Naked Single: r2c6=5
Naked Single: r1c2=5
Naked Single: r3c9=6
Full House: r2c9=9
Naked Single: r2c2=6
Full House: r2c7=4
Full House: r3c2=2
Naked Single: r3c6=3
Full House: r1c6=7
Full House: r1c7=3
Full House: r3c7=5
|
normal_sudoku_4482
|
.2...9.1...57..9....9.8...6..42..1...1...723.....6...8.5.3..7....1..4.2.9........
|
327649815685713942149582376594238167816457239273961458458326791761894523932175684
|
Basic 9x9 Sudoku 4482
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . . 9 . 1 .
. . 5 7 . . 9 . .
. . 9 . 8 . . . 6
. . 4 2 . . 1 . .
. 1 . . . 7 2 3 .
. . . . 6 . . . 8
. 5 . 3 . . 7 . .
. . 1 . . 4 . 2 .
9 . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
327649815685713942149582376594238167816457239273961458458326791761894523932175684 #1 Extreme (19648) bf
Brute Force: r5c7=2
Hidden Single: r3c6=2
Hidden Single: r2c9=2
Hidden Single: r4c8=6
Finned Swordfish: 6 r157 c134 fr7c6 => r89c4<>6
Hidden Single: r1c4=6
Forcing Chain Contradiction in c2 => r6c1<>7
r6c1=7 r6c8<>7 r3c8=7 r3c2<>7
r6c1=7 r4c2<>7
r6c1=7 r6c2<>7
r6c1=7 r6c1<>2 r6c3=2 r9c3<>2 r9c5=2 r9c5<>7 r8c5=7 r8c2<>7
r6c1=7 r6c1<>2 r7c1=2 r7c1<>4 r9c2=4 r9c2<>7
Forcing Net Contradiction in r9 => r6c1=2
r6c1<>2 r7c1=2 r7c1<>4 r9c2=4 r9c2<>3
r6c1<>2 (r6c3=2 r9c3<>2 r9c5=2 r9c5<>7) r7c1=2 r7c1<>4 r9c2=4 r9c2<>7 r9c3=7 r9c3<>3
r6c1<>2 (r6c3=2 r6c3<>3) (r6c3=2 r9c3<>2 r9c5=2 r9c5<>7) r7c1=2 r7c1<>4 r9c2=4 r9c2<>7 r9c3=7 r9c3<>3 r1c3=3 (r3c1<>3) r3c2<>3 r3c7=3 r9c7<>3
r6c1<>2 (r6c3=2 r6c3<>3) r7c1=2 r7c1<>4 r9c2=4 (r3c2<>4) r9c2<>7 r9c3=7 (r1c3<>7) r9c3<>3 r1c3=3 r3c2<>3 r3c2=7 r3c8<>7 r6c8=7 (r6c8<>9 r7c8=9 r7c5<>9) r6c3<>7 r9c3=7 (r1c3<>7) r9c3<>2 r9c5=2 (r9c5<>1) (r9c5<>7) r7c5<>2 r7c5=1 (r9c4<>1) r9c6<>1 r9c9=1 r9c9<>3
Almost Locked Set XZ-Rule: A=r246c6 {1358}, B=r4c12,r6c23 {35789}, X=8, Z=5 => r4c5<>5
Forcing Net Contradiction in c2 => r1c5<>3
r1c5=3 (r2c5<>3) r2c6<>3 r2c6=1 r2c5<>1 r2c5=4 r2c8<>4 r2c8=8 r2c2<>8
r1c5=3 (r1c5<>5 r3c4=5 r9c4<>5) r2c6<>3 r2c6=1 r6c6<>1 r6c4=1 r9c4<>1 r9c4=8 (r7c6<>8) r9c6<>8 r4c6=8 r4c2<>8
r1c5=3 (r1c5<>5 r3c4=5 r9c4<>5) r2c6<>3 r2c6=1 (r2c5<>1 r2c5=4 r2c8<>4 r2c8=8 r1c7<>8) r6c6<>1 r6c4=1 r9c4<>1 r9c4=8 r9c7<>8 r8c7=8 r8c2<>8
r1c5=3 (r1c5<>5 r3c4=5 r9c4<>5) r2c6<>3 r2c6=1 r6c6<>1 r6c4=1 r9c4<>1 r9c4=8 r9c2<>8
Locked Candidates Type 1 (Pointing): 3 in b2 => r2c12<>3
Forcing Net Contradiction in r9c3 => r1c7<>4
r1c7=4 (r1c5<>4 r1c5=5 r3c4<>5) r6c7<>4 r6c7=5 r3c7<>5 r3c8=5 r9c8<>5 r9c8=4 (r7c9<>4) (r7c8<>4) r2c8<>4 r2c8=8 (r9c8<>8) r7c8<>8 r7c8=9 (r7c5<>9) r7c9<>9 r7c9=1 r7c5<>1 r7c5=2 r9c5<>2 r9c3=2
r1c7=4 (r1c5<>4 r1c5=5 r3c4<>5) r6c7<>4 r6c7=5 r3c7<>5 (r3c7=3 r1c9<>3 r1c9=7 r1c3<>7) r3c8=5 r3c8<>7 r6c8=7 r6c3<>7 r9c3=7
Forcing Net Contradiction in c4 => r1c7<>5
r1c7=5 (r3c7<>5) r3c8<>5 r3c4=5
r1c7=5 (r8c7<>5) (r1c5<>5 r1c5=4 r1c9<>4) (r6c7<>5 r6c7=4 r3c7<>4) r1c7<>8 r2c8=8 r2c8<>4 r3c8=4 (r9c8<>4 r9c8=5 r8c9<>5) (r3c2<>4 r3c2=7 r4c2<>7 r4c1=7 r8c1<>7) r3c8<>7 r6c8=7 (r6c3<>7) r4c9<>7 r1c9=7 r1c3<>7 r9c3=7 r8c2<>7 r8c5=7 r8c5<>5 r8c4=5
Forcing Net Contradiction in r9 => r3c8=7
r3c8<>7 r6c8=7 r4c9<>7 r1c9=7 (r1c9<>4) r1c9<>5 r1c5=5 r1c5<>4 r1c1=4 (r2c2<>4) r3c2<>4 r9c2=4 r9c2<>3
r3c8<>7 r6c8=7 r6c3<>7 r6c3=3 r9c3<>3
r3c8<>7 r6c8=7 (r4c9<>7 r1c9=7 r1c3<>7) r6c3<>7 r6c3=3 r1c3<>3 r1c3=8 r1c7<>8 r1c7=3 r9c7<>3
r3c8<>7 r6c8=7 (r6c8<>9 r7c8=9 r7c5<>9) r4c9<>7 r1c9=7 (r1c3<>7) r3c8<>7 r6c8=7 (r6c8<>9 r7c8=9 r7c5<>9) r6c3<>7 r9c3=7 r9c3<>2 r9c5=2 (r9c5<>1) r7c5<>2 r7c5=1 (r9c4<>1) r9c6<>1 r9c9=1 r9c9<>3
Hidden Single: r4c9=7
Finned X-Wing: 5 c68 r69 fr4c6 => r6c4<>5
Sue de Coq: r4c12 - {3589} (r4c5 - {39}, r5c13 - {568}) => r4c6<>3
Forcing Chain Verity => r1c1<>4
r1c1=3 r1c1<>4
r3c1=3 r3c2<>3 r3c2=4 r1c1<>4
r4c1=3 r6c3<>3 r6c3=7 r1c3<>7 r1c1=7 r1c1<>4
r8c1=3 r8c1<>7 r1c1=7 r1c1<>4
Naked Triple: 3,7,8 in r1c137 => r1c9<>3
Locked Candidates Type 1 (Pointing): 3 in b3 => r89c7<>3
Almost Locked Set XZ-Rule: A=r7c13568 {124689}, B=r9c4678 {14568}, X=1, Z=4 => r7c9<>4
Almost Locked Set XY-Wing: A=r7c9 {19}, B=r79c6,r9c4 {1568}, C=r279c8 {4589}, X,Y=5,9, Z=1 => r7c5<>1
Grouped Discontinuous Nice Loop: 3 r9c3 -3- r9c9 =3= r8c9 =9= r7c89 -9- r7c5 -2- r7c3 =2= r9c3 => r9c3<>3
Forcing Chain Contradiction in r9 => r3c1=1
r3c1<>1 r3c4=1 r3c4<>5 r3c7=5 r3c7<>3 r1c7=3 r1c3<>3 r6c3=3 r6c3<>7 r6c2=7 r9c2<>7
r3c1<>1 r3c4=1 r2c5<>1 r9c5=1 r9c5<>2 r9c3=2 r9c3<>7
r3c1<>1 r3c4=1 r2c5<>1 r9c5=1 r9c5<>7
Naked Pair: 4,5 in r1c5,r3c4 => r2c5<>4
Discontinuous Nice Loop: 5 r9c9 -5- r1c9 =5= r3c7 =3= r3c2 -3- r9c2 =3= r9c9 => r9c9<>5
Grouped Discontinuous Nice Loop: 8 r1c1 -8- r1c7 -3- r3c7 =3= r3c2 -3- r89c2 =3= r8c1 =7= r1c1 => r1c1<>8
Forcing Chain Contradiction in r5c9 => r7c9=1
r7c9<>1 r7c6=1 r6c6<>1 r6c4=1 r6c4<>4 r5c45=4 r5c9<>4
r7c9<>1 r9c9=1 r9c9<>3 r9c2=3 r3c2<>3 r3c7=3 r3c7<>5 r1c9=5 r5c9<>5
r7c9<>1 r7c9=9 r5c9<>9
2-String Kite: 9 in r5c9,r7c5 (connected by r7c8,r8c9) => r5c5<>9
Naked Pair: 4,5 in r15c5 => r89c5<>5
Empty Rectangle: 5 in b8 (r3c47) => r9c7<>5
W-Wing: 6/8 in r5c3,r7c6 connected by 8 in r4c6,r5c4 => r7c3<>6
Discontinuous Nice Loop: 3/8 r4c1 =5= r4c6 =8= r5c4 =9= r5c9 -9- r8c9 =9= r7c8 -9- r7c5 -2- r7c3 -8- r1c3 =8= r1c7 =3= r3c7 =5= r3c4 -5- r1c5 =5= r5c5 -5- r5c1 =5= r4c1 => r4c1<>3, r4c1<>8
Naked Single: r4c1=5
Naked Single: r4c6=8
Naked Single: r7c6=6
Naked Triple: 4,6,8 in r257c1 => r8c1<>6, r8c1<>8
X-Wing: 5 c68 r69 => r6c7,r9c4<>5
Naked Single: r6c7=4
W-Wing: 6/8 in r5c3,r9c7 connected by 8 in r1c37 => r9c3<>6
Hidden Single: r5c3=6
Naked Single: r5c1=8
Naked Single: r7c1=4
Naked Single: r2c1=6
Skyscraper: 8 in r1c7,r7c8 (connected by r17c3) => r2c8,r89c7<>8
Naked Single: r2c8=4
Naked Single: r9c7=6
Naked Single: r1c9=5
Naked Single: r2c2=8
Naked Single: r8c7=5
Naked Single: r1c5=4
Naked Single: r3c7=3
Full House: r1c7=8
Naked Single: r5c9=9
Full House: r6c8=5
Naked Single: r9c8=8
Full House: r7c8=9
Naked Single: r3c4=5
Full House: r3c2=4
Naked Single: r5c5=5
Full House: r5c4=4
Naked Single: r8c9=3
Full House: r9c9=4
Naked Single: r9c4=1
Naked Single: r7c5=2
Full House: r7c3=8
Naked Single: r8c1=7
Full House: r1c1=3
Full House: r1c3=7
Naked Single: r6c4=9
Full House: r8c4=8
Naked Single: r9c6=5
Naked Single: r9c5=7
Full House: r8c5=9
Full House: r8c2=6
Naked Single: r9c2=3
Full House: r9c3=2
Full House: r6c3=3
Naked Single: r4c5=3
Full House: r4c2=9
Full House: r6c2=7
Full House: r6c6=1
Full House: r2c5=1
Full House: r2c6=3
|
normal_sudoku_213
|
.3..6.8...87..4......1..65..9.....8.3...9.726..63..9...6..8.2..42.7..5....1..5...
|
135267894687954312249138657792546183354891726816372945563489271428713569971625438
|
Basic 9x9 Sudoku 213
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . 6 . 8 . .
. 8 7 . . 4 . . .
. . . 1 . . 6 5 .
. 9 . . . . . 8 .
3 . . . 9 . 7 2 6
. . 6 3 . . 9 . .
. 6 . . 8 . 2 . .
4 2 . 7 . . 5 . .
. . 1 . . 5 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
135267894687954312249138657792546183354891726816372945563489271428713569971625438 #1 Easy (246)
Naked Single: r8c2=2
Naked Single: r3c2=4
Naked Single: r9c2=7
Hidden Single: r2c1=6
Hidden Single: r3c6=8
Naked Single: r5c6=1
Naked Single: r5c2=5
Full House: r6c2=1
Naked Single: r6c8=4
Naked Single: r6c9=5
Hidden Single: r5c4=8
Full House: r5c3=4
Naked Single: r4c3=2
Naked Single: r3c3=9
Naked Single: r4c1=7
Full House: r6c1=8
Naked Single: r1c3=5
Naked Single: r3c1=2
Full House: r1c1=1
Naked Single: r4c6=6
Naked Single: r9c1=9
Full House: r7c1=5
Naked Single: r7c3=3
Full House: r8c3=8
Naked Single: r7c6=9
Naked Single: r7c4=4
Naked Single: r8c6=3
Naked Single: r4c4=5
Naked Single: r8c5=1
Naked Single: r9c5=2
Full House: r9c4=6
Naked Single: r4c5=4
Naked Single: r8c9=9
Full House: r8c8=6
Naked Single: r6c5=7
Full House: r6c6=2
Full House: r1c6=7
Naked Single: r9c8=3
Naked Single: r3c5=3
Full House: r2c5=5
Full House: r3c9=7
Naked Single: r1c8=9
Naked Single: r9c7=4
Full House: r9c9=8
Naked Single: r7c9=1
Full House: r7c8=7
Full House: r2c8=1
Naked Single: r1c4=2
Full House: r1c9=4
Full House: r2c4=9
Naked Single: r4c9=3
Full House: r2c9=2
Full House: r2c7=3
Full House: r4c7=1
|
normal_sudoku_6065
|
.3..7......6....7.4....9..5..83..2...9.52.6..5....8..1.....4.1.....8...98..9..54.
|
931875426256413978487269135678391254194527683523648791369754812745182369812936547
|
Basic 9x9 Sudoku 6065
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . 7 . . . .
. . 6 . . . . 7 .
4 . . . . 9 . . 5
. . 8 3 . . 2 . .
. 9 . 5 2 . 6 . .
5 . . . . 8 . . 1
. . . . . 4 . 1 .
. . . . 8 . . . 9
8 . . 9 . . 5 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
931875426256413978487269135678391254194527683523648791369754812745182369812936547 #1 Extreme (23308) bf
Discontinuous Nice Loop: 7 r7c3 -7- r3c3 =7= r3c2 =8= r2c2 =5= r1c3 =9= r7c3 => r7c3<>7
Brute Force: r5c4=5
Hidden Single: r4c8=5
Hidden Single: r4c5=9
Locked Candidates Type 1 (Pointing): 1 in b5 => r1289c6<>1
Locked Candidates Type 1 (Pointing): 4 in b5 => r6c237<>4
Locked Candidates Type 1 (Pointing): 4 in b6 => r12c9<>4
2-String Kite: 5 in r1c3,r7c5 (connected by r1c6,r2c5) => r7c3<>5
Finned Swordfish: 7 c147 r678 fr4c1 fr5c1 => r6c23<>7
Discontinuous Nice Loop: 1 r5c3 -1- r5c6 -7- r6c4 =7= r6c7 -7- r4c9 -4- r4c2 =4= r5c3 => r5c3<>1
Almost Locked Set XY-Wing: A=r6c23 {236}, B=r8c134678 {1234567}, C=r5c136 {1347}, X,Y=3,4, Z=6 => r8c2<>6
Forcing Net Contradiction in r6 => r1c7<>1
r1c7=1 (r1c7<>8) (r1c7<>9) r1c7<>4 r1c4=4 (r1c4<>6) (r1c4<>8) (r2c4<>4) r2c5<>4 r2c7=4 r2c7<>9 r2c1=9 (r1c1<>9) r1c3<>9 r1c8=9 (r1c8<>6) r1c8<>8 r1c9=8 r1c9<>6 r1c6=6 r4c6<>6 r4c12=6 r6c2<>6 r6c2=2
r1c7=1 (r1c7<>9) r1c7<>4 r1c4=4 (r2c4<>4) r2c5<>4 r2c7=4 r2c7<>9 r6c7=9 r6c8<>9 r6c8=3 r6c3<>3 r6c3=2
Forcing Net Verity => r4c9=4
r1c3=1 r1c3<>5 r8c3=5 r8c3<>4 r8c2=4 r4c2<>4 r4c9=4
r3c3=1 (r1c3<>1 r1c4=1 r1c4<>4 r1c7=4 r1c7<>9 r6c7=9 r6c7<>3) (r1c3<>1 r1c4=1 r2c5<>1 r2c7=1 r2c7<>9 r2c1=9 r1c1<>9 r1c1=2 r1c6<>2) r3c3<>7 r3c2=7 r3c2<>8 r2c2=8 r2c2<>5 r1c3=5 r1c6<>5 r1c6=6 r4c6<>6 r4c12=6 r6c2<>6 r6c2=2 r6c3<>2 r6c3=3 r6c8<>3 r6c8=9 r6c7<>9 r6c7=7 r4c9<>7 r4c9=4
r8c3=1 r8c3<>4 r8c2=4 r4c2<>4 r4c9=4
r9c3=1 (r8c2<>1) (r9c2<>1) (r1c3<>1) (r8c1<>1) (r8c2<>1) r8c3<>1 r8c4=1 r1c4<>1 r1c1=1 (r2c2<>1) r3c2<>1 r4c2=1 r4c2<>4 r4c9=4
Hidden Single: r8c2=4
Hidden Single: r5c3=4
X-Wing: 5 r18 c36 => r2c6<>5
Almost Locked Set XY-Wing: A=r8c7 {37}, B=r4c12,r5c1 {1367}, C=r6c2378 {23679}, X,Y=6,7, Z=3 => r8c1<>3
Discontinuous Nice Loop: 2 r7c3 -2- r6c3 -3- r5c1 =3= r7c1 =9= r7c3 => r7c3<>2
Forcing Net Contradiction in r8 => r1c3<>2
r1c3=2 (r1c1<>2) (r2c1<>2) r6c3<>2 r6c3=3 r5c1<>3 r7c1=3 r7c1<>2 r8c1=2 r8c1<>7
r1c3=2 r1c3<>5 r1c6=5 r8c6<>5 r8c3=5 r8c3<>7
r1c3=2 (r1c3<>5 r1c6=5 r8c6<>5 r8c3=5 r8c3<>1) (r1c1<>2) (r2c1<>2) r6c3<>2 r6c3=3 r5c1<>3 r7c1=3 r7c1<>2 r8c1=2 r8c1<>1 r8c4=1 r8c4<>7
r1c3=2 r6c3<>2 r6c3=3 (r6c7<>3) r6c8<>3 r6c8=9 r6c7<>9 r6c7=7 r6c4<>7 r78c4=7 r8c6<>7
r1c3=2 r6c3<>2 r6c3=3 (r6c7<>3) r6c8<>3 r6c8=9 r6c7<>9 r6c7=7 r8c7<>7
Forcing Net Contradiction in r2c1 => r6c5=4
r6c5<>4 (r2c5=4 r2c5<>5 r2c2=5 r1c3<>5) r6c5=6 r6c2<>6 r6c2=2 r6c3<>2 r6c3=3 r7c3<>3 r7c3=9 r1c3<>9 r1c3=1 r2c1<>1
r6c5<>4 (r6c5=6 r3c5<>6) r6c4=4 (r1c4<>4 r1c7=4 r1c7<>9) r6c4<>7 r6c7=7 r6c7<>9 r2c7=9 r2c7<>1 r3c7=1 r3c5<>1 r3c5=3 r2c6<>3 r2c6=2 r2c1<>2
r6c5<>4 r6c4=4 (r1c4<>4 r1c7=4 r1c7<>9) r6c4<>7 r6c7=7 r6c7<>9 r2c7=9 r2c1<>9
Almost Locked Set XY-Wing: A=r2c69 {238}, B=r13678c4 {124678}, C=r1c136789 {1245689}, X,Y=4,8, Z=2 => r2c4<>2
Forcing Chain Contradiction in c4 => r2c2<>1
r2c2=1 r1c13<>1 r1c4=1 r1c4<>8
r2c2=1 r1c13<>1 r1c4=1 r1c4<>4 r2c4=4 r2c4<>8
r2c2=1 r2c2<>8 r3c2=8 r3c4<>8
Forcing Net Contradiction in r3c5 => r7c3=9
r7c3<>9 r7c1=9 r2c1<>9 r2c7=9 r2c7<>1 r3c7=1 r3c5<>1
r7c3<>9 (r7c3=3 r7c1<>3 r5c1=3 r5c8<>3) (r7c3=3 r7c1<>3 r5c1=3 r5c9<>3) (r7c3=3 r7c9<>3) r7c1=9 (r1c1<>9) r2c1<>9 r2c7=9 (r6c7<>9 r6c8=9 r6c8<>3) (r2c7<>4 r2c4=4 r2c4<>8) (r2c7<>8) r1c8<>9 r1c3=9 (r1c7<>9) r1c3<>5 r1c6=5 r2c5<>5 r2c2=5 r2c2<>8 r2c9=8 r2c9<>3 r9c9=3 r8c8<>3 r3c8=3 r3c5<>3
r7c3<>9 (r7c3=3 r7c1<>3 r5c1=3 r5c9<>3) (r7c3=3 r7c9<>3) r1c3=9 (r1c3<>5 r1c6=5 r2c5<>5 r2c2=5 r2c2<>8) r2c1<>9 r2c7=9 (r2c7<>8) r2c7<>4 r2c4=4 r2c4<>8 r2c9=8 r2c9<>3 r9c9=3 (r9c9<>6) r8c7<>3 r8c7=7 r6c7<>7 r6c4=7 r6c4<>6 r6c2=6 (r4c2<>6 r4c6=6 r9c6<>6) r9c2<>6 r9c5=6 r3c5<>6
Forcing Chain Contradiction in r7 => r8c6<>7
r8c6=7 r78c4<>7 r6c4=7 r6c4<>6 r6c2=6 r6c2<>2 r6c3=2 r6c3<>3 r5c1=3 r7c1<>3
r8c6=7 r8c6<>5 r7c5=5 r7c5<>3
r8c6=7 r8c7<>7 r8c7=3 r7c7<>3
r8c6=7 r8c7<>7 r8c7=3 r7c9<>3
Forcing Net Verity => r1c4<>2
r1c1=2 r1c4<>2
r2c1=2 (r2c9<>2) r2c6<>2 r2c6=3 r2c9<>3 r2c9=8 (r1c7<>8) (r1c8<>8) r1c9<>8 r1c4=8 r1c4<>2
r2c2=2 (r2c2<>5 r2c5=5 r1c6<>5) r6c2<>2 r6c2=6 (r4c1<>6) r4c2<>6 r4c6=6 r1c6<>6 r1c6=2 r1c4<>2
r3c2=2 (r6c2<>2 r6c2=6 r4c2<>6 r4c6=6 r1c6<>6) r3c2<>8 r2c2=8 r2c2<>5 r2c5=5 r1c6<>5 r1c6=2 r1c4<>2
r3c3=2 (r3c8<>2) (r1c1<>2) (r2c1<>2) r6c3<>2 r6c3=3 r5c1<>3 r7c1=3 r7c1<>2 r8c1=2 r8c8<>2 r1c8=2 r1c4<>2
Forcing Net Contradiction in c2 => r1c4<>6
r1c4=6 (r3c5<>6 r3c8=6 r3c8<>2) r6c4<>6 (r6c4=7 r7c4<>7 r7c4=2 r3c4<>2) r6c2=6 r6c2<>2 r6c3=2 r3c3<>2 r3c2=2
r1c4=6 (r8c4<>6) (r3c5<>6 r3c8=6 r8c8<>6) r6c4<>6 (r6c4=7 r7c4<>7 r7c4=2 r9c6<>2) (r6c4=7 r7c4<>7 r7c4=2 r8c4<>2) (r6c4=7 r7c4<>7 r7c4=2 r8c6<>2) r6c2=6 (r6c2<>2 r6c3=2 r9c3<>2) (r6c2<>2 r6c3=2 r8c3<>2) (r4c1<>6) r4c2<>6 r4c6=6 r8c6<>6 r8c1=6 r8c1<>2 r8c8=2 r9c9<>2 r9c2=2
Forcing Net Contradiction in r1c1 => r2c2<>2
r2c2=2 (r9c2<>2) r6c2<>2 r6c2=6 (r9c2<>6) r6c4<>6 r6c4=7 (r4c6<>7) r5c6<>7 r9c6=7 r9c2<>7 r9c2=1 r4c2<>1 r45c1=1 r1c1<>1
r2c2=2 (r2c2<>5 r2c5=5 r1c6<>5 r1c3=5 r1c3<>1) (r2c9<>2) r2c6<>2 r2c6=3 r2c9<>3 r2c9=8 (r1c7<>8) (r1c8<>8) r1c9<>8 r1c4=8 r1c4<>1 r1c1=1
Forcing Net Contradiction in r8 => r3c7=1
r3c7<>1 r2c7=1 (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r6c8<>9 r6c8=3 r5c8<>3 r5c8=8 r3c8<>8) (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r1c8<>6) (r2c7<>9) r2c7<>4 r2c4=4 r1c4<>4 r1c7=4 r1c7<>9 r6c7=9 (r6c8<>9 r6c8=3 r3c8<>3) r6c7<>7 r6c4=7 r6c4<>6 r6c2=6 (r4c1<>6) r4c2<>6 r4c6=6 r1c6<>6 r1c9=6 r3c8<>6 r3c8=2 r3c23<>2 r12c1=2 r8c1<>2
r3c7<>1 r2c7=1 (r2c7<>4 r2c4=4 r1c4<>4 r1c7=4 r1c7<>9) r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r6c8<>9 r6c8=3 r6c3<>3 r6c3=2 r8c3<>2
r3c7<>1 r2c7=1 (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r1c8<>6) (r2c7<>9) r2c7<>4 r2c4=4 r1c4<>4 r1c7=4 r1c7<>9 r6c7=9 r6c7<>7 r6c4=7 (r5c6<>7 r9c6=7 r9c6<>6) r6c4<>6 r6c2=6 (r9c2<>6) (r4c1<>6) r4c2<>6 r4c6=6 r1c6<>6 r1c9=6 r9c9<>6 r9c5=6 r9c5<>1 r8c4=1 r8c4<>2
r3c7<>1 r2c7=1 (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r6c8<>9 r6c8=3 r5c8<>3 r5c8=8 r3c8<>8) (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r1c8<>6) (r2c7<>9) r2c7<>4 r2c4=4 r1c4<>4 r1c7=4 r1c7<>9 r6c7=9 (r6c8<>9 r6c8=3 r3c8<>3) r6c7<>7 r6c4=7 r6c4<>6 r6c2=6 (r4c1<>6) r4c2<>6 r4c6=6 r1c6<>6 r1c9=6 r3c8<>6 r3c8=2 r3c4<>2 r78c4=2 r8c6<>2
r3c7<>1 r2c7=1 (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r6c8<>9 r6c8=3 r5c8<>3 r5c8=8 r3c8<>8) (r2c7<>9 r2c1=9 r1c1<>9 r1c8=9 r1c8<>6) (r2c7<>9) r2c7<>4 r2c4=4 r1c4<>4 r1c7=4 r1c7<>9 r6c7=9 (r6c8<>9 r6c8=3 r3c8<>3) r6c7<>7 r6c4=7 r6c4<>6 r6c2=6 (r4c1<>6) r4c2<>6 r4c6=6 r1c6<>6 r1c9=6 r3c8<>6 r3c8=2 r8c8<>2
Discontinuous Nice Loop: 1 r9c3 -1- r9c5 =1= r2c5 =5= r2c2 -5- r1c3 -1- r9c3 => r9c3<>1
Naked Triple: 2,3,7 in r369c3 => r8c3<>2, r8c3<>3, r8c3<>7
Discontinuous Nice Loop: 3 r9c9 -3- r9c3 =3= r6c3 =2= r6c2 =6= r6c4 =7= r6c7 -7- r8c7 -3- r9c9 => r9c9<>3
Sashimi Swordfish: 3 c169 r257 fr8c6 fr9c6 => r7c5<>3
Discontinuous Nice Loop: 2 r1c6 -2- r2c6 -3- r3c5 -6- r7c5 -5- r2c5 =5= r1c6 => r1c6<>2
Discontinuous Nice Loop: 2 r3c2 -2- r6c2 -6- r6c4 =6= r4c6 -6- r1c6 -5- r1c3 =5= r2c2 =8= r3c2 => r3c2<>2
Grouped Discontinuous Nice Loop: 8 r3c8 -8- r3c2 =8= r2c2 =5= r2c5 -5- r1c6 -6- r1c89 =6= r3c8 => r3c8<>8
Grouped Discontinuous Nice Loop: 2 r7c1 -2- r12c1 =2= r3c3 =7= r9c3 =3= r7c1 => r7c1<>2
Grouped Discontinuous Nice Loop: 7 r7c7 -7- r6c7 =7= r6c4 =6= r6c2 =2= r6c3 =3= r9c3 -3- r7c1 =3= r7c79 -3- r8c7 -7- r7c7 => r7c7<>7
Grouped Discontinuous Nice Loop: 3 r8c8 -3- r8c6 =3= r9c56 -3- r9c3 =3= r6c3 =2= r6c2 =6= r6c4 =7= r6c7 -7- r8c7 -3- r8c8 => r8c8<>3
Grouped AIC: 1/5 1- r1c3 -5- r1c6 -6- r1c9 =6= r13c8 -6- r8c8 -2- r8c1 =2= r12c1 -2- r3c3 -7- r3c2 -8- r2c2 -5- r7c2 =5= r8c3 -5 => r8c3<>1, r1c3<>5
Naked Single: r8c3=5
Naked Single: r1c3=1
Hidden Single: r1c6=5
Hidden Single: r2c2=5
Hidden Single: r7c5=5
Hidden Single: r3c2=8
Hidden Single: r3c3=7
Locked Candidates Type 1 (Pointing): 2 in b1 => r8c1<>2
Locked Candidates Type 1 (Pointing): 6 in b2 => r3c8<>6
Naked Triple: 2,3,6 in r2c6,r3c45 => r2c5<>3
Naked Single: r2c5=1
Hidden Single: r8c4=1
Hidden Single: r9c2=1
Skyscraper: 2 in r3c4,r8c6 (connected by r38c8) => r2c6,r7c4<>2
Naked Single: r2c6=3
Naked Single: r3c5=6
Full House: r9c5=3
Naked Single: r3c4=2
Full House: r3c8=3
Naked Single: r9c3=2
Full House: r6c3=3
Naked Single: r5c8=8
Naked Single: r6c8=9
Naked Single: r6c7=7
Full House: r5c9=3
Naked Single: r6c4=6
Full House: r6c2=2
Naked Single: r8c7=3
Naked Single: r7c4=7
Naked Single: r7c7=8
Naked Single: r7c2=6
Full House: r4c2=7
Naked Single: r9c6=6
Full House: r8c6=2
Full House: r9c9=7
Naked Single: r7c1=3
Full House: r7c9=2
Full House: r8c1=7
Full House: r8c8=6
Full House: r1c8=2
Naked Single: r4c6=1
Full House: r4c1=6
Full House: r5c1=1
Full House: r5c6=7
Naked Single: r2c9=8
Full House: r1c9=6
Naked Single: r1c1=9
Full House: r2c1=2
Naked Single: r2c4=4
Full House: r1c4=8
Full House: r1c7=4
Full House: r2c7=9
|
normal_sudoku_5010
|
.6.8.3.....4.5.7...8.2.7.13..5.7.6...2.9.....9....18......2.3.6.92....7465....2..
|
761843925234159768589267413815472639423986157976531842148725396392618574657394281
|
Basic 9x9 Sudoku 5010
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . 8 . 3 . . .
. . 4 . 5 . 7 . .
. 8 . 2 . 7 . 1 3
. . 5 . 7 . 6 . .
. 2 . 9 . . . . .
9 . . . . 1 8 . .
. . . . 2 . 3 . 6
. 9 2 . . . . 7 4
6 5 . . . . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
761843925234159768589267413815472639423986157976531842148725396392618574657394281 #1 Easy (222)
Hidden Single: r3c6=7
Naked Single: r3c1=5
Naked Single: r3c3=9
Naked Single: r3c7=4
Full House: r3c5=6
Naked Single: r2c4=1
Naked Single: r2c6=9
Full House: r1c5=4
Naked Single: r2c2=3
Naked Single: r6c5=3
Naked Single: r2c1=2
Naked Single: r4c4=4
Naked Single: r5c5=8
Naked Single: r2c9=8
Full House: r2c8=6
Naked Single: r4c2=1
Naked Single: r4c6=2
Naked Single: r8c5=1
Full House: r9c5=9
Naked Single: r4c9=9
Naked Single: r8c7=5
Naked Single: r9c8=8
Naked Single: r9c9=1
Full House: r7c8=9
Naked Single: r4c8=3
Full House: r4c1=8
Naked Single: r1c7=9
Full House: r5c7=1
Naked Single: r9c6=4
Naked Single: r8c1=3
Naked Single: r8c4=6
Full House: r8c6=8
Naked Single: r9c3=7
Full House: r9c4=3
Naked Single: r6c4=5
Full House: r5c6=6
Full House: r7c6=5
Full House: r7c4=7
Naked Single: r1c3=1
Full House: r1c1=7
Naked Single: r6c3=6
Naked Single: r7c2=4
Full House: r6c2=7
Naked Single: r5c3=3
Full House: r7c3=8
Full House: r5c1=4
Full House: r7c1=1
Naked Single: r6c9=2
Full House: r6c8=4
Naked Single: r5c8=5
Full House: r1c8=2
Full House: r1c9=5
Full House: r5c9=7
|
normal_sudoku_266
|
31..4........8.1...821....5.....9.6...82....7..783.9.2..3......87.3..25.5....8..3
|
319542678756983124482167395235479861948216537167835942623751489871394256594628713
|
Basic 9x9 Sudoku 266
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 1 . . 4 . . . .
. . . . 8 . 1 . .
. 8 2 1 . . . . 5
. . . . . 9 . 6 .
. . 8 2 . . . . 7
. . 7 8 3 . 9 . 2
. . 3 . . . . . .
8 7 . 3 . . 2 5 .
5 . . . . 8 . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
319542678756983124482167395235479861948216537167835942623751489871394256594628713 #1 Extreme (17904) bf
Hidden Single: r2c5=8
Locked Candidates Type 1 (Pointing): 2 in b2 => r7c6<>2
Hidden Pair: 2,3 in r2c68 => r2c6<>5, r2c6<>6, r2c68<>7, r2c8<>4, r2c8<>9
Brute Force: r5c2=4
Hidden Single: r4c2=3
Hidden Single: r5c1=9
Hidden Single: r4c1=2
Locked Candidates Type 1 (Pointing): 6 in b4 => r6c6<>6
Discontinuous Nice Loop: 1 r4c5 -1- r4c3 -5- r6c2 =5= r6c6 =4= r4c4 =7= r4c5 => r4c5<>1
2-String Kite: 1 in r4c9,r7c1 (connected by r4c3,r6c1) => r7c9<>1
Grouped Discontinuous Nice Loop: 5 r4c4 -5- r4c7 =5= r5c7 =3= r5c8 -3- r2c8 -2- r2c6 =2= r1c6 =5= r12c4 -5- r4c4 => r4c4<>5
Grouped Discontinuous Nice Loop: 1 r7c5 -1- r7c1 =1= r6c1 =6= r6c2 =5= r6c6 -5- r45c5 =5= r7c5 => r7c5<>1
Almost Locked Set XY-Wing: A=r179c7 {4678}, B=r1247c9 {14689}, C=r4c3457 {14578}, X,Y=1,8, Z=4 => r8c9<>4
Finned Franken Swordfish: 9 r38b1 c359 fr2c2 fr3c8 => r2c9<>9
Grouped Discontinuous Nice Loop: 6 r2c1 -6- r2c9 -4- r2c13 =4= r3c1 =7= r2c1 => r2c1<>6
Forcing Chain Verity => r2c3<>4
r2c9=4 r2c3<>4
r4c9=4 r4c4<>4 r6c6=4 r8c6<>4 r8c3=4 r2c3<>4
r7c9=4 r7c1<>4 r23c1=4 r2c3<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r7c1<>4
Naked Pair: 1,6 in r67c1 => r3c1<>6
AIC: 4 4- r2c9 =4= r2c1 =7= r2c4 -7- r4c4 -4- r6c6 =4= r6c8 -4 => r3c8,r4c9<>4
Forcing Chain Contradiction in r8 => r2c1=7
r2c1<>7 r2c1=4 r2c9<>4 r2c9=6 r2c2<>6 r12c3=6 r8c3<>6
r2c1<>7 r2c1=4 r2c9<>4 r2c9=6 r3c7<>6 r3c56=6 r12c4<>6 r79c4=6 r8c5<>6
r2c1<>7 r2c1=4 r2c9<>4 r2c9=6 r3c7<>6 r3c56=6 r12c4<>6 r79c4=6 r8c6<>6
r2c1<>7 r2c1=4 r2c9<>4 r2c9=6 r8c9<>6
Naked Single: r3c1=4
Hidden Single: r2c9=4
Forcing Chain Contradiction in r8c6 => r4c4=4
r4c4<>4 r4c7=4 r4c7<>8 r4c9=8 r4c9<>1 r8c9=1 r8c6<>1
r4c4<>4 r6c6=4 r8c6<>4
r4c4<>4 r4c7=4 r4c7<>5 r5c7=5 r5c7<>3 r3c7=3 r3c7<>6 r3c56=6 r12c4<>6 r79c4=6 r8c6<>6
Hidden Single: r6c8=4
Hidden Single: r4c5=7
Almost Locked Set Chain: 5- r5c578 {1356} -6- r38c5 {169} -1- r178c9 {1689} -8- r4c9,r5c78 {1358} -5 => r5c6<>5
W-Wing: 6/1 in r5c6,r7c1 connected by 1 in r6c16 => r7c6<>6
Discontinuous Nice Loop: 6 r1c6 -6- r5c6 -1- r5c8 -3- r2c8 -2- r2c6 =2= r1c6 => r1c6<>6
Grouped Discontinuous Nice Loop: 6 r8c6 -6- r5c6 -1- r5c8 -3- r5c7 =3= r3c7 =6= r3c56 -6- r12c4 =6= r79c4 -6- r8c6 => r8c6<>6
Discontinuous Nice Loop: 6 r7c7 -6- r7c1 -1- r6c1 =1= r6c6 -1- r8c6 -4- r7c6 =4= r7c7 => r7c7<>6
Discontinuous Nice Loop: 8 r7c7 -8- r4c7 =8= r4c9 =1= r8c9 -1- r8c6 -4- r7c6 =4= r7c7 => r7c7<>8
Discontinuous Nice Loop: 6 r9c3 -6- r7c1 -1- r6c1 =1= r6c6 -1- r8c6 -4- r8c3 =4= r9c3 => r9c3<>6
Grouped Discontinuous Nice Loop: 9 r9c3 -9- r79c2 =9= r2c2 =5= r6c2 -5- r6c6 -1- r8c6 -4- r8c3 =4= r9c3 => r9c3<>9
Almost Locked Set Chain: 6- r5c6 {16} -1- r6c26 {156} -6- r279c2 {2569} -5- r2c4,r3c5 {569} -6 => r3c6<>6
Hidden Single: r5c6=6
2-String Kite: 1 in r5c5,r8c9 (connected by r4c9,r5c8) => r8c5<>1
Naked Pair: 6,9 in r38c5 => r79c5<>6, r79c5<>9
Discontinuous Nice Loop: 9 r7c8 -9- r3c8 =9= r3c5 =6= r3c7 =3= r5c7 =5= r4c7 =8= r4c9 -8- r7c9 =8= r7c8 => r7c8<>9
Discontinuous Nice Loop: 6 r9c2 -6- r6c2 -5- r6c6 -1- r5c5 =1= r9c5 =2= r9c2 => r9c2<>6
Skyscraper: 6 in r3c5,r9c4 (connected by r39c7) => r12c4,r8c5<>6
Naked Single: r8c5=9
Naked Single: r3c5=6
Hidden Single: r3c8=9
Hidden Single: r7c9=9
Hidden Single: r9c2=9
Hidden Single: r7c8=8
Hidden Single: r9c5=2
Naked Single: r7c5=5
Full House: r5c5=1
Full House: r6c6=5
Naked Single: r5c8=3
Full House: r5c7=5
Naked Single: r6c2=6
Full House: r6c1=1
Full House: r4c3=5
Full House: r7c1=6
Naked Single: r2c8=2
Naked Single: r4c7=8
Full House: r4c9=1
Naked Single: r2c2=5
Full House: r7c2=2
Naked Single: r7c4=7
Naked Single: r1c8=7
Full House: r9c8=1
Naked Single: r2c6=3
Naked Single: r8c9=6
Full House: r1c9=8
Naked Single: r2c4=9
Full House: r2c3=6
Full House: r1c3=9
Naked Single: r7c7=4
Full House: r7c6=1
Full House: r9c7=7
Naked Single: r9c4=6
Full House: r9c3=4
Full House: r1c4=5
Full House: r8c6=4
Full House: r8c3=1
Naked Single: r1c6=2
Full House: r1c7=6
Full House: r3c7=3
Full House: r3c6=7
|
normal_sudoku_5984
|
97...5.2...3.....5...87....1....7.4...74.1...45...26........26...1....9.79...6..4
|
974135826813629475526874139182967543637451982459382617345798261261543798798216354
|
Basic 9x9 Sudoku 5984
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 7 . . . 5 . 2 .
. . 3 . . . . . 5
. . . 8 7 . . . .
1 . . . . 7 . 4 .
. . 7 4 . 1 . . .
4 5 . . . 2 6 . .
. . . . . . 2 6 .
. . 1 . . . . 9 .
7 9 . . . 6 . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
974135826813629475526874139182967543637451982459382617345798261261543798798216354 #1 Extreme (14436) bf
Locked Candidates Type 1 (Pointing): 2 in b2 => r2c12<>2
Finned Swordfish: 6 r258 c125 fr2c4 => r1c5<>6
Brute Force: r5c6=1
Locked Candidates Type 1 (Pointing): 8 in b5 => r789c5<>8
Naked Triple: 3,8,9 in r6c345 => r6c89<>3, r6c89<>8, r6c9<>9
Locked Candidates Type 2 (Claiming): 3 in r6 => r4c45,r5c5<>3
Forcing Chain Contradiction in r9 => r1c9<>1
r1c9=1 r3c8<>1 r3c8=3 r3c6<>3 r78c6=3 r9c4<>3
r1c9=1 r3c8<>1 r3c8=3 r3c6<>3 r78c6=3 r9c5<>3
r1c9=1 r123c7<>1 r9c7=1 r9c7<>3
r1c9=1 r3c8<>1 r3c8=3 r9c8<>3
Forcing Chain Contradiction in r1c9 => r2c7<>8
r2c7=8 r2c7<>7 r2c8=7 r6c8<>7 r6c8=1 r3c8<>1 r3c8=3 r1c9<>3
r2c7=8 r2c1<>8 r2c1=6 r2c45<>6 r1c4=6 r1c9<>6
r2c7=8 r1c9<>8
Forcing Chain Contradiction in r9 => r2c8<>1
r2c8=1 r3c8<>1 r3c8=3 r3c6<>3 r78c6=3 r9c4<>3
r2c8=1 r3c8<>1 r3c8=3 r3c6<>3 r78c6=3 r9c5<>3
r2c8=1 r123c7<>1 r9c7=1 r9c7<>3
r2c8=1 r3c8<>1 r3c8=3 r9c8<>3
Grouped Discontinuous Nice Loop: 3 r3c9 -3- r3c8 -1- r6c8 -7- r2c8 -8- r2c1 -6- r3c123 =6= r3c9 => r3c9<>3
Grouped Discontinuous Nice Loop: 3 r7c4 -3- r6c4 -9- r6c3 -8- r1c3 =8= r1c79 -8- r2c8 -7- r2c7 =7= r8c7 -7- r8c4 =7= r7c4 => r7c4<>3
Grouped Discontinuous Nice Loop: 3 r8c4 -3- r6c4 -9- r6c3 -8- r1c3 =8= r1c79 -8- r2c8 -7- r6c8 -1- r3c8 -3- r3c6 =3= r78c6 -3- r8c4 => r8c4<>3
Grouped Discontinuous Nice Loop: 8 r8c7 -8- r9c78 =8= r9c3 -8- r1c3 =8= r1c79 -8- r2c8 -7- r2c7 =7= r8c7 => r8c7<>8
Grouped Discontinuous Nice Loop: 3 r9c4 -3- r6c4 -9- r6c3 -8- r1c3 =8= r1c79 -8- r2c8 -7- r6c8 -1- r3c8 -3- r3c6 =3= r78c6 -3- r9c4 => r9c4<>3
Forcing Chain Verity => r3c8=3
r9c3=8 r1c3<>8 r1c79=8 r2c8<>8 r2c8=7 r6c8<>7 r6c8=1 r3c8<>1 r3c8=3
r9c7=8 r9c7<>1 r123c7=1 r3c8<>1 r3c8=3
r9c8=8 r2c8<>8 r2c8=7 r6c8<>7 r6c8=1 r3c8<>1 r3c8=3
Locked Pair: 4,9 in r23c6 => r12c5,r78c6<>4, r2c45,r7c6<>9
Locked Candidates Type 2 (Claiming): 3 in c6 => r789c5<>3
Hidden Single: r9c7=3
Locked Candidates Type 2 (Claiming): 1 in c7 => r3c9<>1
Naked Triple: 5,8,9 in r45c7,r5c8 => r45c9<>8, r45c9<>9
Hidden Single: r3c9=9
Naked Single: r3c6=4
Naked Single: r2c6=9
Naked Single: r3c7=1
Hidden Single: r1c9=6
Hidden Single: r2c2=1
Hidden Single: r2c7=4
Naked Single: r1c7=8
Full House: r2c8=7
Naked Single: r1c3=4
Naked Single: r6c8=1
Naked Single: r6c9=7
Naked Single: r8c9=8
Naked Single: r7c9=1
Naked Single: r8c6=3
Full House: r7c6=8
Naked Single: r9c8=5
Full House: r5c8=8
Full House: r8c7=7
Naked Single: r7c3=5
Naked Single: r7c1=3
Naked Single: r7c2=4
Naked Single: r7c5=9
Full House: r7c4=7
Hidden Single: r2c1=8
Hidden Single: r9c3=8
Naked Single: r6c3=9
Naked Single: r6c4=3
Full House: r6c5=8
Naked Single: r1c4=1
Full House: r1c5=3
Naked Single: r9c4=2
Full House: r9c5=1
Naked Single: r2c4=6
Full House: r2c5=2
Naked Single: r8c4=5
Full House: r4c4=9
Full House: r8c5=4
Naked Single: r4c7=5
Full House: r5c7=9
Naked Single: r4c5=6
Full House: r5c5=5
Naked Single: r4c3=2
Full House: r3c3=6
Naked Single: r4c9=3
Full House: r4c2=8
Full House: r5c9=2
Naked Single: r5c1=6
Full House: r5c2=3
Naked Single: r3c2=2
Full House: r3c1=5
Full House: r8c1=2
Full House: r8c2=6
|
normal_sudoku_5538
|
....7..5.5.....7...745....16........3...5..94..29..1.......85.2.2.4...1.1....54..
|
961374258538216749274589361659741823317852694482963175746198532825437916193625487
|
Basic 9x9 Sudoku 5538
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 7 . . 5 .
5 . . . . . 7 . .
. 7 4 5 . . . . 1
6 . . . . . . . .
3 . . . 5 . . 9 4
. . 2 9 . . 1 . .
. . . . . 8 5 . 2
. 2 . 4 . . . 1 .
1 . . . . 5 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
961374258538216749274589361659741823317852694482963175746198532825437916193625487 #1 Extreme (25202) bf
Hidden Single: r3c4=5
Hidden Single: r8c3=5
Hidden Single: r1c6=4
Hidden Single: r2c8=4
Locked Candidates Type 2 (Claiming): 2 in r2 => r1c4,r3c56<>2
Brute Force: r5c3=7
Brute Force: r5c4=8
Naked Single: r5c2=1
Forcing Chain Contradiction in c8 => r3c6<>6
r3c6=6 r3c8<>6
r3c6=6 r5c6<>6 r5c7=6 r6c8<>6
r3c6=6 r12c4<>6 r79c4=6 r8c56<>6 r8c79=6 r7c8<>6
r3c6=6 r12c4<>6 r79c4=6 r8c56<>6 r8c79=6 r9c8<>6
Forcing Net Contradiction in c8 => r3c8<>3
r3c8=3 r3c8<>6
r3c8=3 r3c8<>2 r4c8=2 r5c7<>2 r5c7=6 r6c8<>6
r3c8=3 (r3c8<>6) r3c8<>2 r4c8=2 r5c7<>2 r5c7=6 r3c7<>6 r3c5=6 r12c4<>6 r79c4=6 r8c56<>6 r8c79=6 r7c8<>6
r3c8=3 (r3c8<>6) r3c8<>2 r4c8=2 r5c7<>2 r5c7=6 r3c7<>6 r3c5=6 r12c4<>6 r79c4=6 r8c56<>6 r8c79=6 r9c8<>6
Forcing Chain Contradiction in c4 => r4c7<>3
r4c7=3 r3c7<>3 r3c56=3 r1c4<>3
r4c7=3 r3c7<>3 r3c56=3 r2c4<>3
r4c7=3 r4c4<>3
r4c7=3 r46c8<>3 r79c8=3 r8c79<>3 r8c56=3 r7c4<>3
r4c7=3 r46c8<>3 r79c8=3 r8c79<>3 r8c56=3 r9c4<>3
Forcing Chain Contradiction in c8 => r4c5<>2
r4c5=2 r4c8<>2 r3c8=2 r3c8<>8
r4c5=2 r4c7<>2 r4c7=8 r4c8<>8
r4c5=2 r4c7<>2 r4c7=8 r6c8<>8
r4c5=2 r4c5<>4 r4c2=4 r6c1<>4 r6c1=8 r8c1<>8 r8c79=8 r9c8<>8
Forcing Net Contradiction in c8 => r4c3=9
r4c3<>9 r4c3=8 r4c7<>8 r4c7=2 (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6
r4c3<>9 r4c3=8 r4c7<>8 r4c7=2 r5c7<>2 r5c7=6 r6c8<>6
r4c3<>9 r4c3=8 r4c7<>8 r4c7=2 (r5c7<>2 r5c7=6 r8c7<>6) (r5c7<>2 r5c7=6 r6c8<>6) (r5c7<>2 r5c7=6 r6c9<>6) (r5c7<>2 r5c7=6 r3c7<>6) (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6 r3c5=6 (r8c5<>6) r6c5<>6 r6c6=6 r8c6<>6 r8c9=6 r7c8<>6
r4c3<>9 r4c3=8 r4c7<>8 r4c7=2 (r5c7<>2 r5c7=6 r8c7<>6) (r5c7<>2 r5c7=6 r6c8<>6) (r5c7<>2 r5c7=6 r6c9<>6) (r5c7<>2 r5c7=6 r3c7<>6) (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6 r3c5=6 (r8c5<>6) r6c5<>6 r6c6=6 r8c6<>6 r8c9=6 r9c8<>6
Forcing Net Contradiction in c8 => r4c7=8
r4c7<>8 r4c7=2 (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6
r4c7<>8 r4c7=2 r5c7<>2 r5c7=6 r6c8<>6
r4c7<>8 r4c7=2 (r5c7<>2 r5c7=6 r8c7<>6) (r5c7<>2 r5c7=6 r6c8<>6) (r5c7<>2 r5c7=6 r6c9<>6) (r5c7<>2 r5c7=6 r3c7<>6) (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6 r3c5=6 (r8c5<>6) r6c5<>6 r6c6=6 r8c6<>6 r8c9=6 r7c8<>6
r4c7<>8 r4c7=2 (r5c7<>2 r5c7=6 r8c7<>6) (r5c7<>2 r5c7=6 r6c8<>6) (r5c7<>2 r5c7=6 r6c9<>6) (r5c7<>2 r5c7=6 r3c7<>6) (r3c7<>2) r1c7<>2 r1c1=2 r3c1<>2 r3c8=2 r3c8<>6 r3c5=6 (r8c5<>6) r6c5<>6 r6c6=6 r8c6<>6 r8c9=6 r9c8<>6
2-String Kite: 8 in r3c8,r8c1 (connected by r8c9,r9c8) => r3c1<>8
Finned Swordfish: 8 r168 c129 fr1c3 => r2c2<>8
Discontinuous Nice Loop: 6 r6c9 -6- r5c7 -2- r4c8 =2= r3c8 =8= r9c8 -8- r8c9 =8= r8c1 -8- r6c1 =8= r6c2 =5= r6c9 => r6c9<>6
Finned Jellyfish: 6 r3568 c5678 fr8c9 => r79c8<>6
Sue de Coq: r46c8 - {2367} (r7c8 - {37}, r5c7 - {26}) => r9c8<>3, r9c8<>7
Naked Single: r9c8=8
Hidden Single: r3c5=8
Hidden Single: r8c1=8
Naked Single: r6c1=4
Naked Single: r4c2=5
Full House: r6c2=8
Hidden Single: r7c1=7
Naked Single: r7c8=3
Naked Single: r7c3=6
Naked Single: r7c4=1
Naked Single: r9c3=3
Naked Single: r7c5=9
Full House: r7c2=4
Full House: r9c2=9
Hidden Single: r4c5=4
Hidden Single: r6c9=5
Hidden Single: r1c3=1
Full House: r2c3=8
Hidden Single: r4c6=1
Hidden Single: r2c5=1
Hidden Single: r4c9=3
Hidden Single: r1c9=8
Hidden Single: r9c5=2
Locked Candidates Type 2 (Claiming): 6 in r3 => r1c7,r2c9<>6
Naked Single: r2c9=9
Hidden Single: r1c1=9
Full House: r3c1=2
Naked Single: r3c8=6
Naked Single: r3c7=3
Full House: r1c7=2
Full House: r3c6=9
Naked Single: r6c8=7
Full House: r4c8=2
Full House: r5c7=6
Full House: r4c4=7
Full House: r5c6=2
Full House: r8c7=9
Naked Single: r9c4=6
Full House: r9c9=7
Full House: r8c9=6
Naked Single: r1c4=3
Full House: r1c2=6
Full House: r2c4=2
Full House: r2c6=6
Full House: r2c2=3
Naked Single: r8c5=3
Full House: r6c5=6
Full House: r6c6=3
Full House: r8c6=7
|
normal_sudoku_2408
|
....4..2....83..7.8.71.956....6.4....65.8.....92....1..84.1....6.37..2.4......1..
|
936547821251836479847129563178694352365281947492375618584912736613758294729463185
|
Basic 9x9 Sudoku 2408
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 4 . . 2 .
. . . 8 3 . . 7 .
8 . 7 1 . 9 5 6 .
. . . 6 . 4 . . .
. 6 5 . 8 . . . .
. 9 2 . . . . 1 .
. 8 4 . 1 . . . .
6 . 3 7 . . 2 . 4
. . . . . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
936547821251836479847129563178694352365281947492375618584912736613758294729463185 #1 Easy (216)
Naked Single: r3c3=7
Naked Single: r1c4=5
Naked Single: r3c9=3
Naked Single: r3c5=2
Full House: r3c2=4
Naked Single: r9c3=9
Naked Single: r6c4=3
Naked Single: r2c6=6
Full House: r1c6=7
Naked Single: r2c3=1
Naked Single: r6c6=5
Naked Single: r1c2=3
Naked Single: r1c3=6
Full House: r4c3=8
Naked Single: r2c9=9
Naked Single: r6c5=7
Naked Single: r8c6=8
Naked Single: r1c1=9
Naked Single: r1c7=8
Full House: r1c9=1
Full House: r2c7=4
Naked Single: r4c5=9
Naked Single: r6c1=4
Naked Single: r6c7=6
Full House: r6c9=8
Naked Single: r5c4=2
Full House: r5c6=1
Naked Single: r8c5=5
Full House: r9c5=6
Naked Single: r5c9=7
Naked Single: r7c4=9
Full House: r9c4=4
Naked Single: r8c2=1
Full House: r8c8=9
Naked Single: r4c7=3
Naked Single: r5c1=3
Naked Single: r9c9=5
Naked Single: r4c2=7
Full House: r4c1=1
Naked Single: r4c8=5
Full House: r4c9=2
Full House: r7c9=6
Naked Single: r5c7=9
Full House: r5c8=4
Full House: r7c7=7
Naked Single: r7c8=3
Full House: r9c8=8
Naked Single: r9c2=2
Full House: r2c2=5
Full House: r2c1=2
Naked Single: r7c6=2
Full House: r7c1=5
Full House: r9c1=7
Full House: r9c6=3
|
normal_sudoku_2898
|
....6..32...3...8.3...8.5.6.19.35.......2....5....6..4.8.2.3.45....486.3..4...82.
|
178564932956372481342189576819435267463927158527816394681293745295748613734651829
|
Basic 9x9 Sudoku 2898
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 6 . . 3 2
. . . 3 . . . 8 .
3 . . . 8 . 5 . 6
. 1 9 . 3 5 . . .
. . . . 2 . . . .
5 . . . . 6 . . 4
. 8 . 2 . 3 . 4 5
. . . . 4 8 6 . 3
. . 4 . . . 8 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
178564932956372481342189576819435267463927158527816394681293745295748613734651829 #1 Extreme (31890) bf
Hidden Single: r2c4=3
Hidden Single: r5c8=5
Hidden Single: r9c4=6
Hidden Single: r9c2=3
Hidden Single: r4c8=6
Hidden Single: r9c5=5
Hidden Single: r1c4=5
Brute Force: r5c3=3
Hidden Single: r6c7=3
Hidden Single: r4c7=2
Brute Force: r5c2=6
Locked Candidates Type 1 (Pointing): 4 in b4 => r12c1<>4
Discontinuous Nice Loop: 2 r8c3 -2- r8c1 =2= r2c1 =6= r2c3 =5= r8c3 => r8c3<>2
Forcing Net Contradiction in r3 => r8c1<>7
r8c1=7 (r7c3<>7) r8c1<>2 r2c1=2 (r3c3<>2) r2c1<>6 r2c3=6 r7c3<>6 r7c3=1 r3c3<>1 r3c3=7
r8c1=7 (r8c8<>7) r8c1<>2 r8c2=2 r6c2<>2 r6c2=7 r6c8<>7 r3c8=7
Brute Force: r5c4=9
Hidden Single: r6c8=9
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c6<>1
Locked Candidates Type 2 (Claiming): 9 in r8 => r79c1<>9
Naked Pair: 1,7 in r8c48 => r8c13<>1, r8c23<>7
Naked Single: r8c3=5
Hidden Single: r2c2=5
Skyscraper: 9 in r7c5,r9c9 (connected by r2c59) => r7c7,r9c6<>9
Hidden Single: r7c5=9
Hidden Single: r9c9=9
Naked Pair: 1,7 in r2c9,r3c8 => r12c7<>1, r12c7<>7
Naked Pair: 1,7 in r2c59 => r2c136<>1, r2c136<>7
Remote Pair: 1/7 r2c5 -7- r2c9 -1- r3c8 -7- r8c8 -1- r8c4 -7- r9c6 => r13c6<>1, r13c6<>7
Hidden Single: r9c6=1
Full House: r8c4=7
Full House: r9c1=7
Naked Single: r8c8=1
Full House: r3c8=7
Full House: r7c7=7
Naked Single: r2c9=1
Naked Single: r5c7=1
Naked Single: r2c5=7
Full House: r6c5=1
Naked Single: r6c4=8
Naked Single: r4c4=4
Full House: r3c4=1
Full House: r5c6=7
Naked Single: r4c1=8
Full House: r4c9=7
Full House: r5c9=8
Full House: r5c1=4
Naked Single: r3c3=2
Naked Single: r2c3=6
Naked Single: r6c3=7
Full House: r6c2=2
Naked Single: r2c1=9
Naked Single: r7c3=1
Full House: r1c3=8
Full House: r7c1=6
Naked Single: r8c2=9
Full House: r8c1=2
Full House: r1c1=1
Naked Single: r2c7=4
Full House: r1c7=9
Full House: r2c6=2
Naked Single: r3c2=4
Full House: r1c2=7
Full House: r1c6=4
Full House: r3c6=9
|
normal_sudoku_6535
|
.624....88.4.5....3.........869..4..1...8..29.....5.86.....7....285...6..3.8....4
|
762491538894352671351768942286973415175684329943125786619247853428539167537816294
|
Basic 9x9 Sudoku 6535
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 2 4 . . . . 8
8 . 4 . 5 . . . .
3 . . . . . . . .
. 8 6 9 . . 4 . .
1 . . . 8 . . 2 9
. . . . . 5 . 8 6
. . . . . 7 . . .
. 2 8 5 . . . 6 .
. 3 . 8 . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
762491538894352671351768942286973415175684329943125786619247853428539167537816294 #1 Extreme (25448) bf
Hidden Single: r4c2=8
Hidden Single: r3c6=8
Hidden Single: r7c7=8
Hidden Single: r3c8=4
Brute Force: r5c6=4
Hidden Single: r5c4=6
Brute Force: r5c7=3
Hidden Single: r6c3=3
Locked Candidates Type 1 (Pointing): 5 in b6 => r4c1<>5
Locked Candidates Type 2 (Claiming): 7 in r5 => r46c1,r6c2<>7
Naked Single: r4c1=2
Naked Triple: 1,3,9 in r148c6 => r29c6<>1, r2c6<>3, r29c6<>9
Turbot Fish: 2 r2c6 =2= r9c6 -2- r9c7 =2= r7c9 => r2c9<>2
Empty Rectangle: 3 in b3 (r27c4) => r7c8<>3
Locked Candidates Type 1 (Pointing): 3 in b9 => r2c9<>3
Almost Locked Set XY-Wing: A=r2c24689 {123679}, B=r1689c7 {12579}, C=r9c6 {26}, X,Y=2,6, Z=1,7,9 => r2c7<>1, r2c7<>7, r2c7<>9
Naked Pair: 2,6 in r2c67 => r2c4<>2
Forcing Chain Contradiction in r3c4 => r3c7<>7
r3c7=7 r2c9<>7 r2c9=1 r2c2<>1 r3c23=1 r3c4<>1
r3c7=7 r3c7<>6 r3c5=6 r2c6<>6 r2c6=2 r3c4<>2
r3c7=7 r3c4<>7
Forcing Chain Verity => r7c1<>9
r7c4=3 r2c4<>3 r2c8=3 r2c8<>9 r2c2=9 r6c2<>9 r6c1=9 r7c1<>9
r7c5=3 r7c5<>6 r7c1=6 r7c1<>9
r7c9=3 r7c9<>2 r9c7=2 r9c6<>2 r9c6=6 r9c1<>6 r7c1=6 r7c1<>9
Forcing Net Contradiction in r6 => r1c1<>9
r1c1=9 (r1c6<>9 r8c6=9 r8c7<>9) (r8c1<>9) r6c1<>9 r6c1=4 r8c1<>4 r8c1=7 r8c7<>7 r8c7=1 r6c7<>1 r6c7=7 r6c5<>7 r6c4=7
r1c1=9 (r1c6<>9 r8c6=9 r8c7<>9) (r8c1<>9) r6c1<>9 r6c1=4 r8c1<>4 r8c1=7 r8c7<>7 r8c7=1 r6c7<>1 r6c7=7
Grouped Discontinuous Nice Loop: 5 r3c3 -5- r5c3 -7- r5c2 =7= r23c2 -7- r1c1 -5- r3c3 => r3c3<>5
Forcing Net Contradiction in c5 => r6c1=9
r6c1<>9 r6c1=4 r6c2<>4 r6c2=9 (r7c2<>9) (r2c2<>9 r2c8=9 r7c8<>9) (r2c2<>9) r3c2<>9 r3c3=9 r7c3<>9 r7c5=9
r6c1<>9 r6c1=4 (r8c1<>4 r8c5=4 r8c5<>3) r6c2<>4 r6c2=9 (r2c2<>9 r2c8=9 r2c8<>3 r2c4=3 r1c6<>3) (r2c2<>9 r2c8=9 r2c8<>3 r2c4=3 r7c4<>3) (r7c2<>9) (r2c2<>9 r2c8=9 r7c8<>9) (r2c2<>9) r3c2<>9 r3c3=9 r7c3<>9 r7c5=9 (r1c5<>9 r1c6=9 r1c6<>1) r7c5<>3 r7c9=3 (r7c9<>2 r7c4=2 r9c5<>2) (r7c9<>2 r7c4=2 r9c6<>2 r9c6=6 r9c5<>6) r8c9<>3 r8c6=3 r4c6<>3 (r4c6=1 r6c5<>1 r6c7=1 r1c7<>1) r4c5=3 r1c5<>3 r1c8=3 r1c8<>1 r1c5=1 r9c5<>1 r9c5=9
Naked Single: r6c2=4
Naked Triple: 1,5,9 in r7c238 => r7c19<>5, r7c459<>1, r7c5<>9
Naked Pair: 2,3 in r7c49 => r7c5<>2, r7c5<>3
Empty Rectangle: 5 in b9 (r19c1) => r1c8<>5
Grouped AIC: 7 7- r2c9 -1- r1c78 =1= r1c56 -1- r23c4 =1= r6c4 -1- r6c7 -7 => r1c7,r4c9<>7
Sashimi Swordfish: 7 r148 c158 fr8c7 fr8c9 => r9c8<>7
Grouped AIC: 1 1- r2c9 -7- r8c9 =7= r89c7 -7- r6c7 -1 => r13c7,r4c9<>1
Naked Single: r4c9=5
Locked Candidates Type 1 (Pointing): 5 in b3 => r9c7<>5
Finned Swordfish: 1 r148 c568 fr8c7 fr8c9 => r79c8<>1
Locked Pair: 5,9 in r79c8 => r12c8,r89c7<>9
Hidden Single: r2c2=9
Locked Candidates Type 1 (Pointing): 1 in b1 => r3c459<>1
Locked Candidates Type 2 (Claiming): 1 in r7 => r9c3<>1
Locked Candidates Type 2 (Claiming): 9 in r8 => r9c5<>9
Naked Pair: 2,7 in r3c49 => r3c235<>7, r3c57<>2
Naked Single: r3c3=1
Naked Single: r3c2=5
Full House: r1c1=7
Naked Single: r5c2=7
Full House: r7c2=1
Full House: r5c3=5
Naked Single: r8c1=4
Naked Single: r7c3=9
Full House: r9c3=7
Naked Single: r7c1=6
Full House: r9c1=5
Naked Single: r7c8=5
Naked Single: r7c5=4
Naked Single: r9c8=9
Hidden Single: r1c7=5
Hidden Single: r3c7=9
Naked Single: r3c5=6
Naked Single: r2c6=2
Naked Single: r2c7=6
Naked Single: r3c4=7
Full House: r3c9=2
Naked Single: r9c6=6
Naked Single: r7c9=3
Full House: r7c4=2
Naked Single: r6c4=1
Full House: r2c4=3
Naked Single: r9c5=1
Full House: r9c7=2
Naked Single: r4c6=3
Naked Single: r6c7=7
Full House: r4c8=1
Full House: r4c5=7
Full House: r6c5=2
Full House: r8c7=1
Full House: r8c9=7
Full House: r2c9=1
Full House: r2c8=7
Full House: r1c8=3
Naked Single: r1c5=9
Full House: r1c6=1
Full House: r8c6=9
Full House: r8c5=3
|
normal_sudoku_1154
|
..7..4.9.....8.2...1....7.48...3..6....548.....3..6..2..2..96..1......29.5......3
|
387624591495781236216953784841237965629548317573196842732419658168375429954862173
|
Basic 9x9 Sudoku 1154
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 7 . . 4 . 9 .
. . . . 8 . 2 . .
. 1 . . . . 7 . 4
8 . . . 3 . . 6 .
. . . 5 4 8 . . .
. . 3 . . 6 . . 2
. . 2 . . 9 6 . .
1 . . . . . . 2 9
. 5 . . . . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
387624591495781236216953784841237965629548317573196842732419658168375429954862173 #1 Extreme (11540) bf
Brute Force: r5c6=8
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c2<>2
Forcing Net Contradiction in c6 => r6c1=5
r6c1<>5 r4c3=5 (r4c9<>5) r4c3<>1 r5c3=1 (r5c8<>1) (r5c7<>1) (r5c8<>1) r5c9<>1 r5c9=7 r4c9<>7 r4c9=1 (r6c8<>1) (r4c7<>1) (r6c7<>1) r5c9<>1 r5c9=7 r5c8<>7 r5c8=3 r5c7<>3 r1c7=3 r1c7<>1 r9c7=1 r9c8<>1 r2c8=1 (r7c8<>1) r2c6<>1
r6c1<>5 r4c3=5 (r4c9<>5) r4c3<>1 r5c3=1 r5c9<>1 r5c9=7 r4c9<>7 r4c9=1 r4c6<>1
r6c1<>5 r4c3=5 (r4c9<>5) r4c3<>1 r5c3=1 (r5c7<>1) (r5c8<>1) r5c9<>1 r5c9=7 r4c9<>7 r4c9=1 (r4c7<>1) (r6c7<>1) r5c9<>1 r5c9=7 r5c8<>7 r5c8=3 r5c7<>3 r1c7=3 r1c7<>1 r9c7=1 r9c6<>1
Finned Swordfish: 5 r147 c579 fr7c8 => r8c7<>5
Locked Candidates Type 1 (Pointing): 5 in b9 => r7c5<>5
Sue de Coq: r456c7 - {134589} (r8c7 - {48}, r45c9,r5c8 - {1357}) => r6c8<>1, r6c8<>7, r19c7<>8, r9c7<>4
Naked Single: r9c7=1
Locked Candidates Type 2 (Claiming): 1 in r6 => r4c46<>1
Hidden Single: r2c6=1
Hidden Single: r1c9=1
Naked Single: r5c9=7
Naked Single: r4c9=5
Naked Single: r2c9=6
Full House: r7c9=8
Naked Single: r8c7=4
Naked Single: r4c7=9
Naked Single: r9c8=7
Full House: r7c8=5
Naked Single: r5c7=3
Naked Single: r6c7=8
Full House: r1c7=5
Naked Single: r9c6=2
Naked Single: r2c8=3
Full House: r3c8=8
Naked Single: r5c8=1
Full House: r6c8=4
Naked Single: r4c6=7
Naked Single: r9c5=6
Naked Single: r4c2=4
Naked Single: r4c4=2
Full House: r4c3=1
Naked Single: r1c5=2
Naked Single: r2c2=9
Naked Single: r2c1=4
Naked Single: r2c4=7
Full House: r2c3=5
Naked Single: r6c2=7
Naked Single: r9c1=9
Naked Single: r3c3=6
Naked Single: r7c2=3
Naked Single: r1c1=3
Naked Single: r5c3=9
Naked Single: r8c3=8
Full House: r9c3=4
Full House: r9c4=8
Naked Single: r1c2=8
Full House: r1c4=6
Full House: r3c1=2
Naked Single: r7c1=7
Full House: r8c2=6
Full House: r5c1=6
Full House: r5c2=2
Naked Single: r8c4=3
Naked Single: r7c5=1
Full House: r7c4=4
Naked Single: r3c4=9
Full House: r6c4=1
Full House: r6c5=9
Naked Single: r8c6=5
Full House: r3c6=3
Full House: r3c5=5
Full House: r8c5=7
|
normal_sudoku_4659
|
89..54.3.3..987.2..5..3...9..832..7.2..4......7...8...43...2.8..26...15..8.......
|
892654731341987526657231849918326475263475918574198362439512687726849153185763294
|
Basic 9x9 Sudoku 4659
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 9 . . 5 4 . 3 .
3 . . 9 8 7 . 2 .
. 5 . . 3 . . . 9
. . 8 3 2 . . 7 .
2 . . 4 . . . . .
. 7 . . . 8 . . .
4 3 . . . 2 . 8 .
. 2 6 . . . 1 5 .
. 8 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
892654731341987526657231849918326475263475918574198362439512687726849153185763294 #1 Extreme (3478)
Naked Single: r8c2=2
Hidden Single: r5c5=7
Hidden Single: r3c7=8
Hidden Single: r5c9=8
Hidden Single: r8c4=8
Locked Candidates Type 1 (Pointing): 7 in b3 => r1c3<>7
W-Wing: 1/6 in r3c6,r5c2 connected by 6 in r2c2,r3c1 => r5c6<>1
Hidden Rectangle: 1/2 in r1c34,r3c34 => r3c4<>1
Grouped Discontinuous Nice Loop: 1 r6c1 -1- r5c2 -6- r2c2 =6= r3c1 -6- r3c6 -1- r4c6 =1= r6c45 -1- r6c1 => r6c1<>1
Sashimi Swordfish: 1 c168 r349 fr5c8 fr6c8 => r4c9<>1
Grouped Continuous Nice Loop: 1/2/6 6= r1c4 =1= r3c6 -1- r4c6 =1= r4c12 -1- r5c2 -6- r2c2 =6= r3c1 -6- r3c46 =6= r1c4 =1 => r56c3,r9c6<>1, r1c4<>2, r3c8<>6
Hidden Single: r1c3=2
Hidden Single: r3c4=2
Empty Rectangle: 6 in b5 (r3c16) => r6c1<>6
Grouped Discontinuous Nice Loop: 6 r5c6 -6- r5c2 -1- r4c12 =1= r4c6 -1- r3c6 -6- r5c6 => r5c6<>6
Sashimi Swordfish: 6 c168 r349 fr5c8 fr6c8 => r4c79<>6
Sue de Coq: r4c12 - {14569} (r4c79 - {459}, r5c2 - {16}) => r4c6<>5, r4c6<>9
Naked Pair: 1,6 in r34c6 => r9c6<>6
X-Wing: 6 c16 r34 => r4c2<>6
2-String Kite: 5 in r5c6,r7c3 (connected by r7c4,r9c6) => r5c3<>5
Empty Rectangle: 9 in b9 (r4c17) => r9c1<>9
Sue de Coq: r6c45 - {1569} (r6c1 - {59}, r4c6 - {16}) => r6c379<>5, r6c378<>9
Locked Candidates Type 1 (Pointing): 5 in b4 => r9c1<>5
Turbot Fish: 9 r6c5 =9= r5c6 -9- r5c8 =9= r9c8 => r9c5<>9
Finned X-Wing: 9 r68 c15 fr8c6 => r7c5<>9
Skyscraper: 9 in r4c1,r7c3 (connected by r47c7) => r5c3,r8c1<>9
Naked Single: r5c3=3
Naked Single: r8c1=7
Naked Single: r6c3=4
Naked Single: r9c1=1
Naked Single: r2c3=1
Naked Single: r4c2=1
Naked Single: r3c1=6
Naked Single: r3c3=7
Full House: r2c2=4
Full House: r5c2=6
Naked Single: r4c6=6
Naked Single: r3c6=1
Full House: r1c4=6
Full House: r3c8=4
Naked Single: r1c7=7
Full House: r1c9=1
Hidden Single: r5c8=1
Naked Single: r6c8=6
Full House: r9c8=9
Naked Single: r7c7=6
Naked Single: r9c3=5
Full House: r7c3=9
Naked Single: r2c7=5
Full House: r2c9=6
Naked Single: r7c5=1
Naked Single: r7c9=7
Full House: r7c4=5
Naked Single: r9c4=7
Full House: r6c4=1
Naked Single: r9c6=3
Naked Single: r5c7=9
Full House: r5c6=5
Full House: r6c5=9
Full House: r8c6=9
Naked Single: r4c7=4
Naked Single: r6c1=5
Full House: r4c1=9
Full House: r4c9=5
Naked Single: r8c5=4
Full House: r8c9=3
Full House: r9c5=6
Naked Single: r9c7=2
Full House: r6c7=3
Full House: r6c9=2
Full House: r9c9=4
|
normal_sudoku_6992
|
7.....58.4.1...63.56...3..981...6.9.9..2....6....1.......4...6.1.7......65...89..
|
739162584481579632562843179814356297975284316326917458298431765147695823653728941
|
Basic 9x9 Sudoku 6992
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 . . . . . 5 8 .
4 . 1 . . . 6 3 .
5 6 . . . 3 . . 9
8 1 . . . 6 . 9 .
9 . . 2 . . . . 6
. . . . 1 . . . .
. . . 4 . . . 6 .
1 . 7 . . . . . .
6 5 . . . 8 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
739162584481579632562843179814356297975284316326917458298431765147695823653728941 #1 Extreme (32604) bf
Brute Force: r5c9=6
Hidden Single: r6c3=6
Finned X-Wing: 1 c69 r17 fr9c9 => r7c7<>1
Forcing Net Contradiction in c2 => r5c5<>4
r5c5=4 r5c2<>4
r5c5=4 (r6c6<>4 r1c6=4 r1c6<>1 r7c6=1 r7c6<>7) r5c5<>8 r5c7=8 (r6c9<>8 r6c4=8 r6c4<>9 r6c6=9 r6c6<>7) (r6c9<>8 r6c4=8 r3c4<>8) r5c7<>1 r3c7=1 r3c4<>1 r3c4=7 r2c6<>7 r5c6=7 r5c2<>7 r6c2=7 r6c2<>4
r5c5=4 (r3c5<>4) r5c5<>8 r5c7=8 r5c7<>1 (r5c8=1 r9c8<>1 r9c9=1 r9c9<>4) r3c7=1 r3c7<>4 r3c8=4 r9c8<>4 r9c3=4 r8c2<>4
Brute Force: r5c8=1
Hidden Single: r3c7=1
Grouped Discontinuous Nice Loop: 5 r8c4 =6= r1c4 =1= r1c6 -1- r7c6 =1= r7c9 =5= r7c56 -5- r8c4 => r8c4<>5
Forcing Chain Contradiction in r4 => r6c8<>4
r6c8=4 r456c7<>4 r8c7=4 r8c2<>4 r9c3=4 r4c3<>4
r6c8=4 r3c8<>4 r3c5=4 r4c5<>4
r6c8=4 r4c7<>4
r6c8=4 r4c9<>4
Forcing Chain Contradiction in c6 => r6c8<>7
r6c8=7 r3c8<>7 r2c9=7 r2c6<>7
r6c8=7 r6c2<>7 r5c2=7 r5c6<>7
r6c8=7 r6c6<>7
r6c8=7 r456c7<>7 r7c7=7 r7c6<>7
Forcing Chain Contradiction in c4 => r6c6<>5
r6c6=5 r46c4<>5 r2c4=5 r2c4<>8
r6c6=5 r6c8<>5 r6c8=2 r4c79<>2 r4c3=2 r3c3<>2 r3c3=8 r3c4<>8
r6c6=5 r6c6<>9 r6c4=9 r6c4<>8
Forcing Net Contradiction in r6c8 => r6c8=5
r6c8<>5 r6c8=2 (r6c1<>2 r7c1=2 r7c7<>2 r8c7=2 r9c9<>2) (r3c8<>2) (r4c7<>2) r4c9<>2 r4c3=2 r3c3<>2 r3c5=2 (r9c5<>2) r3c5<>4 r3c8=4 r3c8<>7 r9c8=7 r9c8<>2 r9c3=2 r7c1<>2 r6c1=2 r6c8<>2 r6c8=5
Almost Locked Set XZ-Rule: A=r7c1237 {23789}, B=r89c8 {247}, X=7, Z=2 => r7c9<>2
Forcing Chain Contradiction in r7c7 => r9c3<>2
r9c3=2 r9c3<>4 r8c2=4 r8c8<>4 r8c8=2 r7c7<>2
r9c3=2 r7c1<>2 r7c1=3 r7c7<>3
r9c3=2 r3c3<>2 r3c3=8 r3c4<>8 r3c4=7 r3c8<>7 r9c8=7 r7c7<>7
r9c3=2 r9c3<>4 r8c2=4 r8c2<>8 r7c23=8 r7c7<>8
Grouped Discontinuous Nice Loop: 2 r3c5 -2- r9c5 =2= r9c89 -2- r8c8 -4- r3c8 =4= r3c5 => r3c5<>2
Almost Locked Set XY-Wing: A=r6c1 {23}, B=r1278c2 {23489}, C=r7c1,r9c3 {234}, X,Y=2,4, Z=3 => r56c2<>3
Forcing Net Verity => r9c5=2
r9c5=2 r9c5=2
r9c8=2 (r8c8<>2 r8c8=4 r9c9<>4) (r8c8<>2 r8c8=4 r3c8<>4 r3c5=4 r4c5<>4) (r8c8<>2 r8c8=4 r3c8<>4 r3c5=4 r1c6<>4 r1c9=4 r4c9<>4) r9c8<>7 r3c8=7 (r2c9<>7 r2c9=2 r4c9<>2) r3c8<>2 r3c3=2 r4c3<>2 r4c7=2 r4c7<>4 r4c3=4 r9c3<>4 r9c8=4 (r9c8<>2) r8c8<>4 r8c8=2 r9c9<>2 r9c5=2
r9c9=2 (r4c9<>2) (r1c9<>2 r1c9=4 r4c9<>4) (r4c9<>2) (r1c9<>2 r1c9=4 r3c8<>4 r3c5=4 r4c5<>4) (r1c9<>2 r1c9=4 r4c9<>4) (r9c9<>4) r8c8<>2 r8c8=4 r9c8<>4 r9c3=4 r4c3<>4 r4c7=4 r4c7<>2 r4c3=2 r3c3<>2 r3c8=2 r2c9<>2 r2c9=7 r4c9<>7 r4c9=3 (r6c9<>3 r6c9=8 r6c7<>8) r5c7<>3 r5c5=3 (r9c5<>3) r5c5<>8 r5c7=8 r6c9<>8 r6c4=8 r3c4<>8 r3c4=7 (r4c4<>7 r4c4=5 r5c6<>5 r5c3=5 r5c3<>3) r3c8<>7 r9c8=7 r9c5<>7 r9c5=2
Discontinuous Nice Loop: 9 r1c4 -9- r6c4 =9= r6c6 -9- r8c6 -5- r8c9 =5= r7c9 =1= r7c6 -1- r1c6 =1= r1c4 => r1c4<>9
Discontinuous Nice Loop: 9 r7c6 -9- r8c6 -5- r8c9 =5= r7c9 =1= r7c6 => r7c6<>9
Discontinuous Nice Loop: 9 r8c4 -9- r8c6 -5- r8c9 =5= r7c9 =1= r7c6 -1- r1c6 =1= r1c4 =6= r8c4 => r8c4<>9
Discontinuous Nice Loop: 5 r5c5 -5- r4c4 =5= r2c4 =9= r6c4 =8= r5c5 => r5c5<>5
Discontinuous Nice Loop: 7 r9c9 -7- r2c9 -2- r2c6 =2= r1c6 =1= r1c4 -1- r9c4 =1= r9c9 => r9c9<>7
Turbot Fish: 7 r2c9 =7= r3c8 -7- r9c8 =7= r9c4 => r2c4<>7
Almost Locked Set XY-Wing: A=r5c26 {457}, B=r123478c5 {3456789}, C=r13489c4 {135678}, X,Y=5,8, Z=7 => r5c5<>7
Almost Locked Set XY-Wing: A=r7c1237 {23789}, B=r8c456789 {2345689}, C=r9c8 {47}, X,Y=4,7, Z=8,9 => r7c9<>8, r7c5,r8c2<>9
Almost Locked Set Chain: 3- r6c1 {23} -2- r7c1 {23} -3- r9c3 {34} -4- r9c8 {47} -7- r189c4 {1367} -3 => r6c4<>3
Almost Locked Set XZ-Rule: A=r1246c9 {23478}, B=r4c45,r56c6,r6c4 {345789}, X=8, Z=3 => r4c7<>3
Forcing Chain Contradiction in r2 => r2c5<>8
r2c5=8 r5c5<>8 r6c4=8 r6c4<>9 r2c4=9 r2c4<>5
r2c5=8 r2c5<>5
r2c5=8 r5c5<>8 r6c4=8 r6c4<>9 r6c6=9 r8c6<>9 r8c6=5 r2c6<>5
Forcing Chain Contradiction in r4c3 => r1c3<>2
r1c3=2 r4c3<>2
r1c3=2 r3c3<>2 r3c3=8 r3c5<>8 r5c5=8 r5c5<>3 r4c45=3 r4c3<>3
r1c3=2 r3c3<>2 r3c8=2 r8c8<>2 r8c8=4 r8c2<>4 r9c3=4 r4c3<>4
r1c3=2 r3c3<>2 r3c3=8 r2c2<>8 r2c4=8 r2c4<>5 r4c4=5 r4c3<>5
Empty Rectangle: 2 in b1 (r38c8) => r8c2<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c7<>2
Grouped Discontinuous Nice Loop: 2 r7c2 -2- r12c2 =2= r3c3 =8= r7c3 =9= r7c2 => r7c2<>2
Discontinuous Nice Loop: 3 r5c3 -3- r6c1 -2- r7c1 =2= r7c3 =8= r3c3 -8- r2c2 =8= r2c4 =5= r4c4 -5- r4c3 =5= r5c3 => r5c3<>3
Naked Triple: 4,5,7 in r5c236 => r5c7<>4, r5c7<>7
Sue de Coq: r78c7 - {23478} (r5c7 - {38}, r89c8 - {247}) => r7c9<>7, r8c9<>2, r89c9<>4, r6c7<>3, r6c7<>8
Finned Swordfish: 2 r348 c378 fr4c9 => r6c7<>2
AIC: 2/3 3- r6c1 =3= r6c9 =8= r6c4 -8- r2c4 =8= r2c2 -8- r3c3 -2- r7c3 =2= r7c1 -2 => r6c1<>2, r7c1<>3
Naked Single: r6c1=3
Full House: r7c1=2
Swordfish: 2 r126 c269 => r4c9<>2
AIC: 9 9- r1c3 =9= r7c3 =8= r3c3 =2= r4c3 -2- r4c7 =2= r6c9 =8= r6c4 =9= r2c4 -9 => r1c56,r2c2<>9
Naked Pair: 2,8 in r2c2,r3c3 => r1c2<>2
Uniqueness Test 2: 3/9 in r1c23,r7c23 => r7c7,r8c2<>8
Naked Pair: 3,4 in r8c2,r9c3 => r7c23<>3
XY-Wing: 4/7/3 in r7c7,r9c38 => r9c9<>3
Naked Single: r9c9=1
Hidden Single: r7c6=1
Hidden Single: r1c4=1
Hidden Single: r1c5=6
Hidden Single: r8c4=6
2-String Kite: 4 in r1c9,r4c5 (connected by r1c6,r3c5) => r4c9<>4
2-String Kite: 7 in r3c8,r7c5 (connected by r7c7,r9c8) => r3c5<>7
X-Wing: 7 r39 c48 => r46c4<>7
Finned X-Wing: 3 r57 c57 fr7c9 => r8c7<>3
Finned X-Wing: 7 r47 c57 fr4c9 => r6c7<>7
Naked Single: r6c7=4
Hidden Single: r1c9=4
Naked Single: r1c6=2
Hidden Single: r5c6=4
Naked Single: r5c2=7
Naked Single: r5c3=5
Naked Single: r6c2=2
Full House: r4c3=4
Naked Single: r2c2=8
Naked Single: r9c3=3
Naked Single: r3c3=2
Naked Single: r7c2=9
Naked Single: r1c3=9
Full House: r1c2=3
Full House: r8c2=4
Full House: r7c3=8
Naked Single: r9c4=7
Full House: r9c8=4
Naked Single: r3c8=7
Full House: r8c8=2
Full House: r2c9=2
Naked Single: r3c4=8
Full House: r3c5=4
Naked Single: r8c7=8
Naked Single: r6c4=9
Naked Single: r5c7=3
Full House: r5c5=8
Naked Single: r2c4=5
Full House: r4c4=3
Naked Single: r6c6=7
Full House: r4c5=5
Full House: r6c9=8
Naked Single: r4c9=7
Full House: r4c7=2
Full House: r7c7=7
Naked Single: r2c6=9
Full House: r2c5=7
Full House: r8c6=5
Naked Single: r7c5=3
Full House: r7c9=5
Full House: r8c9=3
Full House: r8c5=9
|
normal_sudoku_6818
|
.82..6.3...6...8..3...9......19...5....7....68....29...4......55.83.96..6....53..
|
982476531476531829315298764761983452239754186854612973143867295528349617697125348
|
Basic 9x9 Sudoku 6818
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 2 . . 6 . 3 .
. . 6 . . . 8 . .
3 . . . 9 . . . .
. . 1 9 . . . 5 .
. . . 7 . . . . 6
8 . . . . 2 9 . .
. 4 . . . . . . 5
5 . 8 3 . 9 6 . .
6 . . . . 5 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
982476531476531829315298764761983452239754186854612973143867295528349617697125348 #1 Extreme (42066) bf
Hidden Single: r4c4=9
Hidden Single: r3c8=6
Hidden Single: r7c3=3
Skyscraper: 9 in r1c9,r7c8 (connected by r17c1) => r2c8,r9c9<>9
Brute Force: r5c3=9
Naked Single: r9c3=7
Finned X-Wing: 5 r25 c25 fr2c4 => r1c5<>5
Forcing Net Contradiction in b5 => r5c5<>4
r5c5=4 r5c5<>1
r5c5=4 (r5c7<>4) r5c1<>4 r5c1=2 r5c7<>2 r5c7=1 r5c6<>1
r5c5=4 (r9c5<>4 r9c4=4 r1c4<>4) r5c5<>5 r5c2=5 r6c3<>5 r3c3=5 r3c7<>5 r1c7=5 r1c4<>5 r1c4=1 r6c4<>1
r5c5=4 (r5c5<>5) (r5c5<>3) r5c5<>5 r5c2=5 r5c2<>3 r5c6=3 r2c6<>3 r2c5=3 r2c5<>5 r6c5=5 r6c5<>1
Brute Force: r5c2=3
Hidden Single: r5c5=5
Finned X-Wing: 8 c59 r49 fr7c5 => r9c4<>8
Forcing Net Contradiction in c5 => r3c6<>4
r3c6=4 (r1c5<>4) (r2c5<>4) (r1c4<>4) (r2c4<>4) (r3c4<>4) r3c3<>4 r6c3=4 (r6c5<>4) r6c4<>4 r9c4=4 (r8c5<>4) r9c5<>4 r4c5=4 r4c5<>8
r3c6=4 (r3c6<>8 r3c4=8 r3c4<>2) (r1c4<>4) (r2c4<>4) (r3c4<>4) r3c3<>4 (r3c3=5 r2c2<>5 r2c4=5 r2c4<>2) r6c3=4 r6c4<>4 r9c4=4 r9c4<>2 r7c4=2 r7c4<>6 r7c5=6 r7c5<>8
r3c6=4 (r3c6<>8 r3c4=8 r3c4<>2) r3c3<>4 (r6c3=4 r6c4<>4 r9c4=4 r9c5<>4 r4c5=4 r4c5<>3) (r6c3=4 r6c4<>4 r9c4=4 r9c5<>4 r4c5=4 r4c5<>3) r3c3=5 r2c2<>5 r2c4=5 r2c4<>2 r2c5=2 r2c5<>3 r6c5=3 r4c6<>3 r4c9=3 r4c9<>8 r9c9=8 r9c5<>8
Forcing Net Contradiction in r3 => r5c8<>4
r5c8=4 (r5c1<>4 r5c1=2 r5c7<>2 r5c7=1 r7c7<>1) (r5c1<>4 r5c1=2 r4c1<>2) (r5c1<>4 r5c1=2 r4c2<>2) r5c8<>8 r5c6=8 (r7c6<>8) (r4c5<>8) r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r7c7<>2 r7c7=7 r7c6<>7 r7c6=1 r7c1<>1 r12c1=1 r3c2<>1
r5c8=4 r5c8<>8 r5c6=8 r3c6<>8 r3c4=8 r3c4<>1
r5c8=4 (r5c1<>4 r5c1=2 r5c7<>2 r5c7=1 r7c7<>1) (r5c1<>4 r5c1=2 r4c1<>2) (r5c1<>4 r5c1=2 r4c2<>2) r5c8<>8 r5c6=8 (r7c6<>8) (r4c5<>8) r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r7c7<>2 r7c7=7 r7c6<>7 r7c6=1 r3c6<>1
r5c8=4 (r5c7<>4) r5c1<>4 r5c1=2 r5c7<>2 r5c7=1 r3c7<>1
r5c8=4 (r5c1<>4 r5c1=2 r4c1<>2) (r5c1<>4 r5c1=2 r4c2<>2) r5c8<>8 r5c6=8 (r3c6<>8 r3c4=8 r3c4<>2) (r4c5<>8) r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r3c7<>2 r3c9=2 r3c9<>1
Brute Force: r5c1=2
Grouped Discontinuous Nice Loop: 2 r9c9 -2- r789c8 =2= r2c8 -2- r2c45 =2= r3c4 =8= r3c6 -8- r5c6 =8= r5c8 -8- r4c9 =8= r9c9 => r9c9<>2
Forcing Chain Contradiction in r7 => r3c4<>5
r3c4=5 r3c4<>8 r7c4=8 r7c4<>2
r3c4=5 r3c4<>8 r7c4=8 r7c4<>6 r7c5=6 r7c5<>2
r3c4=5 r3c4<>2 r2c45=2 r2c8<>2 r789c8=2 r7c7<>2
r3c4=5 r2c4<>5 r2c2=5 r2c2<>9 r9c2=9 r9c8<>9 r7c8=9 r7c8<>2
Forcing Chain Contradiction in b2 => r4c5<>4
r4c5=4 r4c1<>4 r6c3=4 r6c3<>5 r6c2=5 r2c2<>5 r2c4=5 r2c4<>2
r4c5=4 r45c6<>4 r2c6=4 r2c6<>3 r2c5=3 r2c5<>2
r4c5=4 r4c5<>8 r79c5=8 r7c4<>8 r3c4=8 r3c4<>2
Forcing Chain Contradiction in r7 => r8c9<>2
r8c9=2 r789c8<>2 r2c8=2 r2c5<>2 r23c4=2 r7c4<>2
r8c9=2 r789c8<>2 r2c8=2 r2c45<>2 r3c4=2 r3c4<>8 r7c4=8 r7c4<>6 r7c5=6 r7c5<>2
r8c9=2 r7c7<>2
r8c9=2 r7c8<>2
Forcing Chain Contradiction in c8 => r9c8<>8
r9c8=8 r9c9<>8 r4c9=8 r4c9<>2 r23c9=2 r2c8<>2
r9c8=8 r9c8<>9 r7c8=9 r7c8<>2
r9c8=8 r9c8<>9 r9c2=9 r9c2<>2 r8c2=2 r8c8<>2
r9c8=8 r9c8<>2
Forcing Net Contradiction in r4c6 => r5c8=8
r5c8<>8 (r5c6=8 r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r3c7<>2 r3c9=2 r2c8<>2) (r5c6=8 r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r3c7<>2 r3c9=2 r2c9<>2) r7c8=8 r7c8<>9 r7c1=9 (r2c1<>9) r1c1<>9 r1c9=9 r2c9<>9 r2c2=9 r2c2<>5 r2c4=5 r2c4<>2 r2c5=2 r2c5<>3 r2c6=3 r4c6<>3
r5c8<>8 (r5c8=1 r5c7<>1 r5c7=4 r3c7<>4) r5c6=8 (r3c6<>8 r3c4=8 r3c4<>4) (r3c6<>8 r3c4=8 r3c4<>2) (r4c5<>8) r4c6<>8 r4c9=8 r4c9<>2 r4c7=2 r3c7<>2 r3c9=2 r3c9<>4 r3c3=4 (r1c1<>4) r2c1<>4 r4c1=4 r4c6<>4
r5c8<>8 r5c6=8 r4c6<>8
Hidden Single: r9c9=8
Forcing Net Contradiction in r7c8 => r4c2=6
r4c2<>6 (r4c2=7 r4c1<>7 r4c1=4 r4c7<>4 r4c7=2 r7c7<>2) r4c5=6 (r7c5<>6 r7c4=6 r7c4<>2) (r7c5<>6 r7c4=6 r7c4<>8) r4c5<>8 r4c6=8 r7c6<>8 r7c5=8 r7c5<>2 r7c8=2
r4c2<>6 (r4c2=7 r4c1<>7 r4c1=4 r4c7<>4) (r4c2=7 r4c1<>7 r4c1=4 r6c3<>4 r3c3=4 r3c7<>4) (r4c2=7 r4c1<>7 r4c1=4 r4c6<>4) r4c5=6 r4c5<>8 r4c6=8 r4c6<>3 r2c6=3 r2c6<>4 r5c6=4 r5c7<>4 r1c7=4 r1c7<>5 r1c4=5 r2c4<>5 r2c2=5 r2c2<>9 r9c2=9 r7c1<>9 r7c8=9
Almost Locked Set XZ-Rule: A=r5c7 {14}, B=r6c238 {1457}, X=1, Z=4 => r6c9<>4
Forcing Net Contradiction in r7c7 => r1c7<>7
r1c7=7 r1c7<>5 r1c4=5 r2c4<>5 r2c2=5 r2c2<>9 r9c2=9 r7c1<>9 r7c1=1 r7c7<>1
r1c7=7 (r4c7<>7) r1c7<>5 r3c7=5 r3c3<>5 r3c3=4 (r1c1<>4) r2c1<>4 r4c1=4 r4c7<>4 r4c7=2 r7c7<>2
r1c7=7 r7c7<>7
Forcing Net Verity => r7c1=1
r3c2=1 (r1c1<>1) r2c1<>1 r7c1=1
r3c2=5 (r2c2<>5 r2c4=5 r1c4<>5 r1c7=5 r1c7<>4) (r3c3<>5 r3c3=4 r3c7<>4) (r2c2<>5 r2c4=5 r1c4<>5 r1c7=5 r1c7<>4) r6c2<>5 r6c2=7 r4c1<>7 r4c1=4 (r4c6<>4) (r4c7<>4) (r4c6<>4) r4c7<>4 r5c7=4 r5c6<>4 r2c6=4 (r1c4<>4) (r1c5<>4) r5c6<>4 r5c7=4 r4c9<>4 r4c1=4 (r4c6<>4) (r4c7<>4) (r4c6<>4) r1c1<>4 r1c9=4 r1c9<>9 r1c1=9 r7c1<>9 r7c1=1
r3c2=7 (r1c1<>7) (r3c6<>7) (r3c7<>7) (r1c1<>7) r2c1<>7 r4c1=7 r4c7<>7 r7c7=7 r7c6<>7 r2c6=7 r1c5<>7 r1c9=7 r1c9<>9 r1c1=9 r7c1<>9 r7c1=1
Naked Single: r8c2=2
Full House: r9c2=9
Hidden Single: r7c8=9
Empty Rectangle: 2 in b2 (r29c8) => r9c4<>2
Finned Swordfish: 1 c267 r235 fr1c7 => r2c89,r3c9<>1
Grouped Continuous Nice Loop: 1/2/4/7/8 2= r3c4 =8= r3c6 -8- r7c6 -7- r7c7 -2- r9c8 =2= r2c8 -2- r2c45 =2= r3c4 =8 => r3c4<>1, r2c9<>2, r3c4<>4, r7c5<>7, r4c6<>8
Hidden Single: r4c5=8
Discontinuous Nice Loop: 7 r2c5 -7- r8c5 =7= r7c6 -7- r7c7 -2- r4c7 =2= r4c9 =3= r4c6 -3- r2c6 =3= r2c5 => r2c5<>7
Almost Locked Set XY-Wing: A=r2c189 {2479}, B=r7c6 {78}, C=r3c23679 {124578}, X,Y=2,8, Z=7 => r2c6<>7
Naked Triple: 1,3,4 in r245c6 => r3c6<>1
Sashimi Swordfish: 7 c167 r347 fr1c1 fr2c1 => r3c2<>7
Almost Locked Set XY-Wing: A=r3c46 {278}, B=r123c9,r2c8 {12479}, C=r1c457 {1457}, X,Y=1,7, Z=2 => r3c7<>2
Forcing Chain Contradiction in r2c8 => r2c5=3
r2c5<>3 r2c6=3 r4c6<>3 r4c9=3 r4c9<>2 r3c9=2 r2c8<>2
r2c5<>3 r2c6=3 r4c6<>3 r4c6=4 r4c1<>4 r6c3=4 r3c3<>4 r3c79=4 r2c8<>4
r2c5<>3 r2c6=3 r4c6<>3 r4c6=4 r4c1<>4 r4c1=7 r1c1<>7 r2c12=7 r2c8<>7
Hidden Single: r4c6=3
Hidden Single: r6c9=3
Locked Candidates Type 1 (Pointing): 2 in b2 => r7c4<>2
Discontinuous Nice Loop: 4 r4c9 -4- r4c1 -7- r6c2 -5- r2c2 =5= r2c4 =2= r2c8 -2- r3c9 =2= r4c9 => r4c9<>4
2-String Kite: 4 in r3c3,r4c7 (connected by r4c1,r6c3) => r3c7<>4
Discontinuous Nice Loop: 7 r1c9 -7- r1c5 =7= r8c5 -7- r7c6 =7= r7c7 =2= r4c7 -2- r4c9 -7- r1c9 => r1c9<>7
Grouped Discontinuous Nice Loop: 4 r1c1 -4- r4c1 =4= r4c7 -4- r5c7 -1- r13c7 =1= r1c9 =9= r1c1 => r1c1<>4
Hidden Rectangle: 7/9 in r1c19,r2c19 => r2c9<>7
Finned Swordfish: 4 c167 r245 fr1c7 => r2c89<>4
Naked Single: r2c9=9
Hidden Single: r1c1=9
Hidden Single: r1c5=7
Naked Single: r3c6=8
Naked Single: r3c4=2
Naked Single: r7c6=7
Naked Single: r7c7=2
Naked Single: r7c5=6
Full House: r7c4=8
Hidden Single: r2c8=2
Hidden Single: r4c9=2
Hidden Single: r9c5=2
Hidden Single: r6c4=6
Remote Pair: 1/4 r6c5 -4- r8c5 -1- r9c4 -4- r9c8 => r6c8<>1, r6c8<>4
Naked Single: r6c8=7
Naked Single: r4c7=4
Full House: r4c1=7
Full House: r5c7=1
Full House: r2c1=4
Full House: r5c6=4
Full House: r2c6=1
Full House: r6c5=1
Full House: r8c5=4
Full House: r9c4=1
Full House: r9c8=4
Full House: r8c8=1
Full House: r8c9=7
Naked Single: r6c2=5
Full House: r6c3=4
Full House: r3c3=5
Naked Single: r1c7=5
Full House: r3c7=7
Naked Single: r2c4=5
Full House: r2c2=7
Full House: r3c2=1
Full House: r3c9=4
Full House: r1c4=4
Full House: r1c9=1
|
normal_sudoku_6997
|
..5.4.....7...5.8.18.67...5..1..4.682.....94..9.....3....2.78....74.6..1....3.6..
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625849713479315286183672495731924568268153947594768132316297854957486321842531679
|
Basic 9x9 Sudoku 6997
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 5 . 4 . . . .
. 7 . . . 5 . 8 .
1 8 . 6 7 . . . 5
. . 1 . . 4 . 6 8
2 . . . . . 9 4 .
. 9 . . . . . 3 .
. . . 2 . 7 8 . .
. . 7 4 . 6 . . 1
. . . . 3 . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
625849713479315286183672495731924568268153947594768132316297854957486321842531679 #1 Extreme (11772) bf
Forcing Net Contradiction in r2c5 => r2c9<>4
r2c9=4 (r9c9<>4) (r6c9<>4) r5c9<>4 r5c9=7 (r9c9<>7) r6c9<>7 r6c9=2 r9c9<>2 r9c9=9 r9c6<>9 r13c6=9 r2c5<>9
r2c9=4 (r3c7<>4 r6c7=4 r6c7<>1) r5c9<>4 r5c9=7 (r6c9<>7 r6c9=2 r4c7<>2 r4c5=2 r2c5<>2) (r4c7<>7) r6c7<>7 r1c7=7 r1c7<>1 r2c7=1 r2c5<>1 r2c5=9
Forcing Net Contradiction in b1 => r7c1<>4
r7c1=4 r2c1<>4
r7c1=4 (r7c8<>4) (r7c2<>4) r9c2<>4 r5c2=4 (r5c8<>4) r5c9<>4 r5c9=7 (r6c9<>7 r6c9=2 r4c7<>2 r4c5=2 r2c5<>2) (r6c9<>7 r6c9=2 r2c9<>2) (r6c7<>7) r9c9<>7 r9c8=7 r9c8<>4 r3c8=4 (r2c7<>4) r3c7<>4 r6c7=4 (r6c7<>1) r5c9<>4 r5c9=7 (r6c9<>7 r6c9=2 r4c7<>2 r4c5=2 r2c5<>2) (r6c9<>7 r6c9=2 r2c9<>2) (r6c7<>7) r4c7<>7 r1c7=7 r1c7<>1 r2c7=1 r2c7<>2 r2c3=2 r2c3<>4
r7c1=4 (r7c8<>4) (r7c2<>4) r9c2<>4 r5c2=4 (r5c8<>4) r5c9<>4 r5c9=7 r9c9<>7 r9c8=7 r9c8<>4 r3c8=4 r3c3<>4
Brute Force: r5c8=4
Naked Single: r5c9=7
Naked Single: r6c9=2
Naked Single: r4c7=5
Full House: r6c7=1
Naked Single: r4c2=3
Naked Single: r6c6=8
Naked Single: r4c1=7
Naked Single: r4c4=9
Full House: r4c5=2
Hidden Single: r1c8=1
Hidden Single: r1c7=7
Hidden Single: r9c8=7
Hidden Single: r1c4=8
Hidden Single: r5c3=8
Hidden Single: r8c5=8
Hidden Single: r6c4=7
Hidden Single: r9c1=8
Locked Candidates Type 1 (Pointing): 2 in b9 => r8c2<>2
Naked Single: r8c2=5
Naked Single: r5c2=6
Naked Single: r1c2=2
Naked Single: r6c3=4
Full House: r6c1=5
Full House: r6c5=6
Hidden Single: r7c8=5
Hidden Single: r9c4=5
Hidden Single: r3c6=2
Naked Single: r3c8=9
Full House: r8c8=2
Naked Single: r3c3=3
Full House: r3c7=4
Naked Single: r8c7=3
Full House: r2c7=2
Full House: r8c1=9
Naked Single: r1c1=6
Naked Single: r7c3=6
Naked Single: r9c3=2
Full House: r2c3=9
Full House: r2c1=4
Full House: r7c1=3
Naked Single: r1c9=3
Full House: r1c6=9
Full House: r2c9=6
Naked Single: r2c5=1
Full House: r2c4=3
Full House: r5c4=1
Naked Single: r9c6=1
Full House: r7c5=9
Full House: r5c5=5
Full House: r5c6=3
Naked Single: r9c2=4
Full House: r7c2=1
Full House: r7c9=4
Full House: r9c9=9
|
normal_sudoku_2716
|
.....6..39.7..816.....1....1.95....8.8..27...4.3869.1...824......5....416...7....
|
251796483937458162864312759179534628586127394423869517318245976795683241642971835
|
Basic 9x9 Sudoku 2716
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 6 . . 3
9 . 7 . . 8 1 6 .
. . . . 1 . . . .
1 . 9 5 . . . . 8
. 8 . . 2 7 . . .
4 . 3 8 6 9 . 1 .
. . 8 2 4 . . . .
. . 5 . . . . 4 1
6 . . . 7 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
251796483937458162864312759179534628586127394423869517318245976795683241642971835 #1 Easy (272)
Naked Single: r6c6=9
Naked Single: r4c5=3
Naked Single: r5c3=6
Naked Single: r5c1=5
Naked Single: r8c6=3
Naked Single: r2c5=5
Naked Single: r4c6=4
Full House: r5c4=1
Naked Single: r1c5=9
Full House: r8c5=8
Naked Single: r3c6=2
Naked Single: r9c4=9
Naked Single: r3c3=4
Naked Single: r8c4=6
Hidden Single: r3c2=6
Hidden Single: r4c7=6
Hidden Single: r7c9=6
Hidden Single: r9c2=4
Hidden Single: r1c2=5
Hidden Single: r1c3=1
Full House: r9c3=2
Naked Single: r8c1=7
Naked Single: r9c9=5
Naked Single: r7c1=3
Naked Single: r8c2=9
Full House: r7c2=1
Full House: r8c7=2
Naked Single: r9c6=1
Full House: r7c6=5
Naked Single: r3c1=8
Full House: r1c1=2
Full House: r2c2=3
Naked Single: r2c4=4
Full House: r2c9=2
Naked Single: r1c4=7
Full House: r3c4=3
Naked Single: r6c9=7
Naked Single: r1c8=8
Full House: r1c7=4
Naked Single: r3c9=9
Full House: r5c9=4
Naked Single: r4c8=2
Full House: r4c2=7
Full House: r6c2=2
Full House: r6c7=5
Naked Single: r9c8=3
Full House: r9c7=8
Naked Single: r3c7=7
Full House: r3c8=5
Naked Single: r5c8=9
Full House: r5c7=3
Full House: r7c7=9
Full House: r7c8=7
|
normal_sudoku_5634
|
6.7.5.21...52.6..9....7.....5.......1...6..3....1.5.8....5.9.215.2.1.....9...76..
|
647953218315286749928471365254398176189762534763145982876539421532614897491827653
|
Basic 9x9 Sudoku 5634
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
6 . 7 . 5 . 2 1 .
. . 5 2 . 6 . . 9
. . . . 7 . . . .
. 5 . . . . . . .
1 . . . 6 . . 3 .
. . . 1 . 5 . 8 .
. . . 5 . 9 . 2 1
5 . 2 . 1 . . . .
. 9 . . . 7 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
647953218315286749928471365254398176189762534763145982876539421532614897491827653 #1 Extreme (40000) bf
Hidden Single: r1c5=5
Hidden Single: r4c7=1
Hidden Single: r2c2=1
Hidden Single: r3c6=1
Hidden Single: r9c3=1
Hidden Single: r9c5=2
Hidden Single: r8c4=6
Hidden Single: r1c4=9
Brute Force: r5c4=7
Brute Force: r5c6=2
Locked Candidates Type 1 (Pointing): 8 in b5 => r4c13<>8
Almost Locked Set XZ-Rule: A=r4c3456 {34689}, B=r4c8,r5c79,r6c7 {45679}, X=6, Z=4 => r4c9<>4
Almost Locked Set XZ-Rule: A=r239c8 {4567}, B=r13589c9 {345678}, X=6, Z=7 => r8c8<>7
Forcing Net Verity => r8c8=9
r4c8=6 r4c8<>9 r8c8=9
r4c9=6 (r4c9<>7) r4c9<>2 r4c1=2 r4c1<>7 r4c8=7 r4c8<>9 r8c8=9
r6c9=6 (r4c9<>6 r4c3=6 r7c3<>6 r7c2=6 r7c2<>7) (r6c9<>7) r6c9<>2 r4c9=2 (r4c9<>7) r4c9<>7 r8c9=7 r7c7<>7 r7c1=7 r4c1<>7 r4c8=7 r4c8<>9 r8c8=9
Forcing Net Verity => r1c9<>4
r2c8=4 r1c9<>4
r3c8=4 r1c9<>4
r4c8=4 (r4c8<>7) (r6c7<>4) (r5c7<>4) r5c9<>4 r5c9=5 r5c7<>5 r5c7=9 r6c7<>9 r6c7=7 (r6c9<>7) (r7c7<>7) r4c9<>7 r4c1=7 (r4c1<>2 r4c9=2 r6c9<>2) r7c1<>7 r7c2=7 r7c2<>6 r6c2=6 r6c9<>6 r6c9=4 r1c9<>4
r9c8=4 r9c8<>5 r9c9=5 r5c9<>5 r5c9=4 r1c9<>4
Forcing Net Contradiction in r3c8 => r3c2<>4
r3c2=4 r3c8<>4
r3c2=4 r3c2<>2 r3c1=2 r3c1<>9 r3c3=9 r5c3<>9 r5c7=9 r5c7<>5 r3c7=5 r3c8<>5
r3c2=4 r3c2<>2 (r3c1=2 r4c1<>2 r4c9=2 r4c9<>6) (r3c1=2 r4c1<>2 r4c9=2 r4c9<>7) r6c2=2 (r6c2<>7) r6c2<>6 r7c2=6 r7c2<>7 r8c2=7 r8c9<>7 r6c9=7 r6c9<>6 r3c9=6 r3c8<>6
Forcing Net Contradiction in r4c3 => r3c2<>8
r3c2=8 (r5c2<>8 r5c2=4 r1c2<>4 r1c2=3 r1c9<>3 r1c9=8 r2c7<>8 r2c5=8 r7c5<>8) (r5c2<>8 r5c2=4 r4c3<>4) (r5c2<>8 r5c2=4 r5c3<>4) (r5c2<>8 r5c2=4 r6c3<>4) r3c2<>2 r3c1=2 r3c1<>9 r3c3=9 r3c3<>4 r7c3=4 r7c5<>4 r7c5=3 r6c5<>3 r4c456=3 r4c3<>3
r3c2=8 r5c2<>8 r5c2=4 r4c3<>4
r3c2=8 r3c2<>2 (r3c1=2 r4c1<>2 r4c9=2 r4c9<>7) r6c2=2 (r6c2<>6) (r6c2<>7) r6c2<>6 r7c2=6 r7c2<>7 r8c2=7 r8c9<>7 r6c9=7 r6c9<>6 r6c3=6 r4c3<>6
r3c2=8 r3c2<>2 r3c1=2 r3c1<>9 r3c3=9 r4c3<>9
Forcing Net Contradiction in b2 => r3c7<>8
r3c7=8 (r1c9<>8) r3c7<>5 r5c7=5 r5c9<>5 r5c9=4 r5c2<>4 r5c2=8 r1c2<>8 r1c6=8
r3c7=8 r2c7<>8 r2c5=8
Forcing Net Verity => r3c9<>4
r3c9=6 r3c9<>4
r4c9=6 (r4c9<>7) r4c9<>2 r4c1=2 r4c1<>7 r4c8=7 r2c8<>7 r2c8=4 r3c9<>4
r6c9=6 (r4c9<>6 r4c3=6 r7c3<>6 r7c2=6 r7c2<>7) (r6c9<>7) r6c9<>2 r4c9=2 (r4c9<>7) r4c9<>7 r8c9=7 r7c7<>7 r7c1=7 r4c1<>7 r4c8=7 r2c8<>7 r2c8=4 r3c9<>4
Forcing Net Contradiction in r2c7 => r4c1<>3
r4c1=3 (r2c1<>3) (r6c1<>3) (r6c2<>3) r6c3<>3 r6c5=3 r2c5<>3 r2c7=3
r4c1=3 (r4c1<>7) r4c1<>2 r4c9=2 r4c9<>7 r4c8=7 r2c8<>7 r2c7=7
Forcing Net Contradiction in r4c6 => r4c8<>4
r4c8=4 (r4c8<>7) (r6c7<>4) (r5c7<>4) r5c9<>4 r5c9=5 r5c7<>5 r5c7=9 r6c7<>9 r6c7=7 (r6c9<>7) (r7c7<>7) r4c9<>7 r4c1=7 (r4c1<>2 r4c9=2 r6c9<>2) r7c1<>7 r7c2=7 r7c2<>6 r6c2=6 r6c9<>6 r6c9=4 r4c8<>4
Forcing Net Contradiction in r8 => r7c2<>4
r7c2=4 (r1c2<>4 r1c6=4 r1c6<>8) (r1c2<>4 r1c6=4 r8c6<>4 r9c4=4 r9c4<>8) (r5c2<>4 r5c2=8 r5c3<>8) r7c2<>6 r7c3=6 r7c3<>8 r3c3=8 r3c4<>8 r4c4=8 r4c6<>8 r8c6=8
r7c2=4 (r5c2<>4 r5c2=8 r8c2<>8) (r5c2<>4 r5c2=8 r1c2<>8) r1c2<>4 r1c6=4 r1c6<>8 r1c9=8 r8c9<>8 r8c7=8
Forcing Net Contradiction in c8 => r7c2<>8
r7c2=8 (r7c2<>6 r7c3=6 r7c3<>4 r3c3=4 r3c8<>4) r5c2<>8 r5c2=4 r5c9<>4 r5c9=5 r9c9<>5 r9c8=5 r9c8<>4 r2c8=4 r2c8<>7
r7c2=8 (r7c2<>7) r7c2<>6 r6c2=6 r6c2<>7 r8c2=7 r8c9<>7 r46c9=7 r4c8<>7
Brute Force: r5c3=9
Hidden Single: r3c1=9
Hidden Single: r4c5=9
Hidden Single: r6c7=9
Hidden Single: r5c2=8
Hidden Single: r3c2=2
Locked Candidates Type 2 (Claiming): 4 in r5 => r6c9<>4
Skyscraper: 8 in r2c5,r3c3 (connected by r7c35) => r2c1,r3c4<>8
Hidden Single: r3c3=8
W-Wing: 3/4 in r2c1,r3c4 connected by 4 in r1c26 => r2c5<>3
Empty Rectangle: 3 in b4 (r67c5) => r7c3<>3
Locked Candidates Type 2 (Claiming): 3 in c3 => r6c12<>3
Finned X-Wing: 8 r18 c69 fr8c7 => r9c9<>8
Sashimi Swordfish: 3 r239 c149 fr2c7 fr3c7 => r1c9<>3
Naked Single: r1c9=8
Hidden Single: r2c5=8
Finned X-Wing: 4 c35 r67 fr4c3 => r6c12<>4
Naked Triple: 2,6,7 in r6c129 => r6c3<>6
Hidden Rectangle: 2/7 in r4c19,r6c19 => r4c9<>7
Forcing Chain Contradiction in r9c4 => r6c2=6
r6c2<>6 r7c2=6 r7c3<>6 r7c3=4 r7c5<>4 r7c5=3 r9c4<>3
r6c2<>6 r6c2=7 r6c9<>7 r4c8=7 r2c8<>7 r2c8=4 r3c78<>4 r3c4=4 r9c4<>4
r6c2<>6 r6c2=7 r46c1<>7 r7c1=7 r7c1<>8 r9c1=8 r9c4<>8
Hidden Single: r7c3=6
Locked Candidates Type 1 (Pointing): 7 in b4 => r7c1<>7
Locked Candidates Type 2 (Claiming): 4 in c3 => r4c1<>4
Uniqueness Test 1: 2/7 in r4c19,r6c19 => r4c9<>2
Naked Single: r4c9=6
Naked Single: r4c8=7
Naked Single: r2c8=4
Naked Single: r4c1=2
Naked Single: r6c9=2
Naked Single: r2c1=3
Full House: r1c2=4
Full House: r2c7=7
Full House: r1c6=3
Full House: r3c4=4
Naked Single: r9c8=5
Full House: r3c8=6
Naked Single: r6c1=7
Hidden Single: r8c9=7
Naked Single: r8c2=3
Full House: r7c2=7
Bivalue Universal Grave + 1 => r7c7<>3, r7c7<>8
Naked Single: r7c7=4
Naked Single: r5c7=5
Full House: r5c9=4
Naked Single: r7c1=8
Full House: r7c5=3
Full House: r9c1=4
Full House: r6c5=4
Full House: r6c3=3
Full House: r4c3=4
Naked Single: r8c7=8
Full House: r9c9=3
Full House: r3c7=3
Full House: r9c4=8
Full House: r8c6=4
Full House: r4c6=8
Full House: r3c9=5
Full House: r4c4=3
|
normal_sudoku_626
|
........73.......1..2.4..6..1..24....385...4.4...86..9..6..2.5..7....9......5.6.3
|
851263497364795281792841365915324876638579142427186539146932758573618924289457613
|
Basic 9x9 Sudoku 626
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . . . 7
3 . . . . . . . 1
. . 2 . 4 . . 6 .
. 1 . . 2 4 . . .
. 3 8 5 . . . 4 .
4 . . . 8 6 . . 9
. . 6 . . 2 . 5 .
. 7 . . . . 9 . .
. . . . 5 . 6 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
851263497364795281792841365915324876638579142427186539146932758573618924289457613 #1 Extreme (12940) bf
Locked Candidates Type 1 (Pointing): 4 in b3 => r7c7<>4
Forcing Net Contradiction in r3 => r3c1<>5
r3c1=5 r3c1<>1
r3c1=5 (r3c1<>7) r3c9<>5 (r3c9=8 r3c7<>8 r3c7=3 r5c7<>3) r4c9=5 r4c9<>6 r4c1=6 (r5c2<>6 r5c2=2 r5c7<>2) r4c1<>7 r5c1=7 r5c7<>7 r5c7=1 (r6c7<>1) r6c8<>1 r6c4=1 r3c4<>1
r3c1=5 (r3c1<>7) r3c9<>5 r4c9=5 r4c9<>6 r4c1=6 r4c1<>7 r5c1=7 (r5c6<>7) (r5c5<>7) r6c3<>7 r2c3=7 (r2c6<>7) (r4c3<>7) r2c5<>7 r7c5=7 r9c6<>7 r3c6=7 r3c6<>1
Brute Force: r5c2=3
Hidden Single: r8c3=3
Hidden Single: r8c1=5
Locked Candidates Type 1 (Pointing): 6 in b4 => r1c1<>6
Locked Candidates Type 1 (Pointing): 3 in b5 => r137c4<>3
Hidden Single: r7c5=3
Locked Candidates Type 1 (Pointing): 2 in b7 => r9c8<>2
Turbot Fish: 7 r3c1 =7= r2c3 -7- r2c5 =7= r5c5 => r5c1<>7
Empty Rectangle: 7 in b5 (r7c47) => r5c7<>7
Locked Candidates Type 2 (Claiming): 7 in r5 => r46c4<>7
Grouped Discontinuous Nice Loop: 1 r8c4 -1- r6c4 =1= r5c56 -1- r5c7 -2- r5c9 =2= r8c9 =4= r8c4 => r8c4<>1
Almost Locked Set XY-Wing: A=r4c4 {39}, B=r123c7,r3c9 {23458}, C=r5c567 {1279}, X,Y=2,9, Z=3 => r4c7<>3
Almost Locked Set XY-Wing: A=r46c4 {139}, B=r1c123,r2c23,r3c2 {1456789}, C=r46c3 {579}, X,Y=7,9, Z=1 => r1c4<>1
Forcing Chain Contradiction in c3 => r4c4=3
r4c4<>3 r4c4=9 r5c5<>9 r12c5=9 r3c46<>9 r3c12=9 r1c3<>9
r4c4<>3 r4c4=9 r5c5<>9 r12c5=9 r3c46<>9 r3c12=9 r2c3<>9
r4c4<>3 r4c4=9 r4c3<>9
r4c4<>3 r4c4=9 r7c4<>9 r7c12=9 r9c3<>9
Naked Single: r6c4=1
Hidden Single: r5c7=1
Hidden Single: r7c1=1
Hidden Single: r3c6=1
Naked Single: r8c6=8
Hidden Single: r1c3=1
Hidden Single: r8c5=1
Naked Single: r8c8=2
Naked Single: r8c9=4
Full House: r8c4=6
Naked Single: r7c9=8
Naked Single: r3c9=5
Naked Single: r7c7=7
Full House: r9c8=1
Naked Single: r4c9=6
Full House: r5c9=2
Hidden Single: r3c7=3
Naked Single: r6c7=5
Naked Single: r4c7=8
Naked Single: r6c2=2
Naked Single: r6c3=7
Full House: r6c8=3
Full House: r4c8=7
Naked Single: r4c1=9
Full House: r4c3=5
Full House: r5c1=6
Naked Single: r1c1=8
Naked Single: r1c8=9
Full House: r2c8=8
Naked Single: r3c1=7
Full House: r9c1=2
Naked Single: r3c2=9
Full House: r3c4=8
Naked Single: r1c4=2
Naked Single: r1c5=6
Naked Single: r2c3=4
Full House: r9c3=9
Naked Single: r7c2=4
Full House: r7c4=9
Full House: r9c2=8
Naked Single: r1c7=4
Full House: r2c7=2
Naked Single: r1c2=5
Full House: r1c6=3
Full House: r2c2=6
Naked Single: r9c6=7
Full House: r9c4=4
Full House: r2c4=7
Naked Single: r5c6=9
Full House: r2c6=5
Full House: r2c5=9
Full House: r5c5=7
|
normal_sudoku_777
|
.1...4..3.538....748..736..3....5..6.9..3..2.2687..3...2....9..6...5...1.....74.2
|
716924583953861247482573619374285196591436728268719354127648935649352871835197462
|
Basic 9x9 Sudoku 777
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . . . 4 . . 3
. 5 3 8 . . . . 7
4 8 . . 7 3 6 . .
3 . . . . 5 . . 6
. 9 . . 3 . . 2 .
2 6 8 7 . . 3 . .
. 2 . . . . 9 . .
6 . . . 5 . . . 1
. . . . . 7 4 . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
716924583953861247482573619374285196591436728268719354127648935649352871835197462 #1 Medium (304)
Naked Single: r3c2=8
Naked Single: r2c1=9
Naked Single: r9c2=3
Naked Single: r1c1=7
Naked Single: r3c3=2
Full House: r1c3=6
Hidden Single: r2c8=4
Locked Candidates Type 1 (Pointing): 5 in b4 => r5c79<>5
Hidden Single: r1c7=5
Naked Single: r3c9=9
Naked Single: r1c8=8
Naked Single: r3c8=1
Full House: r2c7=2
Full House: r3c4=5
Hidden Single: r8c6=2
Hidden Single: r8c7=8
Naked Single: r7c9=5
Naked Single: r6c9=4
Full House: r5c9=8
Naked Single: r9c8=6
Hidden Single: r6c6=9
Naked Single: r6c5=1
Full House: r6c8=5
Naked Single: r2c5=6
Full House: r2c6=1
Naked Single: r5c6=6
Full House: r7c6=8
Naked Single: r5c4=4
Naked Single: r7c1=1
Naked Single: r7c5=4
Naked Single: r9c5=9
Naked Single: r4c4=2
Full House: r4c5=8
Full House: r1c5=2
Full House: r1c4=9
Naked Single: r5c1=5
Full House: r9c1=8
Naked Single: r7c3=7
Naked Single: r8c4=3
Naked Single: r9c3=5
Full House: r9c4=1
Full House: r7c4=6
Full House: r7c8=3
Full House: r8c8=7
Full House: r4c8=9
Naked Single: r5c3=1
Full House: r5c7=7
Full House: r4c7=1
Naked Single: r8c2=4
Full House: r4c2=7
Full House: r4c3=4
Full House: r8c3=9
|
normal_sudoku_760
|
..3..8.4.6..25.....45.73.96..264...95...2......481.35..7...2.3.......8.7...7...14
|
723968541691254783845173296382645179517329468964817352179482635436591827258736914
|
Basic 9x9 Sudoku 760
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 . . 8 . 4 .
6 . . 2 5 . . . .
. 4 5 . 7 3 . 9 6
. . 2 6 4 . . . 9
5 . . . 2 . . . .
. . 4 8 1 . 3 5 .
. 7 . . . 2 . 3 .
. . . . . . 8 . 7
. . . 7 . . . 1 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
723968541691254783845173296382645179517329468964817352179482635436591827258736914 #1 Easy (204)
Naked Single: r3c5=7
Naked Single: r6c9=2
Naked Single: r3c4=1
Naked Single: r7c9=5
Naked Single: r1c4=9
Naked Single: r3c7=2
Full House: r3c1=8
Naked Single: r1c9=1
Naked Single: r1c5=6
Full House: r2c6=4
Naked Single: r5c4=3
Naked Single: r7c4=4
Full House: r8c4=5
Naked Single: r1c2=2
Naked Single: r2c7=7
Naked Single: r5c9=8
Full House: r2c9=3
Naked Single: r1c1=7
Full House: r1c7=5
Full House: r2c8=8
Naked Single: r4c7=1
Naked Single: r4c8=7
Naked Single: r6c1=9
Naked Single: r4c1=3
Naked Single: r4c6=5
Full House: r4c2=8
Naked Single: r5c8=6
Full House: r5c7=4
Full House: r8c8=2
Naked Single: r6c2=6
Full House: r6c6=7
Full House: r5c6=9
Naked Single: r7c1=1
Naked Single: r9c1=2
Full House: r8c1=4
Naked Single: r5c2=1
Full House: r5c3=7
Naked Single: r9c6=6
Full House: r8c6=1
Naked Single: r2c2=9
Full House: r2c3=1
Naked Single: r9c7=9
Full House: r7c7=6
Naked Single: r8c2=3
Full House: r9c2=5
Naked Single: r9c3=8
Full House: r9c5=3
Naked Single: r8c5=9
Full House: r7c5=8
Full House: r7c3=9
Full House: r8c3=6
|
normal_sudoku_6432
|
.2963.7...4...9...6..7....9.53..7..6.94.26..7.6..1..8..3....57.47.2.......6..3..4
|
529634718347189265681752349153847926894326157762915483938461572475298631216573894
|
Basic 9x9 Sudoku 6432
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 9 6 3 . 7 . .
. 4 . . . 9 . . .
6 . . 7 . . . . 9
. 5 3 . . 7 . . 6
. 9 4 . 2 6 . . 7
. 6 . . 1 . . 8 .
. 3 . . . . 5 7 .
4 7 . 2 . . . . .
. . 6 . . 3 . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
529634718347189265681752349153847926894326157762915483938461572475298631216573894 #1 Medium (444)
Naked Single: r6c2=6
Hidden Single: r2c1=3
Hidden Single: r9c5=7
Hidden Single: r3c6=2
Hidden Single: r7c5=6
Hidden Single: r2c3=7
Naked Single: r6c3=2
Naked Single: r6c1=7
Locked Candidates Type 1 (Pointing): 1 in b4 => r179c1<>1
Locked Candidates Type 1 (Pointing): 1 in b1 => r3c78<>1
Locked Candidates Type 1 (Pointing): 8 in b4 => r179c1<>8
Naked Single: r1c1=5
Hidden Single: r8c3=5
Hidden Single: r9c4=5
Hidden Single: r6c6=5
Naked Single: r6c9=3
Naked Single: r5c7=1
Naked Single: r5c1=8
Full House: r4c1=1
Naked Single: r5c8=5
Full House: r5c4=3
Hidden Single: r2c9=5
Naked Single: r2c5=8
Naked Single: r2c4=1
Naked Single: r8c5=9
Naked Single: r1c6=4
Full House: r3c5=5
Full House: r4c5=4
Naked Single: r1c8=1
Full House: r1c9=8
Naked Single: r6c4=9
Full House: r4c4=8
Full House: r6c7=4
Full House: r7c4=4
Naked Single: r8c9=1
Full House: r7c9=2
Naked Single: r3c7=3
Naked Single: r8c6=8
Full House: r7c6=1
Naked Single: r7c1=9
Full House: r7c3=8
Full House: r9c1=2
Full House: r3c3=1
Full House: r9c2=1
Full House: r3c2=8
Full House: r3c8=4
Naked Single: r9c8=9
Full House: r9c7=8
Naked Single: r8c7=6
Full House: r8c8=3
Naked Single: r4c8=2
Full House: r2c8=6
Full House: r2c7=2
Full House: r4c7=9
|
normal_sudoku_1375
|
.2...1..4...3..2....64..731..2.9..7..7...348.8..6....5..8...5...1...5.4....9..1..
|
923781654741356298586429731152894376679513482834672915298147563317265849465938127
|
Basic 9x9 Sudoku 1375
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . . 1 . . 4
. . . 3 . . 2 . .
. . 6 4 . . 7 3 1
. . 2 . 9 . . 7 .
. 7 . . . 3 4 8 .
8 . . 6 . . . . 5
. . 8 . . . 5 . .
. 1 . . . 5 . 4 .
. . . 9 . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
923781654741356298586429731152894376679513482834672915298147563317265849465938127 #1 Extreme (10526) bf
Brute Force: r5c8=8
Hidden Single: r6c8=1
Hidden Single: r5c9=2
Hidden Single: r5c1=6
Hidden Single: r6c7=9
Hidden Single: r5c3=9
Hidden Single: r2c3=1
Hidden Single: r4c1=1
Hidden Single: r4c2=5
Naked Single: r4c4=8
Naked Single: r4c6=4
Locked Candidates Type 2 (Claiming): 2 in c4 => r7c56,r89c5,r9c6<>2
Skyscraper: 9 in r1c8,r8c9 (connected by r18c1) => r2c9,r7c8<>9
Locked Pair: 2,6 in r79c8 => r12c8,r789c9,r8c7<>6
Hidden Single: r8c5=6
Naked Single: r7c6=7
Naked Single: r6c6=2
Naked Single: r8c4=2
Naked Single: r9c6=8
Naked Single: r6c5=7
Naked Single: r7c4=1
Naked Single: r3c6=9
Full House: r2c6=6
Naked Single: r5c4=5
Full House: r1c4=7
Full House: r5c5=1
Naked Single: r3c1=5
Naked Single: r3c2=8
Full House: r3c5=2
Naked Single: r2c9=8
Naked Single: r1c3=3
Naked Single: r1c7=6
Naked Single: r2c5=5
Full House: r1c5=8
Naked Single: r1c1=9
Full House: r1c8=5
Full House: r2c8=9
Naked Single: r6c3=4
Full House: r6c2=3
Naked Single: r8c3=7
Full House: r9c3=5
Naked Single: r4c7=3
Full House: r4c9=6
Full House: r8c7=8
Naked Single: r2c2=4
Full House: r2c1=7
Naked Single: r8c1=3
Full House: r8c9=9
Naked Single: r9c2=6
Full House: r7c2=9
Naked Single: r7c9=3
Full House: r9c9=7
Naked Single: r9c8=2
Full House: r7c8=6
Naked Single: r7c5=4
Full House: r7c1=2
Full House: r9c1=4
Full House: r9c5=3
|
normal_sudoku_1812
|
72......5..3.648.2.8...5...9....7.......5...4..164927.8....1.....45.6.......9..3.
|
726918345513764892489325761942187653678253914351649278897431526234576189165892437
|
Basic 9x9 Sudoku 1812
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 2 . . . . . . 5
. . 3 . 6 4 8 . 2
. 8 . . . 5 . . .
9 . . . . 7 . . .
. . . . 5 . . . 4
. . 1 6 4 9 2 7 .
8 . . . . 1 . . .
. . 4 5 . 6 . . .
. . . . 9 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
726918345513764892489325761942187653678253914351649278897431526234576189165892437 #1 Unfair (1250)
Naked Single: r2c6=4
Hidden Single: r2c4=7
Hidden Single: r6c9=8
Hidden Single: r4c2=4
Hidden Single: r3c1=4
Hidden Single: r8c8=8
Hidden Single: r7c8=2
Hidden Single: r1c8=4
Hidden Single: r4c8=5
Locked Pair: 6,9 in r13c3 => r4579c3<>6, r2c2,r7c3<>9
Hidden Single: r2c8=9
Hidden Single: r5c7=9
Locked Candidates Type 1 (Pointing): 6 in b4 => r5c8<>6
Naked Single: r5c8=1
Full House: r3c8=6
Naked Single: r3c3=9
Naked Single: r1c3=6
Hidden Single: r1c4=9
Locked Candidates Type 1 (Pointing): 3 in b6 => r4c45<>3
Locked Candidates Type 1 (Pointing): 3 in b5 => r5c12<>3
Locked Candidates Type 2 (Claiming): 5 in c3 => r79c2,r9c1<>5
Naked Triple: 1,3,7 in r138c7 => r4c7<>3, r79c7<>7, r9c7<>1
Naked Single: r4c7=6
Full House: r4c9=3
Hidden Pair: 6,9 in r7c29 => r7c2<>3, r7c29<>7
Locked Candidates Type 1 (Pointing): 3 in b7 => r8c5<>3
2-String Kite: 2 in r5c6,r8c1 (connected by r8c5,r9c6) => r5c1<>2
Naked Single: r5c1=6
Naked Single: r5c2=7
Locked Candidates Type 1 (Pointing): 2 in b4 => r9c3<>2
XY-Chain: 3 3- r1c6 -8- r9c6 -2- r8c5 -7- r7c5 -3 => r13c5<>3
Hidden Single: r7c5=3
Naked Single: r7c4=4
Naked Single: r7c7=5
Naked Single: r7c3=7
Naked Single: r9c7=4
Naked Single: r9c3=5
Hidden Single: r8c5=7
Naked Single: r8c7=1
Naked Single: r1c7=3
Full House: r3c7=7
Full House: r3c9=1
Naked Single: r8c9=9
Naked Single: r1c6=8
Full House: r1c5=1
Naked Single: r3c5=2
Full House: r3c4=3
Full House: r4c5=8
Naked Single: r7c9=6
Full House: r7c2=9
Full House: r9c9=7
Naked Single: r8c2=3
Full House: r8c1=2
Naked Single: r9c6=2
Full House: r5c6=3
Full House: r9c4=8
Naked Single: r4c3=2
Full House: r4c4=1
Full House: r5c4=2
Full House: r5c3=8
Naked Single: r6c2=5
Full House: r6c1=3
Naked Single: r9c1=1
Full House: r2c1=5
Full House: r2c2=1
Full House: r9c2=6
|
normal_sudoku_835
|
.3.7.......7.....42...1.67.5..8.2.6....5.18......6...5..4..9.3...2.....91...5.2..
|
936724518817635924245918673591842367763591842428367195654289731382176459179453286
|
Basic 9x9 Sudoku 835
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . 7 . . . . .
. . 7 . . . . . 4
2 . . . 1 . 6 7 .
5 . . 8 . 2 . 6 .
. . . 5 . 1 8 . .
. . . . 6 . . . 5
. . 4 . . 9 . 3 .
. . 2 . . . . . 9
1 . . . 5 . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
936724518817635924245918673591842367763591842428367195654289731382176459179453286 #1 Extreme (13904) bf
Hidden Single: r5c4=5
Locked Candidates Type 1 (Pointing): 5 in b7 => r23c2<>5
Brute Force: r5c8=4
Naked Single: r9c8=8
Hidden Single: r8c7=4
Skyscraper: 4 in r4c5,r6c1 (connected by r1c15) => r4c2,r6c46<>4
Hidden Single: r4c5=4
Discontinuous Nice Loop: 8 r3c2 -8- r3c9 =8= r1c9 =2= r5c9 -2- r5c2 =2= r6c2 =4= r3c2 => r3c2<>8
Discontinuous Nice Loop: 3 r6c1 -3- r8c1 =3= r9c3 =9= r9c2 -9- r3c2 -4- r6c2 =4= r6c1 => r6c1<>3
Sashimi Swordfish: 3 c157 r258 fr4c7 fr6c7 => r5c9<>3
Discontinuous Nice Loop: 7 r6c1 -7- r6c6 =7= r5c5 -7- r5c9 -2- r5c2 =2= r6c2 =4= r6c1 => r6c1<>7
Finned Swordfish: 7 r469 c269 fr4c7 fr6c7 => r5c9<>7
Naked Single: r5c9=2
Hidden Single: r6c2=2
Hidden Single: r6c1=4
Hidden Single: r3c2=4
Hidden Single: r1c6=4
Hidden Single: r6c3=8
Hidden Single: r9c4=4
Locked Candidates Type 1 (Pointing): 6 in b2 => r2c12<>6
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c79<>1
Naked Pair: 3,9 in r36c4 => r28c4<>3, r2c4<>9
Skyscraper: 3 in r4c9,r6c4 (connected by r3c49) => r6c7<>3
Locked Candidates Type 1 (Pointing): 3 in b6 => r4c3<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r5c5<>3
Turbot Fish: 9 r3c3 =9= r3c4 -9- r6c4 =9= r5c5 => r5c3<>9
Multi Colors 1: 9 (r3c3,r6c4) / (r3c4,r5c5), (r9c2) / (r9c3) => r5c2<>9
AIC: 9 9- r3c4 -3- r2c5 =3= r8c5 -3- r8c1 =3= r5c1 =9= r5c5 -9 => r12c5,r6c4<>9
Naked Single: r6c4=3
Naked Single: r3c4=9
Naked Single: r6c6=7
Full House: r5c5=9
Naked Single: r3c3=5
Hidden Single: r2c6=5
Hidden Single: r2c4=6
Naked Single: r8c4=1
Full House: r7c4=2
Naked Single: r8c8=5
Hidden Single: r1c7=5
Hidden Single: r7c2=5
Locked Candidates Type 1 (Pointing): 9 in b4 => r4c7<>9
Locked Candidates Type 1 (Pointing): 7 in b6 => r4c2<>7
Locked Candidates Type 2 (Claiming): 9 in c1 => r1c3,r2c2<>9
Skyscraper: 8 in r2c2,r3c6 (connected by r8c26) => r2c5<>8
Locked Candidates Type 2 (Claiming): 8 in r2 => r1c1<>8
XY-Chain: 6 6- r9c6 -3- r3c6 -8- r3c9 -3- r4c9 -7- r9c9 -6 => r9c23<>6
Sue de Coq: r78c1 - {3678} (r12c1 - {689}, r9c23 - {379}) => r8c2<>7, r5c1<>6
XY-Chain: 1 1- r1c9 -8- r3c9 -3- r4c9 -7- r9c9 -6- r9c6 -3- r9c3 -9- r9c2 -7- r5c2 -6- r8c2 -8- r2c2 -1 => r1c3,r2c78<>1
Naked Single: r1c3=6
Naked Single: r1c1=9
Naked Single: r5c3=3
Naked Single: r2c1=8
Full House: r2c2=1
Naked Single: r5c1=7
Full House: r5c2=6
Naked Single: r9c3=9
Full House: r4c3=1
Full House: r4c2=9
Naked Single: r7c1=6
Full House: r8c1=3
Naked Single: r8c2=8
Full House: r9c2=7
Naked Single: r8c5=7
Full House: r8c6=6
Naked Single: r9c9=6
Full House: r9c6=3
Full House: r7c5=8
Full House: r3c6=8
Full House: r3c9=3
Naked Single: r1c5=2
Full House: r2c5=3
Naked Single: r2c7=9
Full House: r2c8=2
Naked Single: r4c9=7
Full House: r4c7=3
Naked Single: r1c8=1
Full House: r1c9=8
Full House: r7c9=1
Full House: r6c8=9
Full House: r6c7=1
Full House: r7c7=7
|
normal_sudoku_86
|
..4.....7.12...59.9..1.5.241.72.945.4......79....4.2..7516........3..........7...
|
584926317312874596976135824137269458428513679695748231751682943849351762263497185
|
Basic 9x9 Sudoku 86
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 4 . . . . . 7
. 1 2 . . . 5 9 .
9 . . 1 . 5 . 2 4
1 . 7 2 . 9 4 5 .
4 . . . . . . 7 9
. . . . 4 . 2 . .
7 5 1 6 . . . . .
. . . 3 . . . . .
. . . . . 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
584926317312874596976135824137269458428513679695748231751682943849351762263497185 #1 Extreme (17474) bf
Hidden Single: r3c9=4
Hidden Single: r5c2=2
Hidden Single: r3c2=7
Hidden Single: r1c1=5
Hidden Single: r6c4=7
Hidden Single: r8c7=7
Hidden Single: r2c5=7
Hidden Single: r6c3=5
Hidden Single: r6c2=9
Locked Candidates Type 1 (Pointing): 3 in b7 => r9c789<>3
Brute Force: r6c6=8
Naked Single: r5c4=5
Locked Candidates Type 1 (Pointing): 1 in b5 => r5c7<>1
Finned Swordfish: 8 r357 c357 fr7c8 fr7c9 => r9c7<>8
Finned Franken Swordfish: 8 r35b8 c357 fr9c4 => r9c3<>8
Forcing Net Verity => r1c5<>3
r4c2=3 (r1c2<>3) (r4c5<>3 r4c5=6 r3c5<>6) (r4c5<>3 r4c5=6 r5c5<>6) (r4c5<>3 r4c5=6 r5c6<>6) r6c1<>3 r6c1=6 r5c3<>6 r5c7=6 r3c7<>6 r3c3=6 r1c2<>6 r1c2=8 (r2c1<>8) r4c2<>8 r4c9=8 r2c9<>8 r2c4=8 r2c4<>4 r2c6=4 r7c6<>4 r7c6=2 r1c6<>2 r1c5=2 r1c5<>3
r4c5=3 r1c5<>3
r4c9=3 (r2c9<>3) (r6c8<>3) r6c9<>3 r6c1=3 r2c1<>3 r2c6=3 r1c5<>3
Forcing Net Verity => r1c5<>6
r4c2=6 (r1c2<>6) (r4c5<>6 r4c5=3 r3c5<>3) (r4c5<>6 r4c5=3 r5c5<>3) (r4c5<>6 r4c5=3 r5c6<>3) r6c1<>6 r6c1=3 r5c3<>3 r5c7=3 r3c7<>3 r3c3=3 r1c2<>3 r1c2=8 (r2c1<>8) r4c2<>8 r4c9=8 r2c9<>8 r2c4=8 r2c4<>4 r2c6=4 r7c6<>4 r7c6=2 r1c6<>2 r1c5=2 r1c5<>6
r4c5=6 r1c5<>6
r4c9=6 (r2c9<>6) (r6c8<>6) r6c9<>6 r6c1=6 r2c1<>6 r2c6=6 r1c5<>6
Forcing Net Contradiction in r7c7 => r1c7<>8
r1c7=8 (r1c4<>8 r1c4=9 r1c5<>9 r1c5=2 r7c5<>2) (r3c7<>8) r5c7<>8 r5c3=8 r3c3<>8 r3c5=8 r7c5<>8 r7c5=9 r7c7<>9 r9c7=9 r9c7<>1 r1c7=1 r1c7<>8
Forcing Net Verity => r2c9<>8
r4c9=3 (r4c9<>8 r4c2=8 r1c2<>8) (r4c5<>3 r4c5=6 r3c5<>6) (r2c9<>3) (r6c8<>3) r6c9<>3 r6c1=3 r2c1<>3 r2c6=3 r3c5<>3 r3c5=8 (r1c4<>8) r1c5<>8 r1c8=8 r2c9<>8
r4c9=6 (r4c9<>8 r4c2=8 r1c2<>8) (r4c5<>6 r4c5=3 r3c5<>3) (r2c9<>6) (r6c8<>6) r6c9<>6 r6c1=6 r2c1<>6 r2c6=6 r3c5<>6 r3c5=8 (r1c4<>8) r1c5<>8 r1c8=8 r2c9<>8
r4c9=8 r2c9<>8
Forcing Chain Verity => r2c1<>6
r1c8=3 r2c9<>3 r2c9=6 r2c1<>6
r6c8=3 r6c1<>3 r6c1=6 r2c1<>6
r7c8=3 r7c8<>4 r7c6=4 r2c6<>4 r2c4=4 r2c4<>8 r2c1=8 r2c1<>6
Finned Franken Swordfish: 6 r24b1 c259 fr2c6 fr3c3 => r3c5<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r5c6<>6
Discontinuous Nice Loop: 8 r3c3 -8- r2c1 -3- r2c9 -6- r3c7 =6= r3c3 => r3c3<>8
2-String Kite: 8 in r4c9,r8c3 (connected by r4c2,r5c3) => r8c9<>8
Grouped Discontinuous Nice Loop: 8 r9c9 -8- r9c4 =8= r12c4 -8- r3c5 =8= r3c7 -8- r5c7 =8= r4c9 -8- r9c9 => r9c9<>8
Almost Locked Set XY-Wing: A=r3c3 {36}, B=r8c125689 {1245689}, C=r137c5 {2389}, X,Y=3,9, Z=6 => r8c3<>6
Forcing Chain Verity => r1c4=9
r1c7=3 r2c9<>3 r2c9=6 r2c6<>6 r1c6=6 r1c6<>2 r1c5=2 r1c5<>9 r1c4=9
r3c7=3 r3c7<>8 r3c5=8 r1c4<>8 r1c4=9
r5c7=3 r5c6<>3 r45c5=3 r3c5<>3 r3c5=8 r1c4<>8 r1c4=9
r7c7=3 r7c7<>9 r7c5=9 r1c5<>9 r1c4=9
Turbot Fish: 8 r1c2 =8= r2c1 -8- r2c4 =8= r9c4 => r9c2<>8
Forcing Chain Contradiction in r7c5 => r4c9=8
r4c9<>8 r7c9=8 r789c8<>8 r1c8=8 r1c5<>8 r1c5=2 r7c5<>2
r4c9<>8 r7c9=8 r7c5<>8
r4c9<>8 r4c2=8 r5c3<>8 r8c3=8 r8c3<>9 r8c5=9 r7c5<>9
Hidden Single: r5c3=8
Naked Single: r8c3=9
W-Wing: 3/6 in r4c2,r9c3 connected by 6 in r1c2,r3c3 => r9c2<>3
Sashimi Swordfish: 6 r345 c257 fr3c3 => r1c2<>6
Hidden Single: r3c3=6
Full House: r9c3=3
Empty Rectangle: 3 in b5 (r3c57) => r5c7<>3
Naked Single: r5c7=6
Hidden Single: r4c5=6
Full House: r4c2=3
Full House: r6c1=6
Naked Single: r1c2=8
Full House: r2c1=3
Naked Single: r1c5=2
Naked Single: r2c9=6
Naked Single: r2c6=4
Full House: r2c4=8
Full House: r9c4=4
Naked Single: r7c6=2
Naked Single: r3c5=3
Full House: r1c6=6
Full House: r3c7=8
Naked Single: r9c2=6
Full House: r8c2=4
Naked Single: r7c9=3
Naked Single: r8c6=1
Full House: r5c6=3
Full House: r5c5=1
Naked Single: r6c9=1
Full House: r6c8=3
Naked Single: r7c7=9
Naked Single: r1c8=1
Full House: r1c7=3
Full House: r9c7=1
Naked Single: r7c5=8
Full House: r7c8=4
Naked Single: r9c8=8
Full House: r8c8=6
Naked Single: r8c5=5
Full House: r9c5=9
Naked Single: r9c1=2
Full House: r8c1=8
Full House: r8c9=2
Full House: r9c9=5
|
normal_sudoku_2352
|
..35...86.2...419...46..2..54.......2....5...8....2.1.95.476831....3.9....7..8.2.
|
193527486625384197784619253541893762279165348836742519952476831468231975317958624
|
Basic 9x9 Sudoku 2352
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 5 . . . 8 6
. 2 . . . 4 1 9 .
. . 4 6 . . 2 . .
5 4 . . . . . . .
2 . . . . 5 . . .
8 . . . . 2 . 1 .
9 5 . 4 7 6 8 3 1
. . . . 3 . 9 . .
. . 7 . . 8 . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
193527486625384197784619253541893762279165348836742519952476831468231975317958624 #1 Easy (314)
Naked Single: r7c7=8
Full House: r7c3=2
Naked Single: r2c5=8
Naked Single: r8c6=1
Naked Single: r8c4=2
Naked Single: r9c4=9
Full House: r9c5=5
Naked Single: r9c9=4
Naked Single: r9c7=6
Hidden Single: r1c7=4
Hidden Single: r1c5=2
Hidden Single: r2c3=5
Hidden Single: r9c1=3
Full House: r9c2=1
Hidden Single: r4c9=2
Hidden Single: r8c3=8
Naked Single: r8c2=6
Full House: r8c1=4
Hidden Single: r3c2=8
Hidden Single: r6c7=5
Hidden Single: r5c8=4
Hidden Single: r6c5=4
Hidden Single: r3c5=1
Naked Single: r3c1=7
Naked Single: r1c1=1
Full House: r2c1=6
Full House: r1c2=9
Full House: r1c6=7
Naked Single: r3c8=5
Naked Single: r2c4=3
Full House: r2c9=7
Full House: r3c9=3
Full House: r3c6=9
Full House: r4c6=3
Naked Single: r8c8=7
Full House: r8c9=5
Full House: r4c8=6
Naked Single: r6c4=7
Naked Single: r6c9=9
Full House: r5c9=8
Naked Single: r4c7=7
Full House: r5c7=3
Naked Single: r4c5=9
Full House: r5c5=6
Naked Single: r6c2=3
Full House: r6c3=6
Full House: r5c2=7
Naked Single: r5c4=1
Full House: r4c4=8
Full House: r4c3=1
Full House: r5c3=9
|
normal_sudoku_4774
|
.785........42...82....8.5.1...4..6..8...54.1..9...3....3...9..6..1...2..2...4..6
|
978561234536429718241738659157943862382675491469812375813256947694187523725394186
|
Basic 9x9 Sudoku 4774
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 8 5 . . . . .
. . . 4 2 . . . 8
2 . . . . 8 . 5 .
1 . . . 4 . . 6 .
. 8 . . . 5 4 . 1
. . 9 . . . 3 . .
. . 3 . . . 9 . .
6 . . 1 . . . 2 .
. 2 . . . 4 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
978561234536429718241738659157943862382675491469812375813256947694187523725394186 #1 Extreme (20864) bf
Skyscraper: 8 in r4c4,r8c5 (connected by r48c7) => r6c5,r79c4<>8
Brute Force: r5c7=4
Grouped Discontinuous Nice Loop: 7 r5c3 =2= r5c4 -2- r6c46 =2= r6c9 =5= r4c79 -5- r4c2 -3- r5c1 -7- r5c3 => r5c3<>7
Grouped Discontinuous Nice Loop: 7 r6c1 =4= r6c2 =6= r5c3 =2= r5c4 -2- r6c46 =2= r6c9 =5= r4c79 -5- r4c2 -3- r5c1 -7- r6c1 => r6c1<>7
Almost Locked Set XZ-Rule: A=r5c1458 {23679}, B=r6c4568 {12678}, X=2,6 => r4c46<>2, r6c9<>7
Forcing Chain Contradiction in r1c1 => r1c8<>9
r1c8=9 r5c8<>9 r5c8=7 r5c1<>7 r5c1=3 r1c1<>3
r1c8=9 r5c8<>9 r5c8=7 r5c1<>7 r5c1=3 r4c2<>3 r4c2=5 r6c1<>5 r6c1=4 r1c1<>4
r1c8=9 r1c1<>9
Forcing Net Contradiction in c6 => r5c8=9
r5c8<>9 r5c8=7 r5c1<>7 r5c1=3 (r1c1<>3) r4c2<>3 r4c2=5 r6c1<>5 r6c1=4 r1c1<>4 r1c1=9 r1c6<>9
r5c8<>9 r2c8=9 r2c6<>9
r5c8<>9 r2c8=9 (r1c9<>9) r3c9<>9 r4c9=9 r4c6<>9
r5c8<>9 (r2c8=9 r2c2<>9) r5c8=7 r5c1<>7 r5c1=3 (r1c1<>3) r4c2<>3 r4c2=5 r6c1<>5 r6c1=4 r1c1<>4 r1c1=9 r3c2<>9 r8c2=9 r8c6<>9
Forcing Chain Contradiction in r8 => r3c2<>9
r3c2=9 r8c2<>9
r3c2=9 r2c12<>9 r2c6=9 r4c6<>9 r4c4=9 r4c4<>8 r4c7=8 r8c7<>8 r8c5=8 r8c5<>9
r3c2=9 r2c12<>9 r2c6=9 r8c6<>9
Forcing Chain Contradiction in r1c1 => r4c4<>3
r4c4=3 r4c2<>3 r5c1=3 r1c1<>3
r4c4=3 r4c2<>3 r4c2=5 r6c1<>5 r6c1=4 r1c1<>4
r4c4=3 r4c4<>9 r4c6=9 r2c6<>9 r2c12=9 r1c1<>9
Forcing Net Contradiction in r1c7 => r1c7=2
r1c7<>2 r1c9=2 (r6c9<>2 r6c9=5 r6c1<>5 r6c1=4 r1c1<>4 r1c8=4 r1c8<>3) (r1c9<>3) (r1c9<>9 r3c9=9 r3c5<>9) (r1c9<>9 r3c9=9 r3c4<>9) r1c7<>2 r4c7=2 r4c7<>8 r4c4=8 r4c4<>9 r9c4=9 (r9c4<>3 r9c5=3 r3c5<>3) (r8c5<>9) r9c5<>9 r1c5=9 r1c5<>3 r1c6=3 (r3c4<>3) r4c6<>3 r4c2=3 r3c2<>3 r3c9=3 r3c9<>9 r1c9=9 r1c9<>2 r1c7=2
Locked Candidates Type 2 (Claiming): 6 in r1 => r2c6,r3c45<>6
Almost Locked Set XZ-Rule: A=r6c124569 {1245678}, B=r349c4 {3789}, X=8, Z=7 => r5c4<>7
Forcing Net Contradiction in r5c1 => r1c1<>4
r1c1=4 (r1c1<>3) (r3c3<>4 r3c9=4 r3c9<>9 r1c9=9 r1c9<>3) r6c1<>4 (r6c2=4 r6c2<>6 r5c3=6 r5c5<>6) r6c1=5 r4c2<>5 r4c2=3 r5c1<>3 r5c1=7 r5c5<>7 r5c5=3 (r3c5<>3) r1c5<>3 r1c6=3 (r3c4<>3) r4c6<>3 r4c2=3 r3c2<>3 r3c9=3 r3c9<>4 r1c89=4 r1c1<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c9<>4
Almost Locked Set XY-Wing: A=r1c1 {39}, B=r248c6 {1379}, C=r2c12378 {135679}, X,Y=1,9, Z=3 => r1c6<>3
Forcing Net Contradiction in r3c2 => r6c1=4
r6c1<>4 (r6c1=5 r4c2<>5 r4c2=3 r2c2<>3) (r7c1=4 r8c3<>4 r8c9=4 r8c9<>3) (r6c1=5 r4c2<>5 r4c2=3 r5c1<>3 r5c1=7 r5c5<>7) r6c2=4 r6c2<>6 r5c3=6 r5c5<>6 r5c5=3 r8c5<>3 r8c6=3 (r2c6<>3) r9c5<>3 r9c8=3 (r9c4<>3) r2c8<>3 r2c1=3 (r2c1<>9) r1c1<>3 r1c1=9 r2c2<>9 r2c6=9 (r2c6<>7) r4c6<>9 r4c4=9 r4c4<>8 r4c7=8 r6c8<>8 r6c8=7 r2c8<>7 r2c7=7 (r2c7<>1) r2c7<>6 r3c7=6 r3c7<>1 r9c7=1 r7c8<>1 r7c2=1 r3c2<>1
r6c1<>4 r6c1=5 r4c2<>5 r4c2=3 r3c2<>3
r6c1<>4 r6c2=4 r3c2<>4
r6c1<>4 (r6c1=5 r4c2<>5 r4c2=3 r2c2<>3) (r7c1=4 r8c3<>4 r8c9=4 r8c9<>3) (r6c1=5 r4c2<>5 r4c2=3 r5c1<>3 r5c1=7 r5c5<>7) r6c2=4 r6c2<>6 r5c3=6 r5c5<>6 r5c5=3 r8c5<>3 r8c6=3 (r2c6<>3) r9c5<>3 r9c8=3 (r9c4<>3) r2c8<>3 r2c1=3 (r2c1<>9) r1c1<>3 r1c1=9 r2c2<>9 r2c6=9 (r2c6<>7) r4c6<>9 r4c4=9 r4c4<>8 r4c7=8 r6c8<>8 r6c8=7 r2c8<>7 r2c7=7 r2c7<>6 r3c7=6 r3c2<>6
Forcing Net Verity => r8c2=9
r2c1=3 r1c1<>3 r1c1=9 r2c2<>9 r8c2=9
r2c2=3 r2c2<>9 r8c2=9
r2c6=3 (r8c6<>3) (r3c4<>3) (r3c5<>3) r4c6<>3 r4c2=3 r3c2<>3 r3c9=3 r8c9<>3 r8c5=3 (r8c5<>9) r8c5<>8 r8c7=8 r4c7<>8 r4c4=8 r4c4<>9 r4c6=9 r8c6<>9 r8c2=9
r2c8=3 (r2c2<>3) (r2c6<>3) (r1c9<>3) r3c9<>3 r8c9=3 r8c6<>3 r4c6=3 r4c2<>3 r3c2=3 r1c1<>3 r1c1=9 r2c2<>9 r8c2=9
Almost Locked Set XZ-Rule: A=r4c2 {35}, B=r579c1 {3578}, X=3, Z=5 => r7c2<>5
Forcing Chain Contradiction in r2 => r2c6<>7
r2c6=7 r2c6<>9 r2c1=9 r2c1<>3
r2c6=7 r2c6<>9 r2c1=9 r1c1<>9 r1c1=3 r2c2<>3
r2c6=7 r2c6<>3
r2c6=7 r8c6<>7 r8c6=3 r8c9<>3 r9c8=3 r2c8<>3
Locked Candidates Type 1 (Pointing): 7 in b2 => r3c79<>7
Forcing Chain Verity => r3c2<>3
r3c4=3 r3c2<>3
r5c4=3 r5c1<>3 r4c2=3 r3c2<>3
r9c4=3 r9c8<>3 r8c9=3 r8c9<>4 r8c3=4 r3c3<>4 r3c2=4 r3c2<>3
Naked Triple: 1,4,6 in r3c237 => r3c5<>1
Sashimi Swordfish: 3 c269 r248 fr1c9 fr3c9 => r2c8<>3
Naked Triple: 1,6,7 in r2c78,r3c7 => r1c8<>1
Locked Candidates Type 2 (Claiming): 1 in r1 => r2c6<>1
Naked Triple: 3,7,9 in r2c6,r3c45 => r1c5<>3, r1c56<>9
Naked Triple: 3,7,9 in r248c6 => r67c6<>7
Uniqueness Test 4: 1/6 in r1c56,r6c56 => r6c56<>6
Finned X-Wing: 7 c69 r48 fr7c9 => r8c7<>7
Finned Swordfish: 7 c369 r478 fr9c3 => r7c1<>7
Finned Swordfish: 7 r367 c458 fr7c9 => r9c8<>7
Finned Swordfish: 7 c369 r489 fr7c9 => r9c7<>7
Discontinuous Nice Loop: 7 r7c4 -7- r3c4 =7= r3c5 -7- r6c5 -1- r6c6 -2- r7c6 =2= r7c4 => r7c4<>7
Naked Pair: 2,6 in r7c46 => r7c5<>6
W-Wing: 2/6 in r5c3,r7c4 connected by 6 in r6c24 => r5c4<>2
Hidden Single: r5c3=2
Hidden Single: r4c9=2
Naked Single: r6c9=5
Naked Single: r6c2=6
Locked Candidates Type 2 (Claiming): 7 in c9 => r7c8<>7
Naked Pair: 1,4 in r37c2 => r2c2<>1
Naked Triple: 3,5,9 in r12c1,r2c2 => r2c3<>5
XY-Wing: 7/8/5 in r4c37,r8c7 => r8c3<>5
Naked Triple: 3,4,7 in r8c369 => r8c5<>3, r8c5<>7
Empty Rectangle: 3 in b2 (r8c69) => r3c9<>3
Naked Single: r3c9=9
Hidden Single: r1c1=9
Hidden Single: r9c5=9
Hidden Single: r2c6=9
Hidden Single: r4c4=9
Hidden Single: r4c7=8
Full House: r6c8=7
Naked Single: r8c7=5
Naked Single: r2c8=1
Naked Single: r6c5=1
Naked Single: r8c5=8
Naked Single: r9c7=1
Naked Single: r2c3=6
Naked Single: r3c7=6
Full House: r2c7=7
Naked Single: r1c5=6
Naked Single: r6c6=2
Full House: r6c4=8
Naked Single: r1c6=1
Naked Single: r7c6=6
Naked Single: r7c4=2
Hidden Single: r7c5=5
Naked Single: r7c1=8
Naked Single: r7c8=4
Naked Single: r1c8=3
Full House: r1c9=4
Full House: r9c8=8
Naked Single: r7c2=1
Full House: r7c9=7
Full House: r8c9=3
Naked Single: r3c2=4
Naked Single: r8c6=7
Full House: r4c6=3
Full House: r8c3=4
Full House: r9c4=3
Naked Single: r3c3=1
Naked Single: r4c2=5
Full House: r2c2=3
Full House: r4c3=7
Full House: r2c1=5
Full House: r5c1=3
Full House: r9c3=5
Full House: r9c1=7
Naked Single: r5c4=6
Full House: r5c5=7
Full House: r3c4=7
Full House: r3c5=3
|
normal_sudoku_2890
|
7..53.28...8..25.4.2...4.3.......3.238.4...75.527..84.86....9...9..87............
|
714536289638972514529814736476158392381429675952763841863241957195687423247395168
|
Basic 9x9 Sudoku 2890
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 . . 5 3 . 2 8 .
. . 8 . . 2 5 . 4
. 2 . . . 4 . 3 .
. . . . . . 3 . 2
3 8 . 4 . . . 7 5
. 5 2 7 . . 8 4 .
8 6 . . . . 9 . .
. 9 . . 8 7 . . .
. . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
714536289638972514529814736476158392381429675952763841863241957195687423247395168 #1 Extreme (11734) bf
Hidden Single: r1c7=2
Hidden Single: r2c2=3
Hidden Single: r5c5=2
Hidden Single: r2c5=7
Hidden Single: r6c6=3
Hidden Single: r3c4=8
Hidden Single: r9c9=8
Hidden Single: r4c6=8
Hidden Single: r4c5=5
Finned Franken Swordfish: 9 r15b6 c369 fr4c8 => r4c3<>9
Brute Force: r6c5=6
2-String Kite: 9 in r2c8,r6c1 (connected by r4c8,r6c9) => r2c1<>9
W-Wing: 1/9 in r4c4,r6c1 connected by 9 in r5c36 => r4c123<>1
AIC: 6 6- r1c6 =6= r2c4 =9= r2c8 -9- r4c8 =9= r6c9 =1= r6c1 -1- r2c1 -6 => r1c3,r2c4<>6
Hidden Single: r1c6=6
Naked Pair: 1,9 in r24c4 => r789c4<>1, r9c4<>9
Naked Pair: 1,9 in r16c9 => r378c9<>1, r3c9<>9
X-Wing: 9 c48 r24 => r4c1<>9
Locked Triple: 4,6,7 in r4c123 => r4c8,r5c3<>6
Hidden Single: r5c7=6
Remote Pair: 1/9 r1c9 -9- r6c9 -1- r6c1 -9- r5c3 -1- r5c6 -9- r4c4 -1- r2c4 -9- r3c5 => r1c3,r3c17<>1, r1c3,r3c1<>9
Naked Single: r3c7=7
Naked Single: r1c3=4
Naked Single: r3c9=6
Naked Single: r1c2=1
Full House: r1c9=9
Full House: r2c8=1
Naked Single: r3c1=5
Naked Single: r8c9=3
Naked Single: r2c1=6
Full House: r2c4=9
Full House: r3c3=9
Full House: r3c5=1
Naked Single: r6c9=1
Full House: r4c8=9
Full House: r7c9=7
Full House: r6c1=9
Naked Single: r4c1=4
Naked Single: r4c4=1
Full House: r5c6=9
Full House: r5c3=1
Naked Single: r7c5=4
Full House: r9c5=9
Naked Single: r4c2=7
Full House: r4c3=6
Full House: r9c2=4
Naked Single: r8c3=5
Naked Single: r9c7=1
Full House: r8c7=4
Naked Single: r7c3=3
Full House: r9c3=7
Naked Single: r9c1=2
Full House: r8c1=1
Naked Single: r9c6=5
Full House: r7c6=1
Naked Single: r7c4=2
Full House: r7c8=5
Naked Single: r9c8=6
Full House: r8c8=2
Full House: r8c4=6
Full House: r9c4=3
|
normal_sudoku_1197
|
.25....1....6..2.7.3.75...4......5.........7197...63.82...4...9.139..74.........2
|
725489613849631257136752984381274596562893471974516328258347169613928745497165832
|
Basic 9x9 Sudoku 1197
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 5 . . . . 1 .
. . . 6 . . 2 . 7
. 3 . 7 5 . . . 4
. . . . . . 5 . .
. . . . . . . 7 1
9 7 . . . 6 3 . 8
2 . . . 4 . . . 9
. 1 3 9 . . 7 4 .
. . . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
725489613849631257136752984381274596562893471974516328258347169613928745497165832 #1 Easy (250)
Naked Single: r6c9=8
Naked Single: r4c9=6
Naked Single: r6c8=2
Naked Single: r1c9=3
Full House: r8c9=5
Naked Single: r4c8=9
Full House: r5c7=4
Naked Single: r6c5=1
Naked Single: r6c3=4
Full House: r6c4=5
Naked Single: r4c2=8
Hidden Single: r1c1=7
Hidden Single: r2c8=5
Hidden Single: r3c6=2
Naked Single: r8c6=8
Naked Single: r8c1=6
Full House: r8c5=2
Naked Single: r7c2=5
Naked Single: r5c2=6
Naked Single: r5c3=2
Naked Single: r4c3=1
Naked Single: r4c1=3
Full House: r5c1=5
Naked Single: r4c5=7
Naked Single: r4c6=4
Full House: r4c4=2
Naked Single: r1c6=9
Naked Single: r1c5=8
Naked Single: r5c6=3
Naked Single: r1c4=4
Full House: r1c7=6
Naked Single: r2c5=3
Full House: r2c6=1
Naked Single: r5c4=8
Full House: r5c5=9
Full House: r9c5=6
Naked Single: r3c8=8
Full House: r3c7=9
Naked Single: r7c6=7
Full House: r9c6=5
Naked Single: r3c1=1
Full House: r3c3=6
Naked Single: r9c8=3
Full House: r7c8=6
Naked Single: r7c3=8
Naked Single: r9c4=1
Full House: r7c4=3
Full House: r7c7=1
Full House: r9c7=8
Naked Single: r2c3=9
Full House: r9c3=7
Naked Single: r9c1=4
Full House: r2c1=8
Full House: r2c2=4
Full House: r9c2=9
|
normal_sudoku_2547
|
.1.8.......65..3...97.....6..8.3..1......9..3375....9.....41.65...2......51...72.
|
513876942846592371297413586928635417164789253375124698732941865689257134451368729
|
Basic 9x9 Sudoku 2547
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . 8 . . . . .
. . 6 5 . . 3 . .
. 9 7 . . . . . 6
. . 8 . 3 . . 1 .
. . . . . 9 . . 3
3 7 5 . . . . 9 .
. . . . 4 1 . 6 5
. . . 2 . . . . .
. 5 1 . . . 7 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
513876942846592371297413586928635417164789253375124698732941865689257134451368729 #1 Extreme (2094)
Hidden Single: r6c1=3
Hidden Single: r4c1=9
Hidden Single: r8c8=3
Hidden Single: r1c3=3
Hidden Single: r5c1=1
Hidden Single: r7c2=3
Locked Candidates Type 1 (Pointing): 9 in b2 => r89c5<>9
Locked Candidates Type 1 (Pointing): 6 in b4 => r8c2<>6
Hidden Pair: 1,9 in r2c59 => r2c59<>2, r2c59<>7, r2c9<>4, r2c9<>8
Hidden Triple: 5,6,7 in r8c156 => r8c1<>4, r8c156<>8
Locked Candidates Type 1 (Pointing): 8 in b8 => r9c19<>8
2-String Kite: 7 in r2c6,r4c9 (connected by r1c9,r2c8) => r4c6<>7
Continuous Nice Loop: 6/8/9 9= r9c4 =3= r9c6 =8= r6c6 -8- r6c9 =8= r8c9 -8- r7c7 -9- r7c4 =9= r9c4 =3 => r9c46<>6, r6c57,r8c7<>8, r7c3<>9
Naked Single: r7c3=2
Naked Single: r5c3=4
Full House: r8c3=9
Locked Candidates Type 1 (Pointing): 2 in b4 => r2c2<>2
Locked Candidates Type 2 (Claiming): 6 in c4 => r46c6,r56c5<>6
Locked Candidates Type 2 (Claiming): 4 in c8 => r1c79,r3c7<>4
Naked Pair: 1,2 in r36c5 => r15c5<>2, r2c5<>1
Naked Single: r2c5=9
Naked Single: r2c9=1
Hidden Single: r8c7=1
Locked Candidates Type 1 (Pointing): 4 in b9 => r46c9<>4
W-Wing: 7/6 in r1c5,r8c1 connected by 6 in r9c15 => r8c5<>7
Skyscraper: 7 in r4c9,r5c5 (connected by r1c59) => r4c4,r5c8<>7
Hidden Single: r4c9=7
Skyscraper: 2 in r1c9,r3c5 (connected by r6c59) => r1c6,r3c7<>2
Locked Candidates Type 1 (Pointing): 2 in b3 => r1c1<>2
Hidden Pair: 2,9 in r1c79 => r1c7<>5
Sue de Coq: r6c456 - {12468} (r6c9 - {28}, r4c4 - {46}) => r4c6<>4, r5c4<>6, r6c7<>2
Naked Single: r5c4=7
Naked Single: r7c4=9
Naked Single: r7c7=8
Full House: r7c1=7
Naked Single: r9c4=3
Naked Single: r3c7=5
Naked Single: r8c9=4
Full House: r9c9=9
Naked Single: r8c1=6
Naked Single: r9c6=8
Naked Single: r8c2=8
Full House: r9c1=4
Full House: r9c5=6
Naked Single: r1c9=2
Full House: r6c9=8
Naked Single: r8c5=5
Full House: r8c6=7
Naked Single: r2c2=4
Naked Single: r1c1=5
Naked Single: r1c5=7
Naked Single: r1c7=9
Naked Single: r5c8=5
Naked Single: r5c5=8
Naked Single: r2c6=2
Naked Single: r1c8=4
Full House: r1c6=6
Naked Single: r2c1=8
Full House: r2c8=7
Full House: r3c8=8
Full House: r3c1=2
Naked Single: r3c5=1
Full House: r6c5=2
Naked Single: r4c6=5
Naked Single: r6c6=4
Full House: r3c6=3
Full House: r3c4=4
Naked Single: r4c4=6
Full House: r6c4=1
Full House: r6c7=6
Naked Single: r4c2=2
Full House: r4c7=4
Full House: r5c7=2
Full House: r5c2=6
|
normal_sudoku_1967
|
.73.4..8.126....3..5.2......9......3....3.7.42....596...89....65.9.16.7.....8....
|
973641285126758439854293617497862153685139724231475968318927546549316872762584391
|
Basic 9x9 Sudoku 1967
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 3 . 4 . . 8 .
1 2 6 . . . . 3 .
. 5 . 2 . . . . .
. 9 . . . . . . 3
. . . . 3 . 7 . 4
2 . . . . 5 9 6 .
. . 8 9 . . . . 6
5 . 9 . 1 6 . 7 .
. . . . 8 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
973641285126758439854293617497862153685139724231475968318927546549316872762584391 #1 Easy (216)
Naked Single: r1c3=3
Naked Single: r6c5=7
Naked Single: r1c1=9
Naked Single: r3c3=4
Full House: r3c1=8
Naked Single: r1c6=1
Naked Single: r6c3=1
Naked Single: r5c1=6
Naked Single: r5c3=5
Naked Single: r6c9=8
Naked Single: r5c2=8
Naked Single: r4c3=7
Full House: r9c3=2
Naked Single: r6c4=4
Full House: r6c2=3
Full House: r4c1=4
Naked Single: r8c9=2
Naked Single: r5c4=1
Naked Single: r8c4=3
Naked Single: r8c2=4
Full House: r8c7=8
Naked Single: r1c9=5
Naked Single: r5c8=2
Full House: r5c6=9
Naked Single: r7c2=1
Full House: r9c2=6
Naked Single: r1c4=6
Full House: r1c7=2
Naked Single: r2c7=4
Naked Single: r3c5=9
Naked Single: r4c4=8
Naked Single: r2c5=5
Naked Single: r3c8=1
Naked Single: r4c6=2
Full House: r4c5=6
Full House: r7c5=2
Naked Single: r2c4=7
Full House: r9c4=5
Naked Single: r3c7=6
Naked Single: r3c9=7
Full House: r2c9=9
Full House: r2c6=8
Full House: r3c6=3
Full House: r9c9=1
Naked Single: r4c8=5
Full House: r4c7=1
Naked Single: r9c7=3
Full House: r7c7=5
Naked Single: r7c8=4
Full House: r9c8=9
Naked Single: r9c1=7
Full House: r7c1=3
Full House: r7c6=7
Full House: r9c6=4
|
normal_sudoku_2524
|
..3.......6.......9...5.32....51.24..1582...32....981...7.9.1..........48..1..59.
|
153482769762931458948756321389517246615824973274369815437695182591278634826143597
|
Basic 9x9 Sudoku 2524
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 . . . . . .
. 6 . . . . . . .
9 . . . 5 . 3 2 .
. . . 5 1 . 2 4 .
. 1 5 8 2 . . . 3
2 . . . . 9 8 1 .
. . 7 . 9 . 1 . .
. . . . . . . . 4
8 . . 1 . . 5 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
153482769762931458948756321389517246615824973274369815437695182591278634826143597 #1 Extreme (17028) bf
Brute Force: r5c3=5
Hidden Single: r6c9=5
Hidden Single: r5c7=9
Naked Triple: 3,6,7 in r4c169 => r4c2<>3, r4c2<>7, r4c3<>6
Forcing Net Contradiction in r7c4 => r1c6<>6
r1c6=6 (r4c6<>6) (r3c4<>6) r3c6<>6 r3c9=6 r4c9<>6 r4c1=6 (r6c3<>6 r6c3=4 r5c1<>4 r5c6=4 r7c6<>4) (r6c3<>6 r6c3=4 r9c3<>4) r4c1<>3 r4c6=3 (r9c6<>3) (r6c4<>3) r6c5<>3 r6c2=3 r9c2<>3 r9c5=3 r9c5<>4 r9c2=4 (r7c1<>4) (r9c6<>4) r7c2<>4 r7c4=4
r1c6=6 (r7c6<>6) (r1c7<>6 r8c7=6 r7c8<>6) (r1c7<>6 r8c7=6 r7c9<>6) (r4c6<>6) (r3c4<>6) r3c6<>6 r3c9=6 r4c9<>6 r4c1=6 r7c1<>6 r7c4=6
Forcing Net Contradiction in r3 => r4c1<>6
r4c1=6 (r6c3<>6 r6c3=4 r9c3<>4) (r6c3<>6 r6c3=4 r5c1<>4 r5c6=4 r9c6<>4) r4c1<>3 r4c6=3 (r9c6<>3) (r6c4<>3) r6c5<>3 r6c2=3 r9c2<>3 r9c5=3 r9c5<>4 r9c2=4 r3c2<>4
r4c1=6 r6c3<>6 r6c3=4 r3c3<>4
r4c1=6 (r6c3<>6 r6c3=4 r5c1<>4 r5c6=4 r7c6<>4) (r6c3<>6 r6c3=4 r9c3<>4) (r6c3<>6 r6c3=4 r5c1<>4 r5c6=4 r9c6<>4) r4c1<>3 r4c6=3 (r9c6<>3) (r6c4<>3) r6c5<>3 r6c2=3 r9c2<>3 r9c5=3 r9c5<>4 r9c2=4 (r7c1<>4) r7c2<>4 r7c4=4 r3c4<>4
r4c1=6 r6c3<>6 r6c3=4 r5c1<>4 r5c6=4 r3c6<>4
Forcing Chain Contradiction in r9 => r1c5<>6
r1c5=6 r1c789<>6 r3c9=6 r4c9<>6 r4c6=6 r6c45<>6 r6c3=6 r9c3<>6
r1c5=6 r9c5<>6
r1c5=6 r1c789<>6 r3c9=6 r4c9<>6 r4c6=6 r9c6<>6
r1c5=6 r1c7<>6 r8c7=6 r9c9<>6
Forcing Net Contradiction in r3 => r1c9<>6
r1c9=6 (r9c9<>6) r4c9<>6 (r4c9=7 r3c9<>7) (r4c9=7 r9c9<>7) r4c6=6 (r3c6<>6 r3c4=6 r3c4<>7) (r9c6<>6) (r6c4<>6) r6c5<>6 r6c3=6 r9c3<>6 r9c5=6 r9c5<>7 r9c6=7 r3c6<>7 r3c2=7 r3c2<>4
r1c9=6 r4c9<>6 (r4c9=7 r9c9<>7 r9c9=2 r9c3<>2) r4c6=6 (r6c4<>6) r6c5<>6 r6c3=6 r9c3<>6 r9c3=4 r3c3<>4
r1c9=6 (r3c9<>6) r4c9<>6 r4c6=6 r3c6<>6 r3c4=6 r3c4<>4
r1c9=6 (r9c9<>6) r4c9<>6 (r4c9=7 r9c9<>7) r4c6=6 (r5c6<>6) (r9c6<>6) (r6c4<>6) r6c5<>6 r6c3=6 r9c3<>6 r9c5=6 r9c5<>7 r9c6=7 r5c6<>7 r5c6=4 r3c6<>4
Forcing Net Contradiction in r3c4 => r5c6<>7
r5c6=7 (r5c6<>4 r5c1=4 r6c3<>4 r6c3=6 r9c3<>6) (r9c6<>7) r5c8<>7 r4c9=7 r9c9<>7 r9c5=7 r9c5<>6 r9c9=6 (r3c9<>6) r4c9<>6 r4c6=6 (r9c6<>6) r3c6<>6 r3c4=6
r5c6=7 (r3c6<>7) (r5c8<>7 r4c9=7 r3c9<>7) (r6c4<>7) r6c5<>7 r6c2=7 r3c2<>7 r3c4=7
Forcing Net Contradiction in c4 => r1c4<>6
r1c4=6 (r6c4<>6) (r1c7<>6 r8c7=6 r8c7<>7) (r3c4<>6) r3c6<>6 r3c9=6 r4c9<>6 r4c9=7 r9c9<>7 (r9c9=2 r9c3<>2) r8c8=7 r5c8<>7 (r5c1=7 r6c2<>7 r6c2=4 r3c2<>4) r5c8=6 (r5c6<>6 r5c6=4 r3c6<>4) r4c9<>6 r4c6=6 r6c5<>6 r6c3=6 r9c3<>6 r9c3=4 r3c3<>4 r3c4=4
r1c4=6 (r1c7<>6 r8c7=6 r8c8<>6 r5c8=6 r5c6<>6 r5c6=4 r7c6<>4) (r3c4<>6) r3c6<>6 r3c9=6 r4c9<>6 (r4c6=6 r7c6<>6 r7c1=6 r7c1<>4) r4c9=7 (r4c1<>7 r4c1=3 r6c2<>3) r5c8<>7 r5c1=7 r6c2<>7 r6c2=4 r7c2<>4 r7c4=4
Locked Candidates Type 1 (Pointing): 6 in b2 => r3c9<>6
W-Wing: 7/6 in r5c8,r8c7 connected by 6 in r1c78 => r8c8<>7
Forcing Net Contradiction in r7 => r4c9=6
r4c9<>6 (r4c9=7 r9c9<>7 r8c7=7 r2c7<>7 r2c7=4 r2c1<>4) (r4c9=7 r5c8<>7 r5c1=7 r5c1<>4) (r4c9=7 r5c8<>7 r5c1=7 r6c2<>7 r6c2=4 r3c2<>4) (r4c9=7 r5c8<>7 r5c8=6 r5c6<>6 r5c6=4 r3c6<>4) r4c6=6 r3c6<>6 r3c4=6 r3c4<>4 r3c3=4 r1c1<>4 r7c1=4 r7c1<>6
r4c9<>6 r4c6=6 r3c6<>6 r3c4=6 r7c4<>6
r4c9<>6 r4c6=6 r7c6<>6
r4c9<>6 r4c9=7 r5c8<>7 r5c8=6 r7c8<>6
r4c9<>6 (r4c9=7 r5c8<>7 r5c1=7 r6c2<>7 r6c2=4 r3c2<>4) (r4c9=7 r5c8<>7 r5c8=6 r5c6<>6 r5c6=4 r3c6<>4) r4c6=6 r3c6<>6 r3c4=6 r3c4<>4 r3c3=4 (r9c3<>4) r6c3<>4 r6c3=6 r9c3<>6 r9c3=2 r9c9<>2 r7c9=2 r7c9<>6
Full House: r5c8=7
Naked Pair: 4,6 in r5c1,r6c3 => r6c2<>4
Almost Locked Set XZ-Rule: A=r69c3 {246}, B=r8c7,r9c9 {267}, X=2, Z=6 => r8c3<>6
2-String Kite: 6 in r5c6,r9c3 (connected by r5c1,r6c3) => r9c6<>6
Forcing Net Contradiction in r3 => r4c1=3
r4c1<>3 r4c1=7 (r4c6<>7 r4c6=3 r9c6<>3) r6c2<>7 r6c2=3 r9c2<>3 r9c5=3 (r9c5<>4) r9c5<>6 r9c3=6 (r9c3<>4) (r7c1<>6) r8c1<>6 r5c1=6 r5c6<>6 r5c6=4 r9c6<>4 r9c2=4 r3c2<>4
r4c1<>3 r4c1=7 (r4c6<>7 r4c6=3 r9c6<>3) r6c2<>7 r6c2=3 r9c2<>3 r9c5=3 r9c5<>6 r9c3=6 r6c3<>6 r6c3=4 r3c3<>4
r4c1<>3 r4c1=7 (r4c6<>7 r4c6=3 r9c6<>3) r6c2<>7 r6c2=3 r9c2<>3 r9c5=3 (r9c5<>4) r9c5<>6 r9c3=6 (r9c3<>4) (r7c1<>6) r8c1<>6 r5c1=6 r5c6<>6 r5c6=4 (r7c6<>4) r9c6<>4 r9c2=4 (r7c1<>4) r7c2<>4 r7c4=4 r3c4<>4
r4c1<>3 r4c1=7 (r4c6<>7 r4c6=3 r9c6<>3) r6c2<>7 r6c2=3 r9c2<>3 r9c5=3 r9c5<>6 r9c3=6 (r7c1<>6) r8c1<>6 r5c1=6 r5c6<>6 r5c6=4 r3c6<>4
Naked Single: r4c6=7
Naked Single: r6c2=7
Skyscraper: 7 in r3c4,r9c5 (connected by r39c9) => r12c5,r8c4<>7
AIC: 4 4- r5c6 -6- r3c6 =6= r3c4 =7= r3c9 -7- r9c9 =7= r9c5 =6= r9c3 -6- r6c3 -4 => r5c1,r6c45<>4
Naked Single: r5c1=6
Full House: r5c6=4
Naked Single: r6c3=4
Hidden Single: r9c3=6
Skyscraper: 4 in r3c4,r9c5 (connected by r39c2) => r12c5,r7c4<>4
Naked Single: r1c5=8
Naked Single: r2c5=3
Naked Single: r6c5=6
Full House: r6c4=3
Naked Single: r8c5=7
Full House: r9c5=4
Naked Single: r8c7=6
Naked Single: r8c4=2
Naked Single: r7c4=6
Naked Single: r9c6=3
Naked Single: r9c2=2
Full House: r9c9=7
Hidden Single: r1c8=6
Hidden Single: r2c3=2
Naked Single: r2c6=1
Naked Single: r1c6=2
Naked Single: r3c6=6
Hidden Single: r7c9=2
Hidden Single: r3c4=7
Hidden Single: r2c8=5
Hidden Single: r3c2=4
Naked Single: r1c2=5
Naked Single: r2c1=7
Naked Single: r7c2=3
Naked Single: r1c1=1
Full House: r3c3=8
Full House: r3c9=1
Naked Single: r2c7=4
Full House: r1c7=7
Naked Single: r7c8=8
Full House: r8c8=3
Naked Single: r8c2=9
Full House: r4c2=8
Full House: r4c3=9
Full House: r8c3=1
Naked Single: r1c9=9
Full House: r1c4=4
Full House: r2c4=9
Full House: r2c9=8
Naked Single: r8c1=5
Full House: r7c1=4
Full House: r7c6=5
Full House: r8c6=8
|
normal_sudoku_896
|
.8...9......74.6..7.6..5..1........6.6.9.....2.1..65........1.7.3....2.55.7..2.6.
|
485619372312748659796325481954273816863951724271486593628594137139867245547132968
|
Basic 9x9 Sudoku 896
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 . . . 9 . . .
. . . 7 4 . 6 . .
7 . 6 . . 5 . . 1
. . . . . . . . 6
. 6 . 9 . . . . .
2 . 1 . . 6 5 . .
. . . . . . 1 . 7
. 3 . . . . 2 . 5
5 . 7 . . 2 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
485619372312748659796325481954273816863951724271486593628594137139867245547132968 #1 Extreme (42168) bf
Hidden Single: r2c7=6
Brute Force: r5c5=5
Hidden Single: r7c4=5
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c8<>2
Forcing Net Contradiction in b2 => r1c4<>2
r1c4=2 r1c4<>1
r1c4=2 r1c4<>6 r1c5=6 r1c5<>1
r1c4=2 (r4c4<>2 r4c5=2 r4c5<>7) (r1c4<>1) r1c4<>6 (r8c4=6 r8c4<>1) r1c5=6 r1c5<>1 r1c1=1 (r8c1<>1) (r2c1<>1) r2c2<>1 r2c6=1 r8c6<>1 r8c5=1 r8c5<>7 (r8c6=7 r5c6<>7) r6c5=7 r6c2<>7 r4c2=7 r4c2<>5 r4c3=5 r1c3<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c8=7 r5c8<>1 r5c6=1 r2c6<>1
Brute Force: r5c3=3
Forcing Net Verity => r2c8<>3
r1c8=2 r1c8<>5 r1c3=5 (r2c2<>5) r2c3<>5 r2c8=5 r2c8<>3
r2c8=2 r2c8<>3
r3c8=2 (r3c5<>2) r3c4<>2 r4c4=2 r4c5<>2 r1c5=2 (r1c5<>1) r1c5<>6 r1c4=6 r1c4<>1 r1c1=1 r1c1<>3 r2c1=3 r2c8<>3
r5c8=2 (r5c8<>7) r5c8<>1 r5c6=1 r5c6<>7 r5c7=7 r1c7<>7 r1c8=7 r1c8<>5 r1c3=5 (r2c2<>5) r2c3<>5 r2c8=5 r2c8<>3
Brute Force: r5c1=8
Grouped Discontinuous Nice Loop: 4 r4c7 -4- r5c7 -7- r1c7 =7= r1c8 =5= r1c3 -5- r4c3 =5= r4c2 =7= r6c2 =4= r4c123 -4- r4c7 => r4c7<>4
Grouped Discontinuous Nice Loop: 4 r4c8 -4- r5c7 -7- r1c7 =7= r1c8 =5= r1c3 -5- r4c3 =5= r4c2 =7= r6c2 =4= r4c123 -4- r4c8 => r4c8<>4
Forcing Net Contradiction in r9 => r1c8<>3
r1c8=3 (r1c9<>3) r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 (r3c7<>4) r5c9<>4 r5c9=2 r1c9<>2 r1c9=4 r3c8<>4 r3c2=4 r9c2<>4
r1c8=3 (r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r6c8<>4) (r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r6c9<>4) r1c8<>5 r1c3=5 r4c3<>5 r4c2=5 r4c2<>7 r6c2=7 r6c2<>4 r6c4=4 r9c4<>4
r1c8=3 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r9c7<>4
r1c8=3 (r1c9<>3) r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r5c9<>4 r5c9=2 r1c9<>2 r1c9=4 r9c9<>4
Forcing Net Contradiction in b3 => r2c8<>9
r2c8=9 r2c8<>5 r1c8=5 r1c8<>2
r2c8=9 r2c8<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r5c9<>4 r5c9=2 r1c9<>2
r2c8=9 r2c8<>2
r2c8=9 r2c8<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r5c9<>4 r5c9=2 r2c9<>2
r2c8=9 (r3c8<>9 r3c2=9 r3c2<>4) r2c8<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r3c7<>4 r3c8=4 r3c8<>2
Forcing Net Contradiction in r7c8 => r2c9<>2
r2c9=2 r5c9<>2 r5c9=4 (r1c9<>4 r1c9=3 r1c1<>3 r2c1=3 r2c1<>1) (r1c9<>4 r1c9=3 r1c1<>3) (r1c9<>4 r1c9=3 r1c7<>3) r5c7<>4 r5c7=7 r1c7<>7 r1c7=4 r1c1<>4 r1c1=1 r2c2<>1 r2c6=1 r5c6<>1 r5c8=1 r5c8<>2 r5c9=2 r2c9<>2
Forcing Net Contradiction in r7c8 => r4c4<>4
r4c4=4 (r4c4<>2 r4c5=2 r1c5<>2) (r4c4<>2 r3c4=2 r3c2<>2 r3c2=9 r2c3<>9 r2c3=2 r1c3<>2) (r4c3<>4) r4c1<>4 r4c1=9 r4c3<>9 r4c3=5 r1c3<>5 r1c8=5 r1c8<>2 r1c9=2 r5c9<>2 r5c9=4 r5c7<>4 r5c7=7 r1c7<>7 r1c8=7 r1c8<>5 r1c3=5 r4c3<>5 r4c2=5 r4c2<>7 r6c2=7 r6c2<>4 r4c123=4 r4c4<>4
Forcing Net Contradiction in r1c9 => r4c7<>7
r4c7=7 (r4c2<>7 r6c2=7 r6c2<>4 r6c4=4 r9c4<>4) r5c7<>7 r5c7=4 (r9c7<>4) (r1c7<>4 r1c7=3 r1c9<>3) r5c9<>4 r5c9=2 r1c9<>2 r1c9=4 r9c9<>4 r9c2=4 r3c2<>4 r1c13=4 r1c9<>4
r4c7=7 r5c7<>7 r5c7=4 (r1c7<>4 r1c7=3 r1c9<>3) r5c9<>4 r5c9=2 r1c9<>2 r1c9=4
Forcing Net Contradiction in r1c1 => r5c8<>4
r5c8=4 r5c8<>1 r5c6=1 r2c6<>1 r1c45=1 r1c1<>1
r5c8=4 (r5c9<>4 r5c9=2 r1c9<>2) r5c7<>4 r5c7=7 r1c7<>7 r1c8=7 (r1c8<>2) r1c8<>5 r1c3=5 r1c3<>2 r1c5=2 (r1c5<>1) r1c5<>6 r1c4=6 r1c4<>1 r1c1=1
Forcing Net Contradiction in b8 => r6c8<>4
r6c8=4 (r5c7<>4) r5c9<>4 r5c6=4 r7c6<>4
r6c8=4 (r5c9<>4 r5c9=2 r1c9<>2) r5c7<>4 r5c7=7 r1c7<>7 r1c8=7 (r1c8<>2) r1c8<>5 r1c3=5 (r2c3<>5 r2c8=5 r2c8<>2 r3c8=2 r3c4<>2 r4c4=2 r4c4<>1) r1c3<>2 r1c5=2 (r1c5<>1) r1c5<>6 r1c4=6 r1c4<>1 r1c1=1 (r8c1<>1) (r2c1<>1) r2c2<>1 r2c6=1 (r8c6<>1) r5c6<>1 r5c8=1 r4c8<>1 r4c5=1 (r4c6<>1) r8c5<>1 r8c4=1 r8c4<>4
r6c8=4 (r5c7<>4) r5c9<>4 r5c6=4 r8c6<>4
r6c8=4 r78c8<>4 r9c79=4 r9c4<>4
Forcing Net Contradiction in c4 => r1c9<>4
r1c9=4 (r6c9<>4) (r3c7<>4) r3c8<>4 r3c2=4 r6c2<>4 r6c4=4
r1c9=4 (r3c8<>4 r3c2=4 r9c2<>4) (r9c9<>4) (r5c9<>4) r6c9<>4 r5c7=4 r9c7<>4 r9c4=4
Almost Locked Set XY-Wing: A=r1c9 {23}, B=r2c6,r3c45 {1238}, C=r5c679 {1247}, X,Y=1,2, Z=3 => r1c45<>3
Forcing Chain Contradiction in c9 => r4c7<>9
r4c7=9 r4c123<>9 r6c2=9 r3c2<>9 r2c123=9 r2c9<>9
r4c7=9 r6c9<>9
r4c7=9 r4c123<>9 r6c2=9 r6c2<>7 r4c2=7 r4c2<>5 r4c3=5 r1c3<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r56c9<>4 r9c9=4 r9c9<>9
Forcing Chain Contradiction in c9 => r4c8<>9
r4c8=9 r4c123<>9 r6c2=9 r3c2<>9 r2c123=9 r2c9<>9
r4c8=9 r6c9<>9
r4c8=9 r4c123<>9 r6c2=9 r6c2<>7 r4c2=7 r4c2<>5 r4c3=5 r1c3<>5 r1c8=5 r1c8<>7 r1c7=7 r5c7<>7 r5c7=4 r56c9<>4 r9c9=4 r9c9<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r6c2<>9
Forcing Chain Contradiction in r2 => r8c6<>1
r8c6=1 r5c6<>1 r5c8=1 r5c8<>2 r5c9=2 r1c9<>2 r1c9=3 r1c1<>3 r2c1=3 r2c1<>1
r8c6=1 r8c1<>1 r9c2=1 r2c2<>1
r8c6=1 r2c6<>1
Forcing Chain Contradiction in r1c5 => r4c4<>1
r4c4=1 r89c4<>1 r89c5=1 r1c5<>1
r4c4=1 r4c4<>2 r4c5=2 r1c5<>2
r4c4=1 r1c4<>1 r1c4=6 r1c5<>6
Forcing Net Verity => r6c2=7
r6c4=4 r6c2<>4 r6c2=7
r8c4=4 (r8c4<>1) (r8c4<>1) r8c4<>6 r1c4=6 r1c4<>1 r9c4=1 r8c5<>1 r8c1=1 r9c2<>1 r2c2=1 r2c2<>5 r4c2=5 r4c2<>7 r6c2=7
r9c4=4 r9c9<>4 r56c9=4 r5c7<>4 r5c7=7 r1c7<>7 r1c8=7 r1c8<>5 r1c3=5 r4c3<>5 r4c2=5 r4c2<>7 r6c2=7
Locked Candidates Type 1 (Pointing): 4 in b4 => r4c6<>4
Forcing Net Contradiction in r9 => r2c1=3
r2c1<>3 r1c1=3 (r1c7<>3) r1c9<>3 r1c9=2 r5c9<>2 r5c9=4 r5c7<>4 r5c7=7 r1c7<>7 r1c7=4 (r3c7<>4) r3c8<>4 r3c2=4 r9c2<>4
r2c1<>3 r1c1=3 r1c9<>3 r1c9=2 r5c9<>2 r5c9=4 r6c9<>4 r6c4=4 r9c4<>4
r2c1<>3 r1c1=3 (r1c7<>3) r1c9<>3 r1c9=2 r5c9<>2 r5c9=4 r5c7<>4 r5c7=7 r1c7<>7 r1c7=4 r9c7<>4
r2c1<>3 r1c1=3 r1c9<>3 r1c9=2 r5c9<>2 r5c9=4 r9c9<>4
Locked Candidates Type 1 (Pointing): 3 in b2 => r3c78<>3
Finned X-Wing: 1 c14 r18 fr9c4 => r8c5<>1
Finned X-Wing: 3 c68 r47 fr6c8 => r4c7<>3
Naked Single: r4c7=8
Sashimi X-Wing: 8 c69 r29 fr7c6 fr8c6 => r9c45<>8
Hidden Single: r9c9=8
Naked Single: r2c9=9
Naked Single: r3c7=4
Naked Single: r5c7=7
Naked Single: r1c7=3
Full House: r9c7=9
Naked Single: r1c9=2
Naked Single: r8c8=4
Full House: r7c8=3
Naked Single: r3c8=8
Naked Single: r5c9=4
Full House: r6c9=3
Naked Single: r4c8=1
Naked Single: r6c8=9
Full House: r5c8=2
Full House: r5c6=1
Naked Single: r2c8=5
Full House: r1c8=7
Naked Single: r6c5=8
Full House: r6c4=4
Naked Single: r2c6=8
Naked Single: r2c3=2
Full House: r2c2=1
Naked Single: r7c6=4
Naked Single: r8c6=7
Full House: r4c6=3
Naked Single: r3c2=9
Naked Single: r1c1=4
Full House: r1c3=5
Naked Single: r9c2=4
Naked Single: r4c4=2
Full House: r4c5=7
Naked Single: r7c2=2
Full House: r4c2=5
Naked Single: r4c1=9
Full House: r4c3=4
Naked Single: r3c4=3
Full House: r3c5=2
Naked Single: r7c1=6
Full House: r8c1=1
Naked Single: r9c4=1
Full House: r9c5=3
Naked Single: r7c5=9
Full House: r7c3=8
Full House: r8c3=9
Naked Single: r1c4=6
Full House: r1c5=1
Full House: r8c5=6
Full House: r8c4=8
|
normal_sudoku_807
|
.9...861...3.6..2..6.1....734..9....52.....93..9..5......7..1.......6..8..2.4..3.
|
295378614173564829468129357347692581526817493819435276954783162731256948682941735
|
Basic 9x9 Sudoku 807
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . . . 8 6 1 .
. . 3 . 6 . . 2 .
. 6 . 1 . . . . 7
3 4 . . 9 . . . .
5 2 . . . . . 9 3
. . 9 . . 5 . . .
. . . 7 . . 1 . .
. . . . . 6 . . 8
. . 2 . 4 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
295378614173564829468129357347692581526817493819435276954783162731256948682941735 #1 Extreme (13860) bf
Brute Force: r5c9=3
Hidden Single: r3c7=3
Hidden Single: r7c6=3
Hidden Single: r3c6=9
Naked Single: r9c6=1
Hidden Single: r8c2=3
Hidden Single: r4c6=2
Naked Pair: 2,5 in r38c5 => r17c5<>2, r17c5<>5
Naked Single: r7c5=8
Naked Single: r7c2=5
Hidden Single: r7c9=2
Hidden Single: r6c7=2
Hidden Single: r7c1=9
2-String Kite: 6 in r6c1,r7c8 (connected by r7c3,r9c1) => r6c8<>6
Finned X-Wing: 4 r37 c38 fr3c1 => r1c3<>4
Discontinuous Nice Loop: 4 r1c1 -4- r1c9 -5- r1c3 =5= r3c3 -5- r3c5 -2- r3c1 =2= r1c1 => r1c1<>4
Discontinuous Nice Loop: 4 r2c9 -4- r2c4 -5- r9c4 -9- r9c9 =9= r2c9 => r2c9<>4
Grouped Discontinuous Nice Loop: 4 r2c1 -4- r2c4 -5- r9c4 -9- r8c4 =9= r8c7 =4= r78c8 -4- r3c8 =4= r3c13 -4- r2c1 => r2c1<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c8<>4
AIC: 9 9- r2c9 =9= r9c9 =6= r9c1 -6- r7c3 -4- r3c3 =4= r3c1 =2= r3c5 -2- r8c5 =2= r8c4 =9= r8c7 -9 => r2c7,r9c9<>9
Hidden Single: r2c9=9
2-String Kite: 5 in r2c7,r8c5 (connected by r2c4,r3c5) => r8c7<>5
Discontinuous Nice Loop: 4 r8c7 -4- r8c1 =4= r3c1 =2= r3c5 -2- r8c5 =2= r8c4 =9= r8c7 => r8c7<>4
Locked Candidates Type 1 (Pointing): 4 in b9 => r6c8<>4
X-Wing: 4 r16 c49 => r25c4<>4
Naked Single: r2c4=5
Naked Single: r3c5=2
Naked Single: r9c4=9
Naked Single: r8c5=5
Full House: r8c4=2
Hidden Single: r1c1=2
Hidden Single: r8c7=9
Naked Pair: 6,8 in r45c4 => r6c4<>6, r6c4<>8
X-Wing: 6 r69 c19 => r4c9<>6
2-String Kite: 7 in r1c3,r5c6 (connected by r1c5,r2c6) => r5c3<>7
Empty Rectangle: 7 in b4 (r1c35) => r6c5<>7
Locked Candidates Type 1 (Pointing): 7 in b5 => r5c7<>7
Naked Pair: 4,8 in r25c7 => r4c7<>8
W-Wing: 8/7 in r6c8,r9c2 connected by 7 in r49c7 => r6c2<>8
2-String Kite: 8 in r2c7,r6c1 (connected by r5c7,r6c8) => r2c1<>8
XY-Wing: 7/8/5 in r36c8,r4c7 => r4c8<>5
Hidden Single: r3c8=5
Naked Single: r1c9=4
Full House: r2c7=8
Naked Single: r1c4=3
Naked Single: r5c7=4
Naked Single: r1c5=7
Full House: r1c3=5
Full House: r2c6=4
Full House: r5c6=7
Naked Single: r6c4=4
Naked Single: r5c5=1
Full House: r6c5=3
Hidden Single: r9c2=8
Naked Triple: 4,6,8 in r357c3 => r4c3<>6, r4c3<>8, r8c3<>4
Naked Pair: 1,7 in r4c3,r6c2 => r6c1<>1, r6c1<>7
Naked Triple: 1,5,7 in r4c379 => r4c8<>7
Bivalue Universal Grave + 1 => r8c1<>1, r8c1<>4
Naked Single: r8c1=7
Naked Single: r2c1=1
Full House: r2c2=7
Full House: r6c2=1
Naked Single: r8c3=1
Full House: r8c8=4
Naked Single: r9c1=6
Full House: r7c3=4
Full House: r7c8=6
Naked Single: r4c3=7
Naked Single: r6c9=6
Naked Single: r6c1=8
Full House: r3c1=4
Full House: r3c3=8
Full House: r5c3=6
Full House: r6c8=7
Full House: r4c8=8
Full House: r5c4=8
Full House: r4c4=6
Naked Single: r9c9=5
Full House: r4c9=1
Full House: r4c7=5
Full House: r9c7=7
|
normal_sudoku_1549
|
......81........979378..25..2...6748...7.2.6.5...........2...3..486........9..1.5
|
652479813814325697937861254321596748489732561576184329795218436148653972263947185
|
Basic 9x9 Sudoku 1549
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . 8 1 .
. . . . . . . 9 7
9 3 7 8 . . 2 5 .
. 2 . . . 6 7 4 8
. . . 7 . 2 . 6 .
5 . . . . . . . .
. . . 2 . . . 3 .
. 4 8 6 . . . . .
. . . 9 . . 1 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
652479813814325697937861254321596748489732561576184329795218436148653972263947185 #1 Easy (250)
Naked Single: r1c8=1
Naked Single: r8c7=9
Naked Single: r6c8=2
Naked Single: r6c7=3
Naked Single: r8c9=2
Naked Single: r8c8=7
Full House: r9c8=8
Naked Single: r5c7=5
Hidden Single: r6c2=7
Naked Single: r9c2=6
Naked Single: r1c2=5
Hidden Single: r1c9=3
Naked Single: r1c4=4
Naked Single: r3c6=1
Naked Single: r6c4=1
Naked Single: r3c5=6
Full House: r3c9=4
Full House: r2c7=6
Full House: r7c7=4
Full House: r7c9=6
Naked Single: r6c9=9
Full House: r5c9=1
Hidden Single: r6c3=6
Naked Single: r1c3=2
Naked Single: r1c1=6
Naked Single: r9c3=3
Naked Single: r8c1=1
Naked Single: r4c1=3
Naked Single: r7c1=7
Naked Single: r7c2=9
Naked Single: r4c4=5
Full House: r2c4=3
Naked Single: r9c1=2
Full House: r7c3=5
Naked Single: r5c2=8
Full House: r2c2=1
Naked Single: r4c5=9
Full House: r4c3=1
Naked Single: r2c6=5
Naked Single: r7c6=8
Full House: r7c5=1
Naked Single: r5c1=4
Full House: r2c1=8
Full House: r2c3=4
Full House: r2c5=2
Full House: r5c3=9
Full House: r5c5=3
Naked Single: r1c5=7
Full House: r1c6=9
Naked Single: r8c6=3
Full House: r8c5=5
Naked Single: r6c6=4
Full House: r6c5=8
Full House: r9c5=4
Full House: r9c6=7
|
normal_sudoku_5103
|
.45.6..377.9.....4......95...65......3.1.25...5..7..9...4.3..75.....746.6.....3..
|
845961237729358614361724958186593742937142586452876193214639875593287461678415329
|
Basic 9x9 Sudoku 5103
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 5 . 6 . . 3 7
7 . 9 . . . . . 4
. . . . . . 9 5 .
. . 6 5 . . . . .
. 3 . 1 . 2 5 . .
. 5 . . 7 . . 9 .
. . 4 . 3 . . 7 5
. . . . . 7 4 6 .
6 . . . . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
845961237729358614361724958186593742937142586452876193214639875593287461678415329 #1 Extreme (14158) bf
Hidden Single: r5c7=5
Hidden Single: r3c4=7
Hidden Single: r8c1=5
Hidden Single: r5c9=6
Hidden Single: r5c3=7
Hidden Single: r4c7=7
Hidden Single: r8c3=3
Hidden Single: r3c1=3
Hidden Single: r3c2=6
Hidden Single: r2c7=6
Hidden Single: r9c2=7
Brute Force: r5c8=8
Hidden Single: r4c8=4
Avoidable Rectangle Type 2: 4/8 in r4c58,r5c58 => r4c6,r89c5<>9
Finned Franken Swordfish: 1 c38b6 r369 fr2c8 fr4c9 => r3c9<>1
W-Wing: 2/1 in r6c7,r9c8 connected by 1 in r1c7,r2c8 => r7c7<>2
Sashimi Swordfish: 2 c378 r369 fr1c7 fr2c8 => r3c9<>2
Naked Single: r3c9=8
Hidden Single: r7c7=8
Forcing Chain Contradiction in r6c3 => r1c1<>1
r1c1=1 r1c7<>1 r6c7=1 r6c3<>1
r1c1=1 r3c3<>1 r3c3=2 r6c3<>2
r1c1=1 r1c1<>8 r46c1=8 r6c3<>8
2-String Kite: 1 in r1c6,r9c8 (connected by r1c7,r2c8) => r9c6<>1
Turbot Fish: 1 r3c3 =1= r2c2 -1- r2c8 =1= r9c8 => r9c3<>1
AIC: 2 2- r2c8 -1- r2c2 =1= r3c3 =2= r3c5 -2 => r2c45<>2
Grouped Discontinuous Nice Loop: 1 r3c5 -1- r3c3 =1= r6c3 -1- r46c1 =1= r7c1 -1- r7c6 =1= r89c5 -1- r3c5 => r3c5<>1
Grouped Discontinuous Nice Loop: 8 r9c4 -8- r9c3 -2- r7c12 =2= r7c4 =6= r6c4 =4= r9c4 => r9c4<>8
Almost Locked Set XY-Wing: A=r6c37 {128}, B=r89c9 {129}, C=r9c38 {128}, X,Y=1,8, Z=2 => r6c9<>2
Forcing Chain Contradiction in r6c3 => r1c1=8
r1c1<>8 r1c1=2 r3c3<>2 r3c3=1 r6c3<>1
r1c1<>8 r1c1=2 r1c7<>2 r6c7=2 r6c3<>2
r1c1<>8 r46c1=8 r6c3<>8
Naked Pair: 1,2 in r2c28 => r2c56<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r7c6<>1
Locked Candidates Type 2 (Claiming): 1 in r7 => r8c2<>1
Swordfish: 1 c367 r136 => r6c19<>1
Naked Single: r6c9=3
Hidden Single: r4c6=3
Hidden Single: r2c4=3
Remote Pair: 2/1 r3c3 -1- r2c2 -2- r2c8 -1- r9c8 => r9c3<>2
Naked Single: r9c3=8
Hidden Single: r4c2=8
Naked Single: r4c5=9
Naked Single: r5c5=4
Full House: r5c1=9
Naked Single: r3c5=2
Naked Single: r1c4=9
Naked Single: r3c3=1
Full House: r2c2=2
Full House: r3c6=4
Full House: r6c3=2
Naked Single: r1c6=1
Full House: r1c7=2
Full House: r2c8=1
Full House: r6c7=1
Full House: r9c8=2
Full House: r4c9=2
Full House: r4c1=1
Full House: r6c1=4
Full House: r7c1=2
Naked Single: r8c2=9
Full House: r7c2=1
Naked Single: r9c4=4
Naked Single: r7c4=6
Full House: r7c6=9
Naked Single: r8c9=1
Full House: r9c9=9
Naked Single: r6c4=8
Full House: r6c6=6
Full House: r8c4=2
Full House: r8c5=8
Naked Single: r9c6=5
Full House: r2c6=8
Full House: r2c5=5
Full House: r9c5=1
|
normal_sudoku_1351
|
..9.6.1.7371.495.........39.....5.2.82....75..35.8....4..92..........9...5..37..8
|
289563147371249586546178239697415823824396751135782694468921375713854962952637418
|
Basic 9x9 Sudoku 1351
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . 6 . 1 . 7
3 7 1 . 4 9 5 . .
. . . . . . . 3 9
. . . . . 5 . 2 .
8 2 . . . . 7 5 .
. 3 5 . 8 . . . .
4 . . 9 2 . . . .
. . . . . . 9 . .
. 5 . . 3 7 . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
289563147371249586546178239697415823824396751135782694468921375713854962952637418 #1 Unfair (1732)
Hidden Single: r2c6=9
Hidden Single: r6c8=9
Hidden Single: r7c9=5
Hidden Single: r9c1=9
Hidden Single: r4c2=9
Hidden Single: r4c7=8
Hidden Single: r5c5=9
Hidden Single: r7c7=3
Hidden Single: r8c3=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r3c7<>6
Locked Candidates Type 1 (Pointing): 1 in b4 => r8c1<>1
Locked Candidates Type 1 (Pointing): 4 in b4 => r3c3<>4
Locked Candidates Type 1 (Pointing): 1 in b6 => r8c9<>1
Naked Pair: 4,8 in r1c28 => r1c46<>8
X-Wing: 2 c37 r39 => r3c146<>2
XY-Wing: 2/4/6 in r2c9,r36c7 => r456c9<>6
Hidden Single: r6c7=6
Locked Candidates Type 1 (Pointing): 4 in b6 => r8c9<>4
Sue de Coq: r4c13 - {1467} (r4c5 - {17}, r5c3 - {46}) => r4c49<>1, r4c4<>7
Continuous Nice Loop: 6/8 8= r7c3 =7= r8c1 =2= r8c9 =6= r2c9 -6- r2c8 -8- r1c8 =8= r1c2 -8- r3c3 =8= r7c3 =7 => r7c3,r8c1<>6, r3c2<>8
XY-Chain: 8 8- r1c2 -4- r3c2 -6- r3c1 -5- r1c1 -2- r8c1 -7- r7c3 -8 => r3c3,r78c2<>8
Hidden Single: r7c3=8
Hidden Single: r1c2=8
Naked Single: r1c8=4
Naked Single: r3c7=2
Full House: r9c7=4
Naked Single: r2c9=6
Full House: r2c8=8
Full House: r2c4=2
Naked Single: r3c3=6
Naked Single: r8c9=2
Naked Single: r1c6=3
Naked Single: r3c1=5
Naked Single: r3c2=4
Full House: r1c1=2
Full House: r1c4=5
Naked Single: r5c3=4
Naked Single: r9c3=2
Full House: r4c3=7
Naked Single: r8c1=7
Naked Single: r4c5=1
Naked Single: r6c1=1
Full House: r4c1=6
Naked Single: r3c5=7
Full House: r8c5=5
Naked Single: r5c6=6
Naked Single: r6c9=4
Naked Single: r5c4=3
Full House: r5c9=1
Full House: r4c9=3
Full House: r4c4=4
Naked Single: r7c6=1
Naked Single: r6c4=7
Full House: r6c6=2
Naked Single: r3c6=8
Full House: r3c4=1
Full House: r8c6=4
Naked Single: r7c2=6
Full House: r7c8=7
Full House: r8c2=1
Naked Single: r9c4=6
Full House: r8c4=8
Full House: r8c8=6
Full House: r9c8=1
|
normal_sudoku_197
|
.........45.6...899.7.1.64....82.59..9.7...6.5..9..1.......7.....64....57.5.8..3.
|
268349751451672389937518642674821593192735468583964127349257816816493275725186934
|
Basic 9x9 Sudoku 197
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . . . .
4 5 . 6 . . . 8 9
9 . 7 . 1 . 6 4 .
. . . 8 2 . 5 9 .
. 9 . 7 . . . 6 .
5 . . 9 . . 1 . .
. . . . . 7 . . .
. . 6 4 . . . . 5
7 . 5 . 8 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
268349751451672389937518642674821593192735468583964127349257816816493275725186934 #1 Hard (1256)
Hidden Single: r4c8=9
Hidden Single: r2c3=1
Hidden Single: r1c8=5
Hidden Single: r7c3=9
Hidden Single: r1c9=1
Locked Candidates Type 1 (Pointing): 7 in b3 => r8c7<>7
Hidden Single: r8c8=7
Naked Single: r6c8=2
Full House: r7c8=1
Hidden Single: r9c4=1
Locked Candidates Type 1 (Pointing): 4 in b7 => r46c2<>4
Naked Pair: 2,3 in r1c4,r2c6 => r1c56,r2c5,r3c46<>3, r13c6,r3c4<>2
Naked Single: r2c5=7
Naked Single: r3c4=5
Naked Single: r3c6=8
Hidden Single: r1c7=7
Hidden Single: r5c6=5
Hidden Single: r7c5=5
Hidden Single: r5c1=1
Hidden Single: r4c6=1
Hidden Single: r7c9=6
Hidden Single: r6c5=6
Hidden Single: r9c6=6
Hidden Single: r8c2=1
Hidden Single: r5c3=2
Hidden Single: r9c7=9
Locked Candidates Type 1 (Pointing): 8 in b4 => r6c9<>8
Hidden Single: r5c9=8
X-Wing: 2 r39 c29 => r17c2<>2
Remote Pair: 3/2 r3c2 -2- r3c9 -3- r2c7 -2- r2c6 -3- r1c4 -2- r7c4 => r7c7<>2, r7c2<>3
Locked Candidates Type 1 (Pointing): 3 in b7 => r14c1<>3
Naked Single: r4c1=6
Hidden Single: r1c2=6
Naked Pair: 4,8 in r7c27 => r7c1<>8
X-Wing: 2 r17 c14 => r8c1<>2
Skyscraper: 3 in r2c6,r5c5 (connected by r25c7) => r6c6<>3
Naked Single: r6c6=4
Full House: r5c5=3
Full House: r5c7=4
Naked Single: r1c6=9
Naked Single: r8c5=9
Full House: r1c5=4
Naked Single: r7c7=8
Naked Single: r7c2=4
Naked Single: r8c7=2
Full House: r2c7=3
Full House: r9c9=4
Full House: r9c2=2
Full House: r2c6=2
Full House: r8c6=3
Full House: r3c9=2
Full House: r3c2=3
Full House: r1c4=3
Full House: r7c4=2
Full House: r7c1=3
Full House: r8c1=8
Full House: r1c1=2
Full House: r1c3=8
Naked Single: r4c2=7
Full House: r6c2=8
Naked Single: r6c3=3
Full House: r4c3=4
Full House: r4c9=3
Full House: r6c9=7
|
normal_sudoku_1639
|
.67....121.4..7...9.2..8...3...8.1....6..9..8.......73..5..13.9....2......3.4...5
|
867394512134257896952618437329785164476139258581462973645871329798523641213946785
|
Basic 9x9 Sudoku 1639
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 7 . . . . 1 2
1 . 4 . . 7 . . .
9 . 2 . . 8 . . .
3 . . . 8 . 1 . .
. . 6 . . 9 . . 8
. . . . . . . 7 3
. . 5 . . 1 3 . 9
. . . . 2 . . . .
. . 3 . 4 . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
867394512134257896952618437329785164476139258581462973645871329798523641213946785 #1 Easy (294)
Naked Single: r3c3=2
Naked Single: r2c9=6
Naked Single: r9c6=6
Naked Single: r4c3=9
Naked Single: r4c9=4
Naked Single: r7c5=7
Naked Single: r3c9=7
Full House: r8c9=1
Naked Single: r7c4=8
Naked Single: r8c3=8
Full House: r6c3=1
Naked Single: r9c4=9
Hidden Single: r9c2=1
Hidden Single: r2c4=2
Hidden Single: r2c8=9
Hidden Single: r6c7=9
Hidden Single: r8c2=9
Hidden Single: r1c5=9
Hidden Single: r3c8=3
Naked Single: r3c2=5
Naked Single: r1c1=8
Full House: r2c2=3
Naked Single: r3c7=4
Naked Single: r2c5=5
Full House: r2c7=8
Full House: r1c7=5
Naked Single: r6c5=6
Naked Single: r5c7=2
Naked Single: r3c5=1
Full House: r3c4=6
Full House: r5c5=3
Naked Single: r5c8=5
Full House: r4c8=6
Naked Single: r9c7=7
Full House: r8c7=6
Naked Single: r8c8=4
Naked Single: r9c1=2
Full House: r9c8=8
Full House: r7c8=2
Naked Single: r8c1=7
Naked Single: r7c2=4
Full House: r7c1=6
Naked Single: r5c1=4
Full House: r6c1=5
Naked Single: r5c2=7
Full House: r5c4=1
Naked Single: r6c4=4
Naked Single: r4c2=2
Full House: r6c2=8
Full House: r6c6=2
Naked Single: r1c4=3
Full House: r1c6=4
Naked Single: r4c6=5
Full House: r4c4=7
Full House: r8c4=5
Full House: r8c6=3
|
normal_sudoku_1238
|
............4...8.7..839.2.1.7....3..985.4.......2....9.......8.8.1....52..6.71..
|
842716953639452781715839426127968534398574612564321897971245368486193275253687149
|
Basic 9x9 Sudoku 1238
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . . . .
. . . 4 . . . 8 .
7 . . 8 3 9 . 2 .
1 . 7 . . . . 3 .
. 9 8 5 . 4 . . .
. . . . 2 . . . .
9 . . . . . . . 8
. 8 . 1 . . . . 5
2 . . 6 . 7 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
842716953639452781715839426127968534398574612564321897971245368486193275253687149 #1 Easy (362)
Naked Single: r3c4=8
Naked Single: r4c4=9
Hidden Single: r5c1=3
Hidden Single: r1c1=8
Hidden Single: r4c2=2
Hidden Single: r7c2=7
Hidden Single: r9c5=8
Naked Single: r4c5=6
Naked Single: r4c6=8
Naked Single: r4c9=4
Full House: r4c7=5
Hidden Single: r5c9=2
Hidden Single: r7c3=1
Hidden Single: r8c5=9
Hidden Single: r6c7=8
Hidden Single: r1c8=5
Hidden Single: r7c5=4
Naked Single: r7c8=6
Hidden Single: r7c6=5
Hidden Single: r2c5=5
Naked Single: r2c1=6
Naked Single: r8c1=4
Full House: r6c1=5
Naked Single: r8c8=7
Naked Single: r5c8=1
Naked Single: r5c5=7
Full House: r1c5=1
Full House: r5c7=6
Naked Single: r6c8=9
Full House: r6c9=7
Full House: r9c8=4
Naked Single: r6c4=3
Full House: r6c6=1
Naked Single: r2c6=2
Naked Single: r3c7=4
Naked Single: r7c4=2
Full House: r1c4=7
Full House: r1c6=6
Full House: r8c6=3
Full House: r7c7=3
Naked Single: r3c3=5
Naked Single: r8c3=6
Full House: r8c7=2
Full House: r9c9=9
Naked Single: r1c7=9
Full House: r2c7=7
Naked Single: r3c2=1
Full House: r3c9=6
Naked Single: r9c3=3
Full House: r9c2=5
Naked Single: r6c3=4
Full House: r6c2=6
Naked Single: r1c9=3
Full House: r2c9=1
Naked Single: r2c2=3
Full House: r2c3=9
Full House: r1c3=2
Full House: r1c2=4
|
normal_sudoku_3451
|
.2.......4....36....82...5...4.7...8.5..1..7.6....41..3..69...1.....1......43.9..
|
526748319497153682138269754914576238853912476672384195345697821769821543281435967
|
Basic 9x9 Sudoku 3451
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . . . . . .
4 . . . . 3 6 . .
. . 8 2 . . . 5 .
. . 4 . 7 . . . 8
. 5 . . 1 . . 7 .
6 . . . . 4 1 . .
3 . . 6 9 . . . 1
. . . . . 1 . . .
. . . 4 3 . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
526748319497153682138269754914576238853912476672384195345697821769821543281435967 #1 Extreme (22800) bf
Hidden Pair: 3,6 in r1c3,r3c2 => r1c3,r3c2<>1, r1c3<>5, r1c3,r3c2<>7, r1c3,r3c2<>9
Brute Force: r5c5=1
Hidden Single: r3c1=1
Hidden Single: r9c3=1
Hidden Single: r4c2=1
Locked Candidates Type 1 (Pointing): 6 in b5 => r13c6<>6
Naked Triple: 2,5,8 in r268c5 => r1c5<>5, r1c5<>8
Forcing Chain Contradiction in r7 => r1c7<>7
r1c7=7 r1c1<>7 r89c1=7 r7c2<>7
r1c7=7 r1c1<>7 r89c1=7 r7c3<>7
r1c7=7 r3c79<>7 r3c6=7 r7c6<>7
r1c7=7 r7c7<>7
Forcing Net Contradiction in r7c7 => r2c4<>9
r2c4=9 (r2c4<>5) (r2c3<>9 r1c1=9 r1c1<>5) r2c4<>1 r2c8=1 r1c8<>1 r1c4=1 r1c4<>5 r1c6=5 (r7c6<>5) r2c5<>5 r2c3=5 r7c3<>5 r7c7=5
r2c4=9 (r3c6<>9 r3c6=7 r7c6<>7) r2c2<>9 r2c2=7 (r7c2<>7) r6c2<>7 r6c3=7 r7c3<>7 r7c7=7
Forcing Net Verity => r4c8<>9
r4c7=2 r4c1<>2 r4c1=9 r4c8<>9
r4c8=2 r4c8<>9
r5c7=2 r5c7<>4 r5c9=4 r5c9<>6 r5c6=6 r4c6<>6 r4c8=6 r4c8<>9
r5c9=2 r5c9<>6 r5c6=6 r4c6<>6 r4c8=6 r4c8<>9
r6c8=2 (r9c8<>2) (r2c8<>2 r2c9=2 r9c9<>2) r6c5<>2 r8c5=2 r9c6<>2 r9c1=2 r4c1<>2 r4c1=9 r4c8<>9
r6c9=2 (r2c9<>2 r2c8=2 r9c8<>2) (r9c9<>2) r6c5<>2 r8c5=2 r9c6<>2 r9c1=2 r4c1<>2 r4c1=9 r4c8<>9
Forcing Chain Contradiction in r5 => r6c2<>9
r6c2=9 r6c2<>8 r5c1=8 r5c1<>2
r6c2=9 r4c1<>9 r4c1=2 r5c3<>2
r6c2=9 r6c89<>9 r5c9=9 r5c9<>6 r5c6=6 r5c6<>2
r6c2=9 r6c89<>9 r5c9=9 r5c9<>4 r5c7=4 r5c7<>2
r6c2=9 r6c89<>9 r5c9=9 r5c9<>2
Forcing Chain Contradiction in r5 => r6c3<>9
r6c3=9 r4c1<>9 r4c1=2 r5c1<>2
r6c3=9 r4c1<>9 r4c1=2 r5c3<>2
r6c3=9 r6c89<>9 r5c9=9 r5c9<>6 r5c6=6 r5c6<>2
r6c3=9 r6c89<>9 r5c9=9 r5c9<>4 r5c7=4 r5c7<>2
r6c3=9 r6c89<>9 r5c9=9 r5c9<>2
Forcing Net Contradiction in r7 => r1c1<>9
r1c1=9 (r1c1<>5 r2c3=5 r7c3<>5) r2c2<>9 (r8c2=9 r8c2<>4 r7c2=4 r7c2<>8) (r8c2=9 r8c2<>4 r7c2=4 r7c8<>4) r2c2=7 r6c2<>7 r6c3=7 r7c3<>7 r7c3=2 r7c8<>2 r7c8=8 r7c7<>8 r7c6=8
r1c1=9 (r1c1<>5 r2c3=5 r7c3<>5) r2c2<>9 (r8c2=9 r8c2<>4 r7c2=4 r7c8<>4) r2c2=7 r6c2<>7 r6c3=7 r7c3<>7 r7c3=2 r7c8<>2 r7c8=8
Locked Candidates Type 1 (Pointing): 9 in b1 => r2c89<>9
Forcing Net Contradiction in r4c1 => r4c6<>5
r4c6=5 (r1c6<>5) (r9c6<>5) (r6c4<>5) r6c5<>5 r6c9=5 r9c9<>5 r9c1=5 (r7c3<>5) r1c1<>5 (r1c1=7 r1c4<>7) r1c4=5 r1c4<>1 r1c8=1 r2c8<>1 r2c4=1 r2c4<>7 (r2c9=7 r3c7<>7) r8c4=7 r8c7<>7 r7c7=7 r7c7<>5 r7c6=5 r4c6<>5
Forcing Chain Contradiction in r7 => r8c4<>5
r8c4=5 r79c6<>5 r1c6=5 r1c1<>5 r2c3=5 r7c3<>5
r8c4=5 r7c6<>5
r8c4=5 r4c4<>5 r4c7=5 r7c7<>5
Forcing Chain Contradiction in r6 => r8c3<>7
r8c3=7 r6c3<>7 r6c2=7 r6c2<>8
r8c3=7 r8c4<>7 r8c4=8 r6c4<>8
r8c3=7 r89c1<>7 r1c1=7 r1c1<>5 r2c3=5 r2c5<>5 r2c5=8 r6c5<>8
Forcing Net Contradiction in r5c9 => r1c4<>5
r1c4=5 (r4c4<>5 r4c7=5 r4c7<>2) (r4c4<>5 r4c7=5 r6c9<>5 r6c5=5 r8c5<>5 r8c5=2 r8c7<>2) (r1c4<>7) r1c4<>1 r1c8=1 r2c8<>1 r2c4=1 r2c4<>7 (r2c9=7 r3c7<>7) r8c4=7 r8c7<>7 r7c7=7 r7c7<>2 r5c7=2 r5c7<>4 r5c9=4
r1c4=5 (r4c4<>5 r4c7=5 r6c9<>5 r6c5=5 r8c5<>5 r8c5=2 r9c6<>2) (r4c4<>5 r4c7=5 r7c7<>5 r7c6=5 r9c6<>5) (r1c4<>7) r1c4<>1 r1c8=1 r2c8<>1 (r2c8=2 r9c8<>2) r2c4=1 r2c4<>7 r8c4=7 r9c6<>7 r9c6=8 r9c8<>8 r9c8=6 r89c9<>6 r5c9=6
Empty Rectangle: 5 in b8 (r1c16) => r8c1<>5
Grouped Discontinuous Nice Loop: 2 r6c9 -2- r6c5 =2= r8c5 =5= r79c6 -5- r1c6 =5= r1c1 =7= r2c23 -7- r2c9 -2- r6c9 => r6c9<>2
Forcing Net Contradiction in r1c1 => r2c9=2
r2c9<>2 r2c9=7 (r2c2<>7 r2c2=9 r2c3<>9 r2c3=5 r8c3<>5) (r2c2<>7) r2c3<>7 r1c1=7 r1c1<>5 r1c6=5 (r7c6<>5) r9c6<>5 r8c5=5 r8c7<>5 r8c9=5 r8c5<>5 r79c6=5 r1c6<>5 r1c1=5
r2c9<>2 r2c9=7 (r2c2<>7) r2c3<>7 r1c1=7
Hidden Rectangle: 1/8 in r1c48,r2c48 => r1c4<>8
Forcing Chain Contradiction in c9 => r5c6<>9
r5c6=9 r3c6<>9 r3c6=7 r3c79<>7 r1c9=7 r1c9<>4
r5c6=9 r3c6<>9 r3c9=9 r3c9<>4
r5c6=9 r5c6<>6 r5c9=6 r5c9<>4
r5c6=9 r456c4<>9 r1c4=9 r1c4<>1 r1c8=1 r1c8<>4 r78c8=4 r8c9<>4
Forcing Chain Contradiction in r6 => r7c3<>7
r7c3=7 r6c3<>7 r6c2=7 r6c2<>8
r7c3=7 r89c1<>7 r1c1=7 r2c23<>7 r2c4=7 r8c4<>7 r8c4=8 r6c4<>8
r7c3=7 r89c1<>7 r1c1=7 r1c1<>5 r1c6=5 r2c5<>5 r2c5=8 r6c5<>8
Forcing Chain Contradiction in r7c6 => r7c2<>7
r7c2=7 r89c1<>7 r1c1=7 r1c1<>5 r9c1=5 r7c3<>5 r7c3=2 r7c6<>2
r7c2=7 r89c1<>7 r1c1=7 r1c1<>5 r1c6=5 r7c6<>5
r7c2=7 r7c6<>7
r7c2=7 r89c1<>7 r1c1=7 r2c23<>7 r2c4=7 r8c4<>7 r8c4=8 r7c6<>8
Forcing Chain Contradiction in c7 => r1c4<>9
r1c4=9 r1c4<>1 r1c8=1 r2c8<>1 r2c8=8 r1c7<>8
r1c4=9 r3c6<>9 r3c6=7 r7c6<>7 r7c7=7 r7c7<>8
r1c4=9 r1c4<>1 r1c8=1 r2c8<>1 r2c8=8 r1c78<>8 r1c6=8 r79c6<>8 r8c45=8 r8c7<>8
Locked Candidates Type 1 (Pointing): 9 in b2 => r4c6<>9
Forcing Chain Contradiction in r8 => r7c7<>4
r7c7=4 r5c7<>4 r5c9=4 r5c9<>6 r5c6=6 r4c6<>6 r4c6=2 r4c1<>2 r4c1=9 r8c1<>9
r7c7=4 r7c2<>4 r8c2=4 r8c2<>9
r7c7=4 r78c8<>4 r1c8=4 r1c5<>4 r1c5=6 r1c3<>6 r8c3=6 r8c3<>9
Forcing Chain Contradiction in r6 => r8c7<>4
r8c7=4 r78c8<>4 r1c8=4 r1c5<>4 r1c5=6 r1c3<>6 r1c3=3 r3c2<>3 r6c2=3 r6c2<>7 r6c3=7 r6c3<>2
r8c7=4 r5c7<>4 r5c9=4 r5c9<>6 r5c6=6 r4c6<>6 r4c6=2 r6c5<>2
r8c7=4 r78c8<>4 r1c8=4 r1c8<>9 r6c8=9 r6c8<>2
Forcing Chain Contradiction in r9c9 => r9c2<>7
r9c2=7 r89c1<>7 r1c1=7 r1c1<>5 r9c1=5 r9c9<>5
r9c2=7 r89c1<>7 r1c1=7 r1c1<>5 r1c6=5 r79c6<>5 r8c5=5 r8c5<>2 r6c5=2 r4c6<>2 r4c6=6 r4c8<>6 r5c9=6 r9c9<>6
r9c2=7 r9c9<>7
Forcing Net Contradiction in r1c1 => r1c1=5
r1c1<>5 (r1c1=7 r2c3<>7 r2c4=7 r8c4<>7 r8c4=8 r8c1<>8) (r1c6=5 r7c6<>5) r9c1=5 r7c3<>5 (r7c3=2 r8c1<>2) r7c7=5 r4c7<>5 r4c4=5 r4c4<>9 r4c1=9 r8c1<>9 r8c1=7 r1c1<>7 r1c1=5
Locked Candidates Type 1 (Pointing): 7 in b1 => r2c4<>7
Locked Candidates Type 2 (Claiming): 7 in c1 => r8c2<>7
Locked Candidates Type 2 (Claiming): 5 in c6 => r8c5<>5
Forcing Chain Contradiction in c1 => r5c6<>8
r5c6=8 r5c1<>8
r5c6=8 r79c6<>8 r8c45=8 r8c1<>8
r5c6=8 r1c6<>8 r1c78=8 r2c8<>8 r2c8=1 r2c4<>1 r1c4=1 r1c4<>7 r8c4=7 r8c1<>7 r9c1=7 r9c1<>8
Locked Pair: 2,6 in r45c6 => r6c5,r79c6<>2
Hidden Single: r8c5=2
Skyscraper: 2 in r6c3,r9c1 (connected by r69c8) => r45c1,r7c3<>2
Naked Single: r4c1=9
Naked Single: r7c3=5
Naked Single: r5c1=8
Naked Single: r8c1=7
Full House: r9c1=2
Naked Single: r8c4=8
Naked Single: r7c6=7
Full House: r9c6=5
Naked Single: r3c6=9
Naked Single: r1c6=8
Naked Single: r2c5=5
Naked Single: r2c4=1
Naked Single: r6c5=8
Naked Single: r1c4=7
Naked Single: r2c8=8
Naked Single: r9c8=6
Naked Single: r9c2=8
Full House: r9c9=7
Naked Single: r7c2=4
Naked Single: r7c8=2
Full House: r7c7=8
Naked Single: r4c8=3
Naked Single: r4c4=5
Naked Single: r6c8=9
Naked Single: r8c8=4
Full House: r1c8=1
Naked Single: r4c7=2
Full House: r4c6=6
Full House: r5c6=2
Naked Single: r6c4=3
Full House: r5c4=9
Naked Single: r6c9=5
Naked Single: r5c7=4
Full House: r5c9=6
Full House: r5c3=3
Naked Single: r6c2=7
Full House: r6c3=2
Naked Single: r8c9=3
Full House: r8c7=5
Naked Single: r1c7=3
Full House: r3c7=7
Naked Single: r1c3=6
Naked Single: r2c2=9
Full House: r2c3=7
Full House: r3c2=3
Full House: r8c3=9
Full House: r8c2=6
Naked Single: r3c9=4
Full House: r1c9=9
Full House: r1c5=4
Full House: r3c5=6
|
normal_sudoku_372
|
..73...8.4..65....385.91..2....6...72..1.3..4......21.74...9....36.....95..42.3..
|
967342581421658793385791642194265837258173964673984215742839156836517429519426378
|
Basic 9x9 Sudoku 372
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 7 3 . . . 8 .
4 . . 6 5 . . . .
3 8 5 . 9 1 . . 2
. . . . 6 . . . 7
2 . . 1 . 3 . . 4
. . . . . . 2 1 .
7 4 . . . 9 . . .
. 3 6 . . . . . 9
5 . . 4 2 . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
967342581421658793385791642194265837258173964673984215742839156836517429519426378 #1 Hard (518)
Naked Single: r3c3=5
Naked Single: r3c4=7
Naked Single: r1c5=4
Naked Single: r1c6=2
Full House: r2c6=8
Hidden Single: r9c6=6
Naked Single: r9c8=7
Hidden Single: r4c4=2
Hidden Single: r8c8=2
Hidden Single: r7c3=2
Hidden Single: r7c5=3
Hidden Single: r2c2=2
Hidden Single: r2c7=7
Hidden Single: r6c4=9
Hidden Single: r8c7=4
Naked Single: r3c7=6
Full House: r3c8=4
Hidden Single: r8c5=1
Naked Single: r8c1=8
Naked Single: r6c1=6
Naked Single: r8c4=5
Full House: r7c4=8
Full House: r8c6=7
Hidden Single: r9c9=8
Hidden Single: r1c2=6
Hidden Single: r5c8=6
Naked Single: r7c8=5
Naked Single: r7c7=1
Full House: r7c9=6
Naked Pair: 1,9 in r29c3 => r4c3<>1, r45c3<>9
Naked Single: r5c3=8
Naked Single: r5c5=7
Full House: r6c5=8
Hidden Single: r4c7=8
Hidden Single: r6c2=7
Bivalue Universal Grave + 1 => r4c2<>1, r4c2<>5
Naked Single: r4c2=9
Naked Single: r4c1=1
Full House: r1c1=9
Full House: r2c3=1
Naked Single: r4c8=3
Full House: r2c8=9
Full House: r2c9=3
Naked Single: r5c2=5
Full House: r9c2=1
Full House: r9c3=9
Full House: r5c7=9
Full House: r1c7=5
Full House: r6c9=5
Full House: r1c9=1
Naked Single: r4c3=4
Full House: r4c6=5
Full House: r6c6=4
Full House: r6c3=3
|
normal_sudoku_3574
|
..7.3.....6.......3...758...2.6.1.7.5...8.1....159...46....9.4.19..28..62..1..9..
|
857936412469812735312475869923641578546287193781593624678359241194728356235164987
|
Basic 9x9 Sudoku 3574
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 7 . 3 . . . .
. 6 . . . . . . .
3 . . . 7 5 8 . .
. 2 . 6 . 1 . 7 .
5 . . . 8 . 1 . .
. . 1 5 9 . . . 4
6 . . . . 9 . 4 .
1 9 . . 2 8 . . 6
2 . . 1 . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
857936412469812735312475869923641578546287193781593624678359241194728356235164987 #1 Medium (412)
Naked Single: r6c5=9
Naked Single: r7c5=5
Naked Single: r4c5=4
Naked Single: r2c5=1
Full House: r9c5=6
Hidden Single: r1c6=6
Hidden Single: r5c3=6
Hidden Single: r3c8=6
Hidden Single: r6c1=7
Hidden Single: r7c9=1
Hidden Single: r6c7=6
Hidden Single: r5c2=4
Naked Single: r3c2=1
Hidden Single: r1c8=1
Hidden Single: r7c7=2
Locked Candidates Type 1 (Pointing): 9 in b4 => r4c9<>9
Locked Candidates Type 1 (Pointing): 4 in b7 => r23c3<>4
Hidden Single: r3c4=4
Naked Single: r2c6=2
Naked Single: r6c6=3
Naked Single: r5c6=7
Full House: r5c4=2
Full House: r9c6=4
Naked Single: r6c2=8
Full House: r6c8=2
Naked Single: r1c2=5
Naked Single: r4c1=9
Full House: r4c3=3
Naked Single: r1c7=4
Naked Single: r4c7=5
Full House: r4c9=8
Naked Single: r7c3=8
Naked Single: r1c1=8
Full House: r2c1=4
Naked Single: r2c3=9
Full House: r3c3=2
Full House: r3c9=9
Naked Single: r9c3=5
Full House: r8c3=4
Naked Single: r1c4=9
Full House: r2c4=8
Full House: r1c9=2
Naked Single: r5c9=3
Full House: r5c8=9
Naked Single: r9c9=7
Full House: r2c9=5
Naked Single: r8c7=3
Full House: r2c7=7
Full House: r2c8=3
Naked Single: r9c2=3
Full House: r9c8=8
Full House: r8c8=5
Full House: r8c4=7
Full House: r7c2=7
Full House: r7c4=3
|
normal_sudoku_4573
|
..79..2..82.6.5.9........68...2.985.9..57...6..5.....7..8......1.2.....94....85..
|
367981245824635791519427368746219853981573426235846917658792134172354689493168572
|
Basic 9x9 Sudoku 4573
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 7 9 . . 2 . .
8 2 . 6 . 5 . 9 .
. . . . . . . 6 8
. . . 2 . 9 8 5 .
9 . . 5 7 . . . 6
. . 5 . . . . . 7
. . 8 . . . . . .
1 . 2 . . . . . 9
4 . . . . 8 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
367981245824635791519427368746219853981573426235846917658792134172354689493168572 #1 Extreme (17854) bf
Hidden Single: r5c4=5
Hidden Single: r2c7=7
Hidden Single: r6c7=9
Hidden Single: r5c8=2
Hidden Single: r6c1=2
Hidden Single: r1c5=8
Hidden Single: r8c8=8
Hidden Single: r1c9=5
Hidden Single: r5c2=8
Hidden Single: r6c4=8
Grouped Discontinuous Nice Loop: 1 r7c6 -1- r79c4 =1= r3c4 =7= r3c6 =2= r7c6 => r7c6<>1
Grouped Discontinuous Nice Loop: 3 r7c6 -3- r789c4 =3= r3c4 =7= r3c6 =2= r7c6 => r7c6<>3
Grouped Discontinuous Nice Loop: 4 r7c6 -4- r78c4 =4= r3c4 =7= r3c6 =2= r7c6 => r7c6<>4
Forcing Chain Contradiction in r7 => r7c5<>3
r7c5=3 r789c4<>3 r3c4=3 r3c1<>3 r3c1=5 r7c1<>5
r7c5=3 r7c5<>9 r7c2=9 r7c2<>5
r7c5=3 r7c5<>5
Brute Force: r6c2=3
Locked Candidates Type 1 (Pointing): 6 in b4 => r4c5<>6
Discontinuous Nice Loop: 6 r4c1 -6- r4c3 =6= r9c3 =3= r7c1 =7= r4c1 => r4c1<>6
Naked Single: r4c1=7
Finned Franken Swordfish: 3 r24b7 c359 fr7c1 => r7c9<>3
Forcing Chain Verity => r9c9<>3
r1c6=3 r1c8<>3 r79c8=3 r9c9<>3
r3c6=3 r3c6<>2 r3c5=2 r9c5<>2 r9c9=2 r9c9<>3
r5c6=3 r5c7<>3 r4c9=3 r9c9<>3
r8c6=3 r789c4<>3 r3c4=3 r3c4<>7 r3c6=7 r3c6<>2 r3c5=2 r9c5<>2 r9c9=2 r9c9<>3
Forcing Net Verity => r4c3=6
r4c3=1 (r4c5<>1) (r2c3<>1) r5c3<>1 r5c3=4 (r4c2<>4) r2c3<>4 r2c3=3 r2c9<>3 r4c9=3 (r5c7<>3 r5c6=3 r1c6<>3) (r5c7<>3 r5c7=1 r3c7<>1) r4c5<>3 r4c5=4 (r2c5<>4) r4c3<>4 r5c3=4 (r4c2<>4) r2c3<>4 r2c9=4 r3c7<>4 r3c7=3 r1c8<>3 r1c1=3 r1c1<>6 r1c2=6 r4c2<>6 r4c3=6
r4c3=4 (r4c3<>1) (r2c3<>4) r5c3<>4 r5c3=1 (r2c3<>1) (r4c2<>1) (r5c7<>1) r2c3<>1 r2c3=3 r2c9<>3 r4c9=3 r5c7<>3 r5c7=4 (r3c7<>4) r6c8<>4 r6c8=1 r4c9<>1 r4c5=1 r2c5<>1 r2c9=1 (r2c9<>4 r7c9=4 r7c8<>4 r1c8=4 r1c8<>3) r3c7<>1 r3c7=3 r5c7<>3 r5c6=3 r1c6<>3 r1c1=3 r1c1<>6 r1c2=6 r4c2<>6 r4c3=6
r4c3=6 r4c3=6
Finned Franken Swordfish: 1 r16b4 c268 fr5c3 fr6c5 => r5c6<>1
W-Wing: 4/1 in r4c2,r6c8 connected by 1 in r5c37 => r4c9<>4
Sashimi Swordfish: 4 r146 c268 fr4c5 fr6c5 => r5c6<>4
Naked Single: r5c6=3
Hidden Single: r4c9=3
Turbot Fish: 3 r1c8 =3= r1c1 -3- r7c1 =3= r9c3 => r9c8<>3
Finned X-Wing: 3 r29 c35 fr9c4 => r8c5<>3
Grouped Discontinuous Nice Loop: 4 r7c5 -4- r4c5 =4= r4c2 -4- r5c3 =4= r5c7 -4- r8c7 =4= r7c789 -4- r7c5 => r7c5<>4
Forcing Chain Contradiction in c2 => r8c5=5
r8c5<>5 r7c5=5 r7c5<>9 r7c2=9 r7c2<>7
r8c5<>5 r8c2=5 r8c2<>7
r8c5<>5 r7c5=5 r7c5<>9 r9c5=9 r9c5<>6 r9c2=6 r9c2<>7
Forcing Chain Contradiction in r2 => r9c8=7
r9c8<>7 r9c8=1 r6c8<>1 r6c8=4 r5c7<>4 r5c3=4 r2c3<>4
r9c8<>7 r9c8=1 r6c8<>1 r6c8=4 r6c6<>4 r46c5=4 r2c5<>4
r9c8<>7 r9c8=1 r79c9<>1 r2c9=1 r2c9<>4
Hidden Rectangle: 6/9 in r7c25,r9c25 => r7c5<>6
Discontinuous Nice Loop: 1 r7c5 -1- r9c4 -3- r9c3 -9- r9c5 =9= r7c5 => r7c5<>1
Almost Locked Set XY-Wing: A=r9c3459 {12369}, B=r168c6 {1467}, C=r1489c2 {14679}, X,Y=7,9, Z=6 => r7c6<>6
Forcing Chain Contradiction in r8 => r1c8<>1
r1c8=1 r1c8<>3 r7c8=3 r8c7<>3 r8c4=3 r8c4<>4
r1c8=1 r1c6<>1 r1c6=4 r8c6<>4
r1c8=1 r1c8<>3 r1c1=3 r1c1<>6 r7c1=6 r7c7<>6 r8c7=6 r8c7<>4
Skyscraper: 1 in r1c6,r4c5 (connected by r14c2) => r23c5,r6c6<>1
Locked Candidates Type 1 (Pointing): 1 in b5 => r9c5<>1
Locked Candidates Type 1 (Pointing): 1 in b8 => r3c4<>1
Skyscraper: 1 in r2c9,r5c7 (connected by r25c3) => r3c7<>1
Hidden Single: r2c9=1
Naked Single: r9c9=2
Full House: r7c9=4
Hidden Single: r9c4=1
X-Wing: 3 r29 c35 => r3c35<>3
Skyscraper: 4 in r2c3,r4c2 (connected by r24c5) => r13c2,r5c3<>4
Naked Single: r5c3=1
Full House: r4c2=4
Full House: r5c7=4
Full House: r4c5=1
Full House: r6c8=1
Naked Single: r3c7=3
Full House: r1c8=4
Full House: r7c8=3
Naked Single: r3c1=5
Naked Single: r8c7=6
Full House: r7c7=1
Naked Single: r1c6=1
Naked Single: r7c4=7
Naked Single: r7c1=6
Full House: r1c1=3
Full House: r1c2=6
Naked Single: r8c2=7
Naked Single: r3c4=4
Full House: r8c4=3
Full House: r8c6=4
Naked Single: r7c6=2
Naked Single: r9c2=9
Naked Single: r2c3=4
Full House: r2c5=3
Naked Single: r3c3=9
Full House: r3c2=1
Full House: r7c2=5
Full House: r7c5=9
Full House: r9c3=3
Full House: r9c5=6
Naked Single: r3c5=2
Full House: r3c6=7
Full House: r6c6=6
Full House: r6c5=4
|
normal_sudoku_2000
|
.3.6...85.5..2..172.8.4.6..9..27...1.7....3..5.68..9..7....4.69...7...4.....8....
|
437691285659328417218547693943276851871459326526813974782134569395762148164985732
|
Basic 9x9 Sudoku 2000
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . 6 . . . 8 5
. 5 . . 2 . . 1 7
2 . 8 . 4 . 6 . .
9 . . 2 7 . . . 1
. 7 . . . . 3 . .
5 . 6 8 . . 9 . .
7 . . . . 4 . 6 9
. . . 7 . . . 4 .
. . . . 8 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
437691285659328417218547693943276851871459326526813974782134569395762148164985732 #1 Easy (212)
Naked Single: r3c7=6
Naked Single: r4c8=5
Naked Single: r2c7=4
Naked Single: r3c9=3
Naked Single: r5c8=2
Naked Single: r1c7=2
Full House: r3c8=9
Naked Single: r2c1=6
Naked Single: r2c3=9
Naked Single: r4c7=8
Naked Single: r9c9=2
Naked Single: r6c8=7
Full House: r9c8=3
Naked Single: r6c9=4
Full House: r5c9=6
Full House: r8c9=8
Naked Single: r3c2=1
Naked Single: r2c4=3
Full House: r2c6=8
Naked Single: r4c2=4
Naked Single: r1c1=4
Full House: r1c3=7
Naked Single: r3c4=5
Full House: r3c6=7
Naked Single: r6c2=2
Naked Single: r4c3=3
Full House: r4c6=6
Naked Single: r5c3=1
Full House: r5c1=8
Naked Single: r9c1=1
Full House: r8c1=3
Naked Single: r7c4=1
Naked Single: r7c2=8
Naked Single: r9c4=9
Full House: r5c4=4
Naked Single: r7c7=5
Naked Single: r9c2=6
Full House: r8c2=9
Naked Single: r9c6=5
Naked Single: r7c3=2
Full House: r7c5=3
Naked Single: r8c7=1
Full House: r9c7=7
Full House: r9c3=4
Full House: r8c3=5
Naked Single: r5c6=9
Full House: r5c5=5
Naked Single: r8c5=6
Full House: r8c6=2
Naked Single: r6c5=1
Full House: r1c5=9
Full House: r1c6=1
Full House: r6c6=3
|
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