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_621
|
...3.....1....7..3.3..6.9.7..869.......12..4..2...36.9..........9.2..7.62.5.....1
|
752319864169847523834562917348695172976128345521473689617954238493281756285736491
|
Basic 9x9 Sudoku 621
|
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 . . . . 7 . . 3
. 3 . . 6 . 9 . 7
. . 8 6 9 . . . .
. . . 1 2 . . 4 .
. 2 . . . 3 6 . 9
. . . . . . . . .
. 9 . 2 . . 7 . 6
2 . 5 . . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
752319864169847523834562917348695172976128345521473689617954238493281756285736491 #1 Extreme (15074) bf
Brute Force: r5c4=1
Locked Candidates Type 1 (Pointing): 7 in b5 => r6c138<>7
Hidden Single: r4c8=7
Locked Candidates Type 1 (Pointing): 3 in b6 => r79c7<>3
Naked Pair: 5,8 in r5c69 => r5c127<>5, r5c7<>8
Naked Single: r5c7=3
Hidden Single: r4c1=3
Naked Triple: 4,5,8 in r368c1 => r17c1<>4, r1c1<>5, r17c1<>8
Empty Rectangle: 5 in b5 (r36c1) => r3c6<>5
Finned Swordfish: 1 r368 c368 fr8c5 => r7c6<>1
Discontinuous Nice Loop: 2 r1c9 -2- r1c6 =2= r3c6 =1= r3c8 -1- r6c8 =1= r4c7 =2= r4c9 -2- r1c9 => r1c9<>2
Forcing Chain Contradiction in c4 => r3c8<>5
r3c8=5 r3c8<>1 r3c6=1 r3c6<>2 r1c6=2 r1c6<>9 r2c4=9 r2c4<>5
r3c8=5 r3c4<>5
r3c8=5 r3c1<>5 r6c1=5 r6c4<>5
r3c8=5 r8c8<>5 r7c789=5 r7c4<>5
Forcing Chain Contradiction in r8c6 => r3c8<>8
r3c8=8 r3c8<>1 r3c6=1 r8c6<>1
r3c8=8 r6c8<>8 r5c9=8 r5c9<>5 r5c6=5 r4c6<>5 r4c6=4 r8c6<>4
r3c8=8 r6c8<>8 r5c9=8 r5c9<>5 r5c6=5 r8c6<>5
r3c8=8 r3c1<>8 r8c1=8 r8c6<>8
XY-Wing: 2/4/1 in r3c38,r6c3 => r6c8<>1
Hidden Single: r6c3=1
Hidden Single: r4c7=1
Hidden Single: r7c2=1
Hidden Single: r4c9=2
XY-Wing: 4/5/8 in r6c18,r8c1 => r8c8<>8
XY-Chain: 8 8- r5c6 -5- r5c9 -8- r6c8 -5- r6c1 -4- r8c1 -8 => r8c6<>8
Sashimi X-Wing: 8 r38 c15 fr3c4 fr3c6 => r12c5<>8
W-Wing: 4/5 in r2c5,r6c1 connected by 5 in r3c14 => r6c5<>4
AIC: 4 4- r2c5 -5- r3c4 =5= r3c1 -5- r6c1 -4- r6c4 =4= r4c6 -4 => r13c6<>4
Finned Swordfish: 4 r368 c134 fr8c5 fr8c6 => r79c4<>4
Discontinuous Nice Loop: 8 r1c6 -8- r5c6 -5- r5c9 =5= r6c8 -5- r8c8 -3- r8c3 -4- r3c3 -2- r3c6 =2= r1c6 => r1c6<>8
Grouped AIC: 5 5- r3c4 =5= r3c1 -5- r6c1 -4- r6c4 =4= r23c4 -4- r2c5 -5 => r1c56,r2c4<>5
Turbot Fish: 5 r2c5 =5= r3c4 -5- r3c1 =5= r6c1 => r6c5<>5
Sashimi Swordfish: 5 r368 c148 fr8c5 fr8c6 => r7c4<>5
X-Wing: 5 c14 r36 => r6c8<>5
Naked Single: r6c8=8
Full House: r5c9=5
Naked Single: r6c5=7
Naked Single: r5c6=8
Locked Candidates Type 1 (Pointing): 8 in b2 => r79c4<>8
Locked Pair: 7,9 in r79c4 => r2c4,r79c6<>9
Hidden Single: r2c3=9
Hidden Single: r1c6=9
Hidden Single: r5c1=9
Hidden Single: r3c6=2
Naked Single: r3c3=4
Naked Single: r3c8=1
Naked Single: r8c3=3
Naked Single: r8c8=5
Hidden Single: r1c3=2
Naked Single: r1c8=6
Naked Single: r1c1=7
Naked Single: r2c8=2
Naked Single: r7c1=6
Naked Single: r7c3=7
Full House: r5c3=6
Full House: r5c2=7
Naked Single: r7c4=9
Naked Single: r7c8=3
Full House: r9c8=9
Naked Single: r9c4=7
Hidden Single: r8c6=1
Hidden Single: r1c5=1
Hidden Single: r2c2=6
Hidden Single: r7c7=2
Hidden Single: r9c6=6
Hidden Single: r9c5=3
Locked Candidates Type 1 (Pointing): 4 in b2 => r2c7<>4
Swordfish: 4 r268 c145 => r7c5<>4
Remote Pair: 8/4 r1c9 -4- r7c9 -8- r9c7 -4- r9c2 => r1c2<>8
Naked Single: r1c2=5
Full House: r3c1=8
Full House: r3c4=5
Naked Single: r4c2=4
Full House: r4c6=5
Full House: r6c4=4
Full House: r6c1=5
Full House: r8c1=4
Full House: r9c2=8
Full House: r7c6=4
Full House: r2c4=8
Full House: r2c5=4
Full House: r8c5=8
Full House: r9c7=4
Full House: r7c9=8
Full House: r2c7=5
Full House: r7c5=5
Full House: r1c7=8
Full House: r1c9=4
|
normal_sudoku_1646
|
..92..4.6....1.2..62............4.8.7..58.629..6.....4..5.3....86.7..9.59.7..5...
|
379258416458316297621497853293674581714583629586129374145932768862741935937865142
|
Basic 9x9 Sudoku 1646
|
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 . . 4 . 6
. . . . 1 . 2 . .
6 2 . . . . . . .
. . . . . 4 . 8 .
7 . . 5 8 . 6 2 9
. . 6 . . . . . 4
. . 5 . 3 . . . .
8 6 . 7 . . 9 . 5
9 . 7 . . 5 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
379258416458316297621497853293674581714583629586129374145932768862741935937865142 #1 Unfair (946)
Naked Single: r5c5=8
Hidden Single: r6c2=8
Hidden Single: r1c6=8
Hidden Single: r4c2=9
Locked Candidates Type 1 (Pointing): 5 in b4 => r12c1<>5
Naked Triple: 1,3,4 in r579c2 => r1c2<>1, r12c2<>3, r2c2<>4
Naked Pair: 5,7 in r1c25 => r1c8<>5, r1c8<>7
Skyscraper: 3 in r1c1,r8c3 (connected by r18c8) => r23c3<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r46c1<>3
AIC: 1 1- r1c8 -3- r8c8 =3= r8c3 =2= r7c1 =4= r2c1 =3= r1c1 =1= r3c3 -1 => r1c1,r3c789<>1
Naked Single: r1c1=3
Naked Single: r1c8=1
Naked Single: r2c1=4
Naked Single: r2c3=8
Naked Single: r3c3=1
Hidden Single: r8c6=1
Naked Single: r5c6=3
Naked Single: r5c3=4
Full House: r5c2=1
Naked Single: r7c2=4
Naked Single: r9c2=3
Naked Single: r8c3=2
Full House: r4c3=3
Full House: r7c1=1
Naked Single: r8c5=4
Full House: r8c8=3
Hidden Single: r3c4=4
Hidden Single: r9c8=4
Hidden Single: r6c7=3
Hidden Single: r2c4=3
Naked Single: r2c9=7
Naked Single: r2c2=5
Full House: r1c2=7
Full House: r1c5=5
Naked Single: r4c9=1
Naked Single: r2c8=9
Full House: r2c6=6
Naked Single: r4c4=6
Naked Single: r3c8=5
Naked Single: r9c4=8
Naked Single: r3c7=8
Full House: r3c9=3
Naked Single: r6c8=7
Full House: r4c7=5
Full House: r7c8=6
Naked Single: r7c4=9
Full House: r6c4=1
Naked Single: r9c7=1
Full House: r7c7=7
Naked Single: r9c9=2
Full House: r7c9=8
Full House: r7c6=2
Full House: r9c5=6
Naked Single: r4c1=2
Full House: r4c5=7
Full House: r6c1=5
Naked Single: r6c6=9
Full House: r3c6=7
Full House: r3c5=9
Full House: r6c5=2
|
normal_sudoku_3659
|
..314..6.1.....8.46...581374.....5......2..4.....7...186.51.4.....7....8.45..36..
|
983147265157236894624958137471389526538621749296475381869512473312764958745893612
|
Basic 9x9 Sudoku 3659
|
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 1 4 . . 6 .
1 . . . . . 8 . 4
6 . . . 5 8 1 3 7
4 . . . . . 5 . .
. . . . 2 . . 4 .
. . . . 7 . . . 1
8 6 . 5 1 . 4 . .
. . . 7 . . . . 8
. 4 5 . . 3 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
983147265157236894624958137471389526538621749296475381869512473312764958745893612 #1 Hard (608)
Hidden Single: r3c7=1
Hidden Single: r1c2=8
Hidden Single: r3c3=4
Hidden Single: r8c6=4
Hidden Single: r6c4=4
Hidden Single: r8c8=5
Hidden Single: r1c9=5
Hidden Single: r7c9=3
Hidden Single: r9c8=1
Hidden Single: r5c7=7
Hidden Single: r8c5=6
Hidden Single: r2c2=5
Hidden Single: r9c1=7
Hidden Single: r7c8=7
Hidden Single: r6c7=3
Hidden Single: r4c2=7
Hidden Single: r1c6=7
Hidden Single: r2c3=7
Locked Candidates Type 1 (Pointing): 3 in b4 => r5c4<>3
Naked Pair: 2,9 in r36c2 => r58c2<>9, r8c2<>2
Remote Pair: 2/9 r3c4 -9- r3c2 -2- r1c1 -9- r1c7 -2- r8c7 -9- r9c9 => r9c4<>2, r9c4<>9
Naked Single: r9c4=8
Naked Single: r9c5=9
Full House: r7c6=2
Full House: r9c9=2
Full House: r7c3=9
Full House: r8c7=9
Full House: r1c7=2
Full House: r1c1=9
Full House: r2c8=9
Full House: r3c2=2
Full House: r3c4=9
Naked Single: r2c5=3
Full House: r4c5=8
Naked Single: r2c6=6
Full House: r2c4=2
Naked Single: r6c2=9
Naked Single: r5c4=6
Full House: r4c4=3
Naked Single: r4c8=2
Full House: r6c8=8
Naked Single: r6c6=5
Naked Single: r5c9=9
Full House: r4c9=6
Naked Single: r6c1=2
Full House: r6c3=6
Naked Single: r5c6=1
Full House: r4c6=9
Full House: r4c3=1
Naked Single: r8c1=3
Full House: r5c1=5
Naked Single: r5c2=3
Full House: r5c3=8
Full House: r8c3=2
Full House: r8c2=1
|
normal_sudoku_5951
|
941..6..3.7.5..1...8.3....61.2...4....71....5.59..43...1.7.32.4....8..3..2.4..5..
|
941826753673549128285317946132958467467132895859674312516793284794285631328461579
|
Basic 9x9 Sudoku 5951
|
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 4 1 . . 6 . . 3
. 7 . 5 . . 1 . .
. 8 . 3 . . . . 6
1 . 2 . . . 4 . .
. . 7 1 . . . . 5
. 5 9 . . 4 3 . .
. 1 . 7 . 3 2 . 4
. . . . 8 . . 3 .
. 2 . 4 . . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
941826753673549128285317946132958467467132895859674312516793284794285631328461579 #1 Easy (274)
Naked Single: r1c2=4
Naked Single: r3c3=5
Naked Single: r3c1=2
Hidden Single: r8c2=9
Hidden Single: r1c8=5
Hidden Single: r8c3=4
Hidden Single: r5c1=4
Hidden Single: r4c4=9
Hidden Single: r6c1=8
Hidden Single: r1c4=8
Naked Single: r1c7=7
Full House: r1c5=2
Naked Single: r3c7=9
Naked Single: r8c7=6
Full House: r5c7=8
Naked Single: r2c6=9
Naked Single: r3c8=4
Naked Single: r8c4=2
Full House: r6c4=6
Naked Single: r4c9=7
Naked Single: r5c6=2
Naked Single: r2c5=4
Naked Single: r9c6=1
Naked Single: r5c5=3
Naked Single: r6c5=7
Naked Single: r4c8=6
Naked Single: r8c9=1
Naked Single: r3c6=7
Full House: r3c5=1
Naked Single: r8c6=5
Full House: r4c6=8
Full House: r4c5=5
Full House: r4c2=3
Full House: r5c2=6
Full House: r5c8=9
Full House: r8c1=7
Naked Single: r6c9=2
Full House: r6c8=1
Naked Single: r7c8=8
Naked Single: r2c9=8
Full House: r2c8=2
Full House: r9c8=7
Full House: r9c9=9
Naked Single: r7c3=6
Naked Single: r9c5=6
Full House: r7c5=9
Full House: r7c1=5
Naked Single: r2c3=3
Full House: r2c1=6
Full House: r9c1=3
Full House: r9c3=8
|
normal_sudoku_3509
|
...14.5.9..19.3..8..98..6..7.........2.3.7.9...351.2.79...3......87....4.6.....5.
|
382146579671953428549872631715629843426387195893514267954231786238765914167498352
|
Basic 9x9 Sudoku 3509
|
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 . 5 . 9
. . 1 9 . 3 . . 8
. . 9 8 . . 6 . .
7 . . . . . . . .
. 2 . 3 . 7 . 9 .
. . 3 5 1 . 2 . 7
9 . . . 3 . . . .
. . 8 7 . . . . 4
. 6 . . . . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
382146579671953428549872631715629843426387195893514267954231786238765914167498352 #1 Extreme (5132)
Hidden Single: r1c9=9
Empty Rectangle: 6 in b9 (r47c4) => r4c8<>6
Forcing Chain Contradiction in r6 => r5c5=8
r5c5<>8 r5c5=6 r2c5<>6 r2c1=6 r6c1<>6
r5c5<>8 r5c5=6 r6c6<>6
r5c5<>8 r5c5=6 r4c4<>6 r7c4=6 r7c9<>6 r78c8=6 r6c8<>6
Forcing Chain Contradiction in r8 => r2c1<>4
r2c1=4 r2c1<>6 r2c5=6 r1c6<>6 r1c6=2 r1c3<>2 r123c1=2 r8c1<>2
r2c1=4 r2c1<>6 r2c5=6 r1c6<>6 r1c6=2 r3c6<>2 r3c6=5 r23c5<>5 r8c5=5 r8c5<>2
r2c1=4 r2c1<>6 r2c5=6 r1c6<>6 r1c6=2 r8c6<>2
r2c1=4 r2c78<>4 r3c8=4 r3c8<>1 r3c9=1 r3c9<>2 r123c8=2 r8c8<>2
Forcing Chain Contradiction in r8 => r4c3<>6
r4c3=6 r4c456<>6 r6c6=6 r1c6<>6 r1c6=2 r1c3<>2 r123c1=2 r8c1<>2
r4c3=6 r4c456<>6 r6c6=6 r1c6<>6 r1c6=2 r3c6<>2 r3c6=5 r23c5<>5 r8c5=5 r8c5<>2
r4c3=6 r4c456<>6 r6c6=6 r1c6<>6 r1c6=2 r8c6<>2
r4c3=6 r4c4<>6 r7c4=6 r7c89<>6 r8c8=6 r8c8<>2
Forcing Chain Contradiction in c1 => r3c5<>2
r3c5=2 r3c5<>7 r2c5=7 r2c5<>6 r2c1=6 r2c1<>5
r3c5=2 r3c6<>2 r3c6=5 r3c1<>5
r3c5=2 r3c5<>7 r2c5=7 r2c7<>7 r2c7=4 r5c7<>4 r5c13=4 r4c3<>4 r4c3=5 r5c1<>5
r3c5=2 r3c6<>2 r3c6=5 r7c6<>5 r7c23=5 r8c1<>5
Forcing Chain Contradiction in r6 => r4c5<>6
r4c5=6 r2c5<>6 r2c1=6 r6c1<>6
r4c5=6 r6c6<>6
r4c5=6 r4c4<>6 r7c4=6 r7c9<>6 r78c8=6 r6c8<>6
Naked Pair: 2,9 in r49c5 => r28c5<>2, r8c5<>9
Locked Candidates Type 1 (Pointing): 2 in b2 => r4789c6<>2
X-Wing: 2 r28 c18 => r1c18,r3c18,r7c8,r9c1<>2
Sue de Coq: r1c123 - {23678} (r1c6 - {26}, r23c2,r3c1 - {3457}) => r2c1<>5
Discontinuous Nice Loop: 5 r8c1 -5- r8c5 -6- r2c5 =6= r2c1 =2= r8c1 => r8c1<>5
AIC: 5/6 5- r5c1 =5= r3c1 -5- r3c6 -2- r1c6 -6- r1c3 =6= r5c3 -6 => r5c3<>5, r5c1<>6
XYZ-Wing: 1/4/5 in r4c3,r5c17 => r5c3<>4
Naked Single: r5c3=6
X-Wing: 6 c49 r47 => r47c6,r7c8<>6
Hidden Rectangle: 4/9 in r4c26,r6c26 => r6c2<>4
AIC: 2 2- r1c3 -7- r9c3 =7= r9c7 -7- r2c7 -4- r5c7 =4= r5c1 =5= r3c1 -5- r3c6 -2- r3c9 =2= r2c8 -2- r2c1 =2= r8c1 -2 => r2c1,r79c3<>2
Naked Single: r2c1=6
Hidden Single: r2c8=2
Hidden Single: r8c1=2
Hidden Single: r1c3=2
Naked Single: r1c6=6
Hidden Single: r8c5=6
Hidden Single: r3c6=2
Hidden Single: r6c8=6
Hidden Single: r4c4=6
Hidden Single: r7c9=6
Hidden Single: r4c5=2
Naked Single: r9c5=9
Hidden Single: r7c4=2
Full House: r9c4=4
Naked Single: r9c3=7
Hidden Single: r9c9=2
Hidden Single: r8c7=9
Locked Candidates Type 1 (Pointing): 8 in b6 => r4c2<>8
Skyscraper: 4 in r2c2,r5c1 (connected by r25c7) => r3c1,r4c2<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r7c2<>4
Hidden Single: r7c3=4
Full House: r4c3=5
Hidden Single: r5c9=5
Hidden Single: r3c1=5
Naked Single: r3c5=7
Full House: r2c5=5
2-String Kite: 3 in r1c1,r8c8 (connected by r8c2,r9c1) => r1c8<>3
Naked Single: r1c8=7
Naked Single: r2c7=4
Full House: r2c2=7
Naked Single: r5c7=1
Full House: r5c1=4
Naked Single: r4c9=3
Full House: r3c9=1
Full House: r3c8=3
Full House: r3c2=4
Naked Single: r6c1=8
Naked Single: r4c7=8
Full House: r4c8=4
Naked Single: r8c8=1
Full House: r7c8=8
Naked Single: r1c1=3
Full House: r1c2=8
Full House: r9c1=1
Naked Single: r6c2=9
Full House: r4c2=1
Full House: r4c6=9
Full House: r6c6=4
Naked Single: r7c7=7
Full House: r9c7=3
Full House: r9c6=8
Naked Single: r8c6=5
Full House: r7c6=1
Full House: r7c2=5
Full House: r8c2=3
|
normal_sudoku_3465
|
.....93....958..27..7.2..8..9....8..4.....5...58.6..7...16..492..5.1.7.....8.2.1.
|
812749356349586127567321984296157843473298561158463279781635492625914738934872615
|
Basic 9x9 Sudoku 3465
|
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 . .
. . 9 5 8 . . 2 7
. . 7 . 2 . . 8 .
. 9 . . . . 8 . .
4 . . . . . 5 . .
. 5 8 . 6 . . 7 .
. . 1 6 . . 4 9 2
. . 5 . 1 . 7 . .
. . . 8 . 2 . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
812749356349586127567321984296157843473298561158463279781635492625914738934872615 #1 Easy (252)
Naked Single: r7c7=4
Naked Single: r9c7=6
Naked Single: r2c7=1
Naked Single: r8c8=3
Naked Single: r3c7=9
Full House: r6c7=2
Naked Single: r5c8=6
Naked Single: r8c6=4
Naked Single: r8c9=8
Full House: r9c9=5
Naked Single: r4c8=4
Full House: r1c8=5
Naked Single: r8c4=9
Hidden Single: r5c6=8
Hidden Single: r2c2=4
Hidden Single: r3c1=5
Hidden Single: r1c5=4
Naked Single: r1c9=6
Full House: r3c9=4
Naked Single: r1c3=2
Naked Single: r5c3=3
Naked Single: r4c3=6
Full House: r9c3=4
Naked Single: r6c1=1
Naked Single: r1c1=8
Naked Single: r6c6=3
Naked Single: r1c2=1
Full House: r1c4=7
Naked Single: r2c6=6
Full House: r2c1=3
Full House: r3c2=6
Naked Single: r6c4=4
Full House: r6c9=9
Naked Single: r3c6=1
Full House: r3c4=3
Naked Single: r7c1=7
Naked Single: r8c2=2
Full House: r8c1=6
Naked Single: r5c9=1
Full House: r4c9=3
Naked Single: r4c1=2
Full House: r9c1=9
Full House: r5c2=7
Naked Single: r7c6=5
Full House: r4c6=7
Naked Single: r9c2=3
Full House: r7c2=8
Full House: r7c5=3
Full House: r9c5=7
Naked Single: r5c4=2
Full House: r4c4=1
Full House: r5c5=9
Full House: r4c5=5
|
normal_sudoku_5497
|
.465........7.369.5...8..1.1...9..28.53...9.7...4..1...8..5.2.99.2...4.1..5.3..8.
|
346519872821743695579286314164397528253861947798425163687154239932678451415932786
|
Basic 9x9 Sudoku 5497
|
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 . 3 6 9 .
5 . . . 8 . . 1 .
1 . . . 9 . . 2 8
. 5 3 . . . 9 . 7
. . . 4 . . 1 . .
. 8 . . 5 . 2 . 9
9 . 2 . . . 4 . 1
. . 5 . 3 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
346519872821743695579286314164397528253861947798425163687154239932678451415932786 #1 Easy (204)
Naked Single: r5c7=9
Naked Single: r9c9=6
Naked Single: r9c7=7
Naked Single: r3c7=3
Naked Single: r7c8=3
Full House: r8c8=5
Naked Single: r9c1=4
Naked Single: r9c2=1
Naked Single: r1c7=8
Full House: r4c7=5
Naked Single: r1c8=7
Naked Single: r1c9=2
Naked Single: r6c8=6
Full House: r5c8=4
Full House: r6c9=3
Naked Single: r2c2=2
Naked Single: r7c3=7
Naked Single: r1c1=3
Naked Single: r1c5=1
Full House: r1c6=9
Naked Single: r3c9=4
Full House: r2c9=5
Naked Single: r2c1=8
Naked Single: r3c3=9
Naked Single: r4c3=4
Naked Single: r7c1=6
Full House: r8c2=3
Naked Single: r2c5=4
Full House: r2c3=1
Full House: r3c2=7
Full House: r6c3=8
Naked Single: r9c6=2
Full House: r9c4=9
Naked Single: r5c1=2
Full House: r6c1=7
Naked Single: r7c4=1
Full House: r7c6=4
Naked Single: r4c2=6
Full House: r6c2=9
Naked Single: r3c6=6
Full House: r3c4=2
Naked Single: r5c5=6
Naked Single: r6c5=2
Full House: r6c6=5
Full House: r8c5=7
Naked Single: r4c4=3
Full House: r4c6=7
Naked Single: r5c4=8
Full House: r5c6=1
Full House: r8c6=8
Full House: r8c4=6
|
normal_sudoku_5943
|
.6...7...1..5.34....3.12..89...3..1...42....5.7..5.3...8.3.69..5...2.7.3..91...8.
|
465987132128563497793412568952738614634291875871654329287346951516829743349175286
|
Basic 9x9 Sudoku 5943
|
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 . . . 7 . . .
1 . . 5 . 3 4 . .
. . 3 . 1 2 . . 8
9 . . . 3 . . 1 .
. . 4 2 . . . . 5
. 7 . . 5 . 3 . .
. 8 . 3 . 6 9 . .
5 . . . 2 . 7 . 3
. . 9 1 . . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
465987132128563497793412568952738614634291875871654329287346951516829743349175286 #1 Easy (368)
Hidden Single: r2c6=3
Hidden Single: r7c8=5
Hidden Single: r9c6=5
Hidden Single: r1c8=3
Hidden Single: r1c7=1
Hidden Single: r7c9=1
Hidden Single: r4c4=7
Hidden Single: r1c3=5
Hidden Single: r3c7=5
Hidden Single: r2c9=7
Hidden Single: r5c8=7
Hidden Single: r4c2=5
Hidden Single: r7c3=7
Naked Single: r7c5=4
Full House: r7c1=2
Naked Single: r9c5=7
Hidden Single: r3c1=7
Hidden Single: r1c9=2
Hidden Single: r2c2=2
Naked Single: r2c3=8
Naked Single: r1c1=4
Full House: r3c2=9
Naked Single: r3c8=6
Full House: r2c8=9
Full House: r3c4=4
Full House: r2c5=6
Naked Single: r8c8=4
Full House: r6c8=2
Naked Single: r8c2=1
Naked Single: r9c9=6
Full House: r9c7=2
Naked Single: r5c2=3
Full House: r9c2=4
Full House: r9c1=3
Full House: r8c3=6
Naked Single: r4c9=4
Full House: r6c9=9
Naked Single: r4c3=2
Full House: r6c3=1
Naked Single: r4c6=8
Full House: r4c7=6
Full House: r5c7=8
Naked Single: r5c5=9
Full House: r1c5=8
Full House: r1c4=9
Naked Single: r6c4=6
Full House: r8c4=8
Full House: r8c6=9
Naked Single: r6c6=4
Full House: r5c6=1
Full House: r5c1=6
Full House: r6c1=8
|
normal_sudoku_2709
|
1.23.8...87..4.1....3...2.9..893.5.7.2...4.......1.6.8..5..6..1.6...345.....753..
|
192358764876249135453761289618932547527684913349517628935426871761893452284175396
|
Basic 9x9 Sudoku 2709
|
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 . 2 3 . 8 . . .
8 7 . . 4 . 1 . .
. . 3 . . . 2 . 9
. . 8 9 3 . 5 . 7
. 2 . . . 4 . . .
. . . . 1 . 6 . 8
. . 5 . . 6 . . 1
. 6 . . . 3 4 5 .
. . . . 7 5 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
192358764876249135453761289618932547527684913349517628935426871761893452284175396 #1 Easy (204)
Naked Single: r4c7=5
Naked Single: r8c9=2
Naked Single: r4c6=2
Naked Single: r1c7=7
Naked Single: r5c7=9
Full House: r7c7=8
Naked Single: r5c9=3
Naked Single: r9c9=6
Naked Single: r2c6=9
Naked Single: r6c6=7
Full House: r3c6=1
Naked Single: r5c8=1
Naked Single: r2c9=5
Full House: r1c9=4
Naked Single: r9c8=9
Full House: r7c8=7
Naked Single: r2c3=6
Naked Single: r6c4=5
Naked Single: r4c8=4
Full House: r6c8=2
Naked Single: r1c8=6
Naked Single: r2c4=2
Full House: r2c8=3
Full House: r3c8=8
Naked Single: r5c3=7
Naked Single: r4c1=6
Full House: r4c2=1
Naked Single: r1c5=5
Full House: r1c2=9
Naked Single: r7c4=4
Naked Single: r5c1=5
Naked Single: r3c5=6
Full House: r3c4=7
Naked Single: r7c2=3
Naked Single: r3c1=4
Full House: r3c2=5
Naked Single: r5c5=8
Full House: r5c4=6
Naked Single: r6c2=4
Full House: r9c2=8
Naked Single: r9c1=2
Naked Single: r8c5=9
Full House: r7c5=2
Full House: r7c1=9
Naked Single: r6c3=9
Full House: r6c1=3
Full House: r8c1=7
Naked Single: r9c4=1
Full House: r8c4=8
Full House: r8c3=1
Full House: r9c3=4
|
normal_sudoku_2385
|
8..........3..76..1.7..5..29......143.48..2...5.94.7.....1.4......7.9..3..9....41
|
846392175523417698197685432978526314364871259251943786685134927412759863739268541
|
Basic 9x9 Sudoku 2385
|
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 . . . . . . . .
. . 3 . . 7 6 . .
1 . 7 . . 5 . . 2
9 . . . . . . 1 4
3 . 4 8 . . 2 . .
. 5 . 9 4 . 7 . .
. . . 1 . 4 . . .
. . . 7 . 9 . . 3
. . 9 . . . . 4 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
846392175523417698197685432978526314364871259251943786685134927412759863739268541 #1 Medium (390)
Hidden Single: r7c6=4
Hidden Single: r2c5=1
Hidden Single: r1c7=1
Hidden Single: r9c6=8
Naked Single: r9c7=5
Naked Single: r8c7=8
Naked Single: r4c7=3
Naked Single: r7c7=9
Full House: r3c7=4
Hidden Single: r3c5=8
Hidden Single: r4c4=5
Hidden Single: r6c6=3
Hidden Single: r1c5=9
Hidden Single: r6c3=1
Hidden Single: r5c6=1
Hidden Single: r8c2=1
Hidden Single: r6c1=2
Hidden Single: r8c1=4
Naked Single: r2c1=5
Locked Pair: 8,9 in r2c89 => r2c2,r3c8<>9
Naked Single: r3c8=3
Naked Single: r3c4=6
Full House: r3c2=9
Naked Single: r1c6=2
Full House: r4c6=6
Naked Single: r1c3=6
Naked Single: r2c4=4
Full House: r1c4=3
Full House: r9c4=2
Naked Single: r4c3=8
Naked Single: r5c5=7
Full House: r4c5=2
Full House: r4c2=7
Full House: r5c2=6
Naked Single: r1c2=4
Full House: r2c2=2
Naked Single: r9c2=3
Full House: r7c2=8
Naked Single: r9c5=6
Full House: r9c1=7
Full House: r7c1=6
Naked Single: r8c5=5
Full House: r7c5=3
Naked Single: r7c9=7
Naked Single: r8c3=2
Full House: r7c3=5
Full House: r7c8=2
Full House: r8c8=6
Naked Single: r1c9=5
Full House: r1c8=7
Naked Single: r6c8=8
Full House: r6c9=6
Naked Single: r5c9=9
Full House: r2c9=8
Full House: r2c8=9
Full House: r5c8=5
|
normal_sudoku_2185
|
..73...2.5.4.6....1....5..82.9.34....4..27.9....9..2.48.....1........6....24...7.
|
987341526534862719126795438259134867648527391713986254895673142471259683362418975
|
Basic 9x9 Sudoku 2185
|
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 .
5 . 4 . 6 . . . .
1 . . . . 5 . . 8
2 . 9 . 3 4 . . .
. 4 . . 2 7 . 9 .
. . . 9 . . 2 . 4
8 . . . . . 1 . .
. . . . . . 6 . .
. . 2 4 . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
987341526534862719126795438259134867648527391713986254895673142471259683362418975 #1 Extreme (6670)
Hidden Single: r6c7=2
Hidden Single: r7c8=4
Hidden Single: r8c1=4
Hidden Single: r6c1=7
Locked Candidates Type 1 (Pointing): 8 in b1 => r46c2<>8
Naked Pair: 3,6 in r3c38 => r3c27<>3, r3c2<>6
Empty Rectangle: 3 in b6 (r3c38) => r5c3<>3
Empty Rectangle: 9 in b9 (r19c1) => r1c9<>9
Grouped AIC: 3 3- r3c3 =3= r3c8 -3- r6c8 =3= r5c79 -3- r5c1 =3= r9c1 -3 => r78c3<>3
Almost Locked Set XZ-Rule: A=r789c9 {2359}, B=r1c9,r23c8 {1356}, X=5, Z=3 => r2c9,r8c8<>3
Empty Rectangle: 3 in b9 (r59c1) => r5c9<>3
Locked Candidates Type 2 (Claiming): 3 in c9 => r9c7<>3
Almost Locked Set XZ-Rule: A=r78c3,r9c12 {13569}, B=r8c8,r9c79 {3589}, X=3,9 => r9c56<>9, r9c6<>3, r8c2<>1, r7c29,r8c29<>5, r7c2<>6
Forcing Chain Contradiction in r2c9 => r2c4<>7
r2c4=7 r3c4<>7 r3c4=2 r3c2<>2 r3c2=9 r1c1<>9 r1c1=6 r5c1<>6 r5c1=3 r5c7<>3 r2c7=3 r2c8<>3 r2c8=1 r2c9<>1
r2c4=7 r2c9<>7
r2c4=7 r3c4<>7 r3c4=2 r3c2<>2 r3c2=9 r1c1<>9 r9c1=9 r9c7<>9 r123c7=9 r2c9<>9
Locked Candidates Type 1 (Pointing): 7 in b2 => r3c7<>7
Hidden Rectangle: 4/9 in r1c57,r3c57 => r1c5<>9
Forcing Chain Contradiction in c9 => r2c9<>1
r2c9=1 r2c8<>1 r2c8=3 r3c8<>3 r3c8=6 r1c9<>6
r2c9=1 r2c9<>7 r4c9=7 r4c9<>6
r2c9=1 r2c9<>7 r2c7=7 r2c7<>3 r5c7=3 r5c1<>3 r5c1=6 r5c9<>6
Grouped Discontinuous Nice Loop: 5 r4c7 =7= r4c9 -7- r2c9 -9- r123c7 =9= r9c7 =8= r8c8 =5= r46c8 -5- r4c7 => r4c7<>5
Forcing Chain Contradiction in r5 => r8c4<>5
r8c4=5 r7c45<>5 r7c3=5 r5c3<>5
r8c4=5 r5c4<>5
r8c4=5 r8c8<>5 r46c8=5 r5c7<>5
r8c4=5 r8c8<>5 r46c8=5 r5c9<>5
Forcing Net Contradiction in r5 => r2c8=1
r2c8<>1 r2c8=3 (r3c8<>3 r3c8=6 r6c8<>6) (r3c8<>3 r3c8=6 r3c3<>6) r2c7<>3 r5c7=3 r5c1<>3 r5c1=6 (r6c3<>6) (r9c1<>6) (r5c3<>6) r6c3<>6 r7c3=6 r9c2<>6 r9c6=6 r6c6<>6 r6c2=6 r5c1<>6 r5c1=3
r2c8<>1 r2c8=3 r2c7<>3 r5c7=3
X-Wing: 3 c38 r36 => r6c2<>3
Finned Swordfish: 1 r169 c256 fr6c3 => r4c2<>1
Discontinuous Nice Loop: 5 r4c9 -5- r4c2 -6- r5c1 -3- r5c7 =3= r2c7 -3- r3c8 -6- r1c9 -5- r4c9 => r4c9<>5
Sashimi Swordfish: 5 c279 r159 fr4c2 fr6c2 => r5c3<>5
Forcing Chain Contradiction in r7c4 => r5c3<>1
r5c3=1 r5c3<>8 r6c3=8 r6c56<>8 r45c4=8 r2c4<>8 r2c4=2 r7c4<>2
r5c3=1 r8c3<>1 r8c3=5 r8c8<>5 r46c8=5 r5c79<>5 r5c4=5 r7c4<>5
r5c3=1 r8c3<>1 r8c3=5 r7c3<>5 r7c3=6 r7c4<>6
r5c3=1 r5c3<>8 r6c3=8 r6c56<>8 r45c4=8 r2c4<>8 r2c4=2 r3c4<>2 r3c4=7 r7c4<>7
Locked Candidates Type 1 (Pointing): 1 in b4 => r6c56<>1
Locked Candidates Type 1 (Pointing): 1 in b5 => r8c4<>1
Naked Triple: 2,7,8 in r238c4 => r45c4<>8, r7c4<>2, r7c4<>7
Locked Candidates Type 1 (Pointing): 8 in b5 => r6c38<>8
Hidden Single: r5c3=8
Naked Pair: 5,6 in r7c34 => r7c5<>5, r7c6<>6
2-String Kite: 6 in r6c6,r7c3 (connected by r7c4,r9c6) => r6c3<>6
Empty Rectangle: 5 in b5 (r7c34) => r6c3<>5
Locked Candidates Type 1 (Pointing): 5 in b4 => r9c2<>5
XY-Wing: 3/6/5 in r4c2,r5c17 => r4c8<>5
Finned Swordfish: 5 r159 c479 fr9c5 => r7c4<>5
Naked Single: r7c4=6
Naked Single: r7c3=5
Naked Single: r8c3=1
Naked Single: r6c3=3
Full House: r3c3=6
Naked Single: r5c1=6
Naked Single: r1c1=9
Full House: r9c1=3
Naked Single: r3c8=3
Naked Single: r4c2=5
Full House: r6c2=1
Naked Single: r1c2=8
Naked Single: r3c2=2
Full House: r2c2=3
Naked Single: r4c4=1
Naked Single: r1c6=1
Naked Single: r3c4=7
Naked Single: r5c4=5
Naked Single: r1c5=4
Naked Single: r9c6=8
Naked Single: r5c7=3
Full House: r5c9=1
Naked Single: r6c5=8
Full House: r6c6=6
Full House: r6c8=5
Naked Single: r1c7=5
Full House: r1c9=6
Naked Single: r3c5=9
Full House: r3c7=4
Naked Single: r8c4=2
Full House: r2c4=8
Full House: r2c6=2
Naked Single: r8c8=8
Full House: r4c8=6
Naked Single: r9c7=9
Naked Single: r4c9=7
Full House: r4c7=8
Full House: r2c7=7
Full House: r2c9=9
Naked Single: r7c5=7
Naked Single: r8c9=3
Naked Single: r9c2=6
Naked Single: r9c9=5
Full House: r7c9=2
Full House: r9c5=1
Full House: r8c5=5
Naked Single: r7c2=9
Full House: r7c6=3
Full House: r8c6=9
Full House: r8c2=7
|
normal_sudoku_89
|
..6.1...4..1.7629..7.9...1.7...54.3..5...9.....37.2....3.4...5.2.....8......97..1
|
986213574341576298572948613728654139654139782193782465837421956219365847465897321
|
Basic 9x9 Sudoku 89
|
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 . 1 . . . 4
. . 1 . 7 6 2 9 .
. 7 . 9 . . . 1 .
7 . . . 5 4 . 3 .
. 5 . . . 9 . . .
. . 3 7 . 2 . . .
. 3 . 4 . . . 5 .
2 . . . . . 8 . .
. . . . 9 7 . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
986213574341576298572948613728654139654139782193782465837421956219365847465897321 #1 Unfair (1626)
Hidden Single: r2c5=7
Hidden Single: r3c5=4
Hidden Single: r3c3=2
Hidden Single: r7c5=2
Hidden Single: r1c4=2
Hidden Single: r4c2=2
Hidden Single: r9c8=2
Hidden Single: r5c9=2
Locked Candidates Type 1 (Pointing): 5 in b1 => r9c1<>5
Locked Candidates Type 1 (Pointing): 1 in b5 => r8c4<>1
Locked Candidates Type 2 (Claiming): 8 in c5 => r45c4<>8
Locked Candidates Type 2 (Claiming): 7 in c9 => r7c7,r8c8<>7
Finned Swordfish: 6 c158 r568 fr7c1 fr9c1 => r8c2<>6
AIC: 6/8 6- r9c2 =6= r6c2 =1= r8c2 -1- r8c6 =1= r7c6 =8= r9c4 -8 => r9c4<>6, r9c2<>8
Locked Candidates Type 1 (Pointing): 6 in b8 => r8c89<>6
Naked Single: r8c8=4
Locked Candidates Type 2 (Claiming): 6 in c8 => r4c79,r56c7,r6c9<>6
Hidden Single: r4c4=6
Naked Single: r6c5=8
Naked Single: r5c5=3
Full House: r5c4=1
Full House: r8c5=6
Naked Single: r6c8=6
Hidden Single: r4c7=1
Hidden Single: r5c1=6
Hidden Single: r9c2=6
Naked Single: r9c7=3
Locked Candidates Type 1 (Pointing): 8 in b4 => r79c3<>8
Locked Candidates Type 1 (Pointing): 8 in b7 => r123c1<>8
Naked Triple: 6,7,9 in r7c379 => r7c1<>9
2-String Kite: 9 in r4c3,r7c7 (connected by r4c9,r6c7) => r7c3<>9
Naked Single: r7c3=7
Hidden Single: r8c9=7
W-Wing: 4/8 in r2c2,r9c1 connected by 8 in r29c4 => r2c1<>4
Hidden Single: r2c2=4
Hidden Single: r1c2=8
Naked Single: r1c8=7
Full House: r5c8=8
Naked Single: r1c7=5
Naked Single: r4c9=9
Full House: r4c3=8
Naked Single: r5c3=4
Full House: r5c7=7
Naked Single: r1c6=3
Full House: r1c1=9
Naked Single: r3c7=6
Naked Single: r6c7=4
Full House: r6c9=5
Full House: r7c7=9
Full House: r7c9=6
Naked Single: r9c3=5
Full House: r8c3=9
Naked Single: r6c1=1
Full House: r6c2=9
Full House: r8c2=1
Naked Single: r9c4=8
Full House: r9c1=4
Full House: r7c1=8
Full House: r7c6=1
Naked Single: r8c6=5
Full House: r3c6=8
Full House: r2c4=5
Full House: r8c4=3
Naked Single: r3c9=3
Full House: r2c9=8
Full House: r2c1=3
Full House: r3c1=5
|
normal_sudoku_3742
|
16.5.9.8...8...6.9.4.68.5.....1....6.849.........46...27...1..5....6.4..........1
|
163529784528714639947683512395178246684952173712346958279431865831265497456897321
|
Basic 9x9 Sudoku 3742
|
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.
|
1 6 . 5 . 9 . 8 .
. . 8 . . . 6 . 9
. 4 . 6 8 . 5 . .
. . . 1 . . . . 6
. 8 4 9 . . . . .
. . . . 4 6 . . .
2 7 . . . 1 . . 5
. . . . 6 . 4 . .
. . . . . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
163529784528714639947683512395178246684952173712346958279431865831265497456897321 #1 Extreme (16846) bf
Hidden Single: r3c4=6
Hidden Single: r5c1=6
Hidden Single: r2c5=1
Hidden Single: r1c9=4
Hidden Single: r4c8=4
Hidden Single: r7c4=4
Hidden Single: r9c1=4
Hidden Single: r3c8=1
Hidden Single: r2c6=4
Hidden Single: r7c7=8
Hidden Single: r8c1=8
Hidden Single: r5c7=1
Hidden Single: r4c6=8
Hidden Single: r6c9=8
Hidden Single: r9c4=8
Brute Force: r6c1=7
Forcing Chain Contradiction in c9 => r1c5<>7
r1c5=7 r1c3<>7 r3c3=7 r3c9<>7
r1c5=7 r4c5<>7 r4c7=7 r5c9<>7
r1c5=7 r2c4<>7 r8c4=7 r8c9<>7
Forcing Net Contradiction in r7c8 => r2c4<>2
r2c4=2 (r1c5<>2 r1c5=3 r1c7<>3) (r6c4<>2 r6c4=3 r6c7<>3) r2c4<>7 (r2c8=7 r9c8<>7) r8c4=7 (r9c5<>7) r9c6<>7 r9c7=7 r9c7<>3 r4c7=3 r4c123<>3 r6c23=3 r6c4<>3 r6c4=2 r2c4<>2
Finned Franken Swordfish: 2 c49b2 r358 fr1c5 fr6c4 => r5c5<>2
Forcing Chain Contradiction in c7 => r9c6<>2
r9c6=2 r3c6<>2 r1c5=2 r1c7<>2
r9c6=2 r5c6<>2 r5c89=2 r4c7<>2
r9c6=2 r5c6<>2 r5c89=2 r6c7<>2
r9c6=2 r9c7<>2
Forcing Net Contradiction in r7c8 => r2c4=7
r2c4<>7 (r8c4=7 r9c6<>7 r9c7=7 r9c7<>2 r9c8=2 r5c8<>2) r2c4=3 (r1c5<>3 r1c5=2 r4c5<>2) (r2c2<>3) r2c1<>3 r2c1=5 r2c2<>5 r2c2=2 r4c2<>2 r4c7=2 r5c9<>2 r5c6=2 r6c4<>2 r6c4=3 r2c4<>3 r2c4=7
Finned Franken Swordfish: 3 r27b2 c358 fr2c1 fr2c2 fr3c6 => r3c3<>3
Finned Franken Swordfish: 3 c49b2 r358 fr1c5 fr6c4 => r5c5<>3
Forcing Chain Contradiction in r8c9 => r4c5<>3
r4c5=3 r1c5<>3 r1c5=2 r9c5<>2 r8c46=2 r8c9<>2
r4c5=3 r6c4<>3 r8c4=3 r8c9<>3
r4c5=3 r4c5<>7 r4c7=7 r1c7<>7 r3c9=7 r8c9<>7
W-Wing: 2/3 in r3c6,r8c4 connected by 3 in r5c6,r6c4 => r8c6<>2
Forcing Chain Contradiction in c9 => r1c7<>3
r1c7=3 r1c7<>7 r3c9=7 r3c9<>2
r1c7=3 r1c5<>3 r1c5=2 r3c6<>2 r5c6=2 r5c9<>2
r1c7=3 r1c5<>3 r1c5=2 r9c5<>2 r8c4=2 r8c9<>2
Discontinuous Nice Loop: 2 r3c3 -2- r3c6 -3- r1c5 =3= r1c3 =7= r3c3 => r3c3<>2
Discontinuous Nice Loop: 3 r6c8 -3- r2c8 -2- r1c7 -7- r4c7 =7= r4c5 -7- r5c5 -5- r5c8 =5= r6c8 => r6c8<>3
Grouped AIC: 3 3- r8c4 =3= r6c4 -3- r5c6 =3= r5c89 -3- r46c7 =3= r9c7 -3 => r8c89,r9c56<>3
Empty Rectangle: 3 in b8 (r1c35) => r8c3<>3
AIC: 2/7 7- r4c5 =7= r4c7 -7- r1c7 =7= r3c9 -7- r8c9 -2- r8c4 =2= r9c5 -2 => r4c5<>2, r9c5<>7
Locked Pair: 5,7 in r45c5 => r5c6,r9c5<>5, r5c6<>7
Naked Pair: 2,3 in r35c6 => r8c6<>3
X-Wing: 3 c69 r35 => r3c1,r5c8<>3
Naked Single: r3c1=9
Naked Single: r3c3=7
Hidden Single: r1c7=7
Hidden Single: r4c5=7
Naked Single: r5c5=5
Hidden Single: r6c8=5
Locked Candidates Type 1 (Pointing): 9 in b6 => r9c7<>9
Remote Pair: 2/3 r2c8 -3- r3c9 -2- r3c6 -3- r5c6 -2- r6c4 -3- r8c4 => r58c8<>2
Naked Single: r5c8=7
Naked Single: r8c8=9
Hidden Single: r8c9=7
Naked Single: r8c6=5
Naked Single: r8c3=1
Naked Single: r9c6=7
Naked Single: r8c2=3
Full House: r8c4=2
Full House: r6c4=3
Full House: r5c6=2
Full House: r3c6=3
Full House: r5c9=3
Full House: r1c5=2
Full House: r3c9=2
Full House: r1c3=3
Full House: r2c8=3
Naked Single: r9c5=9
Full House: r7c5=3
Naked Single: r2c1=5
Full House: r2c2=2
Full House: r4c1=3
Naked Single: r7c8=6
Full House: r7c3=9
Full House: r9c8=2
Full House: r9c7=3
Naked Single: r9c2=5
Full House: r9c3=6
Naked Single: r6c3=2
Full House: r4c3=5
Naked Single: r4c2=9
Full House: r4c7=2
Full House: r6c7=9
Full House: r6c2=1
|
normal_sudoku_6195
|
....2..968....95...9......8...1....4..82.76..3...5..2.5......6...3..67....74....1
|
745328196831649572692571438279163854458297613316854927584712369123986745967435281
|
Basic 9x9 Sudoku 6195
|
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
8 . . . . 9 5 . .
. 9 . . . . . . 8
. . . 1 . . . . 4
. . 8 2 . 7 6 . .
3 . . . 5 . . 2 .
5 . . . . . . 6 .
. . 3 . . 6 7 . .
. . 7 4 . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
745328196831649572692571438279163854458297613316854927584712369123986745967435281 #1 Extreme (29910) bf
Brute Force: r5c4=2
Forcing Chain Contradiction in r5 => r7c6<>8
r7c6=8 r4c6<>8 r4c6=3 r5c5<>3
r7c6=8 r789c5<>8 r4c5=8 r4c78<>8 r6c7=8 r6c7<>1 r5c8=1 r5c8<>3
r7c6=8 r7c6<>2 r9c6=2 r9c6<>5 r9c8=5 r8c9<>5 r5c9=5 r5c9<>3
Forcing Chain Contradiction in r5 => r9c6<>8
r9c6=8 r4c6<>8 r4c6=3 r5c5<>3
r9c6=8 r789c5<>8 r4c5=8 r4c78<>8 r6c7=8 r6c7<>1 r5c8=1 r5c8<>3
r9c6=8 r9c6<>5 r9c8=5 r8c9<>5 r5c9=5 r5c9<>3
Forcing Net Contradiction in r8c4 => r7c5<>9
r7c5=9 (r5c5<>9) (r7c3<>9) (r7c4<>9) r8c4<>9 r6c4=9 r6c3<>9 r4c3=9 r5c1<>9 r5c9=9 r5c9<>5 r8c9=5 r8c4<>5
r7c5=9 (r7c4<>9) r8c4<>9 r6c4=9 r6c4<>6 r4c5=6 r4c5<>8 r789c5=8 r8c4<>8
r7c5=9 r8c4<>9
Forcing Net Contradiction in c9 => r8c4<>8
r8c4=8 (r6c4<>8) r1c4<>8 r1c6=8 (r4c6<>8 r4c6=3 r5c5<>3) r6c6<>8 r6c7=8 r6c7<>1 r5c8=1 r5c8<>3 r5c9=3
r8c4=8 (r8c4<>5 r9c6=5 r9c6<>2 r7c6=2 r7c9<>2) (r8c4<>9) (r7c5<>8) (r8c5<>8) r9c5<>8 r4c5=8 r4c5<>6 r6c4=6 r6c4<>9 r7c4=9 r7c9<>9 r7c9=3
Forcing Net Contradiction in r5 => r8c5<>9
r8c5=9 (r8c9<>9) r8c4<>9 (r6c4=9 r6c9<>9) r8c4=5 r8c9<>5 r5c9=5 r5c9<>9 r7c9=9 r7c3<>9 r89c1=9 r5c1<>9
r8c5=9 r5c5<>9
r8c5=9 r8c4<>9 r8c4=5 r8c9<>5 r5c9=5 r5c9<>9
Forcing Net Contradiction in c7 => r4c5<>8
r4c5=8 (r8c5<>8 r8c5=1 r8c1<>1) (r8c5<>8 r8c5=1 r7c6<>1) (r4c6<>8) r6c6<>8 (r6c7=8 r6c7<>1 r5c8=1 r5c1<>1) r1c6=8 r1c6<>1 r3c6=1 r3c1<>1 r1c1=1 r1c7<>1
r4c5=8 (r8c5<>8 r8c5=1 r7c6<>1) (r4c6<>8) r6c6<>8 r1c6=8 r1c6<>1 r3c6=1 r3c7<>1
r4c5=8 (r6c4<>8) r6c6<>8 r6c7=8 r6c7<>1
Locked Candidates Type 2 (Claiming): 8 in c5 => r7c4<>8
Brute Force: r5c5=9
Hidden Single: r6c6=4
Locked Candidates Type 1 (Pointing): 3 in b5 => r4c78<>3
Discontinuous Nice Loop: 5 r1c6 -5- r9c6 =5= r9c8 -5- r8c9 =5= r5c9 =3= r5c8 =1= r6c7 =8= r6c4 -8- r1c4 =8= r1c6 => r1c6<>5
Discontinuous Nice Loop: 6 r4c2 -6- r4c5 -3- r4c6 -8- r4c7 -9- r9c7 =9= r9c1 =6= r9c2 -6- r4c2 => r4c2<>6
Discontinuous Nice Loop: 3 r7c6 -3- r4c6 -8- r6c4 =8= r6c7 =1= r5c8 =3= r5c9 =5= r8c9 -5- r8c4 =5= r9c6 =2= r7c6 => r7c6<>3
Discontinuous Nice Loop: 3 r9c6 -3- r4c6 -8- r6c4 =8= r6c7 =1= r5c8 =3= r5c9 =5= r8c9 -5- r8c4 =5= r9c6 => r9c6<>3
Grouped Discontinuous Nice Loop: 6 r6c2 -6- r9c2 =6= r9c1 =9= r9c7 -9- r46c7 =9= r6c9 =7= r6c2 => r6c2<>6
Sue de Coq: r4c123 - {25679} (r4c567 - {3689}, r5c12,r6c2 - {1457}) => r6c3<>1, r4c8<>8
Locked Candidates Type 1 (Pointing): 8 in b6 => r79c7<>8
Discontinuous Nice Loop: 3 r2c9 -3- r5c9 -5- r4c8 -7- r6c9 =7= r2c9 => r2c9<>3
Discontinuous Nice Loop: 2 r7c2 -2- r7c6 -1- r8c5 -8- r7c5 =8= r7c2 => r7c2<>2
Discontinuous Nice Loop: 1 r7c6 -1- r8c5 -8- r8c8 =8= r9c8 =5= r9c6 =2= r7c6 => r7c6<>1
Naked Single: r7c6=2
Naked Single: r9c6=5
Naked Single: r8c4=9
Locked Candidates Type 1 (Pointing): 1 in b8 => r23c5<>1
Naked Pair: 3,8 in r9c58 => r9c2<>8, r9c7<>3
Hidden Rectangle: 1/8 in r7c25,r8c25 => r7c2<>1
Sue de Coq: r56c9 - {3579} (r7c9 - {39}, r4c8 - {57}) => r5c8<>5
Sue de Coq: r78c9 - {2359} (r5c9 - {35}, r9c7 - {29}) => r7c7<>9
XY-Chain: 1 1- r3c6 -3- r4c6 -8- r4c7 -9- r9c7 -2- r8c9 -5- r5c9 -3- r5c8 -1 => r3c8<>1
2-String Kite: 1 in r2c8,r6c2 (connected by r5c8,r6c7) => r2c2<>1
AIC: 6 6- r4c5 -3- r9c5 -8- r8c5 -1- r7c5 =1= r7c3 -1- r2c3 =1= r2c8 -1- r5c8 =1= r6c7 =8= r6c4 =6= r6c3 -6 => r4c13,r6c4<>6
Naked Single: r6c4=8
Naked Single: r4c6=3
Full House: r4c5=6
Naked Single: r3c6=1
Full House: r1c6=8
Hidden Single: r6c3=6
Hidden Single: r4c7=8
AIC: 3 3- r7c9 =3= r5c9 -3- r5c8 -1- r2c8 =1= r2c3 -1- r7c3 =1= r7c5 -1- r8c5 -8- r9c5 -3 => r7c45,r9c8<>3
Naked Single: r7c4=7
Naked Single: r9c8=8
Naked Single: r9c5=3
Locked Candidates Type 2 (Claiming): 7 in r1 => r2c2,r3c1<>7
Uniqueness Test 4: 1/8 in r7c25,r8c25 => r8c2<>1
XY-Chain: 4 4- r2c5 -7- r2c9 -2- r8c9 -5- r8c8 -4 => r2c8<>4
AIC: 1 1- r2c3 =1= r2c8 -1- r5c8 -3- r5c9 =3= r7c9 =9= r7c3 =1= r8c1 -1 => r1c1,r7c3<>1
Hidden Single: r7c5=1
Full House: r8c5=8
Hidden Single: r8c1=1
Naked Single: r5c1=4
Naked Single: r1c1=7
Hidden Single: r7c2=8
Locked Candidates Type 1 (Pointing): 1 in b4 => r1c2<>1
2-String Kite: 4 in r3c8,r7c3 (connected by r7c7,r8c8) => r3c3<>4
W-Wing: 6/2 in r3c1,r9c2 connected by 2 in r39c7 => r2c2,r9c1<>6
Hidden Single: r2c4=6
Hidden Single: r9c2=6
Hidden Single: r3c1=6
Finned X-Wing: 4 r17 c37 fr1c2 => r2c3<>4
AIC: 2 2- r2c9 =2= r8c9 -2- r8c2 -4- r7c3 =4= r1c3 =1= r1c7 -1- r6c7 -9- r9c7 -2- r3c7 =2= r3c3 -2 => r2c23,r3c7<>2
Naked Single: r2c3=1
Hidden Single: r2c9=2
Naked Single: r8c9=5
Naked Single: r5c9=3
Naked Single: r8c8=4
Full House: r8c2=2
Naked Single: r5c8=1
Full House: r5c2=5
Naked Single: r7c9=9
Full House: r6c9=7
Naked Single: r7c7=3
Full House: r7c3=4
Full House: r9c1=9
Full House: r9c7=2
Full House: r4c1=2
Naked Single: r6c7=9
Full House: r4c8=5
Full House: r6c2=1
Naked Single: r4c2=7
Full House: r4c3=9
Naked Single: r3c7=4
Full House: r1c7=1
Naked Single: r1c3=5
Full House: r3c3=2
Naked Single: r3c5=7
Full House: r2c5=4
Naked Single: r1c4=3
Full House: r1c2=4
Full House: r2c2=3
Full House: r3c4=5
Full House: r3c8=3
Full House: r2c8=7
|
normal_sudoku_1155
|
4....69...2.....8..95.....3....57..978.61....25149.7...381...2...43....51....43..
|
413826957627935481895741263346257819789613542251498736538179624964382175172564398
|
Basic 9x9 Sudoku 1155
|
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 9 . .
. 2 . . . . . 8 .
. 9 5 . . . . . 3
. . . . 5 7 . . 9
7 8 . 6 1 . . . .
2 5 1 4 9 . 7 . .
. 3 8 1 . . . 2 .
. . 4 3 . . . . 5
1 . . . . 4 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
413826957627935481895741263346257819789613542251498736538179624964382175172564398 #1 Medium (414)
Hidden Single: r6c2=5
Hidden Single: r5c3=9
Hidden Single: r3c1=8
Hidden Single: r4c2=4
Hidden Single: r9c3=2
Hidden Single: r1c2=1
Hidden Single: r7c1=5
Naked Single: r7c6=9
Hidden Single: r9c4=5
Hidden Single: r2c9=1
Hidden Single: r2c6=5
Hidden Single: r8c1=9
Hidden Single: r2c4=9
Hidden Single: r9c8=9
Hidden Single: r1c8=5
Hidden Single: r3c6=1
Hidden Single: r5c7=5
Locked Candidates Type 1 (Pointing): 6 in b1 => r2c7<>6
Naked Single: r2c7=4
Naked Single: r7c7=6
Naked Single: r3c7=2
Naked Single: r7c5=7
Full House: r7c9=4
Naked Single: r1c9=7
Full House: r3c8=6
Naked Single: r3c4=7
Full House: r3c5=4
Naked Single: r2c5=3
Naked Single: r5c9=2
Naked Single: r1c3=3
Naked Single: r9c9=8
Full House: r6c9=6
Naked Single: r6c8=3
Full House: r6c6=8
Naked Single: r2c1=6
Full House: r2c3=7
Full House: r4c3=6
Full House: r4c1=3
Naked Single: r5c6=3
Full House: r5c8=4
Full House: r4c4=2
Full House: r8c6=2
Full House: r1c4=8
Full House: r1c5=2
Naked Single: r8c7=1
Full House: r4c7=8
Full House: r4c8=1
Full House: r8c8=7
Naked Single: r9c5=6
Full House: r8c5=8
Full House: r8c2=6
Full House: r9c2=7
|
normal_sudoku_835
|
..8...2.6.9..5....5.......8..7....4.28...671.3.4..9..5.7....9..913..7.....54.....
|
748931256692854371531672498157328649289546713364719825476185932913267584825493167
|
Basic 9x9 Sudoku 835
|
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 . 6
. 9 . . 5 . . . .
5 . . . . . . . 8
. . 7 . . . . 4 .
2 8 . . . 6 7 1 .
3 . 4 . . 9 . . 5
. 7 . . . . 9 . .
9 1 3 . . 7 . . .
. . 5 4 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
748931256692854371531672498157328649289546713364719825476185932913267584825493167 #1 Easy (314)
Naked Single: r5c1=2
Naked Single: r5c3=9
Naked Single: r6c2=6
Naked Single: r5c9=3
Naked Single: r4c1=1
Full House: r4c2=5
Naked Single: r6c7=8
Naked Single: r9c2=2
Naked Single: r5c4=5
Full House: r5c5=4
Naked Single: r4c7=6
Naked Single: r6c8=2
Full House: r4c9=9
Naked Single: r7c3=6
Naked Single: r9c1=8
Full House: r7c1=4
Naked Single: r1c1=7
Full House: r2c1=6
Hidden Single: r1c8=5
Hidden Single: r8c7=5
Hidden Single: r9c5=9
Hidden Single: r7c6=5
Hidden Single: r3c8=9
Hidden Single: r8c9=4
Hidden Single: r1c4=9
Hidden Single: r9c8=6
Naked Single: r8c8=8
Naked Single: r7c8=3
Full House: r2c8=7
Naked Single: r9c7=1
Naked Single: r2c9=1
Naked Single: r7c9=2
Full House: r9c9=7
Full House: r9c6=3
Naked Single: r2c3=2
Full House: r3c3=1
Hidden Single: r1c6=1
Naked Single: r1c5=3
Full House: r1c2=4
Full House: r3c2=3
Naked Single: r2c4=8
Naked Single: r3c7=4
Full House: r2c7=3
Full House: r2c6=4
Naked Single: r7c4=1
Full House: r7c5=8
Naked Single: r3c6=2
Full House: r4c6=8
Naked Single: r6c4=7
Full House: r6c5=1
Naked Single: r4c5=2
Full House: r4c4=3
Naked Single: r3c4=6
Full House: r3c5=7
Full House: r8c5=6
Full House: r8c4=2
|
normal_sudoku_1594
|
...48..9.....738...9...2....1.....7...9...3.66..7...5.......72.2..63....3.52194..
|
537481692126973845498562137812356974759124386643798251961845723284637519375219468
|
Basic 9x9 Sudoku 1594
|
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 . . 9 .
. . . . 7 3 8 . .
. 9 . . . 2 . . .
. 1 . . . . . 7 .
. . 9 . . . 3 . 6
6 . . 7 . . . 5 .
. . . . . . 7 2 .
2 . . 6 3 . . . .
3 . 5 2 1 9 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
537481692126973845498562137812356974759124386643798251961845723284637519375219468 #1 Medium (370)
Naked Single: r9c5=1
Naked Single: r9c9=8
Naked Single: r8c8=1
Naked Single: r9c8=6
Full House: r9c2=7
Naked Single: r2c8=4
Naked Single: r3c8=3
Full House: r5c8=8
Hidden Single: r2c4=9
Hidden Single: r4c4=3
Hidden Single: r7c9=3
Hidden Single: r7c1=9
Hidden Single: r8c6=7
Hidden Single: r5c1=7
Hidden Single: r7c4=8
Hidden Single: r7c3=1
Hidden Single: r7c2=6
Hidden Single: r2c3=6
Locked Pair: 1,5 in r12c1 => r3c1<>1, r12c2,r34c1<>5
Naked Single: r2c2=2
Naked Single: r1c2=3
Naked Single: r1c3=7
Hidden Single: r5c2=5
Naked Single: r5c4=1
Full House: r3c4=5
Naked Single: r5c6=4
Full House: r5c5=2
Naked Single: r3c5=6
Full House: r1c6=1
Naked Single: r6c6=8
Naked Single: r7c6=5
Full House: r4c6=6
Full House: r7c5=4
Naked Single: r6c5=9
Full House: r4c5=5
Naked Single: r3c7=1
Naked Single: r1c1=5
Naked Single: r6c2=4
Full House: r8c2=8
Full House: r8c3=4
Naked Single: r2c9=5
Full House: r2c1=1
Naked Single: r3c9=7
Naked Single: r6c7=2
Naked Single: r1c9=2
Full House: r1c7=6
Naked Single: r4c1=8
Full House: r3c1=4
Full House: r3c3=8
Naked Single: r8c9=9
Full House: r8c7=5
Full House: r4c7=9
Naked Single: r6c3=3
Full House: r6c9=1
Full House: r4c3=2
Full House: r4c9=4
|
normal_sudoku_219
|
9...8...3.4..7..6....2..9..6..9..15.7.4.16..219.....8...78....9..9...5..4....7.1.
|
961485723342179865578263941623948157784516392195732486217854639839621574456397218
|
Basic 9x9 Sudoku 219
|
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 . . . 3
. 4 . . 7 . . 6 .
. . . 2 . . 9 . .
6 . . 9 . . 1 5 .
7 . 4 . 1 6 . . 2
1 9 . . . . . 8 .
. . 7 8 . . . . 9
. . 9 . . . 5 . .
4 . . . . 7 . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
961485723342179865578263941623948157784516392195732486217854639839621574456397218 #1 Easy (376)
Naked Single: r5c9=2
Naked Single: r5c7=3
Naked Single: r5c4=5
Naked Single: r5c8=9
Full House: r5c2=8
Hidden Single: r2c6=9
Hidden Single: r4c6=8
Hidden Single: r9c5=9
Hidden Single: r4c9=7
Hidden Single: r6c4=7
Hidden Single: r6c3=5
Hidden Single: r1c7=7
Naked Single: r3c8=4
Naked Single: r1c8=2
Naked Single: r2c7=8
Naked Single: r7c8=3
Full House: r8c8=7
Hidden Single: r4c5=4
Hidden Single: r9c2=5
Naked Single: r7c1=2
Hidden Single: r3c2=7
Hidden Single: r1c6=5
Hidden Single: r2c3=2
Naked Single: r4c3=3
Full House: r4c2=2
Hidden Single: r9c7=2
Hidden Single: r7c5=5
Hidden Single: r1c4=4
Hidden Single: r8c2=3
Naked Single: r8c1=8
Naked Single: r9c3=6
Full House: r7c2=1
Full House: r1c2=6
Full House: r1c3=1
Full House: r3c3=8
Naked Single: r9c4=3
Full House: r9c9=8
Naked Single: r7c6=4
Full House: r7c7=6
Full House: r6c7=4
Full House: r8c9=4
Full House: r6c9=6
Naked Single: r2c4=1
Full House: r8c4=6
Naked Single: r2c9=5
Full House: r2c1=3
Full House: r3c9=1
Full House: r3c1=5
Naked Single: r3c6=3
Full House: r3c5=6
Naked Single: r8c5=2
Full House: r6c5=3
Full House: r6c6=2
Full House: r8c6=1
|
normal_sudoku_5304
|
..1...4...7.1.698.6..93........63..1...7.18..7...9.2.35.4...6..1....857.......3..
|
951287436473156982628934157285463791349721865716895243594372618132648579867519324
|
Basic 9x9 Sudoku 5304
|
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.
|
. . 1 . . . 4 . .
. 7 . 1 . 6 9 8 .
6 . . 9 3 . . . .
. . . . 6 3 . . 1
. . . 7 . 1 8 . .
7 . . . 9 . 2 . 3
5 . 4 . . . 6 . .
1 . . . . 8 5 7 .
. . . . . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
951287436473156982628934157285463791349721865716895243594372618132648579867519324 #1 Hard (656)
Naked Single: r6c7=2
Naked Single: r4c7=7
Full House: r3c7=1
Hidden Single: r6c2=1
Hidden Single: r1c8=3
Hidden Single: r1c5=8
Hidden Single: r9c3=7
Hidden Single: r1c9=6
Hidden Single: r7c5=7
Hidden Single: r1c6=7
Hidden Single: r3c9=7
Hidden Single: r7c8=1
Hidden Single: r9c5=1
X-Wing: 5 c59 r25 => r25c3,r5c28<>5
W-Wing: 2/5 in r1c4,r3c8 connected by 5 in r2c59 => r3c6<>2
Locked Candidates Type 2 (Claiming): 2 in c6 => r789c4,r8c5<>2
Naked Single: r7c4=3
Naked Single: r8c5=4
Naked Single: r8c4=6
Naked Single: r9c4=5
Naked Single: r1c4=2
Naked Single: r1c1=9
Full House: r1c2=5
Naked Single: r2c5=5
Full House: r3c6=4
Full House: r5c5=2
Naked Single: r2c9=2
Full House: r3c8=5
Naked Single: r6c6=5
Naked Single: r2c3=3
Full House: r2c1=4
Naked Single: r8c9=9
Naked Single: r5c1=3
Naked Single: r7c9=8
Naked Single: r8c3=2
Full House: r8c2=3
Naked Single: r9c9=4
Full House: r5c9=5
Full House: r9c8=2
Naked Single: r3c3=8
Full House: r3c2=2
Naked Single: r7c2=9
Full House: r7c6=2
Full House: r9c6=9
Naked Single: r9c1=8
Full House: r4c1=2
Full House: r9c2=6
Naked Single: r6c3=6
Naked Single: r5c2=4
Full House: r4c2=8
Naked Single: r5c3=9
Full House: r4c3=5
Full House: r5c8=6
Naked Single: r6c8=4
Full House: r4c8=9
Full House: r4c4=4
Full House: r6c4=8
|
normal_sudoku_2882
|
2..4.3.7.........4...8......5..4.1.7..27.5.4.47........2.5.7.3...3.9...67...8...2
|
281453679937621584564879321358942167192765843476138295629517438813294756745386912
|
Basic 9x9 Sudoku 2882
|
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 . 7 .
. . . . . . . . 4
. . . 8 . . . . .
. 5 . . 4 . 1 . 7
. . 2 7 . 5 . 4 .
4 7 . . . . . . .
. 2 . 5 . 7 . 3 .
. . 3 . 9 . . . 6
7 . . . 8 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
281453679937621584564879321358942167192765843476138295629517438813294756745386912 #1 Extreme (12030) bf
Hidden Single: r4c9=7
Hidden Single: r8c7=7
Hidden Single: r9c4=3
Hidden Single: r4c1=3
Brute Force: r5c2=9
Grouped Discontinuous Nice Loop: 6 r7c3 -6- r7c5 -1- r5c5 =1= r5c1 =6= r46c3 -6- r7c3 => r7c3<>6
Finned Swordfish: 6 r157 c157 fr1c2 fr1c3 => r23c1<>6
Continuous Nice Loop: 1/8 6= r5c1 =1= r5c5 -1- r7c5 -6- r7c1 =6= r5c1 =1 => r1236c5<>1, r5c1<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r127c3<>8
Locked Candidates Type 2 (Claiming): 8 in r5 => r46c8,r6c79<>8
Turbot Fish: 1 r6c3 =1= r5c1 -1- r5c5 =1= r7c5 => r7c3<>1
Empty Rectangle: 8 in b1 (r28c8) => r8c2<>8
Locked Candidates Type 1 (Pointing): 8 in b7 => r2c1<>8
Naked Triple: 1,2,4 in r8c246 => r8c18<>1
Hidden Rectangle: 6/8 in r4c36,r6c36 => r6c6<>6
Sashimi Swordfish: 1 r157 c159 fr1c2 fr1c3 => r23c1<>1
Locked Pair: 5,9 in r23c1 => r123c3,r7c1<>9, r123c3,r8c1<>5
Naked Single: r8c1=8
Naked Single: r8c8=5
Hidden Single: r9c3=5
Hidden Single: r2c8=8
Hidden Single: r7c3=9
Hidden Single: r1c2=8
Hidden Single: r7c7=4
Naked Single: r9c7=9
Naked Single: r9c8=1
Full House: r7c9=8
Naked Single: r5c9=3
Hidden Single: r3c3=4
Hidden Single: r5c7=8
Hidden Single: r1c9=9
Naked Single: r6c9=5
Full House: r3c9=1
Hidden Single: r6c5=3
Hidden Single: r3c5=7
Hidden Single: r2c3=7
Hidden Single: r1c3=1
Hidden Single: r2c5=2
Hidden Single: r8c2=1
Naked Single: r7c1=6
Full House: r7c5=1
Full House: r9c2=4
Full House: r9c6=6
Naked Single: r8c4=2
Full House: r8c6=4
Naked Single: r5c1=1
Full House: r5c5=6
Full House: r1c5=5
Full House: r1c7=6
Naked Single: r3c6=9
Naked Single: r4c4=9
Naked Single: r3c8=2
Naked Single: r6c7=2
Naked Single: r2c6=1
Full House: r2c4=6
Full House: r6c4=1
Naked Single: r3c1=5
Full House: r2c1=9
Naked Single: r4c8=6
Full House: r6c8=9
Naked Single: r6c6=8
Full House: r4c6=2
Full House: r4c3=8
Full House: r6c3=6
Naked Single: r2c2=3
Full House: r2c7=5
Full House: r3c7=3
Full House: r3c2=6
|
normal_sudoku_730
|
......5..5..2.3.....9.4...8..74...8...3..6..7.9..7.24..3.1.98.........1...8.6...2
|
386917524574283961129645738257491683843526197691378245432159876765832419918764352
|
Basic 9x9 Sudoku 730
|
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 . .
5 . . 2 . 3 . . .
. . 9 . 4 . . . 8
. . 7 4 . . . 8 .
. . 3 . . 6 . . 7
. 9 . . 7 . 2 4 .
. 3 . 1 . 9 8 . .
. . . . . . . 1 .
. . 8 . 6 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
386917524574283961129645738257491683843526197691378245432159876765832419918764352 #1 Extreme (13380) bf
Brute Force: r5c3=3
2-String Kite: 3 in r6c9,r8c5 (connected by r4c5,r6c4) => r8c9<>3
Almost Locked Set XY-Wing: A=r5c478 {1589}, B=r12c5 {189}, C=r13689c4 {356789}, X,Y=8,9, Z=1 => r5c5<>1
Forcing Chain Contradiction in b5 => r5c7=1
r5c7<>1 r5c7=9 r4c79<>9 r4c5=9 r4c5<>5
r5c7<>1 r5c7=9 r5c4<>9 r1c4=9 r1c4<>6 r3c4=6 r3c4<>5 r3c6=5 r4c6<>5
r5c7<>1 r5c7=9 r5c8<>9 r5c8=5 r5c4<>5
r5c7<>1 r5c7=9 r5c8<>9 r5c8=5 r5c5<>5
r5c7<>1 r5c7=9 r4c79<>9 r4c5=9 r4c5<>3 r6c4=3 r6c4<>5
r5c7<>1 r5c7=9 r5c4<>9 r1c4=9 r1c4<>6 r3c4=6 r3c4<>5 r3c6=5 r6c6<>5
Finned Swordfish: 1 r349 c126 fr4c5 => r6c6<>1
Locked Candidates Type 1 (Pointing): 1 in b5 => r4c12<>1
XYZ-Wing: 5/8/9 in r5c48,r6c6 => r5c5<>5
Discontinuous Nice Loop: 5 r4c5 -5- r7c5 -2- r8c6 =2= r4c6 =1= r4c5 => r4c5<>5
Locked Candidates Type 2 (Claiming): 5 in c5 => r8c46,r9c46<>5
Discontinuous Nice Loop: 8 r5c4 -8- r6c6 -5- r3c6 =5= r3c4 =6= r1c4 =9= r5c4 => r5c4<>8
Naked Pair: 5,9 in r5c48 => r5c2<>5, r5c5<>9
X-Chain: 5 r5c4 =5= r5c8 -5- r9c8 =5= r9c2 -5- r4c2 =5= r6c3 => r6c46<>5
Naked Single: r6c6=8
Naked Single: r5c5=2
Naked Single: r6c4=3
Naked Single: r7c5=5
Naked Single: r9c4=7
Naked Single: r8c4=8
Naked Single: r9c6=4
Naked Single: r8c5=3
Full House: r8c6=2
XY-Chain: 9 9- r5c8 -5- r6c9 -6- r6c1 -1- r9c1 -9 => r9c8<>9
XY-Wing: 3/5/9 in r59c8,r9c7 => r4c7<>9
2-String Kite: 9 in r1c4,r4c9 (connected by r4c5,r5c4) => r1c9<>9
XY-Chain: 6 6- r4c7 -3- r9c7 -9- r9c1 -1- r6c1 -6 => r4c12,r6c9<>6
Naked Single: r4c1=2
Naked Single: r6c9=5
Naked Single: r4c2=5
Naked Single: r5c8=9
Naked Single: r4c6=1
Naked Single: r9c2=1
Naked Single: r5c4=5
Full House: r4c5=9
Naked Single: r1c6=7
Full House: r3c6=5
Naked Single: r9c1=9
Naked Single: r3c4=6
Full House: r1c4=9
Naked Single: r9c7=3
Full House: r9c8=5
Naked Single: r3c7=7
Naked Single: r4c7=6
Full House: r4c9=3
Naked Single: r2c8=6
Naked Single: r3c2=2
Naked Single: r7c8=7
Naked Single: r3c8=3
Full House: r1c8=2
Full House: r3c1=1
Naked Single: r2c3=4
Naked Single: r6c1=6
Full House: r6c3=1
Naked Single: r1c3=6
Naked Single: r2c7=9
Full House: r8c7=4
Naked Single: r7c1=4
Naked Single: r1c2=8
Naked Single: r7c3=2
Full House: r8c3=5
Full House: r7c9=6
Full House: r8c9=9
Naked Single: r2c9=1
Full House: r1c9=4
Naked Single: r8c1=7
Full House: r8c2=6
Naked Single: r5c1=8
Full House: r1c1=3
Full House: r1c5=1
Full House: r2c2=7
Full House: r5c2=4
Full House: r2c5=8
|
normal_sudoku_5848
|
....7....83.6...7..4.5....9...7.96.5....4.92.96.25..477...2..5...6...29.........4
|
695178432832694571147532869324789615571346928968251347789423156456817293213965784
|
Basic 9x9 Sudoku 5848
|
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 . . . .
8 3 . 6 . . . 7 .
. 4 . 5 . . . . 9
. . . 7 . 9 6 . 5
. . . . 4 . 9 2 .
9 6 . 2 5 . . 4 7
7 . . . 2 . . 5 .
. . 6 . . . 2 9 .
. . . . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
695178432832694571147532869324789615571346928968251347789423156456817293213965784 #1 Extreme (26376) bf
Hidden Single: r5c7=9
Hidden Single: r5c6=6
Hidden Single: r3c3=7
Hidden Single: r5c2=7
Hidden Single: r9c5=6
Hidden Single: r8c6=7
Hidden Single: r9c7=7
Hidden Single: r7c9=6
Hidden Single: r2c5=9
Hidden Single: r9c6=5
Naked Triple: 1,3,8 in r367c7 => r12c7<>1, r1c7<>3, r1c7<>8
Brute Force: r5c1=5
Hidden Single: r8c2=5
Brute Force: r4c8=1
Locked Candidates Type 1 (Pointing): 1 in b4 => r1279c3<>1
Skyscraper: 1 in r7c7,r8c5 (connected by r3c57) => r7c46,r8c9<>1
Hidden Single: r7c7=1
Naked Pair: 3,8 in r58c9 => r1c9<>3, r1c9<>8
Grouped Discontinuous Nice Loop: 2 r1c1 -2- r1c9 -1- r1c12 =1= r3c1 =6= r1c1 => r1c1<>2
Grouped Discontinuous Nice Loop: 2 r1c6 -2- r1c9 -1- r1c12 =1= r3c1 =2= r3c6 -2- r1c6 => r1c6<>2
Finned Franken Swordfish: 3 r57b9 c349 fr7c6 fr9c8 => r9c4<>3
Forcing Chain Contradiction in r3c5 => r5c3<>3
r5c3=3 r5c3<>1 r5c4=1 r6c6<>1 r123c6=1 r3c5<>1
r5c3=3 r4c13<>3 r4c5=3 r3c5<>3
r5c3=3 r5c9<>3 r5c9=8 r6c7<>8 r3c7=8 r3c5<>8
W-Wing: 8/3 in r4c5,r6c7 connected by 3 in r5c49 => r6c6<>8
Turbot Fish: 8 r4c5 =8= r5c4 -8- r5c9 =8= r8c9 => r8c5<>8
Discontinuous Nice Loop: 2 r1c2 -2- r1c9 -1- r2c9 =1= r2c6 -1- r6c6 -3- r4c5 -8- r4c2 -2- r1c2 => r1c2<>2
Grouped Discontinuous Nice Loop: 8 r7c3 -8- r7c6 =8= r789c4 -8- r5c4 =8= r4c5 -8- r4c2 =8= r79c2 -8- r7c3 => r7c3<>8
Grouped Discontinuous Nice Loop: 1 r8c1 -1- r8c5 -3- r7c46 =3= r7c3 =4= r8c1 => r8c1<>1
Locked Candidates Type 1 (Pointing): 1 in b7 => r9c4<>1
Almost Locked Set XZ-Rule: A=r13c1 {126}, B=r147c2 {1289}, X=1, Z=2 => r4c1<>2
Naked Pair: 3,4 in r48c1 => r9c1<>3
Almost Locked Set XY-Wing: A=r3c57 {138}, B=r9c8 {38}, C=r8c159 {1348}, X,Y=1,8, Z=3 => r3c8<>3
Almost Locked Set Chain: 3- r3c57 {138} -1- r8c5 {13} -3- r8c9 {38} -8- r9c8 {38} -3- r13c8 {368} -8- r12c9,r3c7 {1238} -3 => r3c6<>3
Forcing Chain Contradiction in r3c5 => r1c9=2
r1c9<>2 r1c9=1 r2c9<>1 r2c6=1 r3c5<>1
r1c9<>2 r1c9=1 r2c9<>1 r2c6=1 r6c6<>1 r6c6=3 r6c7<>3 r3c7=3 r3c5<>3
r1c9<>2 r1c9=1 r1c2<>1 r1c2=9 r7c2<>9 r7c2=8 r7c6<>8 r13c6=8 r3c5<>8
Naked Single: r2c9=1
Forcing Chain Contradiction in r3c6 => r4c2=2
r4c2<>2 r4c2=8 r4c5<>8 r4c5=3 r6c6<>3 r6c6=1 r3c6<>1
r4c2<>2 r4c3=2 r2c3<>2 r2c6=2 r3c6<>2
r4c2<>2 r4c2=8 r4c5<>8 r3c5=8 r3c6<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r9c3<>8
Forcing Chain Contradiction in r3 => r4c5=8
r4c5<>8 r3c5=8 r13c6<>8 r7c6=8 r7c2<>8 r7c2=9 r1c2<>9 r1c2=1 r3c1<>1
r4c5<>8 r3c5=8 r3c5<>1
r4c5<>8 r4c5=3 r6c6<>3 r6c6=1 r3c6<>1
Locked Candidates Type 2 (Claiming): 3 in r4 => r6c3<>3
Skyscraper: 3 in r3c5,r6c6 (connected by r36c7) => r1c6<>3
Turbot Fish: 3 r1c4 =3= r1c8 -3- r9c8 =3= r8c9 => r8c4<>3
W-Wing: 3/1 in r3c5,r5c4 connected by 1 in r8c45 => r1c4<>3
Hidden Single: r1c8=3
Naked Single: r3c7=8
Naked Single: r9c8=8
Full House: r3c8=6
Full House: r8c9=3
Full House: r5c9=8
Full House: r6c7=3
Naked Single: r9c4=9
Naked Single: r8c1=4
Naked Single: r8c5=1
Full House: r3c5=3
Full House: r8c4=8
Naked Single: r5c3=1
Full House: r5c4=3
Full House: r6c6=1
Full House: r6c3=8
Naked Single: r9c2=1
Naked Single: r4c1=3
Full House: r4c3=4
Naked Single: r7c4=4
Full House: r1c4=1
Full House: r7c6=3
Naked Single: r3c6=2
Full House: r3c1=1
Naked Single: r1c2=9
Full House: r7c2=8
Full House: r7c3=9
Naked Single: r9c1=2
Full House: r1c1=6
Full House: r9c3=3
Naked Single: r2c6=4
Full House: r1c6=8
Naked Single: r1c3=5
Full House: r1c7=4
Full House: r2c7=5
Full House: r2c3=2
|
normal_sudoku_324
|
4......7...79..1...5..7...2..5.2..4.8.3..6....4.3....69....58...3.6...2...4.9..1.
|
418562973267934185359871462695127348873456291142389756926715834731648529584293617
|
Basic 9x9 Sudoku 324
|
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 .
. . 7 9 . . 1 . .
. 5 . . 7 . . . 2
. . 5 . 2 . . 4 .
8 . 3 . . 6 . . .
. 4 . 3 . . . . 6
9 . . . . 5 8 . .
. 3 . 6 . . . 2 .
. . 4 . 9 . . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
418562973267934185359871462695127348873456291142389756926715834731648529584293617 #1 Extreme (18286) bf
Finned Swordfish: 3 r149 c679 fr1c5 => r23c6<>3
Forcing Net Contradiction in r1c6 => r8c6<>1
r8c6=1 (r8c5<>1) r8c3<>1 r8c3=8 r8c5<>8 r8c5=4 (r5c5<>4) (r2c5<>4) (r7c4<>4) r7c5<>4 r7c9=4 r2c9<>4 r2c6=4 (r2c6<>2) r5c6<>4 r5c4=4 r5c4<>5 r1c4=5 r1c4<>2 r1c6=2
r8c6=1 (r7c5<>1) (r8c5<>1) r8c3<>1 r8c3=8 r8c5<>8 r8c5=4 r7c5<>4 r7c5=3 r9c6<>3 r1c6=3
Brute Force: r5c6=6
Finned X-Wing: 4 c67 r38 fr2c6 => r3c4<>4
Forcing Net Contradiction in r3 => r1c5<>1
r1c5=1 (r3c6<>1) r3c4<>1 r3c4=8 r3c6<>8 r3c6=4
r1c5=1 (r8c5<>1 r7c4=1 r7c4<>4) (r1c5<>3) r1c5<>6 r2c5=6 r2c5<>3 r7c5=3 r7c5<>4 r7c9=4 r8c7<>4 r3c7=4
Forcing Net Contradiction in r8c7 => r1c5<>8
r1c5=8 (r3c6<>8) r3c4<>8 r3c4=1 r3c6<>1 r3c6=4 r3c7<>4 r8c7=4
r1c5=8 (r1c9<>8) (r1c5<>5) r1c5<>6 r2c5=6 (r2c5<>3 r7c5=3 r9c6<>3 r1c6=3 r1c9<>3) r2c5<>5 r1c4=5 r1c9<>5 r1c9=9 r8c9<>9 r8c7=9
Forcing Net Contradiction in r2 => r1c6<>1
r1c6=1 (r3c4<>1 r3c4=8 r9c4<>8) r1c6<>3 r9c6=3 (r9c6<>2 r2c6=2 r2c2<>2) r9c6<>8 r9c2=8 r2c2<>8 r2c2=6 (r2c1<>6) (r1c3<>6) r3c3<>6 r7c3=6 r7c8<>6 r7c8=3 r7c5<>3 r2c5=3 (r1c5<>3) r2c1<>3 r2c1=2
r1c6=1 (r1c6<>2) r1c6<>3 r9c6=3 r9c6<>2 r2c6=2
Forcing Net Contradiction in b6 => r1c6<>8
r1c6=8 (r1c9<>8) (r3c6<>8) r3c4<>8 r3c4=1 r3c6<>1 r3c6=4 (r2c5<>4) r2c6<>4 r2c9=4 r2c9<>8 r4c9=8
r1c6=8 (r1c6<>3 r9c6=3 r9c6<>2 r2c6=2 r1c4<>2 r1c4=5 r2c5<>5) (r3c6<>8) r3c4<>8 r3c4=1 r3c6<>1 r3c6=4 (r2c5<>4) r2c6<>4 r2c9=4 r2c9<>5 r2c8=5 (r6c8<>5) r5c8<>5 r5c8=9 r6c8<>9 r6c8=8
Forcing Net Verity => r5c7=2
r2c2=2 r5c2<>2 r5c7=2
r2c2=6 (r1c3<>6) r3c3<>6 r7c3=6 (r7c3<>2) r7c8<>6 r7c8=3 (r9c7<>3) r9c9<>3 r9c6=3 r1c6<>3 r1c6=2 r1c3<>2 r6c3=2 r5c2<>2 r5c7=2
r2c2=8 (r1c2<>8) (r1c3<>8) (r2c5<>8) (r1c3<>8) r3c3<>8 r8c3=8 r8c5<>8 r6c5=8 (r4c4<>8) (r4c4<>8) r4c6<>8 r4c9=8 r1c9<>8 r1c4=8 (r9c4<>8 r9c6=8 r9c6<>3 r1c6=3 r1c6<>2 r2c6=2 r2c1<>2) (r9c4<>8) r3c4<>8 r3c4=1 r4c4<>1 r4c4=7 r9c4<>7 r9c4=2 r9c1<>2 r6c1=2 r5c2<>2 r5c7=2
Forcing Net Contradiction in r1 => r1c7<>5
r1c7=5 (r1c7<>6) (r2c8<>5) r2c9<>5 r2c5=5 (r2c5<>3) r2c5<>6 r1c5=6 r1c5<>3 r7c5=3 r7c8<>3 r7c8=6 (r2c8<>6) r9c7<>6 r3c7=6 (r3c3<>6) r3c8<>6 r7c8=6 (r2c8<>6) r7c3<>6 r1c3=6
r1c7=5 (r2c8<>5) r2c9<>5 r2c5=5 r2c5<>6 r1c5=6
Forcing Net Contradiction in r1 => r1c9<>5
r1c9=5 (r2c8<>5) r2c9<>5 r2c5=5 (r2c5<>3) r2c5<>6 r1c5=6 (r1c7<>6) r1c5<>3 r7c5=3 r7c8<>3 r7c8=6 (r2c8<>6) r9c7<>6 r3c7=6 (r3c3<>6) r3c8<>6 r7c8=6 (r2c8<>6) r7c3<>6 r1c3=6
r1c9=5 (r2c8<>5) r2c9<>5 r2c5=5 r2c5<>6 r1c5=6
Locked Candidates Type 1 (Pointing): 5 in b3 => r2c5<>5
Almost Locked Set XY-Wing: A=r3c46 {148}, B=r56c8 {589}, C=r2c12568 {234568}, X,Y=4,5, Z=8 => r3c8<>8
Sashimi Swordfish: 8 c358 r268 fr1c3 fr3c3 => r2c2<>8
Sue de Coq: r2c56 - {23468} (r2c12 - {236}, r3c46 - {148}) => r1c4<>1, r1c4<>8, r2c89<>3, r2c8<>6
Locked Candidates Type 1 (Pointing): 1 in b2 => r3c13<>1
Naked Triple: 2,3,6 in r2c12,r3c1 => r1c23<>2, r1c23,r3c3<>6
Hidden Single: r7c3=6
Naked Single: r7c8=3
Hidden Single: r3c8=6
Naked Single: r3c1=3
Hidden Single: r9c7=6
Hidden Single: r6c3=2
Hidden Single: r9c6=3
Naked Single: r1c6=2
Naked Single: r1c4=5
Hidden Single: r1c5=6
Hidden Single: r2c5=3
Locked Candidates Type 1 (Pointing): 4 in b2 => r8c6<>4
Locked Candidates Type 1 (Pointing): 9 in b4 => r1c2<>9
Locked Candidates Type 2 (Claiming): 9 in c8 => r4c79,r5c9,r6c7<>9
Hidden Rectangle: 1/4 in r5c45,r7c45 => r5c4<>1
AIC: 7 7- r8c6 -8- r8c5 =8= r6c5 -8- r6c8 =8= r2c8 =5= r2c9 -5- r9c9 -7 => r8c79,r9c4<>7
Locked Candidates Type 1 (Pointing): 7 in b9 => r45c9<>7
XY-Wing: 5/7/1 in r5c9,r6c17 => r5c2<>1
XY-Wing: 5/9/7 in r5c28,r6c7 => r6c1<>7
Naked Single: r6c1=1
XYZ-Wing: 5/8/9 in r56c8,r6c5 => r6c7<>5
Naked Single: r6c7=7
Naked Single: r4c7=3
Naked Single: r1c7=9
Naked Single: r3c7=4
Full House: r8c7=5
Naked Single: r8c1=7
Naked Single: r9c9=7
Naked Single: r4c1=6
Naked Single: r8c6=8
Naked Single: r7c9=4
Full House: r8c9=9
Naked Single: r2c1=2
Full House: r9c1=5
Naked Single: r2c6=4
Naked Single: r3c6=1
Full House: r3c4=8
Full House: r3c3=9
Naked Single: r6c6=9
Full House: r4c6=7
Naked Single: r8c3=1
Full House: r1c3=8
Full House: r8c5=4
Naked Single: r9c4=2
Full House: r9c2=8
Full House: r7c2=2
Naked Single: r7c5=1
Full House: r7c4=7
Naked Single: r2c2=6
Full House: r1c2=1
Full House: r1c9=3
Naked Single: r4c2=9
Full House: r5c2=7
Naked Single: r4c4=1
Full House: r5c4=4
Full House: r4c9=8
Naked Single: r5c5=5
Full House: r6c5=8
Full House: r6c8=5
Naked Single: r2c9=5
Full House: r5c9=1
Full House: r5c8=9
Full House: r2c8=8
|
normal_sudoku_2922
|
.2...37....8.7...2..5....6.......4.1..7495....4...2.7....95..3..1...6..78.....6..
|
921643758638579142475218963259367481187495326346182579762951834514836297893724615
|
Basic 9x9 Sudoku 2922
|
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 7 . .
. . 8 . 7 . . . 2
. . 5 . . . . 6 .
. . . . . . 4 . 1
. . 7 4 9 5 . . .
. 4 . . . 2 . 7 .
. . . 9 5 . . 3 .
. 1 . . . 6 . . 7
8 . . . . . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
921643758638579142475218963259367481187495326346182579762951834514836297893724615 #1 Extreme (36130) bf
Finned Swordfish: 1 r357 c167 fr3c4 fr3c5 => r2c6<>1
Brute Force: r5c6=5
Hidden Single: r5c1=1
Hidden Single: r1c3=1
Locked Candidates Type 1 (Pointing): 4 in b1 => r78c1<>4
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c8<>2
Forcing Net Verity => r3c9<>9
r2c2=9 r2c6<>9 r3c6=9 r3c9<>9
r3c2=9 r3c9<>9
r4c2=9 r4c2<>8 r5c2=8 (r5c2<>6 r5c9=6 r5c9<>3) (r5c7<>8) r5c8<>8 r5c8=2 r5c7<>2 r5c7=3 r6c9<>3 r3c9=3 r3c9<>9
r9c2=9 r9c2<>5 r4c2=5 r4c2<>8 r5c2=8 (r5c2<>6 r5c9=6 r5c9<>3) (r5c7<>8) r5c8<>8 r5c8=2 r5c7<>2 r5c7=3 r6c9<>3 r3c9=3 r3c9<>9
Forcing Net Contradiction in c8 => r5c9<>8
r5c9=8 (r5c9<>6 r5c2=6 r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r1c1<>9) (r7c9<>8 r7c9=4 r9c9<>4) r5c2<>8 r4c2=8 r4c2<>5 r9c2=5 r9c9<>5 r9c9=9 r1c9<>9 r1c8=9 r1c8<>8
r5c9=8 r4c8<>8
r5c9=8 r5c8<>8
r5c9=8 (r5c8<>8 r5c8=2 r9c8<>2) (r7c9<>8 r7c9=4 r9c8<>4) (r7c9<>8 r7c9=4 r9c9<>4) r5c2<>8 r4c2=8 r4c2<>5 r9c2=5 (r9c8<>5) r9c9<>5 r9c9=9 r9c8<>9 r9c8=1 r7c7<>1 r7c6=1 r7c6<>8 r7c79=8 r8c8<>8
Forcing Net Contradiction in r3c2 => r7c6<>7
r7c6=7 (r4c6<>7 r4c6=8 r4c2<>8 r5c2=8 r5c2<>3) r7c2<>7 r7c2=6 r5c2<>6 r5c9=6 (r5c9<>3) r5c9<>3 r5c7=3 r6c9<>3 r3c9=3 r3c2<>3
r7c6=7 r7c1<>7 r3c1=7 r3c2<>7
r7c6=7 (r7c2<>7 r7c2=6 r5c2<>6 r5c9=6 r5c9<>3 r5c7=3 r3c7<>3) (r4c6<>7 r4c6=8 r6c4<>8) (r4c6<>7 r4c6=8 r6c5<>8) (r7c6<>8) r7c6<>1 r7c7=1 (r3c7<>1) r7c7<>8 r7c9=8 r6c9<>8 r6c7=8 r3c7<>8 r3c7=9 r3c2<>9
Locked Candidates Type 1 (Pointing): 7 in b8 => r9c2<>7
Brute Force: r5c8=2
Almost Locked Set XZ-Rule: A=r7c12379 {124678}, B=r2356c7 {13589}, X=1, Z=8 => r8c7<>8
Forcing Net Contradiction in r3c7 => r3c1<>3
r3c1=3 (r2c2<>3 r2c7=3 r2c7<>5) (r3c9<>3) r3c1<>7 r3c2=7 r7c2<>7 r7c2=6 r5c2<>6 r5c2=3 r5c9<>3 r6c9=3 (r6c9<>5) r5c7<>3 r5c7=8 (r5c2<>8) r5c2<>8 r4c2=8 r4c2<>5 r9c2=5 r9c9<>5 r1c9=5 r2c8<>5 r2c4=5 r2c4<>1 r2c78=1 r3c7<>1
r3c1=3 r3c7<>3
r3c1=3 (r2c1<>3) r2c2<>3 r2c7=3 r5c7<>3 r5c7=8 r3c7<>8
r3c1=3 (r2c2<>3) r3c1<>7 r3c2=7 r7c2<>7 r7c2=6 r2c2<>6 r2c2=9 r2c6<>9 r3c6=9 r3c7<>9
Forcing Net Contradiction in r3c7 => r2c7<>3
r2c7=3 (r5c7<>3 r5c7=8 r7c7<>8) (r5c7<>3 r5c7=8 r5c2<>8) (r3c7<>3) r3c9<>3 r3c2=3 (r3c2<>7 r3c1=7 r7c1<>7) r5c2<>3 r5c2=6 (r4c3<>6) r6c3<>6 r7c3=6 r7c1<>6 r7c1=2 r7c7<>2 r7c7=1 r3c7<>1
r2c7=3 r3c7<>3
r2c7=3 r5c7<>3 r5c7=8 r3c7<>8
r2c7=3 (r2c2<>3) (r5c7<>3 r5c7=8 r5c2<>8) (r3c7<>3) r3c9<>3 r3c2=3 r5c2<>3 r5c2=6 r2c2<>6 r2c2=9 r2c6<>9 r3c6=9 r3c7<>9
Locked Candidates Type 1 (Pointing): 3 in b3 => r3c2<>3
Forcing Net Contradiction in b3 => r5c9=6
r5c9<>6 (r6c9=6 r6c9<>5) r5c9=3 r5c7<>3 r5c7=8 r5c2<>8 r4c2=8 r4c2<>5 r9c2=5 r9c9<>5 r1c9=5
r5c9<>6 r5c2=6 (r6c3<>6 r7c3=6 r7c1<>6 r7c1=2 r7c7<>2 r7c7=1 r2c7<>1) r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r3c6<>9 r2c6=9 r2c7<>9 r2c7=5
Forcing Net Contradiction in r8c7 => r3c9<>4
r3c9=4 (r2c8<>4) r3c9<>3 r3c7=3 r5c7<>3 r5c2=3 r2c2<>3 r2c1=3 r2c1<>4 r2c6=4 r2c6<>9 r3c6=9 (r3c1<>9) r3c2<>9 r3c2=7 r3c1<>7 r3c1=4 r3c9<>4
Forcing Net Contradiction in r8c7 => r3c9=3
r3c9<>3 r3c7=3 r5c7<>3 r5c7=8 (r7c7<>8) (r4c8<>8 r8c8=8 r8c8<>5) r5c2<>8 r4c2=8 r4c2<>5 r9c2=5 r8c1<>5 r8c7=5 r8c7<>2 r7c7=2 r7c7<>1 r7c6=1 r7c6<>8 r7c9=8 r3c9<>8 r3c9=3
Forcing Net Contradiction in r8c8 => r2c8<>9
r2c8=9 (r4c8<>9) (r2c6<>9 r2c6=4 r9c6<>4) r2c8<>1 r9c8=1 r9c6<>1 r9c6=7 r4c6<>7 r4c6=8 r4c8<>8 r4c8=5 (r6c9<>5) r4c2<>5 r9c2=5 r9c9<>5 r1c9=5 r1c9<>4 r12c8=4 r8c8<>4
r2c8=9 (r4c8<>9) (r2c6<>9 r2c6=4 r9c6<>4) r2c8<>1 r9c8=1 r9c6<>1 r9c6=7 r4c6<>7 r4c6=8 r4c8<>8 r4c8=5 r8c8<>5
r2c8=9 r2c8<>1 r9c8=1 r7c7<>1 r7c6=1 r7c6<>8 r7c79=8 r8c8<>8
r2c8=9 r8c8<>9
Forcing Net Contradiction in b6 => r4c1<>6
r4c1=6 (r4c1<>9) (r4c1<>2 r4c3=2 r4c3<>9) (r1c1<>6) r2c1<>6 r2c2=6 r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r4c2<>9 r4c8=9
r4c1=6 (r7c1<>6) (r7c1<>6) (r1c1<>6) r2c1<>6 r2c2=6 r7c2<>6 r7c3=6 r7c2<>6 r7c2=7 (r3c2<>7 r3c2=9 r3c7<>9) (r3c2<>7 r3c2=9 r3c6<>9 r2c6=9 r2c7<>9) r7c1<>7 r7c1=2 r7c7<>2 r8c7=2 r8c7<>9 r6c7=9
Forcing Net Contradiction in r4 => r4c2<>6
r4c2=6 (r7c2<>6 r7c2=7 r7c1<>7) (r4c3<>6) r6c3<>6 r7c3=6 r7c1<>6 r7c1=2 r7c7<>2 r8c7=2 r8c7<>5 r8c8=5 (r4c8<>5) r9c9<>5 r9c2=5 (r9c8<>5) (r8c1<>5) r4c2<>5 r4c1=5 r4c1<>9
r4c2=6 r4c2<>9
r4c2=6 (r7c2<>6 r7c2=7 r7c1<>7) (r4c3<>6) r6c3<>6 r7c3=6 r7c1<>6 r7c1=2 r4c1<>2 r4c3=2 r4c3<>9
r4c2=6 (r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r3c7<>9) (r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r3c6<>9 r2c6=9 r2c7<>9) (r7c2<>6 r7c2=7 r7c1<>7) (r4c3<>6) r6c3<>6 r7c3=6 r7c1<>6 r7c1=2 r7c7<>2 r8c7=2 r8c7<>9 r6c7=9 r4c8<>9
Forcing Net Contradiction in r3c7 => r9c4<>1
r9c4=1 r7c6<>1 r7c7=1 r3c7<>1
r9c4=1 (r6c4<>1 r6c5=1 r6c5<>8) (r7c6<>1 r7c7=1 r7c7<>8) r9c4<>7 r9c6=7 r4c6<>7 r4c6=8 (r6c4<>8) r7c6<>8 r7c9=8 r6c9<>8 r6c7=8 r3c7<>8
r9c4=1 (r3c4<>1) (r6c4<>1 r6c5=1 r3c5<>1) r7c6<>1 r7c7=1 (r2c7<>1 r2c8=1 r2c8<>4) r3c7<>1 r3c6=1 r3c6<>9 r2c6=9 r2c6<>4 r2c1=4 (r3c1<>4) r2c1<>3 r2c2=3 r2c2<>6 r7c2=6 r7c2<>7 r7c1=7 r3c1<>7 r3c1=9 r3c7<>9
Forcing Net Contradiction in r8c7 => r3c6<>1
r3c6=1 (r3c6<>9 r2c6=9 r2c6<>4) (r3c6<>4) r7c6<>1 r7c7=1 (r9c8<>1 r9c5=1 r9c5<>2) r7c7<>2 r8c7=2 r8c5<>2 r3c5=2 r3c5<>4 r1c5=4 (r1c8<>4) r1c9<>4 r2c8=4 r2c8<>1 r9c8=1 r7c7<>1 r7c6=1 r3c6<>1
Locked Candidates Type 2 (Claiming): 1 in c6 => r9c5<>1
Forcing Net Verity => r7c6<>4
r1c5=4 (r1c8<>4) r1c9<>4 r2c8=4 r2c8<>1 r9c8=1 r7c7<>1 r7c6=1 r7c6<>4
r3c5=4 (r3c5<>1) r3c5<>2 r3c4=2 r3c4<>1 r3c7=1 r7c7<>1 r7c6=1 r7c6<>4
r8c5=4 r7c6<>4
r9c5=4 r7c6<>4
Discontinuous Nice Loop: 4 r9c8 -4- r7c9 -8- r7c6 -1- r7c7 =1= r9c8 => r9c8<>4
Forcing Net Contradiction in b9 => r9c8<>9
r9c8=9 (r4c8<>9) r9c8<>1 r9c6=1 r7c6<>1 r7c6=8 (r8c4<>8) r8c5<>8 r8c8=8 (r8c8<>5) r4c8<>8 r4c8=5 r4c2<>5 r9c2=5 r8c1<>5 r8c7=5 r8c7<>2 r7c7=2 r7c7<>1
r9c8=9 r9c8<>1
Forcing Net Contradiction in c9 => r5c2=8
r5c2<>8 (r5c2=3 r2c2<>3 r2c1=3 r2c1<>4) r4c2=8 (r4c6<>8 r4c6=7 r9c6<>7) r4c2<>5 r9c2=5 r9c8<>5 r9c8=1 r9c6<>1 r9c6=4 r2c6<>4 r2c8=4 r1c9<>4
r5c2<>8 (r5c2=3 r5c7<>3 r5c7=8 r7c7<>8) r4c2=8 r4c2<>5 r9c2=5 r9c8<>5 r9c8=1 r7c7<>1 r7c6=1 r7c6<>8 r7c9=8 r7c9<>4
r5c2<>8 r4c2=8 (r4c6<>8 r4c6=7 r9c6<>7) r4c2<>5 r9c2=5 r9c8<>5 r9c8=1 r9c6<>1 r9c6=4 r9c9<>4
Full House: r5c7=3
Forcing Net Contradiction in r2c1 => r7c6=1
r7c6<>1 (r7c6=8 r7c9<>8 r7c9=4 r9c9<>4) r7c7=1 r9c8<>1 r9c8=5 (r9c2<>5) r9c9<>5 r9c9=9 r9c2<>9 r9c2=3 r2c2<>3 r2c1=3
r7c6<>1 (r7c6=8 r7c9<>8 r7c9=4 r9c9<>4) r7c7=1 r9c8<>1 r9c8=5 (r4c8<>5 r4c8=9 r1c8<>9) r9c9<>5 r9c9=9 r1c9<>9 r1c1=9 (r1c1<>6) r3c2<>9 r3c2=7 r7c2<>7 r7c2=6 r2c2<>6 r2c1=6
Hidden Single: r9c8=1
Locked Candidates Type 1 (Pointing): 8 in b8 => r8c8<>8
Skyscraper: 8 in r1c8,r3c6 (connected by r4c68) => r1c45,r3c7<>8
Grouped Discontinuous Nice Loop: 6 r1c1 -6- r1c45 =6= r2c4 =1= r2c7 -1- r3c7 -9- r1c89 =9= r1c1 => r1c1<>6
Locked Candidates Type 1 (Pointing): 6 in b1 => r2c4<>6
Naked Triple: 4,7,9 in r13c1,r3c2 => r2c1<>4, r2c12<>9
Discontinuous Nice Loop: 4 r1c8 -4- r2c8 =4= r2c6 =9= r3c6 =8= r4c6 -8- r4c8 =8= r1c8 => r1c8<>4
Forcing Chain Contradiction in c8 => r9c2<>3
r9c2=3 r2c2<>3 r2c2=6 r7c2<>6 r7c2=7 r7c1<>7 r3c1=7 r3c1<>4 r1c1=4 r1c5<>4 r1c5=6 r1c4<>6 r1c4=5 r1c8<>5
r9c2=3 r2c2<>3 r2c2=6 r7c2<>6 r7c2=7 r7c1<>7 r3c1=7 r3c1<>4 r1c1=4 r1c9<>4 r2c8=4 r2c8<>5
r9c2=3 r9c2<>5 r4c2=5 r4c8<>5
r9c2=3 r9c2<>5 r9c9=5 r8c8<>5
Forcing Net Contradiction in r7c9 => r2c1=6
r2c1<>6 r2c1=3 r2c2<>3 (r4c2=3 r4c5<>3) r2c2=6 r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 r1c1<>9 r1c1=4 r1c5<>4 r1c5=6 r4c5<>6 r4c5=8 r4c6<>8 r4c6=7 r9c6<>7 r9c6=4 (r9c9<>4) r2c6<>4 r2c8=4 r1c9<>4 r7c9=4
r2c1<>6 r2c1=3 r2c2<>3 (r4c2=3 r4c2<>5 r9c2=5 r9c9<>5) r2c2=6 r7c2<>6 r7c2=7 r3c2<>7 r3c2=9 (r1c1<>9 r1c1=4 r1c5<>4 r1c5=6 r4c5<>6 r4c5=8 r6c5<>8) (r1c1<>9 r1c1=4 r1c5<>4 r1c5=6 r4c5<>6 r4c5=8 r6c4<>8) (r3c7<>9 r3c7=1 r2c7<>1) r3c6<>9 r2c6=9 r2c7<>9 r2c7=5 r1c9<>5 r6c9=5 r6c9<>8 r6c7=8 r7c7<>8 r7c9=8
Naked Single: r2c2=3
Hidden Single: r7c2=6
Hidden Single: r7c1=7
Hidden Single: r3c2=7
Locked Candidates Type 1 (Pointing): 9 in b1 => r468c1<>9
Almost Locked Set XY-Wing: A=r4c28 {589}, B=r1368c1 {23459}, C=r2368c7 {12589}, X,Y=2,8, Z=5 => r4c1<>5
Skyscraper: 5 in r4c8,r9c9 (connected by r49c2) => r6c9,r8c8<>5
X-Wing: 5 r68 c17 => r2c7<>5
Locked Pair: 1,9 in r23c7 => r1c89,r68c7<>9
Hidden Single: r1c1=9
Full House: r3c1=4
Skyscraper: 9 in r6c9,r8c8 (connected by r68c3) => r4c8,r9c9<>9
Hidden Single: r8c8=9
Hidden Single: r6c9=9
Hidden Single: r2c8=4
Naked Single: r2c6=9
Naked Single: r2c7=1
Full House: r2c4=5
Naked Single: r3c6=8
Naked Single: r3c7=9
Naked Single: r1c4=6
Naked Single: r4c6=7
Full House: r9c6=4
Naked Single: r1c5=4
Naked Single: r9c9=5
Naked Single: r1c9=8
Full House: r1c8=5
Full House: r7c9=4
Full House: r4c8=8
Full House: r6c7=5
Naked Single: r8c7=2
Full House: r7c7=8
Full House: r7c3=2
Naked Single: r9c2=9
Full House: r4c2=5
Naked Single: r4c4=3
Naked Single: r6c1=3
Naked Single: r9c3=3
Naked Single: r4c1=2
Full House: r8c1=5
Full House: r8c3=4
Naked Single: r4c5=6
Full House: r4c3=9
Full House: r6c3=6
Naked Single: r8c4=8
Full House: r8c5=3
Naked Single: r9c5=2
Full House: r9c4=7
Naked Single: r6c4=1
Full House: r3c4=2
Full House: r3c5=1
Full House: r6c5=8
|
normal_sudoku_2887
|
.4..762..2.6.5..4.7..2...3.1....74...246..........5.82...5......1..43629...8617..
|
841376295236159847759284136185927463924638571673415982467592318518743629392861754
|
Basic 9x9 Sudoku 2887
|
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 6 2 . .
2 . 6 . 5 . . 4 .
7 . . 2 . . . 3 .
1 . . . . 7 4 . .
. 2 4 6 . . . . .
. . . . . 5 . 8 2
. . . 5 . . . . .
. 1 . . 4 3 6 2 9
. . . 8 6 1 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
841376295236159847759284136185927463924638571673415982467592318518743629392861754 #1 Hard (584)
Naked Single: r8c6=3
Naked Single: r7c8=1
Naked Single: r9c8=5
Naked Single: r8c4=7
Naked Single: r1c8=9
Naked Single: r4c8=6
Full House: r5c8=7
Hidden Single: r4c5=2
Naked Single: r7c5=9
Full House: r7c6=2
Hidden Single: r3c6=4
Hidden Single: r6c4=4
Hidden Single: r3c9=6
Hidden Single: r9c3=2
Hidden Single: r2c9=7
Locked Candidates Type 1 (Pointing): 3 in b2 => r4c4<>3
Naked Single: r4c4=9
Naked Single: r5c6=8
Full House: r2c6=9
Hidden Single: r3c5=8
Locked Candidates Type 1 (Pointing): 8 in b9 => r7c123<>8
Hidden Pair: 6,7 in r67c2 => r67c2<>3, r6c2<>9
Skyscraper: 5 in r4c2,r5c7 (connected by r3c27) => r4c9,r5c1<>5
Naked Single: r4c9=3
Naked Single: r9c9=4
Naked Single: r7c9=8
Full House: r7c7=3
Naked Single: r7c3=7
Naked Single: r7c2=6
Full House: r7c1=4
Naked Single: r6c2=7
Hidden Single: r2c7=8
Naked Single: r2c2=3
Full House: r2c4=1
Full House: r1c4=3
Naked Single: r9c2=9
Full House: r9c1=3
Naked Single: r3c2=5
Full House: r4c2=8
Full House: r4c3=5
Naked Single: r5c1=9
Naked Single: r1c1=8
Naked Single: r3c7=1
Full House: r1c9=5
Full House: r1c3=1
Full House: r3c3=9
Full House: r5c9=1
Naked Single: r8c3=8
Full House: r6c3=3
Full House: r6c1=6
Full House: r8c1=5
Naked Single: r5c7=5
Full House: r6c7=9
Full House: r5c5=3
Full House: r6c5=1
|
normal_sudoku_1398
|
.79..4......2..9..8..963..76...3...145....2.....6.5.4.7.....1...8.7...93.36.1....
|
279154836365287914814963527628439751453871269197625348742396185581742693936518472
|
Basic 9x9 Sudoku 1398
|
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 9 . . 4 . . .
. . . 2 . . 9 . .
8 . . 9 6 3 . . 7
6 . . . 3 . . . 1
4 5 . . . . 2 . .
. . . 6 . 5 . 4 .
7 . . . . . 1 . .
. 8 . 7 . . . 9 3
. 3 6 . 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
279154836365287914814963527628439751453871269197625348742396185581742693936518472 #1 Unfair (1036)
Hidden Single: r3c4=9
Hidden Single: r4c4=4
Hidden Single: r7c4=3
Hidden Single: r2c2=6
Locked Candidates Type 1 (Pointing): 1 in b5 => r5c3<>1
Locked Candidates Type 2 (Claiming): 4 in r9 => r7c9,r8c7<>4
Skyscraper: 9 in r4c2,r9c1 (connected by r49c6) => r6c1,r7c2<>9
Hidden Single: r9c1=9
XY-Chain: 5 5- r8c7 -6- r8c6 -2- r9c6 -8- r9c4 -5 => r8c5,r9c789<>5
Hidden Single: r9c4=5
Finned Swordfish: 5 r347 c378 fr7c9 => r8c7<>5
Naked Single: r8c7=6
Naked Single: r8c6=2
Naked Single: r8c5=4
Naked Single: r9c6=8
Naked Single: r7c5=9
Full House: r7c6=6
Hidden Single: r6c5=2
Hidden Single: r1c1=2
Hidden Single: r3c8=2
Naked Single: r9c8=7
Naked Single: r9c7=4
Full House: r9c9=2
Naked Single: r3c7=5
Hidden Single: r2c9=4
Hidden Single: r1c5=5
Hidden Single: r7c9=5
Full House: r7c8=8
Naked Single: r4c8=5
Hidden Single: r2c5=8
Full House: r5c5=7
Naked Single: r1c4=1
Full House: r2c6=7
Full House: r5c4=8
Naked Single: r4c6=9
Full House: r5c6=1
Naked Single: r5c3=3
Naked Single: r4c2=2
Naked Single: r5c8=6
Full House: r5c9=9
Naked Single: r6c1=1
Naked Single: r7c2=4
Full House: r7c3=2
Naked Single: r1c8=3
Full House: r2c8=1
Naked Single: r6c9=8
Full House: r1c9=6
Full House: r1c7=8
Naked Single: r6c2=9
Full House: r3c2=1
Full House: r3c3=4
Naked Single: r8c1=5
Full House: r2c1=3
Full House: r2c3=5
Full House: r8c3=1
Naked Single: r4c7=7
Full House: r4c3=8
Full House: r6c3=7
Full House: r6c7=3
|
normal_sudoku_2140
|
...1.5.3..1..6...47.........7.658.13...2...8.8..4..6..6.1..9...53.....4.......259
|
946185732318762594752934861274658913165293487893471625621549378539827146487316259
|
Basic 9x9 Sudoku 2140
|
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 . 5 . 3 .
. 1 . . 6 . . . 4
7 . . . . . . . .
. 7 . 6 5 8 . 1 3
. . . 2 . . . 8 .
8 . . 4 . . 6 . .
6 . 1 . . 9 . . .
5 3 . . . . . 4 .
. . . . . . 2 5 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
946185732318762594752934861274658913165293487893471625621549378539827146487316259 #1 Easy (320)
Naked Single: r4c6=8
Naked Single: r7c8=7
Naked Single: r9c1=4
Naked Single: r7c9=8
Naked Single: r9c2=8
Naked Single: r7c2=2
Naked Single: r7c7=3
Naked Single: r8c7=1
Full House: r8c9=6
Naked Single: r9c3=7
Full House: r8c3=9
Naked Single: r7c4=5
Full House: r7c5=4
Naked Single: r9c4=3
Naked Single: r9c5=1
Full House: r9c6=6
Hidden Single: r5c1=1
Hidden Single: r3c8=6
Hidden Single: r3c6=4
Hidden Single: r3c9=1
Hidden Single: r6c6=1
Hidden Single: r2c1=3
Hidden Single: r5c6=3
Hidden Single: r3c5=3
Hidden Single: r6c3=3
Hidden Single: r3c3=2
Naked Single: r1c1=9
Full House: r4c1=2
Naked Single: r4c3=4
Full House: r4c7=9
Naked Single: r3c2=5
Naked Single: r6c8=2
Full House: r2c8=9
Naked Single: r2c3=8
Naked Single: r3c7=8
Full House: r3c4=9
Naked Single: r6c2=9
Naked Single: r1c3=6
Full House: r1c2=4
Full House: r5c2=6
Full House: r5c3=5
Naked Single: r2c4=7
Full House: r8c4=8
Naked Single: r1c7=7
Naked Single: r6c5=7
Full House: r5c5=9
Full House: r6c9=5
Naked Single: r5c9=7
Full House: r1c9=2
Full House: r2c7=5
Full House: r2c6=2
Full House: r5c7=4
Full House: r1c5=8
Full House: r8c5=2
Full House: r8c6=7
|
normal_sudoku_3785
|
..56..9.379....6......79.1...2.4...6...3.28...1...6.9.8..5.......4..3..5.5.42.7..
|
125684973798135624346279518982741356567392841413856297839517462274963185651428739
|
Basic 9x9 Sudoku 3785
|
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 6 . . 9 . 3
7 9 . . . . 6 . .
. . . . 7 9 . 1 .
. . 2 . 4 . . . 6
. . . 3 . 2 8 . .
. 1 . . . 6 . 9 .
8 . . 5 . . . . .
. . 4 . . 3 . . 5
. 5 . 4 2 . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
125684973798135624346279518982741356567392841413856297839517462274963185651428739 #1 Hard (676)
Hidden Single: r1c7=9
Hidden Single: r2c5=3
Hidden Single: r3c7=5
Hidden Single: r1c8=7
Hidden Single: r2c6=5
Hidden Single: r1c6=4
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c9<>4
Locked Candidates Type 2 (Claiming): 2 in r1 => r3c12<>2
Naked Pair: 2,8 in r3c49 => r3c23<>8
2-String Kite: 7 in r4c6,r8c2 (connected by r7c6,r8c4) => r4c2<>7
Locked Candidates Type 2 (Claiming): 7 in r4 => r6c4<>7
Naked Single: r6c4=8
Naked Single: r3c4=2
Naked Single: r6c5=5
Naked Single: r2c4=1
Full House: r1c5=8
Naked Single: r3c9=8
Naked Single: r2c3=8
Naked Single: r1c2=2
Full House: r1c1=1
Hidden Single: r4c2=8
Hidden Single: r9c6=8
Hidden Single: r8c8=8
Hidden Single: r8c1=2
Naked Single: r8c7=1
Naked Single: r4c7=3
Naked Single: r9c9=9
Naked Single: r4c8=5
Naked Single: r4c1=9
Naked Single: r5c8=4
Naked Single: r4c4=7
Full House: r4c6=1
Full House: r8c4=9
Full House: r5c5=9
Full House: r7c6=7
Naked Single: r2c8=2
Full House: r2c9=4
Naked Single: r6c7=2
Full House: r7c7=4
Naked Single: r8c5=6
Full House: r7c5=1
Full House: r8c2=7
Naked Single: r7c9=2
Naked Single: r6c9=7
Full House: r5c9=1
Naked Single: r5c2=6
Naked Single: r6c3=3
Full House: r6c1=4
Naked Single: r5c1=5
Full House: r5c3=7
Naked Single: r7c2=3
Full House: r3c2=4
Naked Single: r3c3=6
Full House: r3c1=3
Full House: r9c1=6
Naked Single: r7c8=6
Full House: r7c3=9
Full House: r9c3=1
Full House: r9c8=3
|
normal_sudoku_1548
|
8..3...1.4....2..6....5.4..3295.....17.9.8....68...79..437...8.7....6..2....4.5..
|
856394217437182956912657438329571864174968325568423791243715689795836142681249573
|
Basic 9x9 Sudoku 1548
|
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 . . 3 . . . 1 .
4 . . . . 2 . . 6
. . . . 5 . 4 . .
3 2 9 5 . . . . .
1 7 . 9 . 8 . . .
. 6 8 . . . 7 9 .
. 4 3 7 . . . 8 .
7 . . . . 6 . . 2
. . . . 4 . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
856394217437182956912657438329571864174968325568423791243715689795836142681249573 #1 Easy (342)
Naked Single: r4c2=2
Naked Single: r6c1=5
Full House: r5c3=4
Hidden Single: r3c4=6
Hidden Single: r1c6=4
Hidden Single: r8c8=4
Naked Single: r4c8=6
Hidden Single: r6c4=4
Hidden Single: r7c6=5
Hidden Single: r1c3=6
Hidden Single: r3c9=8
Hidden Single: r4c9=4
Hidden Single: r5c5=6
Hidden Single: r7c7=6
Hidden Single: r6c5=2
Hidden Single: r9c4=2
Naked Single: r9c3=1
Naked Single: r8c3=5
Naked Single: r2c3=7
Full House: r3c3=2
Naked Single: r3c1=9
Naked Single: r1c2=5
Naked Single: r7c1=2
Full House: r9c1=6
Hidden Single: r1c7=2
Naked Single: r5c7=3
Naked Single: r2c7=9
Naked Single: r5c9=5
Full House: r5c8=2
Naked Single: r6c9=1
Full House: r4c7=8
Full House: r8c7=1
Full House: r6c6=3
Naked Single: r1c9=7
Full House: r1c5=9
Naked Single: r7c9=9
Full House: r7c5=1
Full House: r9c9=3
Full House: r9c8=7
Naked Single: r8c4=8
Full House: r2c4=1
Naked Single: r9c6=9
Full House: r8c5=3
Full House: r8c2=9
Full House: r9c2=8
Naked Single: r3c8=3
Full House: r2c8=5
Naked Single: r2c5=8
Full House: r4c5=7
Full House: r2c2=3
Full House: r3c6=7
Full House: r3c2=1
Full House: r4c6=1
|
normal_sudoku_5011
|
..475.3.9165..3...973.2.6....8...........874.45.63.8.....17..3...6..51...1......4
|
824756319165983427973421685738249561692518743451637892589174236246395178317862954
|
Basic 9x9 Sudoku 5011
|
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 5 . 3 . 9
1 6 5 . . 3 . . .
9 7 3 . 2 . 6 . .
. . 8 . . . . . .
. . . . . 8 7 4 .
4 5 . 6 3 . 8 . .
. . . 1 7 . . 3 .
. . 6 . . 5 1 . .
. 1 . . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
824756319165983427973421685738249561692518743451637892589174236246395178317862954 #1 Extreme (2324)
Hidden Single: r3c2=7
Hidden Single: r1c6=6
Hidden Single: r9c5=6
Hidden Single: r2c7=4
Hidden Single: r7c9=6
Hidden Single: r1c8=1
Hidden Single: r3c6=1
Hidden Single: r4c8=6
Hidden Single: r5c1=6
Hidden Single: r3c4=4
Locked Candidates Type 1 (Pointing): 8 in b2 => r2c89<>8
Locked Candidates Type 2 (Claiming): 8 in r7 => r8c12,r9c1<>8
Uniqueness Test 4: 2/8 in r1c12,r7c12 => r7c12<>2
AIC: 7 7- r4c1 =7= r4c6 =4= r4c5 =1= r4c9 -1- r6c9 =1= r6c3 =7= r9c3 -7 => r6c3,r89c1<>7
Hidden Single: r6c6=7
Hidden Single: r9c3=7
Hidden Single: r4c1=7
Locked Candidates Type 1 (Pointing): 3 in b4 => r8c2<>3
Uniqueness Test 4: 2/7 in r2c89,r8c89 => r8c89<>2
Hidden Rectangle: 2/3 in r8c14,r9c14 => r9c4<>2
Sashimi Swordfish: 2 c367 r479 fr5c3 fr6c3 => r4c2<>2
Sashimi Swordfish: 9 c367 r479 fr5c3 fr6c3 => r4c2<>9
Naked Single: r4c2=3
Hidden Single: r5c9=3
Hidden Single: r5c4=5
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c79<>2
Locked Candidates Type 1 (Pointing): 2 in b6 => r6c3<>2
Locked Candidates Type 2 (Claiming): 2 in c7 => r9c8<>2
W-Wing: 9/2 in r7c3,r9c6 connected by 2 in r79c7 => r7c6<>9
Turbot Fish: 9 r6c8 =9= r4c7 -9- r4c6 =9= r9c6 => r9c8<>9
Naked Pair: 5,8 in r39c8 => r8c8<>8
AIC: 9 9- r5c2 -2- r1c2 -8- r1c1 =8= r7c1 =5= r7c7 -5- r4c7 =5= r4c9 =1= r4c5 =4= r4c6 -4- r7c6 -2- r7c3 -9 => r56c3,r78c2<>9
Naked Single: r6c3=1
Naked Single: r5c3=2
Full House: r5c2=9
Full House: r7c3=9
Full House: r5c5=1
Naked Single: r6c9=2
Full House: r6c8=9
Naked Single: r2c9=7
Naked Single: r4c7=5
Full House: r4c9=1
Naked Single: r8c8=7
Naked Single: r2c8=2
Naked Single: r8c9=8
Full House: r3c9=5
Full House: r3c8=8
Full House: r9c8=5
Naked Single: r7c7=2
Full House: r9c7=9
Naked Single: r7c6=4
Naked Single: r9c6=2
Full House: r4c6=9
Naked Single: r7c2=8
Full House: r7c1=5
Naked Single: r8c5=9
Naked Single: r9c1=3
Full House: r9c4=8
Full House: r8c4=3
Naked Single: r4c4=2
Full House: r4c5=4
Full House: r2c5=8
Full House: r2c4=9
Naked Single: r1c2=2
Full House: r1c1=8
Full House: r8c1=2
Full House: r8c2=4
|
normal_sudoku_1834
|
1....3..........5..6.4..9......468...46.....98..9...2..238..69..8.6..2..6...7....
|
192583764478169352365427981931246875246758139857931426523814697784695213619372548
|
Basic 9x9 Sudoku 1834
|
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 . . .
. . . . . . . 5 .
. 6 . 4 . . 9 . .
. . . . 4 6 8 . .
. 4 6 . . . . . 9
8 . . 9 . . . 2 .
. 2 3 8 . . 6 9 .
. 8 . 6 . . 2 . .
6 . . . 7 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
192583764478169352365427981931246875246758139857931426523814697784695213619372548 #1 Extreme (14954) bf
Brute Force: r5c3=6
Hidden Single: r1c8=6
Hidden Single: r6c9=6
Hidden Single: r2c5=6
Hidden Single: r6c7=4
Naked Single: r1c7=7
Locked Candidates Type 1 (Pointing): 4 in b3 => r789c9<>4
AIC: 2 2- r1c4 -5- r1c2 -9- r1c5 =9= r8c5 =3= r9c4 =2= r9c6 -2 => r23c6,r9c4<>2
Hidden Single: r9c6=2
Locked Candidates Type 1 (Pointing): 9 in b8 => r8c13<>9
Discontinuous Nice Loop: 8 r1c9 -8- r9c9 =8= r9c8 =4= r9c3 -4- r1c3 =4= r1c9 => r1c9<>8
Grouped Discontinuous Nice Loop: 8 r2c6 -8- r5c6 =8= r5c5 =2= r45c4 -2- r1c4 -5- r1c2 -9- r1c5 =9= r2c6 => r2c6<>8
Discontinuous Nice Loop: 2 r1c5 -2- r1c4 -5- r1c2 -9- r9c2 =9= r9c3 =4= r9c8 =8= r9c9 -8- r2c9 =8= r2c3 -8- r1c3 =8= r1c5 => r1c5<>2
Discontinuous Nice Loop: 1/5/7 r5c6 =8= r5c5 =2= r3c5 -2- r1c4 -5- r1c2 -9- r9c2 =9= r9c3 =4= r9c8 =8= r3c8 -8- r3c6 =8= r5c6 => r5c6<>1, r5c6<>5, r5c6<>7
Naked Single: r5c6=8
Discontinuous Nice Loop: 5 r1c5 -5- r1c2 -9- r9c2 =9= r9c3 =4= r9c8 =8= r3c8 -8- r3c5 =8= r1c5 => r1c5<>5
Discontinuous Nice Loop: 4 r2c3 -4- r9c3 =4= r9c8 =8= r9c9 -8- r2c9 =8= r2c3 => r2c3<>4
AIC: 9 9- r1c2 -5- r1c4 -2- r1c9 -4- r1c3 =4= r2c1 =9= r4c1 -9 => r2c1,r4c2<>9
Hidden Single: r4c1=9
2-String Kite: 2 in r3c5,r4c3 (connected by r4c4,r5c5) => r3c3<>2
Discontinuous Nice Loop: 2 r2c3 -2- r4c3 =2= r4c4 -2- r1c4 -5- r1c2 -9- r9c2 =9= r9c3 =4= r9c8 =8= r9c9 -8- r2c9 =8= r2c3 => r2c3<>2
Discontinuous Nice Loop: 9 r2c2 -9- r2c6 =9= r1c5 =8= r3c5 -8- r3c8 =8= r9c8 =4= r9c3 =9= r9c2 -9- r2c2 => r2c2<>9
Discontinuous Nice Loop: 3 r9c8 -3- r9c4 =3= r8c5 =9= r1c5 =8= r3c5 -8- r3c8 =8= r9c8 => r9c8<>3
Grouped Discontinuous Nice Loop: 7 r4c3 -7- r6c23 =7= r6c6 -7- r3c6 =7= r2c46 -7- r2c2 =7= r46c2 -7- r4c3 => r4c3<>7
Grouped Discontinuous Nice Loop: 7 r5c1 -7- r6c23 =7= r6c6 -7- r3c6 =7= r2c46 -7- r2c2 =7= r46c2 -7- r5c1 => r5c1<>7
Almost Locked Set XZ-Rule: A=r1c24 {259}, B=r2c2467 {12379}, X=2, Z=9 => r1c5,r2c3<>9
Naked Single: r1c5=8
Hidden Single: r8c5=9
Hidden Single: r2c6=9
Hidden Single: r9c4=3
Empty Rectangle: 3 in b1 (r25c7) => r5c1<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r2c2<>3
Naked Single: r2c2=7
Naked Single: r2c3=8
Naked Single: r3c3=5
Naked Single: r1c2=9
Hidden Single: r3c6=7
Hidden Single: r6c3=7
Hidden Single: r1c4=5
Hidden Single: r9c3=9
Hidden Single: r9c8=4
Hidden Single: r9c9=8
Hidden Single: r3c8=8
Skyscraper: 5 in r4c9,r9c7 (connected by r49c2) => r5c7,r78c9<>5
Hidden Single: r9c7=5
Full House: r9c2=1
Naked Single: r8c3=4
Naked Single: r1c3=2
Full House: r1c9=4
Full House: r4c3=1
Naked Single: r3c1=3
Full House: r2c1=4
Hidden Single: r4c9=5
Naked Single: r4c2=3
Full House: r6c2=5
Full House: r5c1=2
Naked Single: r4c8=7
Full House: r4c4=2
Naked Single: r6c6=1
Full House: r6c5=3
Naked Single: r2c4=1
Full House: r5c4=7
Full House: r5c5=5
Full House: r3c5=2
Full House: r7c5=1
Full House: r3c9=1
Naked Single: r8c6=5
Full House: r7c6=4
Naked Single: r2c7=3
Full House: r2c9=2
Full House: r5c7=1
Full House: r5c8=3
Full House: r8c8=1
Naked Single: r7c9=7
Full House: r7c1=5
Full House: r8c1=7
Full House: r8c9=3
|
normal_sudoku_2818
|
..69.3..2.7..6..1..9..4..86168.3..7.3.28..6..7............2..91.....85......7.863
|
416983752873265914295741386168439275352817649749652138587326491634198527921574863
|
Basic 9x9 Sudoku 2818
|
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 9 . 3 . . 2
. 7 . . 6 . . 1 .
. 9 . . 4 . . 8 6
1 6 8 . 3 . . 7 .
3 . 2 8 . . 6 . .
7 . . . . . . . .
. . . . 2 . . 9 1
. . . . . 8 5 . .
. . . . 7 . 8 6 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
416983752873265914295741386168439275352817649749652138587326491634198527921574863 #1 Easy (238)
Hidden Single: r3c9=6
Hidden Single: r6c3=9
Hidden Single: r6c7=1
Naked Single: r6c5=5
Naked Single: r6c2=4
Full House: r5c2=5
Naked Single: r6c9=8
Naked Single: r5c8=4
Naked Single: r1c8=5
Naked Single: r5c9=9
Naked Single: r8c8=2
Full House: r6c8=3
Naked Single: r2c9=4
Naked Single: r4c7=2
Full House: r4c9=5
Full House: r8c9=7
Full House: r7c7=4
Naked Single: r5c5=1
Full House: r5c6=7
Naked Single: r1c7=7
Naked Single: r4c4=4
Full House: r4c6=9
Naked Single: r1c5=8
Full House: r8c5=9
Naked Single: r3c7=3
Full House: r2c7=9
Naked Single: r1c1=4
Full House: r1c2=1
Naked Single: r8c1=6
Naked Single: r3c3=5
Naked Single: r8c2=3
Naked Single: r9c2=2
Full House: r7c2=8
Naked Single: r2c3=3
Naked Single: r3c1=2
Full House: r2c1=8
Naked Single: r7c3=7
Naked Single: r8c4=1
Full House: r8c3=4
Full House: r9c3=1
Naked Single: r7c1=5
Full House: r9c1=9
Naked Single: r3c6=1
Full House: r3c4=7
Naked Single: r9c4=5
Full House: r9c6=4
Naked Single: r7c6=6
Full House: r7c4=3
Naked Single: r2c4=2
Full House: r2c6=5
Full House: r6c6=2
Full House: r6c4=6
|
normal_sudoku_2909
|
85...47...13.564.....9...5.391...6...87..2..1.2..3..7.2..6.8...9.8.......7.59..4.
|
859314762713256489462987153391875624587462391624139875235648917948721536176593248
|
Basic 9x9 Sudoku 2909
|
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 5 . . . 4 7 . .
. 1 3 . 5 6 4 . .
. . . 9 . . . 5 .
3 9 1 . . . 6 . .
. 8 7 . . 2 . . 1
. 2 . . 3 . . 7 .
2 . . 6 . 8 . . .
9 . 8 . . . . . .
. 7 . 5 9 . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
859314762713256489462987153391875624587462391624139875235648917948721536176593248 #1 Easy (274)
Naked Single: r2c2=1
Naked Single: r5c4=4
Naked Single: r9c3=6
Naked Single: r2c1=7
Naked Single: r5c5=6
Naked Single: r9c1=1
Naked Single: r5c1=5
Naked Single: r9c6=3
Naked Single: r6c3=4
Full House: r6c1=6
Full House: r3c1=4
Naked Single: r3c3=2
Naked Single: r7c3=5
Full House: r1c3=9
Full House: r3c2=6
Hidden Single: r6c6=9
Hidden Single: r4c9=4
Hidden Single: r1c4=3
Hidden Single: r6c4=1
Hidden Single: r4c6=5
Hidden Single: r4c8=2
Hidden Single: r2c8=8
Naked Single: r2c4=2
Full House: r2c9=9
Naked Single: r3c9=3
Naked Single: r1c5=1
Naked Single: r8c4=7
Full House: r4c4=8
Full House: r4c5=7
Naked Single: r3c7=1
Naked Single: r7c9=7
Naked Single: r1c8=6
Full House: r1c9=2
Naked Single: r3c6=7
Full House: r8c6=1
Full House: r3c5=8
Naked Single: r7c5=4
Full House: r8c5=2
Naked Single: r9c9=8
Full House: r9c7=2
Naked Single: r8c8=3
Naked Single: r7c2=3
Full House: r8c2=4
Naked Single: r6c9=5
Full House: r6c7=8
Full House: r8c9=6
Full House: r8c7=5
Naked Single: r5c8=9
Full House: r5c7=3
Full House: r7c7=9
Full House: r7c8=1
|
normal_sudoku_3561
|
.8......16.39...4..72.1.6.5..1.59.7.7...649.....7....6.....23..4..58..6.135.....8
|
584326791613975842972418635361859274758264913249731586896142357427583169135697428
|
Basic 9x9 Sudoku 3561
|
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
6 . 3 9 . . . 4 .
. 7 2 . 1 . 6 . 5
. . 1 . 5 9 . 7 .
7 . . . 6 4 9 . .
. . . 7 . . . . 6
. . . . . 2 3 . .
4 . . 5 8 . . 6 .
1 3 5 . . . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
584326791613975842972418635361859274758264913249731586896142357427583169135697428 #1 Easy (204)
Naked Single: r2c3=3
Naked Single: r3c1=9
Naked Single: r5c3=8
Naked Single: r1c1=5
Naked Single: r1c3=4
Full House: r2c2=1
Naked Single: r7c1=8
Naked Single: r6c3=9
Naked Single: r8c3=7
Full House: r7c3=6
Naked Single: r7c2=9
Full House: r8c2=2
Naked Single: r5c2=5
Naked Single: r8c7=1
Naked Single: r8c9=9
Full House: r8c6=3
Naked Single: r6c2=4
Full House: r4c2=6
Naked Single: r7c8=5
Naked Single: r9c8=2
Naked Single: r3c6=8
Naked Single: r3c8=3
Full House: r3c4=4
Naked Single: r6c6=1
Naked Single: r1c8=9
Naked Single: r5c8=1
Full House: r6c8=8
Naked Single: r7c4=1
Naked Single: r9c4=6
Naked Single: r9c6=7
Naked Single: r1c6=6
Full House: r2c6=5
Naked Single: r7c5=4
Full House: r7c9=7
Full House: r9c7=4
Full House: r9c5=9
Naked Single: r2c9=2
Naked Single: r4c7=2
Naked Single: r1c7=7
Full House: r2c7=8
Full House: r2c5=7
Full House: r6c7=5
Naked Single: r5c9=3
Full House: r4c9=4
Full House: r5c4=2
Naked Single: r4c1=3
Full House: r4c4=8
Full House: r1c4=3
Full House: r6c5=3
Full House: r6c1=2
Full House: r1c5=2
|
normal_sudoku_5600
|
.8...2.14...54..........6.3.9....1..6.21.5.89..8..9..6.2...8.61..3.........7..4..
|
586372914931546278274891653395687142642135789718429536427958361153264897869713425
|
Basic 9x9 Sudoku 5600
|
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 . . . 2 . 1 4
. . . 5 4 . . . .
. . . . . . 6 . 3
. 9 . . . . 1 . .
6 . 2 1 . 5 . 8 9
. . 8 . . 9 . . 6
. 2 . . . 8 . 6 1
. . 3 . . . . . .
. . . 7 . . 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
586372914931546278274891653395687142642135789718429536427958361153264897869713425 #1 Extreme (12960) bf
Brute Force: r5c6=5
Hidden Single: r5c2=4
Turbot Fish: 3 r5c5 =3= r5c7 -3- r7c7 =3= r9c8 => r9c5<>3
Forcing Chain Contradiction in c6 => r6c4<>3
r6c4=3 r6c2<>3 r2c2=3 r2c6<>3
r6c4=3 r4c6<>3
r6c4=3 r5c5<>3 r5c7=3 r7c7<>3 r9c8=3 r9c6<>3
Forcing Chain Contradiction in c6 => r6c5<>3
r6c5=3 r6c2<>3 r2c2=3 r2c6<>3
r6c5=3 r4c6<>3
r6c5=3 r5c5<>3 r5c7=3 r7c7<>3 r9c8=3 r9c6<>3
Discontinuous Nice Loop: 7 r4c8 -7- r5c7 =7= r5c5 -7- r6c5 -2- r6c4 -4- r6c8 =4= r4c8 => r4c8<>7
Forcing Chain Contradiction in c7 => r2c7<>7
r2c7=7 r2c7<>2
r2c7=7 r5c7<>7 r5c5=7 r6c5<>7 r6c5=2 r6c7<>2
r2c7=7 r2c7<>8 r8c7=8 r8c7<>2
Forcing Chain Contradiction in r4c1 => r4c9<>7
r4c9=7 r5c7<>7 r5c7=3 r5c5<>3 r4c456=3 r4c1<>3
r4c9=7 r4c3<>7 r4c3=5 r4c1<>5
r4c9=7 r4c1<>7
Finned Jellyfish: 7 r1457 c1357 fr4c6 => r6c5<>7
Naked Single: r6c5=2
Naked Single: r6c4=4
Hidden Single: r8c4=2
Hidden Single: r4c8=4
Hidden Single: r8c6=4
Hidden Single: r2c7=2
Hidden Single: r4c9=2
Hidden Single: r3c1=2
Hidden Single: r9c8=2
Hidden Single: r2c9=8
Naked Single: r9c9=5
Full House: r8c9=7
Naked Single: r8c8=9
Naked Single: r2c8=7
Naked Single: r7c7=3
Full House: r8c7=8
Naked Single: r3c8=5
Full House: r1c7=9
Full House: r6c8=3
Naked Single: r5c7=7
Full House: r5c5=3
Full House: r6c7=5
Naked Single: r7c4=9
Naked Single: r3c4=8
Naked Single: r7c5=5
Naked Single: r4c4=6
Full House: r1c4=3
Naked Single: r4c6=7
Full House: r4c5=8
Naked Single: r3c6=1
Naked Single: r4c3=5
Full House: r4c1=3
Naked Single: r2c6=6
Full House: r9c6=3
Naked Single: r3c2=7
Naked Single: r1c5=7
Full House: r3c5=9
Full House: r3c3=4
Naked Single: r1c1=5
Full House: r1c3=6
Naked Single: r6c2=1
Full House: r6c1=7
Naked Single: r7c3=7
Full House: r7c1=4
Naked Single: r8c1=1
Naked Single: r2c2=3
Naked Single: r9c2=6
Full House: r8c2=5
Full House: r8c5=6
Full House: r9c5=1
Naked Single: r2c1=9
Full House: r2c3=1
Full House: r9c3=9
Full House: r9c1=8
|
normal_sudoku_1843
|
38.4..1.....3..85...6..2.4316......9..3........2.6..7.....57.2..9......1....2....
|
385479162429316857716582943164735289873294615952861374631957428297648531548123796
|
Basic 9x9 Sudoku 1843
|
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 . . 1 . .
. . . 3 . . 8 5 .
. . 6 . . 2 . 4 3
1 6 . . . . . . 9
. . 3 . . . . . .
. . 2 . 6 . . 7 .
. . . . 5 7 . 2 .
. 9 . . . . . . 1
. . . . 2 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
385479162429316857716582943164735289873294615952861374631957428297648531548123796 #1 Extreme (2932)
Hidden Single: r1c1=3
Hidden Single: r5c8=1
Hidden Single: r8c1=2
Hidden Single: r2c2=2
Hidden Single: r1c9=2
Locked Candidates Type 1 (Pointing): 6 in b2 => r89c6<>6
Locked Candidates Type 1 (Pointing): 9 in b4 => r23c1<>9
Locked Candidates Type 2 (Claiming): 1 in c5 => r2c6,r3c4<>1
Hidden Pair: 5,7 in r8c37 => r8c37<>4, r8c3<>8, r8c7<>3, r8c7<>6
Locked Candidates Type 2 (Claiming): 4 in r8 => r9c6<>4
2-String Kite: 7 in r2c9,r8c3 (connected by r8c7,r9c9) => r2c3<>7
Empty Rectangle: 7 in b4 (r1c35) => r5c5<>7
W-Wing: 6/9 in r1c8,r2c6 connected by 9 in r12c3 => r1c6,r2c9<>6
Naked Single: r2c9=7
Naked Single: r2c1=4
Naked Single: r3c7=9
Full House: r1c8=6
Hidden Single: r2c6=6
Hidden Single: r9c8=9
Hidden Single: r7c4=9
Hidden Single: r8c4=6
Locked Candidates Type 1 (Pointing): 1 in b8 => r9c23<>1
X-Wing: 3 c58 r48 => r4c67,r8c6<>3
Hidden Pair: 1,3 in r69c6 => r6c6<>4, r6c6<>5, r69c6<>8, r6c6<>9
Hidden Single: r6c1=9
Empty Rectangle: 8 in b8 (r48c8) => r4c4<>8
Finned X-Wing: 8 c68 r48 fr5c6 => r4c5<>8
Finned Swordfish: 5 r148 c367 fr4c4 => r5c6<>5
Sue de Coq: r6c79 - {3458} (r6c2 - {45}, r4c8 - {38}) => r5c9<>8, r6c4<>5
Naked Pair: 1,8 in r69c4 => r35c4<>8
Hidden Single: r3c5=8
Hidden Single: r3c2=1
Naked Single: r2c3=9
Full House: r2c5=1
Hidden Single: r7c3=1
Naked Pair: 5,7 in r18c3 => r49c3<>5, r49c3<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r5c4<>7
Skyscraper: 8 in r4c3,r6c4 (connected by r9c34) => r4c6<>8
Skyscraper: 8 in r8c8,r9c3 (connected by r4c38) => r9c9<>8
2-String Kite: 8 in r5c1,r9c4 (connected by r5c6,r6c4) => r9c1<>8
W-Wing: 4/8 in r4c3,r8c6 connected by 8 in r5c16 => r4c6<>4
Naked Single: r4c6=5
Naked Single: r1c6=9
Naked Single: r5c4=2
Naked Single: r1c5=7
Full House: r1c3=5
Full House: r3c4=5
Full House: r3c1=7
Naked Single: r4c4=7
Naked Single: r8c3=7
Naked Single: r8c7=5
Hidden Single: r5c5=9
Hidden Single: r4c7=2
Hidden Single: r5c2=7
Hidden Single: r9c7=7
W-Wing: 3/4 in r4c5,r6c7 connected by 4 in r4c3,r6c2 => r4c8,r6c6<>3
Naked Single: r4c8=8
Full House: r8c8=3
Naked Single: r6c6=1
Naked Single: r4c3=4
Full House: r4c5=3
Full House: r8c5=4
Full House: r9c3=8
Full House: r8c6=8
Naked Single: r6c4=8
Full House: r9c4=1
Full House: r9c6=3
Full House: r5c6=4
Naked Single: r6c2=5
Full House: r5c1=8
Naked Single: r7c1=6
Full House: r9c1=5
Naked Single: r5c7=6
Full House: r5c9=5
Naked Single: r6c9=4
Full House: r6c7=3
Full House: r7c7=4
Naked Single: r9c2=4
Full House: r9c9=6
Full House: r7c9=8
Full House: r7c2=3
|
normal_sudoku_1730
|
..394....1.68....9..9651...5.7.96.416.........3...47.....48...........8.8...3..17
|
753942168146873259289651374527396841614728935938514726371485692492167583865239417
|
Basic 9x9 Sudoku 1730
|
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 4 . . . .
1 . 6 8 . . . . 9
. . 9 6 5 1 . . .
5 . 7 . 9 6 . 4 1
6 . . . . . . . .
. 3 . . . 4 7 . .
. . . 4 8 . . . .
. . . . . . . 8 .
8 . . . 3 . . 1 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
753942168146873259289651374527396841614728935938514726371485692492167583865239417 #1 Easy (326)
Hidden Single: r3c4=6
Hidden Single: r5c6=8
Hidden Single: r8c5=6
Hidden Single: r1c7=1
Hidden Single: r2c6=3
Hidden Single: r6c3=8
Naked Single: r4c2=2
Naked Single: r4c4=3
Full House: r4c7=8
Naked Single: r6c1=9
Hidden Single: r8c4=1
Hidden Single: r6c5=1
Hidden Single: r5c4=7
Naked Single: r5c5=2
Full House: r2c5=7
Full House: r6c4=5
Full House: r1c6=2
Full House: r9c4=2
Naked Single: r1c1=7
Hidden Single: r3c1=2
Naked Single: r7c1=3
Full House: r8c1=4
Naked Single: r9c3=5
Naked Single: r8c3=2
Naked Single: r9c6=9
Naked Single: r7c3=1
Full House: r5c3=4
Full House: r5c2=1
Naked Single: r9c2=6
Full House: r9c7=4
Naked Single: r3c7=3
Naked Single: r3c8=7
Hidden Single: r3c9=4
Full House: r3c2=8
Naked Single: r1c2=5
Full House: r2c2=4
Naked Single: r1c8=6
Full House: r1c9=8
Naked Single: r6c8=2
Full House: r6c9=6
Naked Single: r2c8=5
Full House: r2c7=2
Naked Single: r7c8=9
Full House: r5c8=3
Naked Single: r7c2=7
Full House: r8c2=9
Naked Single: r8c7=5
Naked Single: r5c9=5
Full House: r5c7=9
Full House: r7c7=6
Naked Single: r7c6=5
Full House: r7c9=2
Full House: r8c6=7
Full House: r8c9=3
|
normal_sudoku_961
|
.4....75....13.....295..13....9.5.....2.....38...6...92....14..9........3.6......
|
143289756568137924729546138437925681692814573851763249285391467974658312316472895
|
Basic 9x9 Sudoku 961
|
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.
|
. 4 . . . . 7 5 .
. . . 1 3 . . . .
. 2 9 5 . . 1 3 .
. . . 9 . 5 . . .
. . 2 . . . . . 3
8 . . . 6 . . . 9
2 . . . . 1 4 . .
9 . . . . . . . .
3 . 6 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
143289756568137924729546138437925681692814573851763249285391467974658312316472895 #1 Medium (606)
Hidden Single: r3c8=3
Hidden Single: r5c2=9
Hidden Single: r1c3=3
Hidden Single: r8c7=3
Hidden Single: r8c3=4
Hidden Single: r7c4=3
Hidden Single: r4c2=3
Hidden Single: r1c1=1
Hidden Single: r6c6=3
Hidden Single: r2c2=6
Naked Single: r3c1=7
Naked Single: r2c1=5
Full House: r2c3=8
Hidden Single: r2c6=7
Hidden Single: r5c7=5
Naked Single: r6c7=2
Naked Single: r2c7=9
Naked Single: r9c7=8
Full House: r4c7=6
Naked Single: r4c1=4
Full House: r5c1=6
Hidden Single: r4c5=2
Hidden Single: r5c5=1
Locked Candidates Type 1 (Pointing): 2 in b2 => r1c9<>2
Locked Candidates Type 1 (Pointing): 4 in b2 => r3c9<>4
Hidden Single: r2c9=4
Full House: r2c8=2
Locked Candidates Type 1 (Pointing): 6 in b3 => r78c9<>6
Hidden Single: r7c8=6
Hidden Single: r7c5=9
Naked Single: r1c5=8
Naked Single: r1c9=6
Full House: r3c9=8
Naked Single: r3c5=4
Full House: r3c6=6
Naked Single: r1c4=2
Full House: r1c6=9
Hidden Single: r9c8=9
Hidden Single: r7c2=8
Hidden Single: r8c4=6
Hidden Single: r4c8=8
Hidden Single: r8c6=8
Naked Single: r5c6=4
Full House: r9c6=2
Naked Single: r5c8=7
Full House: r5c4=8
Full House: r6c4=7
Full House: r9c4=4
Naked Single: r4c9=1
Full House: r4c3=7
Full House: r6c8=4
Full House: r8c8=1
Naked Single: r7c3=5
Full House: r6c3=1
Full House: r7c9=7
Full House: r6c2=5
Naked Single: r8c2=7
Full House: r9c2=1
Naked Single: r9c9=5
Full House: r8c9=2
Full House: r8c5=5
Full House: r9c5=7
|
normal_sudoku_2997
|
.54..6...6..5238.......4...8..9..35.2..63....5.12.8..7...1......7...9..1.8..5..9.
|
754816239619523874328794615846971352297635148531248967965187423472369581183452796
|
Basic 9x9 Sudoku 2997
|
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.
|
. 5 4 . . 6 . . .
6 . . 5 2 3 8 . .
. . . . . 4 . . .
8 . . 9 . . 3 5 .
2 . . 6 3 . . . .
5 . 1 2 . 8 . . 7
. . . 1 . . . . .
. 7 . . . 9 . . 1
. 8 . . 5 . . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
754816239619523874328794615846971352297635148531248967965187423472369581183452796 #1 Easy (266)
Naked Single: r6c6=8
Naked Single: r6c5=4
Naked Single: r6c8=6
Naked Single: r6c7=9
Full House: r6c2=3
Hidden Single: r5c6=5
Hidden Single: r4c9=2
Hidden Single: r3c3=8
Naked Single: r3c4=7
Naked Single: r1c4=8
Hidden Single: r9c1=1
Hidden Single: r4c6=1
Full House: r4c5=7
Naked Single: r4c3=6
Full House: r4c2=4
Naked Single: r5c2=9
Full House: r5c3=7
Naked Single: r2c2=1
Naked Single: r2c3=9
Naked Single: r3c2=2
Full House: r7c2=6
Naked Single: r2c9=4
Full House: r2c8=7
Naked Single: r3c1=3
Full House: r1c1=7
Naked Single: r7c5=8
Naked Single: r5c9=8
Naked Single: r3c8=1
Naked Single: r8c1=4
Full House: r7c1=9
Naked Single: r8c5=6
Naked Single: r1c7=2
Naked Single: r3c5=9
Full House: r1c5=1
Naked Single: r5c8=4
Full House: r5c7=1
Naked Single: r8c4=3
Full House: r9c4=4
Naked Single: r1c8=3
Full House: r1c9=9
Naked Single: r8c7=5
Naked Single: r7c8=2
Full House: r8c8=8
Full House: r8c3=2
Naked Single: r3c7=6
Full House: r3c9=5
Naked Single: r7c9=3
Full House: r9c9=6
Naked Single: r7c6=7
Full House: r9c6=2
Naked Single: r9c3=3
Full House: r9c7=7
Full House: r7c3=5
Full House: r7c7=4
|
normal_sudoku_6844
|
..14...233.......5.9....7.1.68.2..47.7......95.....36.1..67...8...2.591...2.18...
|
781459623326781495495362781968523147273146859514897362159674238847235916632918574
|
Basic 9x9 Sudoku 6844
|
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 . . . 2 3
3 . . . . . . . 5
. 9 . . . . 7 . 1
. 6 8 . 2 . . 4 7
. 7 . . . . . . 9
5 . . . . . 3 6 .
1 . . 6 7 . . . 8
. . . 2 . 5 9 1 .
. . 2 . 1 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
781459623326781495495362781968523147273146859514897362159674238847235916632918574 #1 Easy (208)
Naked Single: r4c9=7
Naked Single: r3c8=8
Naked Single: r4c1=9
Naked Single: r6c9=2
Naked Single: r1c7=6
Naked Single: r2c8=9
Full House: r2c7=4
Naked Single: r5c8=5
Naked Single: r6c3=4
Naked Single: r9c7=5
Naked Single: r4c7=1
Full House: r5c7=8
Full House: r7c7=2
Naked Single: r7c8=3
Full House: r9c8=7
Naked Single: r5c1=2
Naked Single: r5c3=3
Full House: r6c2=1
Naked Single: r4c6=3
Full House: r4c4=5
Naked Single: r5c4=1
Naked Single: r3c4=3
Naked Single: r9c4=9
Naked Single: r7c6=4
Full House: r8c5=3
Naked Single: r5c6=6
Full House: r5c5=4
Naked Single: r7c2=5
Full House: r7c3=9
Naked Single: r3c6=2
Naked Single: r1c2=8
Naked Single: r1c1=7
Naked Single: r2c2=2
Naked Single: r8c2=4
Full House: r9c2=3
Naked Single: r1c6=9
Full House: r1c5=5
Naked Single: r2c3=6
Naked Single: r8c9=6
Full House: r9c9=4
Full House: r9c1=6
Naked Single: r6c6=7
Full House: r2c6=1
Naked Single: r3c5=6
Naked Single: r2c5=8
Full House: r2c4=7
Full House: r6c4=8
Full House: r6c5=9
Naked Single: r3c1=4
Full House: r3c3=5
Full House: r8c3=7
Full House: r8c1=8
|
normal_sudoku_75
|
.....23..21..7...59..5..721....1..8.16......2..9.26.7.52...7..6..7....4..9.......
|
745192368216873495938564721372415689164789532859326174523947816687251943491638257
|
Basic 9x9 Sudoku 75
|
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 . .
2 1 . . 7 . . . 5
9 . . 5 . . 7 2 1
. . . . 1 . . 8 .
1 6 . . . . . . 2
. . 9 . 2 6 . 7 .
5 2 . . . 7 . . 6
. . 7 . . . . 4 .
. 9 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
745192368216873495938564721372415689164789532859326174523947816687251943491638257 #1 Extreme (7862)
Hidden Single: r3c8=2
Hidden Single: r1c4=1
Hidden Single: r6c7=1
Hidden Single: r4c3=2
Hidden Single: r4c7=6
Hidden Single: r5c4=7
Hidden Single: r9c9=7
Hidden Single: r8c6=1
Hidden Single: r6c2=5
Hidden Single: r1c3=5
Hidden Single: r4c6=5
Locked Pair: 6,9 in r12c8 => r1c9,r2c7,r57c8<>9
Empty Rectangle: 4 in b5 (r25c7) => r2c4<>4
XYZ-Wing: 3/8/9 in r7c7,r8c29 => r8c7<>8
Hidden Rectangle: 1/3 in r7c38,r9c38 => r9c3<>3
Finned X-Wing: 8 c29 r18 fr3c2 => r1c1<>8
Almost Locked Set Chain: 8- r1c129 {4678} -6- r8c12 {368} -8- r468c9 {3489} -4- r1c89,r2c8 {4689} -8 => r1c5<>8
Almost Locked Set XY-Wing: A=r2c7 {48}, B=r138c2 {3478}, C=r1c1589 {46789}, X,Y=7,8, Z=4 => r2c3<>4
Forcing Chain Contradiction in r8 => r8c5<>6
r8c5=6 r8c5<>5 r8c7=5 r8c7<>2 r8c4=2 r8c4<>9
r8c5=6 r8c5<>9
r8c5=6 r8c5<>5 r8c7=5 r8c7<>9
r8c5=6 r89c4<>6 r2c4=6 r2c8<>6 r2c8=9 r2c6<>9 r5c6=9 r5c7<>9 r4c9=9 r8c9<>9
Forcing Chain Contradiction in r5 => r9c6<>4
r9c6=4 r9c1<>4 r79c3=4 r5c3<>4
r9c6=4 r79c4<>4 r46c4=4 r5c5<>4
r9c6=4 r5c6<>4
r9c6=4 r2c6<>4 r2c7=4 r5c7<>4
Forcing Net Contradiction in r3 => r2c6<>8
r2c6=8 (r2c7<>8 r1c9=8 r8c9<>8) r2c6<>9 r5c6=9 r4c4<>9 r4c9=9 r8c9<>9 r8c9=3 r8c2<>3 r8c2=8 r3c2<>8
r2c6=8 (r9c6<>8 r9c6=3 r7c5<>3) (r9c6<>8 r9c6=3 r8c5<>3) (r9c6<>8 r9c6=3 r9c5<>3) (r2c7<>8 r2c7=4 r5c7<>4) r2c6<>9 r5c6=9 r5c7<>9 r5c7=5 r5c8<>5 r5c8=3 r5c5<>3 r3c5=3 r3c5<>6 r3c3=6 r3c3<>8
r2c6=8 r3c5<>8
r2c6=8 r3c6<>8
Finned Jellyfish: 8 r2679 c1347 fr7c5 fr9c5 fr9c6 => r8c4<>8
Forcing Chain Verity => r6c1<>3
r2c3=8 r5c3<>8 r6c1=8 r6c1<>3
r2c4=8 r6c4<>8 r6c1=8 r6c1<>3
r2c7=8 r2c7<>4 r5c7=4 r6c9<>4 r6c9=3 r6c1<>3
Forcing Chain Contradiction in r8c9 => r4c4<>3
r4c4=3 r6c4<>3 r6c9=3 r8c9<>3
r4c4=3 r4c1<>3 r89c1=3 r8c2<>3 r8c2=8 r8c9<>8
r4c4=3 r4c4<>9 r4c9=9 r8c9<>9
Forcing Chain Contradiction in r2 => r4c9<>3
r4c9=3 r4c12<>3 r5c3=3 r2c3<>3
r4c9=3 r6c9<>3 r6c4=3 r2c4<>3
r4c9=3 r4c9<>9 r4c4=9 r5c6<>9 r2c6=9 r2c6<>3
Locked Candidates Type 2 (Claiming): 3 in r4 => r5c3<>3
Naked Pair: 4,8 in r5c3,r6c1 => r4c12<>4
Locked Candidates Type 2 (Claiming): 4 in c2 => r1c1,r3c3<>4
Almost Locked Set XZ-Rule: A=r8c12 {368}, B=r14c1 {367}, X=6, Z=3 => r9c1<>3
Forcing Chain Contradiction in r1c5 => r1c1=7
r1c1<>7 r1c2=7 r4c2<>7 r4c2=3 r8c2<>3 r8c2=8 r89c1<>8 r6c1=8 r6c1<>4 r5c3=4 r5c6<>4 r23c6=4 r1c5<>4
r1c1<>7 r1c1=6 r1c5<>6
r1c1<>7 r1c1=6 r1c8<>6 r1c8=9 r1c5<>9
Naked Single: r4c1=3
Naked Single: r4c2=7
Locked Candidates Type 1 (Pointing): 6 in b1 => r9c3<>6
Naked Pair: 4,8 in r1c29 => r1c5<>4
Forcing Chain Contradiction in c2 => r8c1=6
r8c1<>6 r8c1=8 r8c9<>8 r1c9=8 r1c2<>8
r8c1<>6 r8c1=8 r6c1<>8 r6c4=8 r2c4<>8 r3c56=8 r3c2<>8
r8c1<>6 r8c1=8 r8c2<>8
Discontinuous Nice Loop: 4 r9c4 -4- r4c4 -9- r5c6 =9= r2c6 -9- r2c8 -6- r2c4 =6= r9c4 => r9c4<>4
Almost Locked Set XZ-Rule: A=r7c457 {3489}, B=r9c136 {1348}, X=3, Z=4 => r7c3,r9c5<>4
Discontinuous Nice Loop: 8 r7c5 -8- r7c7 -9- r5c7 =9= r4c9 =4= r4c4 -4- r7c4 =4= r7c5 => r7c5<>8
Sashimi Swordfish: 8 r257 c347 fr5c5 fr5c6 => r6c4<>8
Hidden Single: r6c1=8
Full House: r5c3=4
Full House: r9c1=4
Hidden Single: r2c7=4
Naked Single: r1c9=8
Naked Single: r1c2=4
Hidden Single: r3c6=4
Hidden Single: r7c5=4
Skyscraper: 9 in r4c9,r7c7 (connected by r47c4) => r5c7,r8c9<>9
Naked Single: r5c7=5
Naked Single: r8c9=3
Naked Single: r5c8=3
Naked Single: r6c9=4
Full House: r4c9=9
Full House: r6c4=3
Full House: r4c4=4
Naked Single: r7c8=1
Naked Single: r8c2=8
Full House: r3c2=3
Naked Single: r9c8=5
Naked Single: r7c3=3
Full House: r9c3=1
Hidden Single: r8c5=5
Hidden Single: r2c6=3
Naked Single: r9c6=8
Full House: r5c6=9
Full House: r5c5=8
Naked Single: r7c4=9
Full House: r7c7=8
Naked Single: r9c7=2
Full House: r8c7=9
Full House: r8c4=2
Naked Single: r3c5=6
Full House: r3c3=8
Full House: r2c3=6
Naked Single: r9c4=6
Full House: r2c4=8
Full House: r1c5=9
Full House: r9c5=3
Full House: r2c8=9
Full House: r1c8=6
|
normal_sudoku_6128
|
9.......8.6..9...1.....2...49...53..2.3.46.9..56......3.95..4......29.6..2.4.3...
|
912754638765398241834612975497285316283146597156937824379561482541829763628473159
|
Basic 9x9 Sudoku 6128
|
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 . . . . . . . 8
. 6 . . 9 . . . 1
. . . . . 2 . . .
4 9 . . . 5 3 . .
2 . 3 . 4 6 . 9 .
. 5 6 . . . . . .
3 . 9 5 . . 4 . .
. . . . 2 9 . 6 .
. 2 . 4 . 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
912754638765398241834612975497285316283146597156937824379561482541829763628473159 #1 Extreme (13792) bf
Hidden Single: r4c2=9
Hidden Single: r6c4=9
Hidden Single: r4c9=6
Hidden Single: r7c5=6
Hidden Single: r9c1=6
Hidden Single: r8c9=3
Hidden Single: r4c4=2
Hidden Single: r6c5=3
Brute Force: r4c8=1
Skyscraper: 1 in r5c4,r7c6 (connected by r57c2) => r6c6,r8c4<>1
Hidden Single: r6c1=1
Hidden Single: r5c4=1
Forcing Chain Contradiction in c2 => r7c6<>7
r7c6=7 r8c4<>7 r8c4=8 r8c1<>8 r23c1=8 r3c2<>8
r7c6=7 r6c6<>7 r6c6=8 r4c5<>8 r4c3=8 r5c2<>8
r7c6=7 r7c6<>1 r7c2=1 r7c2<>8
r7c6=7 r8c4<>7 r8c4=8 r8c2<>8
Turbot Fish: 7 r4c3 =7= r4c5 -7- r9c5 =7= r8c4 => r8c3<>7
Grouped Discontinuous Nice Loop: 7 r1c3 -7- r4c3 =7= r4c5 -7- r9c5 =7= r8c4 -7- r8c1 =7= r23c1 -7- r1c3 => r1c3<>7
Grouped Discontinuous Nice Loop: 7 r2c3 -7- r4c3 =7= r4c5 -7- r9c5 =7= r8c4 -7- r8c1 =7= r23c1 -7- r2c3 => r2c3<>7
Grouped Discontinuous Nice Loop: 7 r3c3 -7- r4c3 =7= r4c5 -7- r9c5 =7= r8c4 -7- r8c1 =7= r23c1 -7- r3c3 => r3c3<>7
Grouped Discontinuous Nice Loop: 8 r3c5 -8- r4c5 -7- r9c5 =7= r8c4 =8= r23c4 -8- r3c5 => r3c5<>8
Almost Locked Set XZ-Rule: A=r57c2 {178}, B=r7c6,r8c4 {178}, X=1, Z=7 => r8c2<>7
Forcing Chain Contradiction in r9 => r7c6=1
r7c6<>1 r7c6=8 r6c6<>8 r6c6=7 r4c5<>7 r4c3=7 r9c3<>7
r7c6<>1 r9c5=1 r9c5<>7
r7c6<>1 r7c2=1 r7c2<>7 r7c89=7 r9c7<>7
r7c6<>1 r7c2=1 r7c2<>7 r7c89=7 r9c8<>7
r7c6<>1 r7c2=1 r7c2<>7 r7c89=7 r9c9<>7
Naked Pair: 7,8 in r57c2 => r13c2<>7, r38c2<>8
Locked Candidates Type 1 (Pointing): 7 in b1 => r8c1<>7
Naked Pair: 7,8 in r49c5 => r13c5<>7
X-Wing: 7 c35 r49 => r9c789<>7
Remote Pair: 8/7 r7c2 -7- r5c2 -8- r4c3 -7- r4c5 -8- r9c5 -7- r8c4 => r8c13<>8
Naked Single: r8c1=5
Locked Pair: 1,4 in r8c23 => r8c7,r9c3<>1
Hidden Single: r9c7=1
Hidden Single: r9c9=9
Hidden Single: r3c7=9
Hidden Single: r9c8=5
Hidden Single: r3c4=6
Hidden Single: r1c7=6
Locked Candidates Type 1 (Pointing): 8 in b2 => r2c13<>8
Naked Single: r2c1=7
Full House: r3c1=8
Locked Candidates Type 1 (Pointing): 7 in b2 => r1c8<>7
Remote Pair: 7/8 r5c2 -8- r7c2 -7- r9c3 -8- r9c5 -7- r8c4 -8- r8c7 => r5c7<>7, r5c7<>8
Naked Single: r5c7=5
Naked Single: r2c7=2
Naked Single: r5c9=7
Full House: r5c2=8
Full House: r4c3=7
Full House: r4c5=8
Full House: r6c6=7
Naked Single: r6c7=8
Full House: r8c7=7
Naked Single: r7c9=2
Full House: r7c8=8
Full House: r7c2=7
Naked Single: r9c3=8
Full House: r9c5=7
Full House: r8c4=8
Naked Single: r1c6=4
Full House: r2c6=8
Naked Single: r6c9=4
Full House: r3c9=5
Full House: r6c8=2
Naked Single: r2c4=3
Full House: r1c4=7
Naked Single: r1c8=3
Naked Single: r3c5=1
Full House: r1c5=5
Naked Single: r2c8=4
Full House: r2c3=5
Full House: r3c8=7
Naked Single: r1c2=1
Full House: r1c3=2
Naked Single: r3c3=4
Full House: r3c2=3
Full House: r8c2=4
Full House: r8c3=1
|
normal_sudoku_1103
|
.8...5..7......493.....48151.58......3..921....41...3...34...........78.7.1..9...
|
489315627517268493362974815125843976638792154974156238893427561246531789751689342
|
Basic 9x9 Sudoku 1103
|
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 . . . 5 . . 7
. . . . . . 4 9 3
. . . . . 4 8 1 5
1 . 5 8 . . . . .
. 3 . . 9 2 1 . .
. . 4 1 . . . 3 .
. . 3 4 . . . . .
. . . . . . 7 8 .
7 . 1 . . 9 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
489315627517268493362974815125843976638792154974156238893427561246531789751689342 #1 Easy (490)
Hidden Single: r3c9=5
Hidden Single: r1c1=4
Hidden Single: r4c5=4
Hidden Single: r9c7=3
Hidden Single: r1c5=1
Hidden Single: r2c2=1
Hidden Single: r5c3=8
Naked Single: r5c1=6
Naked Single: r5c9=4
Hidden Single: r7c1=8
Hidden Single: r9c5=8
Hidden Single: r3c1=3
Hidden Single: r4c6=3
Hidden Single: r1c4=3
Hidden Single: r2c1=5
Hidden Single: r6c9=8
Hidden Single: r9c8=4
Hidden Single: r8c2=4
Hidden Single: r2c6=8
Hidden Single: r8c5=3
Hidden Single: r1c3=9
Hidden Single: r3c4=9
Hidden Single: r8c4=5
Naked Single: r5c4=7
Full House: r5c8=5
Naked Single: r6c6=6
Full House: r6c5=5
Naked Single: r8c6=1
Full House: r7c6=7
Hidden Single: r9c2=5
Hidden Single: r4c8=7
Hidden Single: r6c2=7
Hidden Single: r7c7=5
Hidden Single: r7c9=1
Hidden Single: r7c2=9
Naked Single: r4c2=2
Full House: r3c2=6
Full House: r6c1=9
Full House: r8c1=2
Full House: r6c7=2
Full House: r8c3=6
Full House: r8c9=9
Naked Single: r1c7=6
Full House: r1c8=2
Full House: r4c7=9
Full House: r4c9=6
Full House: r7c8=6
Full House: r9c9=2
Full House: r7c5=2
Full House: r9c4=6
Full House: r2c4=2
Naked Single: r3c5=7
Full House: r2c5=6
Full House: r2c3=7
Full House: r3c3=2
|
normal_sudoku_2432
|
....36.2.2.....6...5..7..499246.5.3...1.29......3...9.6.....4.....9.2.81.1.4.....
|
489136725237594618156278349924685137361729854578341296695813472743962581812457963
|
Basic 9x9 Sudoku 2432
|
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 . 2 .
2 . . . . . 6 . .
. 5 . . 7 . . 4 9
9 2 4 6 . 5 . 3 .
. . 1 . 2 9 . . .
. . . 3 . . . 9 .
6 . . . . . 4 . .
. . . 9 . 2 . 8 1
. 1 . 4 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
489136725237594618156278349924685137361729854578341296695813472743962581812457963 #1 Easy (336)
Hidden Single: r4c1=9
Hidden Single: r3c3=6
Hidden Single: r2c5=9
Hidden Single: r9c7=9
Hidden Single: r3c4=2
Hidden Single: r2c8=1
Hidden Single: r8c5=6
Hidden Single: r5c9=4
Hidden Single: r6c5=4
Hidden Single: r2c6=4
Hidden Single: r6c7=2
Hidden Single: r6c6=1
Naked Single: r3c6=8
Naked Single: r4c5=8
Full House: r5c4=7
Naked Single: r2c4=5
Full House: r1c4=1
Full House: r7c4=8
Naked Single: r3c7=3
Full House: r3c1=1
Naked Single: r4c9=7
Full House: r4c7=1
Naked Single: r9c5=5
Full House: r7c5=1
Naked Single: r2c9=8
Naked Single: r1c9=5
Full House: r1c7=7
Naked Single: r6c9=6
Naked Single: r8c7=5
Full House: r5c7=8
Full House: r5c8=5
Naked Single: r7c8=7
Full House: r9c8=6
Naked Single: r5c1=3
Full House: r5c2=6
Naked Single: r7c6=3
Full House: r9c6=7
Naked Single: r7c2=9
Naked Single: r7c9=2
Full House: r7c3=5
Full House: r9c9=3
Naked Single: r9c1=8
Full House: r9c3=2
Naked Single: r1c1=4
Naked Single: r1c2=8
Full House: r1c3=9
Naked Single: r8c1=7
Full House: r6c1=5
Naked Single: r6c2=7
Full House: r6c3=8
Naked Single: r8c3=3
Full House: r2c3=7
Full House: r2c2=3
Full House: r8c2=4
|
normal_sudoku_2956
|
97....2....18....784...7.9......6.3...9..5..1.1.97...41..74...9.9.6.........5....
|
975164283261893547843527196587416932429385671316972854152748369798631425634259718
|
Basic 9x9 Sudoku 2956
|
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 . . . . 2 . .
. . 1 8 . . . . 7
8 4 . . . 7 . 9 .
. . . . . 6 . 3 .
. . 9 . . 5 . . 1
. 1 . 9 7 . . . 4
1 . . 7 4 . . . 9
. 9 . 6 . . . . .
. . . . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
975164283261893547843527196587416932429385671316972854152748369798631425634259718 #1 Extreme (30822) bf
Hidden Single: r3c6=7
Hidden Single: r4c7=9
Hidden Single: r9c6=9
Hidden Single: r2c5=9
Locked Candidates Type 1 (Pointing): 4 in b5 => r1c4<>4
Locked Candidates Type 1 (Pointing): 7 in b6 => r5c1<>7
Turbot Fish: 1 r3c7 =1= r1c8 -1- r1c6 =1= r8c6 => r8c7<>1
Brute Force: r5c7=6
Hidden Single: r5c8=7
Brute Force: r5c5=8
Brute Force: r5c4=3
Naked Single: r5c2=2
Full House: r5c1=4
Naked Single: r6c6=2
Naked Single: r4c5=1
Full House: r4c4=4
Hidden Single: r2c1=2
Hidden Single: r4c9=2
Locked Candidates Type 1 (Pointing): 5 in b6 => r6c13<>5
Locked Candidates Type 1 (Pointing): 8 in b6 => r6c3<>8
Naked Triple: 3,5,6 in r136c3 => r478c3<>5, r789c3<>3, r79c3<>6
Locked Candidates Type 2 (Claiming): 5 in c3 => r2c2<>5
Locked Candidates Type 2 (Claiming): 5 in r2 => r1c89,r3c79<>5
Hidden Single: r8c9=5
Hidden Single: r7c2=5
Naked Single: r4c2=8
Naked Single: r4c3=7
Full House: r4c1=5
Hidden Single: r7c8=6
Hidden Single: r2c2=6
Full House: r9c2=3
Naked Single: r8c1=7
Naked Single: r9c9=8
Naked Single: r9c1=6
Full House: r6c1=3
Full House: r6c3=6
Naked Single: r7c7=3
Naked Single: r3c7=1
Naked Single: r7c6=8
Full House: r7c3=2
Naked Single: r8c7=4
Naked Single: r9c3=4
Full House: r8c3=8
Naked Single: r2c7=5
Naked Single: r9c7=7
Full House: r6c7=8
Full House: r6c8=5
Naked Single: r2c8=4
Full House: r2c6=3
Naked Single: r1c8=8
Naked Single: r1c5=6
Naked Single: r8c6=1
Full House: r1c6=4
Naked Single: r1c9=3
Full House: r3c9=6
Naked Single: r3c5=2
Full House: r8c5=3
Full House: r8c8=2
Full House: r9c4=2
Full House: r9c8=1
Naked Single: r1c3=5
Full House: r1c4=1
Full House: r3c4=5
Full House: r3c3=3
|
normal_sudoku_1169
|
...18.....8.4.9.....4.5.9..8.691.4....932...7..2.6.19.2...41.....5....1.46.5..2..
|
953182746687439521124756938836917452519324867742865193298641375375298614461573289
|
Basic 9x9 Sudoku 1169
|
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 8 . . . .
. 8 . 4 . 9 . . .
. . 4 . 5 . 9 . .
8 . 6 9 1 . 4 . .
. . 9 3 2 . . . 7
. . 2 . 6 . 1 9 .
2 . . . 4 1 . . .
. . 5 . . . . 1 .
4 6 . 5 . . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
953182746687439521124756938836917452519324867742865193298641375375298614461573289 #1 Hard (1408)
Naked Single: r5c5=2
Hidden Single: r8c9=4
Hidden Single: r1c8=4
Hidden Single: r9c3=1
Hidden Single: r7c3=8
Locked Candidates Type 2 (Claiming): 2 in r2 => r13c9,r3c8<>2
Locked Candidates Type 2 (Claiming): 3 in c3 => r1c12,r23c1,r3c2<>3
Locked Candidates Type 2 (Claiming): 7 in c3 => r1c12,r23c1,r3c2<>7
Naked Pair: 3,7 in r2c35 => r2c789<>3, r2c78<>7
Naked Triple: 3,7,9 in r8c125 => r8c467<>7, r8c67<>3
Naked Triple: 1,5,6 in r235c1 => r16c1<>5, r1c1<>6
Naked Single: r1c1=9
Naked Triple: 5,6,8 in r258c7 => r17c7<>5, r17c7<>6
Naked Pair: 3,7 in r1c37 => r1c69<>3, r1c6<>7
Naked Pair: 5,6 in r1c9,r2c7 => r2c89<>5, r2c89,r3c89<>6
Naked Single: r2c8=2
Naked Single: r2c9=1
Hidden Single: r4c9=2
X-Wing: 5 c17 r25 => r5c268<>5
Skyscraper: 8 in r5c7,r6c4 (connected by r8c47) => r5c6,r6c9<>8
Naked Single: r5c6=4
Naked Single: r5c2=1
Naked Single: r3c2=2
Naked Single: r5c1=5
Naked Single: r1c2=5
Naked Single: r2c1=6
Naked Single: r1c9=6
Naked Single: r2c7=5
Naked Single: r3c1=1
Naked Single: r1c6=2
Hidden Single: r6c2=4
Hidden Single: r8c4=2
Hidden Single: r6c4=8
Locked Candidates Type 1 (Pointing): 7 in b5 => r39c6<>7
Skyscraper: 7 in r3c4,r9c5 (connected by r39c8) => r2c5,r7c4<>7
Naked Single: r2c5=3
Full House: r2c3=7
Full House: r1c3=3
Full House: r1c7=7
Naked Single: r7c4=6
Full House: r3c4=7
Full House: r3c6=6
Naked Single: r7c7=3
Naked Single: r8c6=8
Naked Single: r8c7=6
Full House: r5c7=8
Full House: r5c8=6
Naked Single: r9c6=3
Bivalue Universal Grave + 1 => r8c2<>3, r8c2<>9
Naked Single: r8c2=7
Naked Single: r4c2=3
Full House: r7c2=9
Full House: r8c1=3
Full House: r8c5=9
Full House: r6c1=7
Full House: r9c5=7
Naked Single: r4c8=5
Full House: r4c6=7
Full House: r6c6=5
Full House: r6c9=3
Naked Single: r7c9=5
Full House: r7c8=7
Naked Single: r9c8=8
Full House: r3c8=3
Full House: r3c9=8
Full House: r9c9=9
|
normal_sudoku_713
|
265.1.....4...2..........2.....7.....52.9..713....52.9.....9.15.2.3......9175.3..
|
265417938143982756879536124916278543452693871387145269734829615528361497691754382
|
Basic 9x9 Sudoku 713
|
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 5 . 1 . . . .
. 4 . . . 2 . . .
. . . . . . . 2 .
. . . . 7 . . . .
. 5 2 . 9 . . 7 1
3 . . . . 5 2 . 9
. . . . . 9 . 1 5
. 2 . 3 . . . . .
. 9 1 7 5 . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
265417938143982756879536124916278543452693871387145269734829615528361497691754382 #1 Extreme (14422) bf
Hidden Single: r1c1=2
Hidden Single: r4c4=2
Hidden Single: r9c9=2
Hidden Single: r8c6=1
Hidden Single: r8c1=5
Hidden Single: r7c5=2
Hidden Single: r5c6=3
Hidden Single: r6c4=1
Locked Candidates Type 2 (Claiming): 3 in r1 => r2c89,r3c9<>3
Brute Force: r4c6=8
Naked Single: r4c2=1
Skyscraper: 8 in r5c7,r9c8 (connected by r59c1) => r6c8,r78c7<>8
Hidden Single: r5c7=8
Naked Pair: 4,6 in r6c58 => r6c3<>4, r6c3<>6
Grouped Discontinuous Nice Loop: 8 r2c8 -8- r9c8 =8= r9c1 -8- r7c123 =8= r7c4 -8- r1c4 =8= r1c89 -8- r2c8 => r2c8<>8
Forcing Chain Contradiction in r9c1 => r7c4<>4
r7c4=4 r5c4<>4 r5c1=4 r9c1<>4
r7c4=4 r9c6<>4 r9c6=6 r9c1<>6
r7c4=4 r7c4<>8 r7c123=8 r9c1<>8
Turbot Fish: 4 r6c8 =4= r6c5 -4- r8c5 =4= r9c6 => r9c8<>4
AIC: 6 6- r3c6 =6= r9c6 =4= r8c5 -4- r6c5 -6 => r23c5<>6
Almost Locked Set XZ-Rule: A=r1c46,r23c5,r3c6 {346789}, B=r1c789,r23c9 {346789}, X=9, Z=6 => r3c7<>6
Almost Locked Set XY-Wing: A=r1c467 {4789}, B=r6c238 {4678}, C=r236c5 {3468}, X,Y=6,8, Z=4 => r1c8<>4
Almost Locked Set XY-Wing: A=r4c789 {3456}, B=r59c1 {468}, C=r69c8 {468}, X,Y=4,8, Z=6 => r4c1<>6
Almost Locked Set Chain: 7- r1c467 {4789} -8- r23c5 {348} -4- r68c5 {468} -8- r1c6,r23c5 {3478} -7 => r1c9<>7
Almost Locked Set Chain: 6- r5c1 {46} -4- r5c4 {46} -6- r6c5 {46} -4- r6c8 {46} -6- r9c8 {68} -8- r59c1 {468} -6 => r7c1<>6
Forcing Chain Contradiction in r9c1 => r7c4=8
r7c4<>8 r7c4=6 r9c6<>6 r9c6=4 r9c1<>4
r7c4<>8 r7c4=6 r5c4<>6 r5c1=6 r9c1<>6
r7c4<>8 r7c123=8 r9c1<>8
Locked Candidates Type 2 (Claiming): 8 in r1 => r23c9<>8
Naked Pair: 4,6 in r68c5 => r3c5<>4
Naked Triple: 4,7,9 in r1c467 => r1c8<>9, r1c9<>4
Remote Pair: 6/4 r6c8 -4- r6c5 -6- r8c5 -4- r9c6 => r9c8<>6
Naked Single: r9c8=8
Naked Single: r1c8=3
Naked Single: r1c9=8
Hidden Single: r8c3=8
Naked Single: r6c3=7
Naked Single: r6c2=8
Hidden Single: r4c9=3
Locked Pair: 3,9 in r23c3 => r23c1,r4c3<>9, r3c2,r7c3<>3
Naked Single: r3c2=7
Full House: r7c2=3
Hidden Single: r4c1=9
Hidden Single: r7c1=7
Hidden Single: r1c6=7
Naked Pair: 4,6 in r3c69 => r3c47<>4, r3c4<>6
Remote Pair: 4/6 r3c9 -6- r3c6 -4- r9c6 -6- r9c1 -4- r7c3 -6- r7c7 => r1c7,r8c9<>4, r2c7,r8c9<>6
Naked Single: r1c7=9
Full House: r1c4=4
Naked Single: r8c9=7
Naked Single: r3c6=6
Full House: r9c6=4
Full House: r8c5=6
Full House: r9c1=6
Full House: r7c3=4
Full House: r7c7=6
Naked Single: r5c4=6
Full House: r6c5=4
Full House: r5c1=4
Full House: r4c3=6
Full House: r6c8=6
Naked Single: r2c9=6
Full House: r3c9=4
Naked Single: r8c7=4
Full House: r8c8=9
Naked Single: r2c8=5
Full House: r4c8=4
Full House: r4c7=5
Naked Single: r2c4=9
Full House: r3c4=5
Naked Single: r3c7=1
Full House: r2c7=7
Naked Single: r2c3=3
Full House: r3c3=9
Naked Single: r3c1=8
Full House: r2c1=1
Full House: r2c5=8
Full House: r3c5=3
|
normal_sudoku_2885
|
..9.4.8...58.7...11..8...6.5..138..6.8.2..5....37...8.3..4...9.9....36...2.9...53
|
269341875458679321137852964592138746781264539643795182315486297974523618826917453
|
Basic 9x9 Sudoku 2885
|
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 . .
. 5 8 . 7 . . . 1
1 . . 8 . . . 6 .
5 . . 1 3 8 . . 6
. 8 . 2 . . 5 . .
. . 3 7 . . . 8 .
3 . . 4 . . . 9 .
9 . . . . 3 6 . .
. 2 . 9 . . . 5 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
269341875458679321137852964592138746781264539643795182315486297974523618826917453 #1 Hard (904)
Naked Single: r4c4=1
Naked Single: r8c4=5
Hidden Single: r9c1=8
Hidden Single: r5c8=3
Hidden Single: r1c6=1
Hidden Single: r7c3=5
Hidden Single: r5c3=1
Hidden Single: r8c8=1
Hidden Single: r6c7=1
Hidden Single: r1c9=5
Hidden Single: r9c3=6
Naked Single: r9c5=1
Naked Single: r9c6=7
Full House: r9c7=4
Hidden Single: r7c2=1
Locked Candidates Type 1 (Pointing): 7 in b7 => r8c9<>7
Locked Candidates Type 2 (Claiming): 6 in c4 => r2c6<>6
Skyscraper: 2 in r1c8,r6c9 (connected by r16c1) => r3c9,r4c8<>2
Locked Candidates Type 2 (Claiming): 2 in c8 => r23c7<>2
Skyscraper: 7 in r4c8,r5c1 (connected by r1c18) => r4c23,r5c9<>7
Hidden Single: r5c1=7
Locked Candidates Type 1 (Pointing): 6 in b4 => r6c56<>6
Skyscraper: 4 in r4c8,r6c1 (connected by r2c18) => r4c23,r6c9<>4
Naked Single: r4c2=9
Naked Single: r4c3=2
Naked Single: r4c7=7
Full House: r4c8=4
Naked Single: r7c7=2
Naked Single: r2c8=2
Full House: r1c8=7
Naked Single: r5c9=9
Full House: r6c9=2
Naked Single: r7c6=6
Naked Single: r8c9=8
Full House: r7c9=7
Full House: r3c9=4
Full House: r7c5=8
Full House: r8c5=2
Naked Single: r2c6=9
Naked Single: r5c5=6
Full House: r5c6=4
Naked Single: r3c3=7
Full House: r8c3=4
Full House: r8c2=7
Naked Single: r2c7=3
Full House: r3c7=9
Naked Single: r3c5=5
Full House: r6c5=9
Full House: r6c6=5
Full House: r3c6=2
Full House: r3c2=3
Naked Single: r2c4=6
Full House: r1c4=3
Full House: r2c1=4
Naked Single: r1c2=6
Full House: r1c1=2
Full House: r6c1=6
Full House: r6c2=4
|
normal_sudoku_6054
|
8.41..9..15..8..74.79..5........2.8...8.......9.8.6.....1.547.9..79......4.....58
|
824173965156289374379465821615392487438517296792846513281654739567938142943721658
|
Basic 9x9 Sudoku 6054
|
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 . 4 1 . . 9 . .
1 5 . . 8 . . 7 4
. 7 9 . . 5 . . .
. . . . . 2 . 8 .
. . 8 . . . . . .
. 9 . 8 . 6 . . .
. . 1 . 5 4 7 . 9
. . 7 9 . . . . .
. 4 . . . . . 5 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
824173965156289374379465821615392487438517296792846513281654739567938142943721658 #1 Extreme (13948) bf
Hidden Single: r6c4=8
Hidden Single: r5c8=9
Hidden Single: r2c6=9
Hidden Single: r4c5=9
Hidden Single: r9c1=9
Hidden Single: r1c9=5
Hidden Single: r8c1=5
Hidden Single: r3c7=8
Hidden Single: r8c6=8
Hidden Single: r7c2=8
Brute Force: r5c6=7
Naked Single: r1c6=3
Full House: r9c6=1
Hidden Single: r1c5=7
Hidden Single: r9c4=7
Finned Franken Swordfish: 2 r17b2 c148 fr1c2 fr3c5 => r3c1<>2
W-Wing: 6/2 in r1c8,r2c4 connected by 2 in r1c2,r2c3 => r2c7<>6
Sashimi Swordfish: 6 r127 c148 fr1c2 fr2c3 => r3c1<>6
Naked Single: r3c1=3
Hidden Single: r2c7=3
Forcing Chain Contradiction in r8c2 => r7c8<>2
r7c8=2 r1c8<>2 r1c2=2 r8c2<>2
r7c8=2 r7c8<>3 r8c89=3 r8c2<>3
r7c8=2 r7c1<>2 r7c1=6 r8c2<>6
Skyscraper: 2 in r2c3,r7c1 (connected by r27c4) => r9c3<>2
2-String Kite: 2 in r1c8,r6c3 (connected by r1c2,r2c3) => r6c8<>2
Grouped Discontinuous Nice Loop: 6 r4c2 -6- r1c2 -2- r8c2 =2= r7c1 =6= r45c1 -6- r4c2 => r4c2<>6
Grouped Discontinuous Nice Loop: 6 r5c2 -6- r1c2 -2- r8c2 =2= r7c1 =6= r45c1 -6- r5c2 => r5c2<>6
Almost Locked Set XY-Wing: A=r3c89 {126}, B=r27c4 {236}, C=r17c8 {236}, X,Y=2,3, Z=6 => r3c4<>6
Forcing Chain Contradiction in r8c2 => r7c8=3
r7c8<>3 r7c8=6 r7c1<>6 r7c1=2 r8c2<>2
r7c8<>3 r8c89=3 r8c2<>3
r7c8<>3 r7c8=6 r1c8<>6 r1c2=6 r8c2<>6
Locked Candidates Type 1 (Pointing): 3 in b8 => r56c5<>3
Locked Pair: 1,4 in r56c5 => r3c5,r45c4<>4
Hidden Single: r3c4=4
Naked Pair: 1,4 in r6c58 => r6c17<>4, r6c79<>1
Remote Pair: 6/2 r2c3 -2- r2c4 -6- r7c4 -2- r7c1 => r9c3<>6
Naked Single: r9c3=3
Hidden Single: r6c9=3
Hidden Single: r8c5=3
Hidden Single: r6c1=7
Hidden Single: r4c9=7
Naked Pair: 2,6 in r18c2 => r5c2<>2
Sashimi Swordfish: 2 r269 c347 fr9c5 => r7c4<>2
Naked Single: r7c4=6
Full House: r7c1=2
Full House: r9c5=2
Full House: r8c2=6
Full House: r9c7=6
Naked Single: r2c4=2
Full House: r3c5=6
Full House: r2c3=6
Full House: r1c2=2
Full House: r1c8=6
Naked Single: r4c3=5
Full House: r6c3=2
Naked Single: r4c4=3
Full House: r5c4=5
Naked Single: r6c7=5
Naked Single: r4c2=1
Full House: r5c2=3
Naked Single: r4c7=4
Full House: r4c1=6
Full House: r5c1=4
Naked Single: r6c8=1
Full House: r6c5=4
Full House: r5c5=1
Naked Single: r3c8=2
Full House: r3c9=1
Full House: r8c8=4
Naked Single: r5c7=2
Full House: r5c9=6
Full House: r8c9=2
Full House: r8c7=1
|
normal_sudoku_2859
|
..6....3.75.9..1.44....892...72..3..325....9.......4.2....5.....7..24...6...7..59
|
296741538758932164413568927947216385325487691861395472132859746579624813684173259
|
Basic 9x9 Sudoku 2859
|
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 . 9 . . 1 . 4
4 . . . . 8 9 2 .
. . 7 2 . . 3 . .
3 2 5 . . . . 9 .
. . . . . . 4 . 2
. . . . 5 . . . .
. 7 . . 2 4 . . .
6 . . . 7 . . 5 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
296741538758932164413568927947216385325487691861395472132859746579624813684173259 #1 Easy (386)
Hidden Single: r5c2=2
Hidden Single: r8c1=5
Hidden Single: r4c9=5
Hidden Single: r1c7=5
Hidden Single: r7c8=4
Hidden Single: r7c6=9
Hidden Single: r4c2=4
Hidden Single: r8c3=9
Hidden Single: r3c4=5
Hidden Single: r6c6=5
Hidden Single: r9c3=4
Hidden Single: r6c8=7
Hidden Single: r6c2=6
Hidden Single: r3c9=7
Naked Single: r1c9=8
Full House: r2c8=6
Naked Single: r2c5=3
Naked Single: r2c6=2
Full House: r2c3=8
Naked Single: r6c3=1
Naked Single: r3c3=3
Full House: r7c3=2
Naked Single: r3c2=1
Full House: r3c5=6
Naked Single: r1c2=9
Full House: r1c1=2
Hidden Single: r9c7=2
Hidden Single: r7c7=7
Hidden Single: r9c6=3
Naked Single: r9c2=8
Full House: r7c2=3
Full House: r7c1=1
Full House: r9c4=1
Naked Single: r7c9=6
Full House: r7c4=8
Full House: r8c4=6
Naked Single: r5c9=1
Full House: r8c9=3
Naked Single: r8c7=8
Full House: r5c7=6
Full House: r4c8=8
Full House: r8c8=1
Naked Single: r6c4=3
Naked Single: r5c6=7
Naked Single: r4c1=9
Full House: r6c1=8
Full House: r6c5=9
Naked Single: r1c6=1
Full House: r4c6=6
Full House: r4c5=1
Naked Single: r5c4=4
Full House: r1c4=7
Full House: r1c5=4
Full House: r5c5=8
|
normal_sudoku_5351
|
.1.....4...3..7..94..3..2..1..8....2..4.9.7...5..6..3......28...6..5..2.3..9....1
|
612589347583427169497316285176834592834295716259761438941672853768153924325948671
|
Basic 9x9 Sudoku 5351
|
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 . . 7 . . 9
4 . . 3 . . 2 . .
1 . . 8 . . . . 2
. . 4 . 9 . 7 . .
. 5 . . 6 . . 3 .
. . . . . 2 8 . .
. 6 . . 5 . . 2 .
3 . . 9 . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
612589347583427169497316285176834592834295716259761438941672853768153924325948671 #1 Extreme (24382) bf
Brute Force: r5c5=9
Locked Candidates Type 1 (Pointing): 2 in b5 => r12c4<>2
Discontinuous Nice Loop: 8 r5c8 -8- r6c9 -4- r6c6 -1- r6c7 =1= r5c8 => r5c8<>8
Locked Candidates Type 1 (Pointing): 8 in b6 => r13c9<>8
Almost Locked Set XZ-Rule: A=r12349c5 {123478}, B=r456c6 {1345}, X=3, Z=1 => r3c6<>1
Forcing Chain Contradiction in c2 => r2c4<>1
r2c4=1 r3c5<>1 r3c5=8 r3c8<>8 r2c8=8 r2c2<>8
r2c4=1 r3c5<>1 r3c5=8 r3c2<>8
r2c4=1 r23c5<>1 r7c5=1 r7c5<>3 r4c5=3 r4c2<>3 r5c2=3 r5c2<>8
r2c4=1 r23c5<>1 r7c5=1 r7c5<>3 r8c6=3 r8c6<>8 r8c13=8 r9c2<>8
Locked Candidates Type 1 (Pointing): 1 in b2 => r7c5<>1
Forcing Net Contradiction in c9 => r1c7<>5
r1c7=5 (r3c9<>5) (r1c4<>5 r1c4=6 r7c4<>6) r1c7<>3 r8c7=3 r8c7<>9 r7c8=9 r7c8<>6 r7c9=6 r3c9<>6 r3c9=7
r1c7=5 (r1c7<>3 r1c9=3 r8c9<>3) (r9c7<>5) r1c4<>5 r1c4=6 (r1c6<>6) r3c6<>6 r9c6=6 r9c7<>6 r9c7=4 r8c9<>4 r8c9=7
Forcing Net Contradiction in r7 => r6c4<>4
r6c4=4 (r6c6<>4 r6c6=1 r8c6<>1) (r2c4<>4 r2c5=4 r9c5<>4) r6c4<>7 r4c5=7 (r7c5<>7 r7c5=3 r8c6<>3) r9c5<>7 r9c5=8 (r9c6<>8) r8c6<>8 r8c6=4 r9c6<>4 r9c6=6 r7c4<>6
r6c4=4 (r6c7<>4) r6c6<>4 r6c6=1 r6c7<>1 r6c7=9 r4c8<>9 r7c8=9 r7c8<>6
r6c4=4 (r6c9<>4) (r6c6<>4 r6c6=1 r8c6<>1) (r2c4<>4 r2c5=4 r9c5<>4) r6c4<>7 r4c5=7 (r7c5<>7 r7c5=3 r8c6<>3) r9c5<>7 r9c5=8 r8c6<>8 r8c6=4 r8c9<>4 r7c9=4 r7c9<>6
Forcing Net Contradiction in r7c8 => r7c5<>4
r7c5=4 (r7c2<>4 r9c2=4 r9c2<>8) (r7c2<>4 r9c2=4 r9c2<>2) r7c5<>3 r4c5=3 r5c6<>3 r5c2=3 (r5c2<>8) r5c2<>2 r2c2=2 (r2c5<>2) r2c2<>8 r3c2=8 (r3c5<>8 r3c5=1 r2c5<>1) r3c8<>8 r2c8=8 r2c5<>8 r2c5=4 r7c5<>4
Forcing Net Verity => r7c9<>5
r3c3=5 (r1c1<>5) r2c1<>5 r7c1=5 r7c9<>5
r3c6=5 (r1c4<>5 r1c4=6 r1c6<>6 r9c6=6 r9c7<>6) (r1c4<>5 r1c4=6 r2c4<>6 r2c4=4 r2c5<>4) (r1c4<>5) r2c4<>5 r5c4=5 r5c4<>2 r6c4=2 r6c4<>7 r4c5=7 r4c5<>4 r9c5=4 r9c7<>4 r9c7=5 r7c9<>5
r3c8=5 (r9c8<>5) r3c8<>8 r2c8=8 r2c2<>8 r2c2=2 r9c2<>2 r9c3=2 r9c3<>5 r9c7=5 r7c9<>5
r3c9=5 r7c9<>5
Forcing Net Contradiction in r8 => r2c7<>5
r2c7=5 (r9c7<>5) r2c7<>1 r6c7=1 (r5c8<>1 r5c8=6 r7c8<>6) r6c6<>1 r6c6=4 (r4c5<>4) r4c6<>4 r4c7=4 r9c7<>4 r9c7=6 r7c9<>6 r7c4=6 (r2c4<>6) r1c4<>6 r1c4=5 r2c4<>5 r2c4=4 r8c4<>4
r2c7=5 r2c7<>1 r6c7=1 r6c6<>1 r6c6=4 r8c6<>4
r2c7=5 r2c7<>1 r6c7=1 r6c6<>1 r6c6=4 (r4c5<>4) r4c6<>4 r4c7=4 r8c7<>4
r2c7=5 (r2c7<>1 r6c7=1 r5c8<>1 r5c8=6 r7c8<>6) (r2c1<>5) (r2c4<>5) (r1c9<>5) r3c9<>5 r5c9=5 r5c4<>5 r1c4=5 r1c1<>5 r7c1=5 r7c8<>5 r7c8=7 (r7c5<>7 r7c5=3 r8c6<>3) r7c8<>9 r4c8=9 (r4c7<>9) (r7c8<>9) r6c7<>9 r8c7=9 r8c7<>3 r8c9=3 r8c9<>4
Forcing Net Contradiction in r3 => r3c5=1
r3c5<>1 r3c8=1 r2c7<>1 (r2c7=6 r4c7<>6) (r2c7=6 r1c7<>6 r1c7=3 r8c7<>3) r6c7=1 r6c6<>1 r6c6=4 (r4c5<>4) r4c6<>4 r4c7=4 r8c7<>4 r8c7=9 r7c8<>9 r4c8=9 r4c8<>6 r4c3=6 r3c3<>6
r3c5<>1 r3c5=8 r3c8<>8 r2c8=8 r2c2<>8 r2c2=2 (r2c1<>2 r2c1=5 r1c3<>5) (r2c1<>2 r2c1=5 r3c3<>5) r9c2<>2 r9c3=2 r9c3<>5 r7c3=5 r7c3<>1 r7c4=1 r7c4<>6 r9c6=6 r3c6<>6
r3c5<>1 r3c8=1 r3c8<>6
r3c5<>1 r3c8=1 r2c7<>1 r2c7=6 r3c9<>6
Forcing Net Contradiction in c6 => r5c8<>6
r5c8=6 (r3c8<>6) (r4c8<>6 r4c3=6 r3c3<>6) r5c8<>1 r2c8=1 r2c7<>1 r2c7=6 r3c9<>6 r3c6=6
r5c8=6 (r9c8<>6) r5c8<>1 r2c8=1 r2c7<>1 r2c7=6 r9c7<>6 r9c6=6
Forcing Net Contradiction in r3 => r1c6<>5
r1c6=5 (r1c4<>5 r1c4=6 r1c7<>6) (r1c4<>5 r1c4=6 r3c6<>6 r9c6=6 r9c7<>6) (r1c4<>5) r2c4<>5 r5c4=5 (r5c4<>2 r6c4=2 r6c4<>7 r4c5=7 r4c3<>7) r5c8<>5 r5c8=1 (r5c6<>1 r5c6=3 r4c6<>3 r4c2=3 r4c2<>9) r2c8<>1 r2c7=1 r2c7<>6 r4c7=6 r4c3<>6 r4c3=9 r4c8<>9 r7c8=9 r7c2<>9 r3c2=9
r1c6=5 r1c6<>9 r3c6=9
Forcing Net Contradiction in r4 => r2c8<>5
r2c8=5 (r2c8<>1 r2c7=1 r2c7<>6) (r2c8<>6) (r1c9<>5) r3c9<>5 r5c9=5 r5c9<>6 r5c1=6 r2c1<>6 r2c4=6 r2c4<>4 r2c5=4 r4c5<>4
r2c8=5 (r4c8<>5) (r1c9<>5) r3c9<>5 r5c9=5 r4c7<>5 r4c6=5 r4c6<>4
r2c8=5 (r2c8<>1 r2c7=1 r2c7<>6) (r2c8<>6) (r2c8<>8 r3c8=8 r3c8<>6) (r2c8<>1 r2c7=1 r2c7<>6) (r2c8<>6) (r1c9<>5) r3c9<>5 r5c9=5 (r4c7<>5 r4c6=5 r3c6<>5 r3c3=5 r3c3<>6) r5c9<>6 r5c1=6 (r4c3<>6) r2c1<>6 r2c4=6 r3c6<>6 r3c9=6 (r7c9<>6) r5c9<>6 r5c1=6 (r4c3<>6) r2c1<>6 r2c4=6 r7c4<>6 r7c8=6 r4c8<>6 r4c7=6 r4c7<>4
Forcing Chain Contradiction in c7 => r2c1<>6
r2c1=6 r2c1<>5 r2c4=5 r1c4<>5 r1c4=6 r1c7<>6
r2c1=6 r2c7<>6
r2c1=6 r5c1<>6 r5c9=6 r4c7<>6
r2c1=6 r2c1<>5 r2c4=5 r1c4<>5 r1c4=6 r7c4<>6 r9c6=6 r9c7<>6
Grouped Discontinuous Nice Loop: 5 r3c3 -5- r2c1 =5= r2c4 -5- r1c4 -6- r1c13 =6= r3c3 => r3c3<>5
Forcing Chain Contradiction in c9 => r1c6<>6
r1c6=6 r1c9<>6
r1c6=6 r2c4<>6 r2c78=6 r3c9<>6
r1c6=6 r1c1<>6 r5c1=6 r5c9<>6
r1c6=6 r9c6<>6 r7c4=6 r7c9<>6
Forcing Net Contradiction in r7c3 => r1c7=3
r1c7<>3 (r1c9=3 r7c9<>3 r7c5=3 r4c5<>3) r1c7=6 (r2c7<>6 r2c7=1 r2c8<>1 r5c8=1 r5c4<>1 r5c4=2 r6c4<>2) (r2c7<>6) r2c8<>6 r2c4=6 r2c4<>4 r2c5=4 r4c5<>4 r4c5=7 r6c4<>7 r6c4=1 r7c4<>1 r7c3=1
r1c7<>3 (r1c7=6 r1c4<>6 r1c4=5 r2c4<>5 r2c1=5 r7c1<>5) r8c7=3 r8c7<>9 r7c8=9 r7c8<>5 r7c3=5
Almost Locked Set XY-Wing: A=r4c23568 {345679}, B=r68c7 {149}, C=r6c6 {14}, X,Y=1,4, Z=9 => r4c7<>9
Almost Locked Set XY-Wing: A=r8c7 {49}, B=r13578c9 {345678}, C=r6c679 {1489}, X,Y=8,9, Z=4 => r9c7<>4
Forcing Chain Contradiction in r6c7 => r6c4<>1
r6c4=1 r6c7<>1
r6c4=1 r6c6<>1 r6c6=4 r6c7<>4
r6c4=1 r6c6<>1 r6c6=4 r6c9<>4 r46c7=4 r8c7<>4 r8c7=9 r6c7<>9
Forcing Chain Verity => r9c8<>5
r1c3=5 r1c4<>5 r1c4=6 r7c4<>6 r9c6=6 r9c7<>6 r9c7=5 r9c8<>5
r7c3=5 r7c3<>1 r7c4=1 r7c4<>6 r9c6=6 r9c7<>6 r9c7=5 r9c8<>5
r9c3=5 r9c8<>5
Forcing Chain Contradiction in b7 => r9c8=7
r9c8<>7 r9c8=6 r9c6<>6 r3c6=6 r1c4<>6 r1c4=5 r1c3<>5 r12c1=5 r7c1<>5
r9c8<>7 r9c8=6 r9c6<>6 r7c4=6 r7c4<>1 r7c3=1 r7c3<>5
r9c8<>7 r9c8=6 r9c7<>6 r9c7=5 r9c3<>5
Naked Triple: 2,4,8 in r129c5 => r4c5<>4
Locked Candidates Type 1 (Pointing): 4 in b5 => r89c6<>4
Sue de Coq: r5c46 - {1235} (r5c8 - {15}, r4c5,r6c4 - {237}) => r4c6<>3, r5c9<>5
Locked Candidates Type 2 (Claiming): 5 in c9 => r3c8<>5
Naked Triple: 1,6,8 in r2c78,r3c8 => r13c9<>6
Discontinuous Nice Loop: 7 r4c3 -7- r4c5 -3- r7c5 =3= r7c9 =6= r5c9 -6- r5c1 =6= r4c3 => r4c3<>7
Hidden Pair: 3,7 in r4c25 => r4c2<>9
2-String Kite: 9 in r4c3,r8c7 (connected by r4c8,r6c7) => r8c3<>9
Discontinuous Nice Loop: 9 r1c1 -9- r8c1 =9= r8c7 -9- r6c7 =9= r4c8 -9- r4c3 -6- r5c1 =6= r1c1 => r1c1<>9
Grouped Discontinuous Nice Loop: 6 r4c8 -6- r23c8 =6= r2c7 =1= r6c7 =9= r4c8 => r4c8<>6
Finned Swordfish: 6 r349 c367 fr3c8 => r2c7<>6
Naked Single: r2c7=1
Hidden Single: r5c8=1
Hidden Single: r6c6=1
Hidden Single: r4c6=4
Locked Candidates Type 1 (Pointing): 6 in b3 => r7c8<>6
XY-Wing: 3/8/4 in r8c69,r9c5 => r8c4<>4
Locked Candidates Type 2 (Claiming): 4 in r8 => r7c9<>4
Hidden Rectangle: 1/7 in r7c34,r8c34 => r7c3<>7
Sue de Coq: r7c45 - {13467} (r7c1238 - {14579}, r89c6 - {368}) => r9c5<>8
Naked Single: r9c5=4
Hidden Single: r2c4=4
Hidden Single: r7c2=4
Hidden Single: r2c1=5
Hidden Single: r2c8=6
Naked Single: r3c8=8
Hidden Single: r3c2=9
Hidden Single: r1c6=9
Hidden Single: r4c2=7
Naked Single: r4c5=3
Naked Single: r5c6=5
Naked Single: r7c5=7
Naked Single: r3c6=6
Naked Single: r5c4=2
Full House: r6c4=7
Naked Single: r7c1=9
Naked Single: r8c4=1
Naked Single: r1c4=5
Full House: r7c4=6
Naked Single: r3c3=7
Full House: r3c9=5
Full House: r1c9=7
Naked Single: r9c6=8
Full House: r8c6=3
Naked Single: r7c8=5
Full House: r4c8=9
Naked Single: r7c9=3
Full House: r7c3=1
Naked Single: r8c3=8
Naked Single: r9c2=2
Naked Single: r8c9=4
Naked Single: r9c7=6
Full House: r9c3=5
Full House: r8c1=7
Full House: r8c7=9
Naked Single: r4c3=6
Full House: r4c7=5
Full House: r6c7=4
Naked Single: r2c2=8
Full House: r2c5=2
Full House: r5c2=3
Full House: r1c5=8
Naked Single: r6c9=8
Full House: r5c9=6
Full House: r5c1=8
Naked Single: r1c3=2
Full House: r1c1=6
Full House: r6c1=2
Full House: r6c3=9
|
normal_sudoku_2129
|
..279.1.57..15..2..5...2......4..5...16...4..5....9..2.8...16..1.3..78.9...98.23.
|
362798145798154326451362987879426513216573498534819762985231674123647859647985231
|
Basic 9x9 Sudoku 2129
|
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 7 9 . 1 . 5
7 . . 1 5 . . 2 .
. 5 . . . 2 . . .
. . . 4 . . 5 . .
. 1 6 . . . 4 . .
5 . . . . 9 . . 2
. 8 . . . 1 6 . .
1 . 3 . . 7 8 . 9
. . . 9 8 . 2 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
362798145798154326451362987879426513216573498534819762985231674123647859647985231 #1 Extreme (6496)
Naked Single: r8c7=8
Hidden Single: r3c3=1
Hidden Single: r9c9=1
Locked Candidates Type 1 (Pointing): 9 in b6 => r3c8<>9
Locked Candidates Type 1 (Pointing): 7 in b9 => r7c3<>7
Discontinuous Nice Loop: 7 r5c8 -7- r6c7 =7= r3c7 =9= r3c1 -9- r5c1 =9= r5c8 => r5c8<>7
Discontinuous Nice Loop: 7 r6c2 -7- r6c7 =7= r3c7 =9= r3c1 -9- r7c1 =9= r7c3 =5= r9c3 =7= r9c2 -7- r6c2 => r6c2<>7
Forcing Chain Contradiction in r7c1 => r5c5=7
r5c5<>7 r5c9=7 r6c7<>7 r6c7=3 r2c7<>3 r2c7=9 r2c2<>9 r4c2=9 r4c2<>2 r8c2=2 r7c1<>2
r5c5<>7 r5c9=7 r7c9<>7 r7c9=4 r7c1<>4
r5c5<>7 r5c9=7 r6c7<>7 r3c7=7 r3c7<>9 r3c1=9 r7c1<>9
2-String Kite: 2 in r5c4,r8c2 (connected by r4c2,r5c1) => r8c4<>2
Forcing Chain Contradiction in r7c1 => r4c9<>7
r4c9=7 r6c7<>7 r6c7=3 r2c7<>3 r2c7=9 r2c2<>9 r4c2=9 r4c2<>2 r8c2=2 r7c1<>2
r4c9=7 r7c9<>7 r7c9=4 r7c1<>4
r4c9=7 r6c7<>7 r3c7=7 r3c7<>9 r3c1=9 r7c1<>9
Forcing Net Contradiction in r6c7 => r6c7=7
r6c7<>7 (r3c7=7 r3c9<>7 r7c9=7 r7c9<>4 r78c8=4 r1c8<>4) r6c7=3 (r6c2<>3 r6c2=4 r9c2<>4) r2c7<>3 r2c7=9 (r3c7<>9 r3c1=9 r7c1<>9) r2c2<>9 r4c2=9 r4c2<>2 r8c2=2 r7c1<>2 r7c1=4 (r1c1<>4) (r9c1<>4) r9c3<>4 r9c6=4 r1c6<>4 r1c2=4 r6c2<>4 r6c2=3 r6c7<>3 r6c7=7
Locked Candidates Type 1 (Pointing): 3 in b6 => r23c9<>3
Hidden Rectangle: 4/7 in r3c89,r7c89 => r3c8<>4
Almost Locked Set XY-Wing: A=r4c125689 {1236789}, B=r26c3 {489}, C=r12689c2 {234679}, X,Y=7,9, Z=8 => r4c3<>8
Forcing Chain Verity => r3c1<>8
r3c1=3 r3c1<>8
r3c4=3 r12c6<>3 r45c6=3 r6c45<>3 r6c2=3 r6c2<>4 r6c3=4 r6c3<>8 r2c3=8 r3c1<>8
r3c5=3 r12c6<>3 r45c6=3 r6c45<>3 r6c2=3 r6c2<>4 r6c3=4 r6c3<>8 r2c3=8 r3c1<>8
r3c7=3 r3c7<>9 r3c1=9 r3c1<>8
Finned Franken Swordfish: 8 r36b1 c348 fr1c1 fr3c9 => r1c8<>8
Grouped Discontinuous Nice Loop: 6 r3c9 -6- r1c8 -4- r78c8 =4= r7c9 =7= r3c9 => r3c9<>6
Almost Locked Set XY-Wing: A=r1c28 {346}, B=r34579c1 {234689}, C=r6c23 {348}, X,Y=3,8, Z=4,6 => r1c1<>4, r1c1<>6
Empty Rectangle: 6 in b2 (r39c1) => r9c6<>6
Locked Candidates Type 1 (Pointing): 6 in b8 => r8c2<>6
Discontinuous Nice Loop: 4 r7c5 -4- r9c6 -5- r5c6 =5= r5c4 =2= r7c4 =3= r7c5 => r7c5<>4
Sashimi X-Wing: 4 c15 r38 fr7c1 fr9c1 => r8c2<>4
Naked Single: r8c2=2
Naked Triple: 4,5,6 in r8c45,r9c6 => r7c4<>5
Discontinuous Nice Loop: 3 r3c5 -3- r7c5 -2- r7c4 =2= r5c4 =5= r5c6 -5- r9c6 -4- r8c5 =4= r3c5 => r3c5<>3
Naked Pair: 4,6 in r38c5 => r46c5<>6
W-Wing: 6/4 in r1c8,r3c5 connected by 4 in r8c58 => r1c6,r3c8<>6
X-Wing: 6 c69 r24 => r2c2,r4c8<>6
W-Wing: 4/6 in r1c8,r3c5 connected by 6 in r2c69 => r1c6,r3c9<>4
Locked Pair: 7,8 in r3c89 => r2c9,r3c4<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r45c6<>8
Naked Pair: 3,8 in r1c16 => r1c2<>3
2-String Kite: 4 in r3c1,r9c6 (connected by r2c6,r3c5) => r9c1<>4
Naked Single: r9c1=6
Hidden Single: r1c2=6
Naked Single: r1c8=4
Naked Single: r2c9=6
Naked Single: r8c8=5
Naked Single: r7c8=7
Full House: r7c9=4
Naked Single: r8c4=6
Full House: r8c5=4
Naked Single: r3c8=8
Naked Single: r7c1=9
Naked Single: r3c4=3
Naked Single: r3c5=6
Naked Single: r9c6=5
Naked Single: r3c9=7
Naked Single: r5c8=9
Naked Single: r7c3=5
Naked Single: r1c6=8
Full House: r1c1=3
Full House: r2c6=4
Naked Single: r3c1=4
Full House: r3c7=9
Full House: r2c7=3
Naked Single: r6c4=8
Naked Single: r7c4=2
Full House: r5c4=5
Full House: r7c5=3
Naked Single: r5c6=3
Full House: r4c6=6
Naked Single: r4c8=1
Full House: r6c8=6
Naked Single: r2c2=9
Full House: r2c3=8
Naked Single: r6c3=4
Naked Single: r6c5=1
Full House: r4c5=2
Full House: r6c2=3
Naked Single: r5c9=8
Full House: r4c9=3
Full House: r5c1=2
Full House: r4c1=8
Naked Single: r9c3=7
Full House: r4c3=9
Full House: r4c2=7
Full House: r9c2=4
|
normal_sudoku_2911
|
......3...5..3.1.49.....57...82...6.7.38.42...6..1........2...8..6.5.93.3....76..
|
614579382857632194932481576148295763793864251265713849579326418426158937381947625
|
Basic 9x9 Sudoku 2911
|
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 . . 3 . 1 . 4
9 . . . . . 5 7 .
. . 8 2 . . . 6 .
7 . 3 8 . 4 2 . .
. 6 . . 1 . . . .
. . . . 2 . . . 8
. . 6 . 5 . 9 3 .
3 . . . . 7 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
614579382857632194932481576148295763793864251265713849579326418426158937381947625 #1 Extreme (3720)
Naked Single: r5c7=2
Hidden Single: r3c2=3
Hidden Single: r5c5=6
Hidden Single: r6c7=8
Locked Candidates Type 2 (Claiming): 8 in r3 => r1c56,r2c6<>8
Locked Candidates Type 2 (Claiming): 5 in r5 => r46c9,r6c8<>5
Hidden Pair: 3,6 in r7c46 => r7c46<>1, r7c4<>4, r7c46<>9
Locked Candidates Type 1 (Pointing): 9 in b8 => r9c23<>9
XY-Wing: 4/7/9 in r4c57,r6c8 => r4c9,r6c46<>9
Locked Candidates Type 1 (Pointing): 9 in b5 => r4c2<>9
Finned Swordfish: 7 c257 r147 fr8c2 => r7c3<>7
Locked Candidates Type 1 (Pointing): 7 in b7 => r1c2<>7
AIC: 9 9- r5c2 =9= r7c2 =7= r7c7 =4= r4c7 -4- r6c8 -9 => r5c89,r6c3<>9
Hidden Single: r5c2=9
Hidden Single: r7c3=9
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c9<>1
Discontinuous Nice Loop: 9 r1c4 -9- r1c9 =9= r6c9 =7= r6c4 =5= r1c4 => r1c4<>9
Discontinuous Nice Loop: 9 r1c5 -9- r1c9 =9= r6c9 =7= r6c4 -7- r4c5 =7= r1c5 => r1c5<>9
AIC: 7 7- r1c5 =7= r4c5 =9= r9c5 -9- r9c4 =9= r2c4 =7= r2c3 -7 => r1c3,r2c4<>7
Hidden Single: r2c3=7
Hidden Pair: 5,7 in r16c4 => r1c4<>1, r1c4<>4, r1c4<>6, r6c4<>3
Hidden Single: r7c4=3
Naked Single: r7c6=6
Discontinuous Nice Loop: 1/2/4/8 r1c1 =6= r1c9 =9= r6c9 =7= r6c4 -7- r4c5 -9- r9c5 =9= r9c4 -9- r2c4 -6- r2c1 =6= r1c1 => r1c1<>1, r1c1<>2, r1c1<>4, r1c1<>8
Naked Single: r1c1=6
Hidden Single: r3c9=6
Hidden Single: r2c4=6
Hidden Single: r9c4=9
Hidden Single: r4c5=9
Hidden Single: r1c5=7
Naked Single: r1c4=5
Naked Single: r6c4=7
Locked Candidates Type 1 (Pointing): 4 in b2 => r3c3<>4
Locked Candidates Type 1 (Pointing): 1 in b8 => r8c129<>1
Hidden Pair: 1,5 in r59c9 => r9c9<>2
Uniqueness Test 1: 1/5 in r5c89,r9c89 => r9c8<>1, r9c8<>5
Naked Triple: 2,4,7 in r7c7,r8c9,r9c8 => r7c8<>4
Finned X-Wing: 2 c29 r18 fr9c2 => r8c1<>2
Naked Triple: 1,4,8 in r8c146 => r8c2<>4, r8c2<>8
XY-Chain: 2 2- r1c9 -9- r6c9 -3- r4c9 -7- r8c9 -2- r9c8 -4- r9c5 -8- r8c6 -1- r8c4 -4- r8c1 -8- r2c1 -2 => r1c23,r2c8<>2
Locked Candidates Type 1 (Pointing): 2 in b3 => r1c6<>2
Locked Candidates Type 2 (Claiming): 2 in c2 => r9c3<>2
XY-Chain: 4 4- r8c1 -8- r2c1 -2- r2c6 -9- r1c6 -1- r8c6 -8- r9c5 -4 => r8c4,r9c23<>4
Naked Single: r8c4=1
Full House: r3c4=4
Naked Single: r8c6=8
Full House: r9c5=4
Full House: r3c5=8
Naked Single: r8c1=4
Naked Single: r9c8=2
Naked Single: r8c9=7
Full House: r8c2=2
Naked Single: r4c9=3
Naked Single: r7c7=4
Full House: r4c7=7
Naked Single: r4c6=5
Full House: r6c6=3
Naked Single: r6c9=9
Naked Single: r4c1=1
Full House: r4c2=4
Naked Single: r1c9=2
Naked Single: r6c8=4
Naked Single: r7c1=5
Naked Single: r6c1=2
Full House: r2c1=8
Full House: r6c3=5
Naked Single: r7c8=1
Full House: r7c2=7
Full House: r9c9=5
Full House: r5c9=1
Full House: r5c8=5
Naked Single: r9c3=1
Full House: r9c2=8
Full House: r1c2=1
Naked Single: r2c8=9
Full House: r1c8=8
Full House: r2c6=2
Naked Single: r1c3=4
Full House: r3c3=2
Full House: r1c6=9
Full House: r3c6=1
|
normal_sudoku_374
|
..4..32.152................24..51.8.7...42.....53..4...6...5328....3.5.4...2...9.
|
674983251528174639391526847246751983739842165815369472167495328982637514453218796
|
Basic 9x9 Sudoku 374
|
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 . . 3 2 . 1
5 2 . . . . . . .
. . . . . . . . .
2 4 . . 5 1 . 8 .
7 . . . 4 2 . . .
. . 5 3 . . 4 . .
. 6 . . . 5 3 2 8
. . . . 3 . 5 . 4
. . . 2 . . . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
674983251528174639391526847246751983739842165815369472167495328982637514453218796 #1 Extreme (15402) bf
Hidden Single: r4c2=4
Hidden Single: r6c9=2
Hidden Single: r9c2=5
Hidden Single: r3c5=2
Hidden Single: r8c3=2
2-String Kite: 3 in r3c2,r4c9 (connected by r4c3,r5c2) => r3c9<>3
Forcing Chain Contradiction in r2 => r3c6<>4
r3c6=4 r9c6<>4 r9c1=4 r9c1<>3 r9c3=3 r2c3<>3
r3c6=4 r3c8<>4 r2c8=4 r2c8<>3
r3c6=4 r9c6<>4 r9c1=4 r9c1<>3 r9c3=3 r4c3<>3 r4c9=3 r2c9<>3
Almost Locked Set XZ-Rule: A=r3c123679 {1356789}, B=r168c8 {1567}, X=5, Z=6,7 => r3c8<>6, r3c8<>7
Brute Force: r5c3=9
Locked Candidates Type 1 (Pointing): 9 in b6 => r4c4<>9
Grouped Discontinuous Nice Loop: 6 r6c8 -6- r6c1 =6= r4c3 -6- r4c4 -7- r4c79 =7= r6c8 => r6c8<>6
Grouped Discontinuous Nice Loop: 7 r9c6 -7- r9c79 =7= r8c8 -7- r6c8 -1- r5c78 =1= r5c2 =3= r3c2 -3- r3c1 =3= r9c1 =4= r9c6 => r9c6<>7
Forcing Chain Contradiction in r8c4 => r1c4<>8
r1c4=8 r5c4<>8 r5c4=6 r5c7<>6 r5c7=1 r9c7<>1 r8c8=1 r8c4<>1
r1c4=8 r5c4<>8 r5c4=6 r8c4<>6
r1c4=8 r5c4<>8 r5c4=6 r4c4<>6 r4c4=7 r8c4<>7
r1c4=8 r8c4<>8
r1c4=8 r5c4<>8 r5c2=8 r5c2<>3 r3c2=3 r3c1<>3 r9c1=3 r9c1<>4 r7c1=4 r7c1<>9 r7c45=9 r8c4<>9
Grouped Discontinuous Nice Loop: 8 r9c5 -8- r9c3 =8= r23c3 -8- r1c12 =8= r1c5 -8- r9c5 => r9c5<>8
Naked Triple: 1,6,7 in r9c579 => r9c13<>1, r9c3<>7, r9c6<>6
Forcing Chain Contradiction in r8c4 => r2c4<>8
r2c4=8 r5c4<>8 r5c4=6 r5c7<>6 r5c7=1 r9c7<>1 r9c5=1 r8c4<>1
r2c4=8 r5c4<>8 r5c4=6 r8c4<>6
r2c4=8 r5c4<>8 r5c4=6 r4c4<>6 r4c4=7 r8c4<>7
r2c4=8 r8c4<>8
r2c4=8 r5c4<>8 r5c2=8 r5c2<>3 r3c2=3 r3c1<>3 r9c1=3 r9c1<>4 r7c1=4 r7c1<>9 r7c45=9 r8c4<>9
Forcing Chain Contradiction in r8c4 => r3c4<>8
r3c4=8 r5c4<>8 r5c4=6 r5c7<>6 r5c7=1 r9c7<>1 r9c5=1 r8c4<>1
r3c4=8 r5c4<>8 r5c4=6 r8c4<>6
r3c4=8 r5c4<>8 r5c4=6 r4c4<>6 r4c4=7 r8c4<>7
r3c4=8 r8c4<>8
r3c4=8 r5c4<>8 r5c2=8 r5c2<>3 r3c2=3 r3c1<>3 r9c1=3 r9c1<>4 r7c1=4 r7c1<>9 r7c45=9 r8c4<>9
Forcing Net Contradiction in r1 => r4c4=7
r4c4<>7 r4c4=6 (r6c5<>6) r6c6<>6 r6c1=6 r1c1<>6
r4c4<>7 r4c4=6 r1c4<>6
r4c4<>7 r4c4=6 (r5c4<>6 r5c4=8 r5c2<>8 r5c2=1 r5c7<>1 r5c7=6 r9c7<>6) (r8c4<>6) (r5c4<>6 r5c4=8 r8c4<>8) r4c3<>6 r4c3=3 r9c3<>3 r9c3=8 (r8c1<>8) r8c2<>8 r8c6=8 r8c6<>6 r8c8=6 r9c9<>6 r9c5=6 r1c5<>6
r4c4<>7 r4c4=6 (r8c4<>6) (r5c4<>6 r5c4=8 r8c4<>8) r4c3<>6 r4c3=3 r9c3<>3 r9c3=8 (r8c1<>8) r8c2<>8 r8c6=8 r8c6<>6 r8c8=6 r1c8<>6
Hidden Single: r6c8=7
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c2<>1
Locked Candidates Type 1 (Pointing): 7 in b9 => r9c5<>7
Skyscraper: 7 in r1c2,r7c3 (connected by r17c5) => r23c3,r8c2<>7
Hidden Single: r7c3=7
Hidden Single: r8c6=7
Locked Candidates Type 2 (Claiming): 1 in c3 => r3c12<>1
Continuous Nice Loop: 3/8 3= r9c1 =4= r9c6 =8= r8c4 -8- r5c4 =8= r5c2 =3= r3c2 -3- r3c1 =3= r9c1 =4 => r23c3,r3c8<>3, r9c1<>8
AIC: 3 3- r4c9 =3= r4c3 -3- r9c3 -8- r9c6 =8= r8c4 =6= r8c8 =1= r5c8 -1- r5c7 -6- r5c4 -8- r5c2 -3 => r4c3,r5c89<>3
Naked Single: r4c3=6
Naked Single: r4c7=9
Full House: r4c9=3
Hidden Single: r9c3=3
Naked Single: r9c1=4
Naked Single: r9c6=8
Hidden Single: r5c2=3
Hidden Single: r2c8=3
Hidden Single: r3c1=3
Hidden Single: r7c4=4
Hidden Single: r2c6=4
Hidden Single: r5c4=8
Hidden Single: r3c8=4
Hidden Single: r1c1=6
Naked Single: r1c8=5
Naked Single: r1c4=9
Naked Single: r3c6=6
Full House: r6c6=9
Full House: r6c5=6
Naked Single: r2c4=1
Naked Single: r9c5=1
Naked Single: r2c3=8
Full House: r3c3=1
Naked Single: r3c4=5
Full House: r8c4=6
Full House: r7c5=9
Full House: r7c1=1
Naked Single: r1c2=7
Full House: r1c5=8
Full House: r2c5=7
Full House: r3c2=9
Naked Single: r8c8=1
Full House: r5c8=6
Naked Single: r6c1=8
Full House: r6c2=1
Full House: r8c2=8
Full House: r8c1=9
Naked Single: r2c7=6
Full House: r2c9=9
Naked Single: r3c9=7
Full House: r3c7=8
Naked Single: r5c7=1
Full House: r5c9=5
Full House: r9c7=7
Full House: r9c9=6
|
normal_sudoku_3721
|
526..1..8..7...6......6..9......38.....12...3.3.84..2....5...7..4..72..19.531....
|
526491738197238645483765192264953817859127463731846529612589374348672951975314286
|
Basic 9x9 Sudoku 3721
|
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 2 6 . . 1 . . 8
. . 7 . . . 6 . .
. . . . 6 . . 9 .
. . . . . 3 8 . .
. . . 1 2 . . . 3
. 3 . 8 4 . . 2 .
. . . 5 . . . 7 .
. 4 . . 7 2 . . 1
9 . 5 3 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
526491738197238645483765192264953817859127463731846529612589374348672951975314286 #1 Extreme (3726)
Hidden Single: r1c3=6
Hidden Single: r9c2=7
Hidden Single: r2c2=9
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c79<>2
Locked Candidates Type 1 (Pointing): 4 in b8 => r23c6<>4
2-String Kite: 1 in r2c1,r6c7 (connected by r2c8,r3c7) => r6c1<>1
Discontinuous Nice Loop: 4/6 r9c8 =8= r9c6 -8- r7c5 -9- r8c4 =9= r8c7 =5= r8c8 =8= r9c8 => r9c8<>4, r9c8<>6
Naked Single: r9c8=8
Locked Candidates Type 1 (Pointing): 8 in b8 => r7c123<>8
2-String Kite: 6 in r4c4,r9c9 (connected by r8c4,r9c6) => r4c9<>6
Finned Swordfish: 6 r679 c169 fr7c2 => r8c1<>6
Locked Pair: 3,8 in r8c13 => r7c13,r8c78<>3
Hidden Single: r7c7=3
Locked Candidates Type 1 (Pointing): 6 in b7 => r7c69<>6
Locked Candidates Type 2 (Claiming): 3 in r3 => r2c1<>3
Uniqueness Test 4: 3/8 in r3c13,r8c13 => r3c13<>8
Hidden Rectangle: 1/2 in r4c13,r7c13 => r4c1<>1
AIC: 1/8 1- r2c1 =1= r2c8 =3= r2c5 =5= r4c5 -5- r4c2 =5= r5c2 =8= r3c2 -8 => r3c2<>1, r2c1<>8
Naked Single: r3c2=8
Discontinuous Nice Loop: 4 r4c1 -4- r2c1 -1- r2c8 =1= r4c8 -1- r4c2 =1= r7c2 =6= r7c1 =2= r4c1 => r4c1<>4
Discontinuous Nice Loop: 5 r4c8 -5- r4c5 =5= r2c5 =3= r2c8 =1= r4c8 => r4c8<>5
Discontinuous Nice Loop: 5 r5c8 -5- r5c2 =5= r4c2 -5- r4c5 -9- r1c5 =9= r1c4 -9- r8c4 -6- r8c8 -5- r5c8 => r5c8<>5
XY-Chain: 5 5- r4c5 -9- r1c5 -3- r1c8 -4- r5c8 -6- r5c2 -5 => r4c2,r5c6<>5
Hidden Single: r5c2=5
XY-Chain: 4 4- r5c8 -6- r8c8 -5- r8c7 -9- r7c9 -4 => r4c9<>4
AIC: 4 4- r7c9 -9- r8c7 -5- r8c8 =5= r2c8 =1= r4c8 -1- r4c2 -6- r4c4 =6= r8c4 -6- r9c6 -4 => r7c6,r9c79<>4
Naked Single: r9c7=2
Naked Single: r9c9=6
Full House: r9c6=4
Naked Single: r8c8=5
Naked Single: r8c7=9
Full House: r7c9=4
Naked Single: r8c4=6
Naked Pair: 4,7 in r15c7 => r3c7<>4, r36c7<>7
Naked Triple: 5,7,9 in r4c459 => r4c1<>7, r4c3<>9
Skyscraper: 7 in r1c7,r4c9 (connected by r14c4) => r3c9,r5c7<>7
Naked Single: r5c7=4
Naked Single: r1c7=7
Naked Single: r5c8=6
Naked Single: r4c8=1
Naked Single: r4c2=6
Full House: r7c2=1
Naked Single: r6c7=5
Full House: r3c7=1
Naked Single: r4c1=2
Naked Single: r6c1=7
Naked Single: r7c3=2
Naked Single: r4c3=4
Naked Single: r7c1=6
Naked Single: r5c1=8
Naked Single: r6c9=9
Full House: r4c9=7
Naked Single: r3c3=3
Naked Single: r5c3=9
Full House: r6c3=1
Full House: r6c6=6
Full House: r8c3=8
Full House: r8c1=3
Full House: r5c6=7
Naked Single: r4c4=9
Full House: r4c5=5
Naked Single: r3c1=4
Full House: r2c1=1
Naked Single: r3c6=5
Naked Single: r1c4=4
Naked Single: r2c6=8
Full House: r7c6=9
Full House: r7c5=8
Naked Single: r3c9=2
Full House: r2c9=5
Full House: r3c4=7
Full House: r2c4=2
Naked Single: r1c8=3
Full House: r1c5=9
Full House: r2c5=3
Full House: r2c8=4
|
normal_sudoku_1103
|
37..9.2.....8...35.152..9.7....24........8..1.......7..21..97....9.3..5.53.7.1...
|
378596214492817635615243987157324896263978541984165372821459763749632158536781429
|
Basic 9x9 Sudoku 1103
|
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 7 . . 9 . 2 . .
. . . 8 . . . 3 5
. 1 5 2 . . 9 . 7
. . . . 2 4 . . .
. . . . . 8 . . 1
. . . . . . . 7 .
. 2 1 . . 9 7 . .
. . 9 . 3 . . 5 .
5 3 . 7 . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
378596214492817635615243987157324896263978541984165372821459763749632158536781429 #1 Extreme (2556)
Hidden Single: r3c9=7
Hidden Single: r3c6=3
Hidden Single: r7c9=3
Hidden Single: r5c5=7
Hidden Single: r8c1=7
Hidden Single: r8c7=1
Hidden Single: r1c8=1
Hidden Single: r8c6=2
Hidden Single: r2c6=7
Hidden Single: r4c3=7
Hidden Single: r2c5=1
Locked Pair: 5,6 in r6c56 => r456c4,r6c12379<>6, r456c4,r6c27<>5
Naked Triple: 4,6,8 in r7c8,r8c9,r9c7 => r9c89<>4, r9c89<>6, r9c89<>8
Skyscraper: 8 in r1c3,r8c2 (connected by r18c9) => r9c3<>8
Finned Franken Swordfish: 4 r29b2 c357 fr1c4 fr2c1 fr2c2 => r1c3<>4
W-Wing: 6/4 in r2c7,r3c5 connected by 4 in r1c49 => r3c8<>6
Sashimi Swordfish: 6 r239 c357 fr2c1 fr2c2 fr3c1 => r1c3<>6
Naked Single: r1c3=8
Hidden Single: r3c8=8
Forcing Chain Contradiction in r9c5 => r7c1<>4
r7c1=4 r3c1<>4 r3c5=4 r9c5<>4
r7c1=4 r9c3<>4 r9c3=6 r9c5<>6
r7c1=4 r7c1<>8 r7c5=8 r9c5<>8
Discontinuous Nice Loop: 4 r8c9 -4- r7c8 -6- r7c1 -8- r8c2 =8= r8c9 => r8c9<>4
Multi Colors 1: 4 (r1c4,r2c7,r3c1,r6c9) / (r1c9,r3c5), (r5c8,r9c7) / (r7c8) => r7c5<>4
W-Wing: 6/4 in r3c1,r9c3 connected by 4 in r39c5 => r2c3,r7c1<>6
Naked Single: r7c1=8
Hidden Single: r9c5=8
Hidden Single: r8c9=8
Hidden Single: r3c5=4
Full House: r3c1=6
Hidden Single: r1c9=4
Full House: r2c7=6
Naked Single: r9c7=4
Naked Single: r7c8=6
Naked Single: r9c3=6
Full House: r8c2=4
Full House: r8c4=6
Naked Single: r4c8=9
Naked Single: r7c5=5
Full House: r6c5=6
Full House: r7c4=4
Naked Single: r2c2=9
Naked Single: r1c4=5
Full House: r1c6=6
Full House: r6c6=5
Naked Single: r4c1=1
Naked Single: r4c9=6
Naked Single: r6c9=2
Full House: r9c9=9
Full House: r9c8=2
Full House: r5c8=4
Naked Single: r6c2=8
Naked Single: r4c4=3
Naked Single: r4c2=5
Full House: r4c7=8
Full House: r5c2=6
Naked Single: r6c7=3
Full House: r5c7=5
Naked Single: r5c4=9
Full House: r6c4=1
Naked Single: r6c3=4
Full House: r6c1=9
Naked Single: r5c1=2
Full House: r2c1=4
Full House: r2c3=2
Full House: r5c3=3
|
normal_sudoku_1669
|
4...2.1....23...57.1.......92....681...8..4....8..23.58.92...3...4.738.6.6...47..
|
493725168682341957517698243925437681136859472748162395879216534254973816361584729
|
Basic 9x9 Sudoku 1669
|
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 . . . 2 . 1 . .
. . 2 3 . . . 5 7
. 1 . . . . . . .
9 2 . . . . 6 8 1
. . . 8 . . 4 . .
. . 8 . . 2 3 . 5
8 . 9 2 . . . 3 .
. . 4 . 7 3 8 . 6
. 6 . . . 4 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
493725168682341957517698243925437681136859472748162395879216534254973816361584729 #1 Easy (204)
Naked Single: r4c9=1
Naked Single: r2c1=6
Naked Single: r2c7=9
Naked Single: r8c2=5
Naked Single: r7c7=5
Full House: r3c7=2
Naked Single: r7c9=4
Naked Single: r1c8=6
Naked Single: r2c2=8
Naked Single: r7c2=7
Naked Single: r3c8=4
Naked Single: r2c6=1
Full House: r2c5=4
Naked Single: r5c2=3
Naked Single: r6c2=4
Full House: r1c2=9
Naked Single: r7c6=6
Full House: r7c5=1
Naked Single: r8c4=9
Naked Single: r9c4=5
Full House: r9c5=8
Naked Single: r1c4=7
Naked Single: r3c4=6
Naked Single: r4c4=4
Full House: r6c4=1
Naked Single: r6c1=7
Naked Single: r4c3=5
Naked Single: r6c8=9
Full House: r6c5=6
Naked Single: r1c3=3
Naked Single: r4c5=3
Full House: r4c6=7
Naked Single: r5c1=1
Full House: r5c3=6
Naked Single: r5c9=2
Full House: r5c8=7
Naked Single: r1c9=8
Full House: r1c6=5
Full House: r3c9=3
Full House: r9c9=9
Naked Single: r3c1=5
Full House: r3c3=7
Full House: r9c3=1
Naked Single: r8c1=2
Full House: r8c8=1
Full House: r9c8=2
Full House: r9c1=3
Naked Single: r3c5=9
Full House: r3c6=8
Full House: r5c6=9
Full House: r5c5=5
|
normal_sudoku_333
|
5.6.7...9.3184..56....9..1....21.....6...45...2.....83..7......6.81.7....9..5....
|
586371249931842756472596318845213697763984521129765483217439865658127934394658172
|
Basic 9x9 Sudoku 333
|
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.
|
5 . 6 . 7 . . . 9
. 3 1 8 4 . . 5 6
. . . . 9 . . 1 .
. . . 2 1 . . . .
. 6 . . . 4 5 . .
. 2 . . . . . 8 3
. . 7 . . . . . .
6 . 8 1 . 7 . . .
. 9 . . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
586371249931842756472596318845213697763984521129765483217439865658127934394658172 #1 Hard (1520)
Naked Single: r2c4=8
Naked Single: r6c5=6
Naked Single: r1c4=3
Naked Single: r2c6=2
Naked Single: r1c6=1
Naked Single: r2c7=7
Full House: r2c1=9
Hidden Single: r7c2=1
Hidden Single: r3c7=3
Hidden Single: r7c9=5
Hidden Single: r8c2=5
Locked Candidates Type 1 (Pointing): 2 in b1 => r3c9<>2
Locked Candidates Type 1 (Pointing): 9 in b8 => r7c78<>9
Locked Candidates Type 2 (Claiming): 4 in r8 => r7c78,r9c789<>4
Naked Triple: 5,7,9 in r56c4,r6c6 => r4c6<>5, r4c6<>9
Hidden Single: r4c3=5
Locked Candidates Type 2 (Claiming): 9 in r4 => r5c8,r6c7<>9
Hidden Pair: 6,9 in r4c78 => r4c78<>4, r4c8<>7
2-String Kite: 3 in r4c6,r9c3 (connected by r4c1,r5c3) => r9c6<>3
W-Wing: 4/2 in r1c8,r8c9 connected by 2 in r5c89 => r3c9,r8c8<>4
Naked Single: r3c9=8
Hidden Single: r1c8=4
Full House: r1c7=2
Full House: r1c2=8
Naked Pair: 4,7 in r4c29 => r4c1<>4, r4c1<>7
XY-Wing: 4/7/2 in r48c9,r5c8 => r5c9,r789c8<>2
Hidden Single: r5c8=2
Hidden Single: r9c8=7
Locked Candidates Type 2 (Claiming): 3 in r9 => r7c1<>3
XYZ-Wing: 1/4/7 in r4c2,r6c17 => r6c3<>4
Naked Single: r6c3=9
Naked Single: r5c3=3
Naked Single: r6c6=5
Naked Single: r4c1=8
Naked Single: r5c5=8
Naked Single: r3c6=6
Full House: r3c4=5
Naked Single: r6c4=7
Naked Single: r4c6=3
Full House: r5c4=9
Naked Single: r9c6=8
Full House: r7c6=9
Hidden Single: r9c1=3
Hidden Single: r7c7=8
Bivalue Universal Grave + 1 => r3c1<>2, r3c1<>7
Naked Single: r3c1=4
Naked Single: r3c2=7
Full House: r3c3=2
Full House: r4c2=4
Full House: r9c3=4
Full House: r7c1=2
Naked Single: r6c1=1
Full House: r5c1=7
Full House: r6c7=4
Full House: r5c9=1
Naked Single: r4c9=7
Naked Single: r9c4=6
Full House: r7c4=4
Naked Single: r7c5=3
Full House: r7c8=6
Full House: r8c5=2
Naked Single: r8c7=9
Naked Single: r9c9=2
Full House: r9c7=1
Full House: r8c9=4
Full House: r4c7=6
Full House: r4c8=9
Full House: r8c8=3
|
normal_sudoku_1013
|
.1..392..7..2..1....2..1.6..2.4..8..1.7.58...4.8.23.....17.54......9..51.....2.86
|
816539247735246198942871563329467815167958324458123679691785432283694751574312986
|
Basic 9x9 Sudoku 1013
|
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.
|
. 1 . . 3 9 2 . .
7 . . 2 . . 1 . .
. . 2 . . 1 . 6 .
. 2 . 4 . . 8 . .
1 . 7 . 5 8 . . .
4 . 8 . 2 3 . . .
. . 1 7 . 5 4 . .
. . . . 9 . . 5 1
. . . . . 2 . 8 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
816539247735246198942871563329467815167958324458123679691785432283694751574312986 #1 Extreme (2244)
Hidden Single: r6c5=2
Hidden Single: r3c5=7
Hidden Single: r4c6=7
Hidden Single: r8c1=2
Locked Candidates Type 1 (Pointing): 4 in b2 => r2c2389<>4
Locked Candidates Type 1 (Pointing): 7 in b9 => r6c7<>7
Naked Triple: 3,6,9 in r5c247 => r5c89<>3, r5c89<>9
2-String Kite: 8 in r2c5,r8c2 (connected by r7c5,r8c4) => r2c2<>8
Empty Rectangle: 3 in b9 (r5c27) => r7c2<>3
XY-Wing: 1/4/6 in r49c5,r8c6 => r7c5<>6
Naked Single: r7c5=8
Hidden Single: r2c9=8
Hidden Single: r8c2=8
Hidden Single: r8c7=7
Hidden Single: r9c2=7
Hidden Single: r3c2=4
Locked Pair: 4,6 in r2c56 => r1c4,r2c23<>6
Locked Candidates Type 1 (Pointing): 6 in b8 => r8c3<>6
Locked Candidates Type 2 (Claiming): 5 in r2 => r1c13,r3c1<>5
Naked Single: r1c3=6
Naked Single: r1c1=8
Naked Single: r1c4=5
Naked Single: r3c4=8
XYZ-Wing: 3/6/9 in r37c1,r7c2 => r9c1<>9
Discontinuous Nice Loop: 5 r4c1 -5- r9c1 -3- r9c4 -1- r9c5 =1= r4c5 =6= r4c1 => r4c1<>5
Hidden Single: r9c1=5
Finned Swordfish: 3 c189 r347 fr2c8 => r3c7<>3
Sashimi Swordfish: 3 r589 c347 fr5c2 => r4c3<>3
Swordfish: 3 r347 c189 => r2c8<>3
Naked Single: r2c8=9
Naked Single: r3c7=5
Naked Single: r3c9=3
Full House: r3c1=9
Skyscraper: 9 in r4c3,r7c2 (connected by r47c9) => r56c2,r9c3<>9
Hidden Single: r7c2=9
Naked Single: r7c9=2
Naked Single: r5c9=4
Naked Single: r7c8=3
Full House: r7c1=6
Full House: r9c7=9
Full House: r4c1=3
Naked Single: r1c9=7
Full House: r1c8=4
Naked Single: r5c8=2
Naked Single: r4c8=1
Full House: r6c8=7
Naked Single: r6c7=6
Full House: r5c7=3
Naked Single: r5c2=6
Full House: r5c4=9
Naked Single: r4c5=6
Full House: r6c4=1
Naked Single: r6c2=5
Full House: r2c2=3
Full House: r4c3=9
Full House: r6c9=9
Full House: r2c3=5
Full House: r4c9=5
Naked Single: r2c5=4
Full House: r2c6=6
Full House: r9c5=1
Full House: r8c6=4
Naked Single: r9c4=3
Full House: r8c4=6
Full House: r8c3=3
Full House: r9c3=4
|
normal_sudoku_1223
|
.9265...85....36........5....4.65..3.......7...832..........4...768....1.5..9..8.
|
192654738547283619683719524724165893315948276968327145839571462476832951251496387
|
Basic 9x9 Sudoku 1223
|
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 2 6 5 . . . 8
5 . . . . 3 6 . .
. . . . . . 5 . .
. . 4 . 6 5 . . 3
. . . . . . . 7 .
. . 8 3 2 . . . .
. . . . . . 4 . .
. 7 6 8 . . . . 1
. 5 . . 9 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
192654738547283619683719524724165893315948276968327145839571462476832951251496387 #1 Hard (628)
Hidden Single: r1c5=5
Hidden Single: r5c3=5
Hidden Single: r7c4=5
Hidden Single: r4c7=8
Hidden Single: r8c8=5
Hidden Single: r7c3=9
Hidden Single: r6c9=5
Hidden Single: r8c7=9
Naked Single: r6c7=1
Naked Single: r5c7=2
Naked Single: r6c2=6
Naked Single: r4c8=9
Naked Single: r6c8=4
Full House: r5c9=6
Hidden Single: r3c1=6
Hidden Single: r7c8=6
Hidden Single: r9c6=6
Hidden Single: r7c1=8
Hidden Single: r9c7=3
Full House: r1c7=7
Naked Single: r9c3=1
Naked Single: r2c3=7
Full House: r3c3=3
Hidden Single: r1c8=3
Locked Candidates Type 1 (Pointing): 4 in b7 => r1c1<>4
Naked Single: r1c1=1
Full House: r1c6=4
Naked Single: r8c6=2
Locked Candidates Type 1 (Pointing): 2 in b9 => r23c9<>2
XY-Wing: 2/4/7 in r49c1,r9c4 => r4c4<>7
Naked Single: r4c4=1
Naked Single: r4c2=2
Full House: r4c1=7
Naked Single: r7c2=3
Naked Single: r6c1=9
Full House: r6c6=7
Naked Single: r5c2=1
Full House: r5c1=3
Naked Single: r8c1=4
Full House: r8c5=3
Full House: r9c1=2
Naked Single: r7c6=1
Naked Single: r9c9=7
Full House: r7c9=2
Full House: r7c5=7
Full House: r9c4=4
Naked Single: r5c4=9
Naked Single: r2c4=2
Full House: r3c4=7
Naked Single: r5c6=8
Full House: r3c6=9
Full House: r5c5=4
Naked Single: r2c8=1
Full House: r3c8=2
Naked Single: r3c9=4
Full House: r2c9=9
Naked Single: r2c5=8
Full House: r2c2=4
Full House: r3c2=8
Full House: r3c5=1
|
normal_sudoku_1805
|
3..481..6....7..9...25.61.....7.83...9..64...4......6.2..8.9..1.1..538....8..7.3.
|
359481726186372495742596183625718349893264517471935268237849651914653872568127934
|
Basic 9x9 Sudoku 1805
|
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 . . 4 8 1 . . 6
. . . . 7 . . 9 .
. . 2 5 . 6 1 . .
. . . 7 . 8 3 . .
. 9 . . 6 4 . . .
4 . . . . . . 6 .
2 . . 8 . 9 . . 1
. 1 . . 5 3 8 . .
. . 8 . . 7 . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
359481726186372495742596183625718349893264517471935268237849651914653872568127934 #1 Easy (418)
Naked Single: r3c6=6
Naked Single: r7c5=4
Naked Single: r2c6=2
Full House: r6c6=5
Naked Single: r2c4=3
Full House: r3c5=9
Hidden Single: r1c3=9
Hidden Single: r6c4=9
Hidden Single: r3c9=3
Hidden Single: r6c5=3
Hidden Single: r5c3=3
Hidden Single: r4c9=9
Hidden Single: r9c7=9
Hidden Single: r7c2=3
Hidden Single: r6c3=1
Hidden Single: r8c1=9
Hidden Single: r4c8=4
Hidden Single: r2c7=4
Hidden Single: r7c7=6
Hidden Single: r2c1=1
Hidden Single: r3c2=4
Hidden Single: r4c5=1
Full House: r5c4=2
Full House: r9c5=2
Naked Single: r8c4=6
Full House: r9c4=1
Hidden Single: r5c8=1
Hidden Single: r8c3=4
Hidden Single: r9c9=4
Hidden Single: r4c2=2
Hidden Single: r3c8=8
Full House: r3c1=7
Naked Single: r2c9=5
Naked Single: r1c2=5
Naked Single: r2c3=6
Full House: r2c2=8
Naked Single: r9c2=6
Full House: r6c2=7
Full House: r9c1=5
Full House: r7c3=7
Full House: r4c3=5
Full House: r4c1=6
Full House: r5c1=8
Full House: r7c8=5
Naked Single: r6c7=2
Full House: r6c9=8
Naked Single: r5c9=7
Full House: r5c7=5
Full House: r1c7=7
Full House: r8c9=2
Full House: r1c8=2
Full House: r8c8=7
|
normal_sudoku_4700
|
6..5..9...53....6.1.9..4....61....3.4...5...99.5.3.....1.47..96...2895.4..4...3..
|
647521983253897461189364752761948235438152679925736148512473896376289514894615327
|
Basic 9x9 Sudoku 4700
|
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 . . 5 . . 9 . .
. 5 3 . . . . 6 .
1 . 9 . . 4 . . .
. 6 1 . . . . 3 .
4 . . . 5 . . . 9
9 . 5 . 3 . . . .
. 1 . 4 7 . . 9 6
. . . 2 8 9 5 . 4
. . 4 . . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
647521983253897461189364752761948235438152679925736148512473896376289514894615327 #1 Easy (388)
Naked Single: r7c5=7
Hidden Single: r5c2=3
Naked Single: r8c2=7
Naked Single: r8c1=3
Naked Single: r8c3=6
Full House: r8c8=1
Hidden Single: r4c5=4
Hidden Single: r9c2=9
Hidden Single: r4c9=5
Hidden Single: r3c8=5
Hidden Single: r2c7=4
Hidden Single: r1c2=4
Hidden Single: r3c4=3
Hidden Single: r7c6=3
Hidden Single: r4c4=9
Hidden Single: r2c5=9
Hidden Single: r6c8=4
Hidden Single: r1c9=3
Hidden Single: r3c5=6
Naked Single: r9c5=1
Full House: r1c5=2
Naked Single: r9c4=6
Full House: r9c6=5
Hidden Single: r7c1=5
Hidden Single: r2c9=1
Hidden Single: r1c6=1
Hidden Single: r2c1=2
Naked Single: r3c2=8
Full House: r1c3=7
Full House: r6c2=2
Full House: r1c8=8
Naked Single: r9c1=8
Full House: r4c1=7
Full House: r5c3=8
Full House: r7c3=2
Full House: r7c7=8
Naked Single: r4c7=2
Full House: r4c6=8
Naked Single: r3c7=7
Full House: r3c9=2
Naked Single: r5c8=7
Full House: r9c8=2
Full House: r9c9=7
Full House: r6c9=8
Naked Single: r2c6=7
Full House: r2c4=8
Naked Single: r5c4=1
Full House: r6c4=7
Naked Single: r6c6=6
Full House: r5c6=2
Full House: r5c7=6
Full House: r6c7=1
|
normal_sudoku_790
|
56..381.........93....6....83..7.5..9..1.3......8.532...4....311....7.6.68.3..754
|
567938142248751693391264875832476519975123486416895327754689231123547968689312754
|
Basic 9x9 Sudoku 790
|
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 6 . . 3 8 1 . .
. . . . . . . 9 3
. . . . 6 . . . .
8 3 . . 7 . 5 . .
9 . . 1 . 3 . . .
. . . 8 . 5 3 2 .
. . 4 . . . . 3 1
1 . . . . 7 . 6 .
6 8 . 3 . . 7 5 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
567938142248751693391264875832476519975123486416895327754689231123547968689312754 #1 Easy (284)
Naked Single: r9c8=5
Hidden Single: r2c7=6
Hidden Single: r4c8=1
Hidden Single: r3c1=3
Hidden Single: r8c3=3
Hidden Single: r3c9=5
Hidden Single: r2c3=8
Hidden Single: r5c3=5
Hidden Single: r5c9=6
Naked Single: r4c9=9
Naked Single: r6c9=7
Naked Single: r1c9=2
Full House: r8c9=8
Naked Single: r6c1=4
Naked Single: r6c2=1
Naked Single: r6c5=9
Full House: r6c3=6
Naked Single: r4c3=2
Full House: r5c2=7
Naked Single: r9c3=9
Naked Single: r1c3=7
Full House: r3c3=1
Naked Single: r1c8=4
Full House: r1c4=9
Naked Single: r2c1=2
Full House: r7c1=7
Naked Single: r3c7=8
Full House: r3c8=7
Full House: r5c8=8
Full House: r5c7=4
Full House: r5c5=2
Naked Single: r2c2=4
Full House: r3c2=9
Naked Single: r9c5=1
Full House: r9c6=2
Naked Single: r2c6=1
Naked Single: r2c5=5
Full House: r2c4=7
Naked Single: r3c6=4
Full House: r3c4=2
Naked Single: r7c5=8
Full House: r8c5=4
Naked Single: r4c6=6
Full House: r4c4=4
Full House: r7c6=9
Naked Single: r8c4=5
Full House: r7c4=6
Naked Single: r7c7=2
Full House: r7c2=5
Full House: r8c2=2
Full House: r8c7=9
|
normal_sudoku_3952
|
6..8......9.........42.6.......3..65.61...39.3.5..91.4.1.......5.6...4.9.395.4.16
|
627893541893145627154276938942731865761458392385629174418967253576312489239584716
|
Basic 9x9 Sudoku 3952
|
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 . . 8 . . . . .
. 9 . . . . . . .
. . 4 2 . 6 . . .
. . . . 3 . . 6 5
. 6 1 . . . 3 9 .
3 . 5 . . 9 1 . 4
. 1 . . . . . . .
5 . 6 . . . 4 . 9
. 3 9 5 . 4 . 1 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
627893541893145627154276938942731865761458392385629174418967253576312489239584716 #1 Extreme (14274) bf
Hidden Single: r6c1=3
Hidden Single: r4c2=4
Hidden Single: r4c1=9
Hidden Single: r7c4=9
Hidden Single: r7c1=4
Hidden Single: r2c7=6
Hidden Single: r7c5=6
Hidden Single: r6c4=6
Locked Candidates Type 2 (Claiming): 3 in r3 => r1c89,r2c89<>3
Brute Force: r4c6=1
Naked Single: r4c4=7
Naked Single: r5c4=4
Finned Franken Swordfish: 2 r49b5 c157 fr4c3 fr5c6 => r5c1<>2
W-Wing: 8/2 in r4c7,r6c5 connected by 2 in r4c3,r6c2 => r6c8<>8
Sashimi Swordfish: 8 r469 c157 fr4c3 fr6c2 => r5c1<>8
Naked Single: r5c1=7
Hidden Single: r6c8=7
Forcing Chain Contradiction in r3 => r1c7<>7
r1c7=7 r9c7<>7 r9c5=7 r8c56<>7 r8c2=7 r3c2<>7
r1c7=7 r9c7<>7 r9c5=7 r3c5<>7
r1c7=7 r3c7<>7
r1c7=7 r3c9<>7
Forcing Chain Contradiction in r9c5 => r8c2<>2
r8c2=2 r6c2<>2 r6c5=2 r9c5<>2
r8c2=2 r8c2<>7 r8c56=7 r9c5<>7
r8c2=2 r9c1<>2 r9c1=8 r9c5<>8
2-String Kite: 2 in r1c2,r4c7 (connected by r4c3,r6c2) => r1c7<>2
Turbot Fish: 2 r4c7 =2= r4c3 -2- r7c3 =2= r9c1 => r9c7<>2
Hidden Rectangle: 5/9 in r1c57,r3c57 => r3c5<>5
Grouped Discontinuous Nice Loop: 8 r2c3 -8- r4c3 -2- r7c3 =2= r9c1 =8= r23c1 -8- r2c3 => r2c3<>8
Turbot Fish: 8 r5c9 =8= r4c7 -8- r4c3 =8= r7c3 => r7c9<>8
Almost Locked Set XY-Wing: A=r5c9 {28}, B=r69c5 {278}, C=r49c7 {278}, X,Y=2,7, Z=8 => r5c5<>8
Forcing Chain Contradiction in r9c5 => r8c2=7
r8c2<>7 r8c2=8 r9c1<>8 r9c1=2 r9c5<>2
r8c2<>7 r8c56=7 r9c5<>7
r8c2<>7 r8c2=8 r6c2<>8 r6c5=8 r9c5<>8
Naked Pair: 2,8 in r47c3 => r12c3<>2
X-Wing: 2 c37 r47 => r7c689<>2
Remote Pair: 8/2 r4c7 -2- r4c3 -8- r7c3 -2- r9c1 => r9c7<>8
Naked Single: r9c7=7
Naked Single: r7c9=3
Hidden Single: r7c6=7
Hidden Single: r3c8=3
Locked Pair: 3,5 in r12c6 => r12c5,r5c6<>5, r2c4,r8c6<>3
Naked Single: r2c4=1
Full House: r8c4=3
Hidden Single: r5c5=5
Hidden Single: r1c9=1
Hidden Single: r3c1=1
Hidden Single: r8c5=1
Remote Pair: 2/8 r2c1 -8- r9c1 -2- r9c5 -8- r6c5 -2- r5c6 -8- r5c9 => r2c9<>2, r2c9<>8
Naked Single: r2c9=7
Naked Single: r2c3=3
Naked Single: r2c5=4
Naked Single: r3c9=8
Full House: r5c9=2
Full House: r4c7=8
Full House: r5c6=8
Full House: r4c3=2
Full House: r6c5=2
Full House: r6c2=8
Naked Single: r1c3=7
Full House: r7c3=8
Full House: r9c1=2
Full House: r9c5=8
Full House: r8c6=2
Full House: r2c1=8
Full House: r8c8=8
Naked Single: r2c6=5
Full House: r1c6=3
Full House: r2c8=2
Naked Single: r3c2=5
Full House: r1c2=2
Naked Single: r1c5=9
Full House: r3c5=7
Full House: r3c7=9
Naked Single: r7c8=5
Full House: r1c8=4
Full House: r1c7=5
Full House: r7c7=2
|
normal_sudoku_2620
|
........9..65...8.9.74.....3........7.89.6....6173.....7..9.3.1.1.....68..3..897.
|
584162739136579284927483516392841657758926143461735892875694321219357468643218975
|
Basic 9x9 Sudoku 2620
|
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
. . 6 5 . . . 8 .
9 . 7 4 . . . . .
3 . . . . . . . .
7 . 8 9 . 6 . . .
. 6 1 7 3 . . . .
. 7 . . 9 . 3 . 1
. 1 . . . . . 6 8
. . 3 . . 8 9 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
584162739136579284927483516392841657758926143461735892875694321219357468643218975 #1 Extreme (27338) bf
Hidden Single: r5c1=7
Hidden Single: r2c6=9
Hidden Single: r6c7=8
Hidden Single: r7c1=8
Hidden Single: r6c8=9
Hidden Single: r8c3=9
Hidden Single: r4c2=9
Hidden Single: r7c4=6
Hidden Single: r9c1=6
Hidden Pair: 6,7 in r4c79 => r4c7<>1, r4c79<>2, r4c79<>4, r4c79<>5
Brute Force: r4c7=6
Naked Single: r4c9=7
Hidden Single: r1c5=6
Hidden Single: r3c9=6
Brute Force: r4c8=5
Hidden Single: r9c9=5
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c5<>1
Skyscraper: 5 in r6c1,r7c3 (connected by r67c6) => r8c1<>5
Hidden Single: r7c3=5
Naked Pair: 2,4 in r8c17 => r8c456<>2, r8c56<>4
Naked Single: r8c4=3
Discontinuous Nice Loop: 1 r2c7 -1- r2c1 =1= r1c1 =5= r6c1 -5- r6c6 =5= r8c6 =7= r8c5 -7- r2c5 =7= r2c7 => r2c7<>1
Finned Franken Swordfish: 2 c34b7 r149 fr8c1 => r1c1<>2
Forcing Chain Verity => r1c1<>4
r4c5=4 r4c3<>4 r1c3=4 r1c1<>4
r5c5=4 r5c5<>5 r5c2=5 r6c1<>5 r1c1=5 r1c1<>4
r9c5=4 r9c2<>4 r8c1=4 r1c1<>4
Discontinuous Nice Loop: 1 r1c7 -1- r1c1 -5- r6c1 =5= r6c6 -5- r8c6 -7- r1c6 =7= r1c7 => r1c7<>1
Continuous Nice Loop: 2 7= r2c5 =1= r2c1 -1- r1c1 -5- r6c1 =5= r6c6 -5- r8c6 -7- r8c5 =7= r2c5 =1 => r2c5<>2
Forcing Chain Contradiction in r4 => r1c2<>2
r1c2=2 r1c3<>2 r1c3=4 r4c3<>4
r1c2=2 r1c2<>8 r1c4=8 r4c4<>8 r4c5=8 r4c5<>4
r1c2=2 r9c2<>2 r9c2=4 r9c5<>4 r7c6=4 r4c6<>4
Forcing Chain Contradiction in r2c1 => r1c7<>2
r1c7=2 r1c7<>7 r1c6=7 r2c5<>7 r2c5=1 r2c1<>1
r1c7=2 r8c7<>2 r8c1=2 r2c1<>2
r1c7=2 r1c3<>2 r1c3=4 r2c1<>4
Forcing Chain Contradiction in r2c1 => r1c7<>4
r1c7=4 r1c7<>7 r1c6=7 r2c5<>7 r2c5=1 r2c1<>1
r1c7=4 r1c3<>4 r1c3=2 r2c1<>2
r1c7=4 r8c7<>4 r8c1=4 r2c1<>4
Discontinuous Nice Loop: 5 r1c2 -5- r1c1 -1- r2c1 =1= r2c5 =7= r2c7 -7- r1c7 -5- r1c2 => r1c2<>5
Grouped Discontinuous Nice Loop: 4 r2c2 -4- r9c2 =4= r9c5 -4- r7c6 =4= r7c8 -4- r1c8 =4= r1c23 -4- r2c2 => r2c2<>4
Forcing Chain Contradiction in c8 => r2c2=3
r2c2<>3 r2c2=2 r1c3<>2 r1c3=4 r1c8<>4
r2c2<>3 r2c9=3 r2c9<>4 r56c9=4 r5c8<>4
r2c2<>3 r2c2=2 r9c2<>2 r9c2=4 r9c5<>4 r7c6=4 r7c8<>4
Hidden Single: r5c9=3
Finned X-Wing: 2 r28 c17 fr2c9 => r3c7<>2
Discontinuous Nice Loop: 1 r4c4 -1- r9c4 -2- r9c2 -4- r1c2 -8- r1c4 =8= r4c4 => r4c4<>1
Grouped Discontinuous Nice Loop: 2 r1c8 -2- r2c79 =2= r2c1 =1= r2c5 =7= r1c6 =3= r1c8 => r1c8<>2
Grouped Discontinuous Nice Loop: 4 r1c8 -4- r1c23 =4= r2c1 =1= r2c5 =7= r1c6 =3= r1c8 => r1c8<>4
Locked Candidates Type 1 (Pointing): 4 in b3 => r2c1<>4
Turbot Fish: 4 r5c8 =4= r7c8 -4- r7c6 =4= r9c5 => r5c5<>4
W-Wing: 2/4 in r4c3,r7c6 connected by 4 in r49c5 => r4c6<>2
W-Wing: 2/4 in r4c3,r9c2 connected by 4 in r1c23 => r5c2<>2
Empty Rectangle: 2 in b8 (r39c2) => r3c6<>2
Empty Rectangle: 2 in b2 (r14c3) => r4c5<>2
W-Wing: 2/4 in r6c9,r7c6 connected by 4 in r57c8 => r6c6<>2
Swordfish: 2 r268 c179 => r5c7<>2
Skyscraper: 2 in r5c5,r7c6 (connected by r57c8) => r9c5<>2
XY-Wing: 1/4/5 in r35c7,r5c2 => r3c2<>5
Hidden Single: r3c7=5
Naked Single: r1c7=7
Hidden Single: r5c2=5
Naked Single: r5c5=2
Naked Single: r4c4=8
Hidden Single: r1c1=5
Hidden Single: r5c7=1
Full House: r5c8=4
Full House: r6c9=2
Full House: r2c9=4
Naked Single: r7c8=2
Full House: r7c6=4
Full House: r8c7=4
Full House: r2c7=2
Naked Single: r6c1=4
Full House: r6c6=5
Full House: r4c3=2
Full House: r1c3=4
Naked Single: r4c6=1
Full House: r4c5=4
Naked Single: r9c5=1
Naked Single: r8c1=2
Full House: r2c1=1
Full House: r2c5=7
Full House: r9c2=4
Full House: r9c4=2
Full House: r1c4=1
Naked Single: r8c6=7
Full House: r8c5=5
Full House: r3c5=8
Naked Single: r1c2=8
Full House: r3c2=2
Naked Single: r3c6=3
Full House: r1c6=2
Full House: r1c8=3
Full House: r3c8=1
|
normal_sudoku_1427
|
..81.9.......3....19.5..6..8.....2..6..38..1..5...6.......9.42.....4....7..26.385
|
468129753527634198193578642831957264674382519952416837386795421215843976749261385
|
Basic 9x9 Sudoku 1427
|
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 . . .
. . . . 3 . . . .
1 9 . 5 . . 6 . .
8 . . . . . 2 . .
6 . . 3 8 . . 1 .
. 5 . . . 6 . . .
. . . . 9 . 4 2 .
. . . . 4 . . . .
7 . . 2 6 . 3 8 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
468129753527634198193578642831957264674382519952416837386795421215843976749261385 #1 Easy (304)
Naked Single: r9c4=2
Naked Single: r9c6=1
Naked Single: r9c2=4
Full House: r9c3=9
Hidden Single: r1c2=6
Hidden Single: r2c4=6
Hidden Single: r4c5=5
Hidden Single: r6c1=9
Hidden Single: r5c7=5
Naked Single: r1c7=7
Naked Single: r1c5=2
Naked Single: r6c7=8
Naked Single: r3c5=7
Full House: r6c5=1
Hidden Single: r4c4=9
Hidden Single: r5c9=9
Hidden Single: r5c6=2
Naked Single: r5c2=7
Full House: r5c3=4
Naked Single: r2c2=2
Naked Single: r3c3=3
Naked Single: r3c8=4
Naked Single: r4c3=1
Naked Single: r6c3=2
Full House: r4c2=3
Naked Single: r1c9=3
Naked Single: r3c6=8
Full House: r2c6=4
Full House: r3c9=2
Naked Single: r1c8=5
Full House: r1c1=4
Naked Single: r2c1=5
Full House: r2c3=7
Naked Single: r4c6=7
Full House: r6c4=4
Naked Single: r2c8=9
Naked Single: r7c1=3
Full House: r8c1=2
Naked Single: r4c8=6
Full House: r4c9=4
Naked Single: r6c9=7
Full House: r6c8=3
Full House: r8c8=7
Naked Single: r2c7=1
Full House: r2c9=8
Full House: r8c7=9
Naked Single: r7c6=5
Full House: r8c6=3
Naked Single: r8c4=8
Full House: r7c4=7
Naked Single: r7c3=6
Full House: r8c3=5
Naked Single: r8c2=1
Full House: r7c2=8
Full House: r7c9=1
Full House: r8c9=6
|
normal_sudoku_5903
|
.5.62...46.............19...7....2..4.5.....8..8.5..7..1..8.5.75..2.34...4.175..2
|
751629384694538721832741956173896245425317698968452173216984537587263419349175862
|
Basic 9x9 Sudoku 5903
|
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 . 6 2 . . . 4
6 . . . . . . . .
. . . . . 1 9 . .
. 7 . . . . 2 . .
4 . 5 . . . . . 8
. . 8 . 5 . . 7 .
. 1 . . 8 . 5 . 7
5 . . 2 . 3 4 . .
. 4 . 1 7 5 . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
751629384694538721832741956173896245425317698968452173216984537587263419349175862 #1 Extreme (2756)
Hidden Single: r8c1=5
Hidden Single: r4c8=4
Hidden Single: r8c3=7
Hidden Single: r4c9=5
Locked Candidates Type 2 (Claiming): 4 in c5 => r2c46,r3c4<>4
Hidden Pair: 2,5 in r23c8 => r2c8<>1, r23c8<>3, r23c8<>8, r3c8<>6
Hidden Single: r3c9=6
Hidden Rectangle: 3/4 in r2c35,r3c35 => r2c3<>3
Hidden Rectangle: 4/9 in r6c46,r7c46 => r6c6<>9
Discontinuous Nice Loop: 9 r5c4 -9- r7c4 -4- r7c6 =4= r6c6 =2= r5c6 =7= r5c4 => r5c4<>9
Grouped Discontinuous Nice Loop: 3 r3c1 -3- r23c2 =3= r56c2 -3- r4c13 =3= r4c45 -3- r5c4 -7- r3c4 =7= r3c1 => r3c1<>3
Grouped Discontinuous Nice Loop: 6 r5c6 -6- r7c6 =6= r8c5 -6- r8c2 =6= r56c2 -6- r4c3 =6= r4c56 -6- r5c6 => r5c6<>6
Grouped Discontinuous Nice Loop: 3 r6c1 -3- r6c9 =3= r2c9 -3- r1c78 =3= r1c13 -3- r23c2 =3= r56c2 -3- r6c1 => r6c1<>3
Grouped Discontinuous Nice Loop: 3 r6c4 -3- r6c9 =3= r2c9 -3- r1c78 =3= r1c13 -3- r23c2 =3= r56c2 -3- r4c13 =3= r4c45 -3- r6c4 => r6c4<>3
Naked Pair: 4,9 in r67c4 => r24c4<>9
Skyscraper: 9 in r7c4,r8c9 (connected by r6c49) => r7c8,r8c5<>9
Naked Single: r8c5=6
Locked Candidates Type 1 (Pointing): 6 in b7 => r4c3<>6
Hidden Single: r4c6=6
Hidden Single: r4c4=8
Locked Candidates Type 1 (Pointing): 9 in b8 => r7c13<>9
Locked Candidates Type 2 (Claiming): 8 in r3 => r1c1,r2c2<>8
Uniqueness Test 1: 4/9 in r6c46,r7c46 => r6c6<>4
Naked Single: r6c6=2
Hidden Single: r6c4=4
Naked Single: r7c4=9
Full House: r7c6=4
Hidden Single: r5c2=2
Hidden Single: r6c2=6
Locked Candidates Type 1 (Pointing): 3 in b4 => r4c5<>3
Locked Candidates Type 1 (Pointing): 3 in b5 => r5c78<>3
Locked Candidates Type 2 (Claiming): 3 in c2 => r1c13,r3c3<>3
Locked Candidates Type 2 (Claiming): 3 in r1 => r2c79<>3
Naked Single: r2c9=1
Naked Single: r8c9=9
Full House: r6c9=3
Naked Single: r8c2=8
Full House: r8c8=1
Naked Single: r6c7=1
Full House: r6c1=9
Naked Single: r3c2=3
Full House: r2c2=9
Naked Single: r5c7=6
Full House: r5c8=9
Naked Single: r9c1=3
Naked Single: r3c5=4
Naked Single: r1c3=1
Naked Single: r5c6=7
Naked Single: r4c1=1
Full House: r4c3=3
Full House: r4c5=9
Naked Single: r7c1=2
Naked Single: r9c7=8
Naked Single: r2c5=3
Full House: r5c5=1
Full House: r5c4=3
Naked Single: r3c3=2
Naked Single: r1c1=7
Full House: r3c1=8
Full House: r2c3=4
Naked Single: r2c6=8
Full House: r1c6=9
Naked Single: r7c3=6
Full House: r7c8=3
Full House: r9c8=6
Full House: r9c3=9
Naked Single: r2c7=7
Full House: r1c7=3
Full House: r1c8=8
Naked Single: r3c8=5
Full House: r2c8=2
Full House: r2c4=5
Full House: r3c4=7
|
normal_sudoku_5013
|
14.93...8..74..9..3.2..8......58..6.87.3....1...217.8..2..4..5..........41...3..7
|
146935278587462913392178645231584769874396521659217384723849156968751432415623897
|
Basic 9x9 Sudoku 5013
|
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 . 9 3 . . . 8
. . 7 4 . . 9 . .
3 . 2 . . 8 . . .
. . . 5 8 . . 6 .
8 7 . 3 . . . . 1
. . . 2 1 7 . 8 .
. 2 . . 4 . . 5 .
. . . . . . . . .
4 1 . . . 3 . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
146935278587462913392178645231584769874396521659217384723849156968751432415623897 #1 Unfair (1362)
Naked Single: r4c4=5
Hidden Single: r3c2=9
Naked Single: r4c2=3
Hidden Single: r2c2=8
Hidden Single: r4c1=2
Hidden Single: r4c3=1
Hidden Single: r4c7=7
Hidden Single: r1c8=7
Locked Candidates Type 1 (Pointing): 6 in b5 => r5c3<>6
2-String Kite: 2 in r1c6,r8c9 (connected by r1c7,r2c9) => r8c6<>2
Locked Candidates Type 1 (Pointing): 2 in b8 => r2c5<>2
Naked Pair: 5,6 in r2c15 => r2c69<>5, r2c69<>6
Skyscraper: 5 in r2c1,r9c3 (connected by r29c5) => r1c3,r8c1<>5
Naked Single: r1c3=6
Full House: r2c1=5
Naked Single: r2c5=6
Naked Single: r5c5=9
Naked Single: r4c6=4
Full House: r4c9=9
Full House: r5c6=6
W-Wing: 2/5 in r1c7,r9c5 connected by 5 in r18c6 => r9c7<>2
Naked Pair: 6,8 in r9c47 => r9c3<>8
Naked Triple: 4,5,9 in r569c3 => r78c3<>9, r8c3<>5
XY-Wing: 3/6/8 in r7c39,r9c7 => r7c7<>8
Finned Swordfish: 5 r359 c357 fr3c9 => r1c7<>5
Naked Single: r1c7=2
Full House: r1c6=5
Naked Single: r2c9=3
Naked Single: r3c5=7
Naked Single: r2c8=1
Full House: r2c6=2
Full House: r3c4=1
Naked Single: r7c9=6
Naked Single: r3c8=4
Naked Single: r9c7=8
Naked Single: r3c9=5
Full House: r3c7=6
Naked Single: r5c8=2
Naked Single: r9c4=6
Naked Single: r6c9=4
Full House: r8c9=2
Naked Single: r9c8=9
Full House: r8c8=3
Naked Single: r5c7=5
Full House: r5c3=4
Full House: r6c7=3
Naked Single: r8c5=5
Full House: r9c5=2
Full House: r9c3=5
Naked Single: r7c7=1
Full House: r8c7=4
Naked Single: r8c3=8
Naked Single: r8c2=6
Full House: r6c2=5
Naked Single: r6c3=9
Full House: r7c3=3
Full House: r6c1=6
Naked Single: r7c6=9
Full House: r8c6=1
Naked Single: r8c4=7
Full House: r7c4=8
Full House: r7c1=7
Full House: r8c1=9
|
normal_sudoku_851
|
..2.3.64.4.........8..46..5...9..4.8.....596..9..8.57.3..12.....74.59..6......1..
|
952831647436597812781246395517963428248715963693482571369128754174359286825674139
|
Basic 9x9 Sudoku 851
|
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 . 6 4 .
4 . . . . . . . .
. 8 . . 4 6 . . 5
. . . 9 . . 4 . 8
. . . . . 5 9 6 .
. 9 . . 8 . 5 7 .
3 . . 1 2 . . . .
. 7 4 . 5 9 . . 6
. . . . . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
952831647436597812781246395517963428248715963693482571369128754174359286825674139 #1 Extreme (1916)
Naked Single: r8c5=5
Hidden Single: r5c2=4
Hidden Single: r2c5=9
Hidden Single: r8c1=1
Locked Candidates Type 1 (Pointing): 1 in b2 => r46c6<>1
Locked Candidates Type 1 (Pointing): 8 in b3 => r2c46<>8
Locked Candidates Type 1 (Pointing): 2 in b7 => r9c89<>2
Locked Candidates Type 1 (Pointing): 6 in b8 => r9c123<>6
Locked Candidates Type 2 (Claiming): 6 in c1 => r4c23,r6c3<>6
Hidden Pair: 4,6 in r69c4 => r6c4<>2, r69c4<>3, r9c4<>7, r9c4<>8
Skyscraper: 1 in r3c8,r6c9 (connected by r36c3) => r12c9,r4c8<>1
Empty Rectangle: 3 in b6 (r24c2) => r2c9<>3
Hidden Rectangle: 5/6 in r2c23,r7c23 => r2c3<>5
Discontinuous Nice Loop: 1 r2c3 -1- r6c3 -3- r4c2 =3= r2c2 =6= r2c3 => r2c3<>1
Discontinuous Nice Loop: 3 r6c6 -3- r6c3 -1- r6c9 =1= r5c9 -1- r5c5 =1= r4c5 =6= r6c4 =4= r6c6 => r6c6<>3
Naked Triple: 2,4,6 in r6c146 => r6c9<>2
Empty Rectangle: 2 in b2 (r25c9) => r5c4<>2
Locked Candidates Type 1 (Pointing): 2 in b5 => r2c6<>2
Empty Rectangle: 3 in b6 (r49c6) => r9c9<>3
Locked Candidates Type 2 (Claiming): 3 in c9 => r4c8<>3
Naked Single: r4c8=2
Hidden Single: r9c2=2
Hidden Single: r6c6=2
Naked Single: r6c1=6
Naked Single: r6c4=4
Naked Single: r9c4=6
Naked Single: r9c5=7
Naked Single: r5c5=1
Full House: r4c5=6
Naked Single: r5c9=3
Full House: r6c9=1
Full House: r6c3=3
Naked Single: r5c4=7
Full House: r4c6=3
Naked Single: r3c4=2
Naked Single: r5c3=8
Full House: r5c1=2
Naked Single: r2c4=5
Naked Single: r1c4=8
Full House: r8c4=3
Naked Single: r8c8=8
Full House: r8c7=2
Naked Single: r7c7=7
Naked Single: r3c7=3
Full House: r2c7=8
Naked Single: r2c8=1
Naked Single: r2c6=7
Full House: r1c6=1
Naked Single: r3c8=9
Naked Single: r2c3=6
Naked Single: r2c9=2
Full House: r1c9=7
Full House: r2c2=3
Naked Single: r1c2=5
Full House: r1c1=9
Naked Single: r3c1=7
Full House: r3c3=1
Naked Single: r7c8=5
Full House: r9c8=3
Naked Single: r4c2=1
Full House: r7c2=6
Naked Single: r4c1=5
Full House: r4c3=7
Full House: r9c1=8
Naked Single: r7c3=9
Full House: r9c3=5
Naked Single: r9c6=4
Full House: r7c6=8
Full House: r7c9=4
Full House: r9c9=9
|
normal_sudoku_5617
|
....7.1....6..48....7....3.8..3.6.4....71..86.....83.1..4.8....95..3.4..6..4...7.
|
295873164136524897487169235819356742543712986762948351374285619951637428628491573
|
Basic 9x9 Sudoku 5617
|
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 . 1 . .
. . 6 . . 4 8 . .
. . 7 . . . . 3 .
8 . . 3 . 6 . 4 .
. . . 7 1 . . 8 6
. . . . . 8 3 . 1
. . 4 . 8 . . . .
9 5 . . 3 . 4 . .
6 . . 4 . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
295873164136524897487169235819356742543712986762948351374285619951637428628491573 #1 Extreme (25032) bf
Hidden Single: r5c8=8
Hidden Single: r1c6=3
Hidden Single: r6c2=6
Hidden Single: r3c5=6
Hidden Single: r6c5=4
Hidden Single: r2c9=7
Hidden Single: r8c6=7
Hidden Single: r4c7=7
Hidden Single: r6c1=7
Hidden Single: r1c8=6
Hidden Single: r7c7=6
Hidden Single: r7c2=7
Hidden Single: r8c4=6
Brute Force: r5c2=4
Brute Force: r5c1=5
Hidden Single: r1c3=5
Hidden Single: r5c3=3
Locked Candidates Type 1 (Pointing): 8 in b1 => r9c2<>8
Locked Candidates Type 1 (Pointing): 9 in b1 => r4c2<>9
Empty Rectangle: 5 in b3 (r6c48) => r3c4<>5
Hidden Rectangle: 2/4 in r1c19,r3c19 => r3c9<>2
Hidden Rectangle: 2/8 in r8c39,r9c39 => r9c3<>2
Finned X-Wing: 5 c67 r39 fr7c6 => r9c5<>5
2-String Kite: 5 in r2c5,r6c8 (connected by r4c5,r6c4) => r2c8<>5
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c6<>5
Locked Candidates Type 2 (Claiming): 5 in c6 => r7c4<>5
Forcing Chain Contradiction in r7c8 => r3c2<>1
r3c2=1 r2c12<>1 r2c4=1 r2c4<>5 r6c4=5 r6c8<>5 r7c8=5 r7c6<>5 r9c6=5 r9c6<>1 r7c46=1 r7c1<>1 r23c1=1 r3c2<>1
Forcing Chain Contradiction in r9c7 => r4c5<>2
r4c5=2 r5c6<>2 r5c7=2 r9c7<>2
r4c5=2 r4c5<>5 r4c9=5 r3c9<>5 r3c7=5 r9c7<>5
r4c5=2 r9c5<>2 r9c5=9 r9c7<>9
W-Wing: 9/2 in r5c7,r6c3 connected by 2 in r5c6,r6c4 => r6c8<>9
Discontinuous Nice Loop: 9 r2c4 -9- r2c8 -2- r6c8 -5- r6c4 =5= r2c4 => r2c4<>9
Finned Franken Swordfish: 2 c57b5 r359 fr2c5 fr6c4 => r3c4<>2
Finned Franken Swordfish: 9 c58b6 r249 fr5c7 fr7c8 => r9c7<>9
AIC: 2 2- r1c1 -4- r1c9 =4= r3c9 =5= r3c7 -5- r9c7 -2- r9c5 =2= r2c5 -2 => r1c4,r2c12<>2
Hidden Rectangle: 8/9 in r1c24,r3c24 => r3c2<>9
AIC: 8/9 9- r1c2 =9= r2c2 -9- r2c8 -2- r2c5 =2= r9c5 -2- r9c7 -5- r3c7 =5= r3c9 =4= r3c1 -4- r1c1 -2- r3c2 -8- r3c4 =8= r1c4 -8 => r1c2<>8, r1c4<>9
Naked Single: r1c4=8
Hidden Single: r3c2=8
AIC: 9 9- r1c2 =9= r1c9 =4= r3c9 =5= r3c7 -5- r9c7 -2- r9c5 =2= r2c5 -2- r2c8 -9 => r1c9,r2c2<>9
Hidden Single: r1c2=9
Locked Pair: 1,3 in r2c12 => r2c4,r3c1<>1
Locked Candidates Type 1 (Pointing): 2 in b1 => r7c1<>2
Uniqueness Test 1: 2/4 in r1c19,r3c19 => r3c9<>4
Hidden Single: r3c1=4
Naked Single: r1c1=2
Full House: r1c9=4
X-Wing: 2 r35 c67 => r79c6,r9c7<>2
Naked Single: r9c7=5
Hidden Single: r3c9=5
Hidden Single: r6c8=5
Hidden Single: r7c6=5
Hidden Single: r4c5=5
Hidden Single: r2c4=5
Remote Pair: 2/9 r4c9 -9- r5c7 -2- r3c7 -9- r2c8 -2- r2c5 -9- r9c5 => r9c9<>2, r9c9<>9
Locked Candidates Type 1 (Pointing): 9 in b9 => r7c4<>9
Remote Pair: 9/2 r3c7 -2- r5c7 -9- r5c6 -2- r6c4 => r3c4<>9
Naked Single: r3c4=1
Naked Single: r7c4=2
Full House: r6c4=9
Full House: r5c6=2
Full House: r6c3=2
Full House: r5c7=9
Full House: r3c7=2
Full House: r3c6=9
Full House: r4c9=2
Full House: r2c8=9
Full House: r2c5=2
Full House: r9c5=9
Full House: r9c6=1
Naked Single: r4c2=1
Full House: r4c3=9
Naked Single: r8c9=8
Naked Single: r7c8=1
Full House: r8c8=2
Full House: r8c3=1
Full House: r9c3=8
Naked Single: r2c2=3
Full House: r2c1=1
Full House: r7c1=3
Full House: r9c2=2
Full House: r9c9=3
Full House: r7c9=9
|
normal_sudoku_728
|
..63....5....4.......7..91.51.2..49..2.83..........7288..69..7...1.7..59.7..28...
|
796381245152946387384752916518267493427839561639514728843695172261473859975128634
|
Basic 9x9 Sudoku 728
|
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 . . . . 5
. . . . 4 . . . .
. . . 7 . . 9 1 .
5 1 . 2 . . 4 9 .
. 2 . 8 3 . . . .
. . . . . . 7 2 8
8 . . 6 9 . . 7 .
. . 1 . 7 . . 5 9
. 7 . . 2 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
796381245152946387384752916518267493427839561639514728843695172261473859975128634 #1 Hard (962)
Naked Single: r4c4=2
Naked Single: r5c8=6
Naked Single: r4c5=6
Naked Single: r8c4=4
Naked Single: r4c9=3
Naked Single: r5c9=1
Full House: r5c7=5
Naked Single: r4c6=7
Full House: r4c3=8
Naked Single: r8c6=3
Naked Single: r8c2=6
Naked Single: r8c1=2
Full House: r8c7=8
Naked Single: r1c7=2
Hidden Single: r2c9=7
Hidden Single: r1c1=7
Hidden Single: r6c1=6
Hidden Single: r7c9=2
Hidden Single: r5c3=7
Hidden Single: r2c1=1
Locked Candidates Type 1 (Pointing): 3 in b3 => r2c23<>3
Locked Candidates Type 1 (Pointing): 4 in b9 => r9c13<>4
Hidden Pair: 2,6 in r23c6 => r23c6<>5, r2c6<>9
Skyscraper: 9 in r1c2,r5c1 (connected by r15c6) => r6c2<>9
Locked Candidates Type 2 (Claiming): 9 in c2 => r2c3<>9
Turbot Fish: 5 r3c5 =5= r2c4 -5- r9c4 =5= r9c3 => r3c3<>5
Hidden Pair: 5,8 in r3c25 => r3c2<>3, r3c2<>4
W-Wing: 3/4 in r3c1,r9c8 connected by 4 in r1c28 => r9c1<>3
Naked Single: r9c1=9
Naked Single: r5c1=4
Full House: r3c1=3
Full House: r5c6=9
Naked Single: r6c2=3
Full House: r6c3=9
Naked Single: r1c6=1
Naked Single: r1c5=8
Naked Single: r7c6=5
Full House: r9c4=1
Naked Single: r1c8=4
Full House: r1c2=9
Naked Single: r3c5=5
Full House: r6c5=1
Naked Single: r6c6=4
Full House: r6c4=5
Full House: r2c4=9
Naked Single: r7c2=4
Naked Single: r3c9=6
Full House: r9c9=4
Naked Single: r9c8=3
Full House: r2c8=8
Full House: r2c7=3
Naked Single: r3c2=8
Full House: r2c2=5
Naked Single: r7c3=3
Full House: r7c7=1
Full House: r9c3=5
Full House: r9c7=6
Naked Single: r3c6=2
Full House: r2c6=6
Full House: r2c3=2
Full House: r3c3=4
|
normal_sudoku_3924
|
.5..78.1..8..24..9..43..8...4..3...1..8..73..57.....6..6....1.........9...7.8.2..
|
352978416786124539194365827249536781618497352573812964865249173421753698937681245
|
Basic 9x9 Sudoku 3924
|
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 . . 7 8 . 1 .
. 8 . . 2 4 . . 9
. . 4 3 . . 8 . .
. 4 . . 3 . . . 1
. . 8 . . 7 3 . .
5 7 . . . . . 6 .
. 6 . . . . 1 . .
. . . . . . . 9 .
. . 7 . 8 . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
352978416786124539194365827249536781618497352573812964865249173421753698937681245 #1 Extreme (28572) bf
Brute Force: r6c2=7
Hidden Single: r6c3=3
Locked Candidates Type 1 (Pointing): 3 in b1 => r789c1<>3
Locked Candidates Type 1 (Pointing): 1 in b4 => r5c45<>1
XY-Wing: 4/6/9 in r1c47,r6c7 => r6c4<>9
Forcing Net Contradiction in r9c6 => r1c1<>9
r1c1=9 (r3c2<>9) (r1c3<>9) r1c4<>9 r1c4=6 r1c3<>6 r1c3=2 r3c2<>2 r3c2=1 (r9c2<>1) r2c3<>1 (r2c4=1 r9c4<>1) r8c3=1 r9c1<>1 r9c6=1
r1c1=9 (r1c4<>9 r1c4=6 r9c4<>6) (r1c4<>9 r1c4=6 r3c5<>6) (r1c4<>9 r1c4=6 r3c6<>6) r1c1<>3 r1c9=3 r2c8<>3 r2c1=3 r2c1<>7 r3c1=7 r3c1<>6 r3c9=6 r9c9<>6 r9c6=6
Forcing Net Contradiction in r6c6 => r6c6<>9
r6c6=9 r6c7<>9 (r4c7=9 r4c3<>9) r6c7=4 r1c7<>4 r1c7=6 r1c4<>6 r1c4=9 (r9c4<>9) r1c3<>9 r7c3=9 (r9c1<>9) r9c2<>9 r9c6=9 r6c6<>9
Brute Force: r5c9=2
Hidden Single: r3c8=2
Hidden Single: r8c2=2
Hidden Single: r9c2=3
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c46<>2
Naked Pair: 4,5 in r59c8 => r247c8<>5, r7c8<>4
2-String Kite: 9 in r1c4,r5c2 (connected by r1c3,r3c2) => r5c4<>9
Turbot Fish: 5 r2c4 =5= r2c7 -5- r4c7 =5= r5c8 => r5c4<>5
Finned Swordfish: 5 r249 c467 fr9c8 fr9c9 => r8c7<>5
Discontinuous Nice Loop: 9 r7c4 -9- r1c4 =9= r1c3 =2= r1c1 =3= r1c9 -3- r2c8 -7- r4c8 -8- r4c4 =8= r6c4 =2= r7c4 => r7c4<>9
Grouped Discontinuous Nice Loop: 9 r3c1 -9- r3c2 -1- r2c3 =1= r8c3 =5= r7c3 =9= r79c1 -9- r3c1 => r3c1<>9
Almost Locked Set XY-Wing: A=r7c135 {4589}, B=r4c8,r6c9 {478}, C=r2579c8 {34578}, X,Y=7,8, Z=4 => r7c9<>4
Almost Locked Set Chain: 45- r7c135 {4589} -8- r27c8 {378} -7- r459c8 {4578} -8- r4c46,r5c45,r6c56 {1245689} -2- r7c56,r8c56,r9c46 {1234569} -45 => r7c4<>4, r7c4<>5
Almost Locked Set Chain: 6- r1c79 {346} -3- r2c8 {37} -7- r4c13468 {256789} -5- r1468c7 {45679} -6 => r2c7<>6
Almost Locked Set XZ-Rule: A=r9c89 {456}, B=r13c9,r2c78 {34567}, X=6, Z=4 => r8c9<>4
Almost Locked Set XY-Wing: A=r4c136 {2569}, B=r8c7,r9c89 {4567}, C=r24c7 {579}, X,Y=7,9, Z=5 => r9c6<>5
Almost Locked Set Chain: 5- r7c135 {4589} -8- r27c8 {378} -7- r459c8 {4578} -8- r4c46,r5c45,r6c56 {1245689} -2- r7c56,r8c456,r9c46 {12345679} -7- r8c7,r9c89 {4567} -5 => r7c9<>5
Forcing Chain Contradiction in r7c6 => r3c6<>9
r3c6=9 r3c2<>9 r1c3=9 r1c3<>2 r1c1=2 r1c1<>3 r1c9=3 r2c8<>3 r2c8=7 r4c8<>7 r4c8=8 r4c4<>8 r6c4=8 r6c4<>2 r6c6=2 r7c6<>2
r3c6=9 r3c2<>9 r1c3=9 r1c3<>2 r1c1=2 r1c1<>3 r1c9=3 r8c9<>3 r8c6=3 r7c6<>3
r3c6=9 r3c2<>9 r1c3=9 r7c3<>9 r7c3=5 r7c6<>5
r3c6=9 r7c6<>9
Finned Swordfish: 9 c346 r147 fr9c4 fr9c6 => r7c5<>9
W-Wing: 4/5 in r7c5,r9c8 connected by 5 in r5c58 => r9c4<>4
Grouped Discontinuous Nice Loop: 4 r6c5 -4- r7c5 -5- r5c5 =5= r5c8 =4= r5c45 -4- r6c5 => r6c5<>4
Almost Locked Set XY-Wing: A=r6c5 {19}, B=r124589c4 {1456789}, C=r168c7 {4679}, X,Y=7,9, Z=1 => r6c4<>1
Finned X-Wing: 1 c34 r28 fr9c4 => r8c56<>1
Almost Locked Set XY-Wing: A=r7c135689 {2345789}, B=r168c7 {4679}, C=r6c56 {129}, X,Y=2,9, Z=7 => r8c9<>7
Forcing Chain Contradiction in r9 => r1c4=9
r1c4<>9 r1c4=6 r9c4<>6
r1c4<>9 r1c3=9 r3c2<>9 r3c2=1 r2c13<>1 r2c4=1 r89c4<>1 r9c6=1 r9c6<>6
r1c4<>9 r1c4=6 r1c7<>6 r8c7=6 r9c9<>6
Hidden Single: r3c2=9
Full House: r5c2=1
Locked Candidates Type 1 (Pointing): 9 in b8 => r4c6<>9
XY-Wing: 4/6/5 in r4c6,r5c48 => r4c7,r5c5<>5
Hidden Single: r2c7=5
Hidden Single: r5c8=5
Naked Single: r9c8=4
Locked Candidates Type 1 (Pointing): 4 in b6 => r6c4<>4
Naked Pair: 1,6 in r2c34 => r2c1<>1, r2c1<>6
Naked Triple: 1,5,9 in r78c3,r9c1 => r7c1<>9, r8c1<>1
X-Wing: 1 r28 c34 => r9c4<>1
Naked Pair: 5,6 in r9c49 => r9c6<>6
Naked Triple: 4,5,6 in r78c5,r9c4 => r78c6,r8c4<>5, r8c4<>4, r8c46<>6
Naked Single: r8c6=3
Hidden Single: r5c4=4
Naked Triple: 1,2,9 in r679c6 => r3c6<>1
2-String Kite: 6 in r2c3,r4c6 (connected by r2c4,r3c6) => r4c3<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r13c1<>6
Empty Rectangle: 6 in b2 (r9c49) => r3c9<>6
Naked Single: r3c9=7
Naked Single: r2c8=3
Naked Single: r3c1=1
Naked Single: r2c1=7
Naked Single: r2c3=6
Full House: r2c4=1
Naked Single: r9c1=9
Naked Single: r1c3=2
Full House: r1c1=3
Naked Single: r8c4=7
Naked Single: r5c1=6
Full House: r5c5=9
Naked Single: r7c3=5
Naked Single: r9c6=1
Naked Single: r4c3=9
Full House: r4c1=2
Full House: r8c3=1
Naked Single: r7c4=2
Naked Single: r8c7=6
Naked Single: r6c5=1
Naked Single: r7c5=4
Naked Single: r6c6=2
Naked Single: r4c7=7
Naked Single: r6c4=8
Naked Single: r7c6=9
Naked Single: r1c7=4
Full House: r1c9=6
Full House: r6c7=9
Full House: r6c9=4
Full House: r4c8=8
Full House: r7c8=7
Naked Single: r9c9=5
Full House: r9c4=6
Full House: r8c5=5
Full House: r4c4=5
Full House: r3c5=6
Full House: r4c6=6
Full House: r3c6=5
Naked Single: r7c1=8
Full House: r7c9=3
Full House: r8c9=8
Full House: r8c1=4
|
normal_sudoku_5820
|
.3...4.2...41.236.2..6..4...6..4..3215..87.94...3..71.8.9...........61...1..2..7.
|
736894521584172369291635487967541832153287694428369715849713256372956148615428973
|
Basic 9x9 Sudoku 5820
|
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 . . . 4 . 2 .
. . 4 1 . 2 3 6 .
2 . . 6 . . 4 . .
. 6 . . 4 . . 3 2
1 5 . . 8 7 . 9 4
. . . 3 . . 7 1 .
8 . 9 . . . . . .
. . . . . 6 1 . .
. 1 . . 2 . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
736894521584172369291635487967541832153287694428369715849713256372956148615428973 #1 Hard (774)
Naked Single: r5c8=9
Naked Single: r5c4=2
Naked Single: r5c7=6
Full House: r5c3=3
Hidden Single: r4c6=1
Hidden Single: r6c5=6
Hidden Single: r7c5=1
Hidden Single: r7c7=2
Hidden Single: r7c9=6
Hidden Single: r7c6=3
Hidden Single: r3c5=3
Skyscraper: 5 in r4c7,r7c8 (connected by r47c4) => r9c7<>5
Skyscraper: 8 in r8c8,r9c6 (connected by r3c68) => r8c4,r9c79<>8
Naked Single: r9c7=9
Naked Pair: 5,8 in r1c7,r3c8 => r123c9<>5, r123c9<>8
Hidden Single: r2c2=8
X-Wing: 9 c26 r36 => r3c9,r6c1<>9
Naked Single: r6c1=4
Hidden Single: r9c4=4
Hidden Single: r9c6=8
Hidden Single: r1c4=8
Naked Single: r1c7=5
Full House: r4c7=8
Full House: r6c9=5
Naked Single: r3c8=8
Naked Single: r4c3=7
Naked Single: r6c6=9
Full House: r3c6=5
Full House: r4c4=5
Full House: r4c1=9
Naked Single: r9c9=3
Naked Single: r6c2=2
Full House: r6c3=8
Naked Single: r3c3=1
Naked Single: r7c4=7
Full House: r8c4=9
Full House: r8c5=5
Naked Single: r8c9=8
Naked Single: r1c3=6
Naked Single: r3c9=7
Full House: r3c2=9
Naked Single: r7c2=4
Full House: r7c8=5
Full House: r8c8=4
Full House: r8c2=7
Naked Single: r8c3=2
Full House: r9c3=5
Full House: r8c1=3
Full House: r9c1=6
Naked Single: r1c1=7
Full House: r2c1=5
Naked Single: r2c9=9
Full House: r1c9=1
Full House: r1c5=9
Full House: r2c5=7
|
normal_sudoku_5088
|
....8..5.4....59.....3.9..2....642...7.2183....65..184.4....7....8..1.9391....8..
|
639182457421675938857349612183964275574218369296537184345896721768421593912753846
|
Basic 9x9 Sudoku 5088
|
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 . . 5 .
4 . . . . 5 9 . .
. . . 3 . 9 . . 2
. . . . 6 4 2 . .
. 7 . 2 1 8 3 . .
. . 6 5 . . 1 8 4
. 4 . . . . 7 . .
. . 8 . . 1 . 9 3
9 1 . . . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
639182457421675938857349612183964275574218369296537184345896721768421593912753846 #1 Easy (258)
Naked Single: r6c7=1
Naked Single: r5c8=6
Naked Single: r5c1=5
Naked Single: r4c8=7
Naked Single: r5c9=9
Full House: r4c9=5
Full House: r5c3=4
Naked Single: r4c4=9
Naked Single: r9c9=6
Naked Single: r7c9=1
Naked Single: r1c9=7
Full House: r2c9=8
Naked Single: r7c8=2
Naked Single: r9c8=4
Full House: r8c7=5
Naked Single: r3c8=1
Full House: r2c8=3
Naked Single: r9c4=7
Hidden Single: r7c4=8
Hidden Single: r1c3=9
Hidden Single: r6c2=9
Hidden Single: r7c5=9
Hidden Single: r3c2=5
Naked Single: r3c3=7
Naked Single: r3c5=4
Naked Single: r3c7=6
Full House: r1c7=4
Full House: r3c1=8
Naked Single: r8c5=2
Naked Single: r2c5=7
Naked Single: r8c2=6
Naked Single: r9c6=3
Naked Single: r6c5=3
Full House: r6c6=7
Full House: r9c5=5
Full House: r6c1=2
Full House: r9c3=2
Naked Single: r2c2=2
Naked Single: r7c1=3
Naked Single: r8c1=7
Full House: r8c4=4
Full House: r7c6=6
Full House: r7c3=5
Full House: r1c6=2
Naked Single: r2c3=1
Full House: r2c4=6
Full House: r4c3=3
Full House: r1c4=1
Naked Single: r1c2=3
Full House: r1c1=6
Full House: r4c1=1
Full House: r4c2=8
|
normal_sudoku_2706
|
67..3...1..2..6...5..9..4....7.6..2.9..4..1...5...3..8..5.1...3.6...8.5.7.....8..
|
679534281142786395538921476317869524986452137254173968895217643461398752723645819
|
Basic 9x9 Sudoku 2706
|
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 7 . . 3 . . . 1
. . 2 . . 6 . . .
5 . . 9 . . 4 . .
. . 7 . 6 . . 2 .
9 . . 4 . . 1 . .
. 5 . . . 3 . . 8
. . 5 . 1 . . . 3
. 6 . . . 8 . 5 .
7 . . . . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
679534281142786395538921476317869524986452137254173968895217643461398752723645819 #1 Extreme (25096) bf
Forcing Net Verity => r2c2<>8
r1c3=4 r1c3<>9 r2c2=9 r2c2<>8
r6c3=4 r6c3<>6 r5c3=6 r5c3<>8 r13c3=8 r2c2<>8
r8c3=4 (r6c3<>4) (r7c1<>4) (r7c2<>4) r1c3<>4 r1c6=4 (r2c5<>4) r7c6<>4 r7c8=4 r6c8<>4 r6c1=4 r2c1<>4 r2c2=4 r2c2<>8
r9c3=4 (r6c3<>4) (r7c1<>4) (r7c2<>4) r1c3<>4 r1c6=4 (r2c5<>4) r7c6<>4 r7c8=4 r6c8<>4 r6c1=4 r2c1<>4 r2c2=4 r2c2<>8
Brute Force: r5c7=1
Hidden Single: r9c8=1
Finned X-Wing: 1 c26 r34 fr2c2 => r3c3<>1
Forcing Chain Contradiction in c1 => r2c2<>3
r2c2=3 r2c1<>3
r2c2=3 r2c7<>3 r4c7=3 r4c1<>3
r2c2=3 r2c78<>3 r3c8=3 r3c8<>6 r3c9=6 r9c9<>6 r9c4=6 r9c4<>3 r8c4=3 r8c1<>3
Forcing Net Contradiction in r9c3 => r2c7<>9
r2c7=9 (r1c8<>9 r1c8=8 r2c8<>8) (r2c8<>9) (r2c9<>9) (r2c7<>5) r2c7<>3 r4c7=3 r4c7<>5 r1c7=5 r2c9<>5 r2c9=7 r2c8<>7 r2c8=3 (r2c1<>3) r2c7<>3 r4c7=3 r4c1<>3 r8c1=3 r9c3<>3
r2c7=9 (r1c8<>9 r1c8=8 r2c8<>8) (r2c8<>9) (r2c9<>9) (r2c7<>5) r2c7<>3 r4c7=3 r4c7<>5 r1c7=5 r2c9<>5 r2c9=7 r2c8<>7 r2c8=3 (r2c1<>3) r2c7<>3 r4c7=3 r4c1<>3 r8c1=3 (r8c1<>1 r8c3=1 r6c3<>1) (r9c2<>3) r9c3<>3 r9c4=3 r9c4<>6 r9c9=6 r7c7<>6 r6c7=6 r6c3<>6 r6c3=4 r9c3<>4
r2c7=9 (r1c7<>9) r1c8<>9 r1c3=9 r9c3<>9
Brute Force: r5c6=2
Hidden Single: r6c1=2
Finned Swordfish: 4 r167 c368 fr7c1 fr7c2 => r89c3<>4
AIC: 7 7- r6c4 -1- r2c4 =1= r3c6 =7= r7c6 -7 => r78c4<>7
Discontinuous Nice Loop: 5 r2c4 -5- r1c6 -4- r1c3 =4= r6c3 =1= r6c4 =7= r2c4 => r2c4<>5
Discontinuous Nice Loop: 7 r2c5 -7- r2c4 =7= r6c4 =1= r6c3 =4= r1c3 -4- r1c6 =4= r2c5 => r2c5<>7
Discontinuous Nice Loop: 2 r9c9 -2- r9c2 =2= r7c2 -2- r7c4 -6- r9c4 =6= r9c9 => r9c9<>2
2-String Kite: 2 in r1c4,r8c9 (connected by r1c7,r3c9) => r8c4<>2
Naked Single: r8c4=3
X-Wing: 3 c17 r24 => r2c8,r4c2<>3
W-Wing: 8/3 in r3c3,r5c2 connected by 3 in r9c23 => r3c2,r5c3<>8
Locked Candidates Type 2 (Claiming): 8 in c3 => r2c1<>8
AIC: 6 6- r5c3 -3- r9c3 =3= r9c2 =2= r7c2 -2- r7c4 -6- r7c7 =6= r6c7 -6 => r5c89,r6c3<>6
Hidden Single: r5c3=6
AIC: 1/8 1- r2c4 =1= r3c6 -1- r3c2 -3- r5c2 -8- r5c5 =8= r4c4 -8 => r4c4<>1, r2c4<>8
Naked Pair: 1,7 in r2c4,r3c6 => r3c5<>7
AIC: 4 4- r2c5 =4= r1c6 -4- r1c3 =4= r6c3 =1= r8c3 -1- r8c1 -4 => r2c1,r8c5<>4
Naked Pair: 1,3 in r2c1,r3c2 => r2c2<>1, r3c3<>3
Naked Single: r3c3=8
Naked Single: r3c5=2
Hidden Single: r9c3=3
Hidden Single: r1c7=2
Hidden Single: r8c9=2
Hidden Single: r8c1=4
Naked Single: r7c1=8
Hidden Single: r8c3=1
Naked Single: r6c3=4
Full House: r1c3=9
Naked Single: r1c8=8
Naked Single: r2c2=4
Naked Single: r1c4=5
Full House: r1c6=4
Naked Single: r2c5=8
Naked Single: r4c4=8
Naked Single: r4c2=1
Naked Single: r3c2=3
Full House: r2c1=1
Full House: r4c1=3
Full House: r5c2=8
Naked Single: r2c4=7
Full House: r3c6=1
Naked Single: r2c8=9
Naked Single: r6c4=1
Naked Single: r2c9=5
Full House: r2c7=3
Naked Single: r5c9=7
Naked Single: r3c9=6
Full House: r3c8=7
Naked Single: r5c5=5
Full House: r5c8=3
Naked Single: r6c8=6
Full House: r7c8=4
Naked Single: r4c6=9
Full House: r6c5=7
Full House: r6c7=9
Naked Single: r9c9=9
Full House: r4c9=4
Full House: r4c7=5
Naked Single: r7c6=7
Full House: r9c6=5
Naked Single: r8c5=9
Full House: r8c7=7
Full House: r9c5=4
Full House: r7c7=6
Naked Single: r9c2=2
Full House: r7c2=9
Full House: r7c4=2
Full House: r9c4=6
|
normal_sudoku_2589
|
..4.3.65..9............5..4...3....6.68..1..24....2..7...6..7..9...53.41..512.8..
|
124739658597486123683215974259378416768541392431962587812694735976853241345127869
|
Basic 9x9 Sudoku 2589
|
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 . 6 5 .
. 9 . . . . . . .
. . . . . 5 . . 4
. . . 3 . . . . 6
. 6 8 . . 1 . . 2
4 . . . . 2 . . 7
. . . 6 . . 7 . .
9 . . . 5 3 . 4 1
. . 5 1 2 . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
124739658597486123683215974259378416768541392431962587812694735976853241345127869 #1 Hard (690)
Naked Single: r8c9=1
Naked Single: r8c7=2
Hidden Single: r6c5=6
Hidden Single: r2c6=6
Hidden Single: r8c3=6
Hidden Single: r9c8=6
Hidden Single: r2c1=5
Hidden Single: r7c9=5
Hidden Single: r3c1=6
Locked Candidates Type 1 (Pointing): 8 in b6 => r23c8<>8
Locked Candidates Type 2 (Claiming): 1 in r1 => r23c3,r3c2<>1
Naked Pair: 3,7 in r59c1 => r14c1<>7, r7c1<>3
Naked Pair: 3,9 in r57c8 => r236c8<>3, r346c8<>9
Locked Pair: 1,8 in r46c8 => r23c8,r46c7<>1
Skyscraper: 3 in r7c8,r9c1 (connected by r5c18) => r7c23,r9c9<>3
Naked Single: r9c9=9
Full House: r7c8=3
Naked Single: r1c9=8
Full House: r2c9=3
Naked Single: r5c8=9
Naked Single: r2c7=1
Naked Single: r3c7=9
Hidden Single: r7c1=8
Naked Single: r8c2=7
Full House: r8c4=8
Naked Single: r9c1=3
Naked Single: r5c1=7
Naked Single: r9c2=4
Full House: r9c6=7
Naked Single: r5c5=4
Naked Single: r1c6=9
Naked Single: r5c4=5
Full House: r5c7=3
Naked Single: r7c5=9
Full House: r7c6=4
Full House: r4c6=8
Naked Single: r6c4=9
Full House: r4c5=7
Naked Single: r6c7=5
Full House: r4c7=4
Naked Single: r4c8=1
Full House: r6c8=8
Naked Single: r2c5=8
Full House: r3c5=1
Naked Single: r4c1=2
Full House: r1c1=1
Naked Single: r4c2=5
Full House: r4c3=9
Naked Single: r1c2=2
Full House: r1c4=7
Naked Single: r2c3=7
Naked Single: r7c2=1
Full House: r7c3=2
Naked Single: r3c4=2
Full House: r2c4=4
Full House: r2c8=2
Full House: r3c8=7
Naked Single: r3c3=3
Full House: r3c2=8
Full House: r6c2=3
Full House: r6c3=1
|
normal_sudoku_1371
|
2.7.39......61..2..19....73..48..26.8...5...4.7..6..8.4..7...5..2......6.3..8.1..
|
287439615543617928619528473154873269896152734372964581468791352721345896935286147
|
Basic 9x9 Sudoku 1371
|
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 . 7 . 3 9 . . .
. . . 6 1 . . 2 .
. 1 9 . . . . 7 3
. . 4 8 . . 2 6 .
8 . . . 5 . . . 4
. 7 . . 6 . . 8 .
4 . . 7 . . . 5 .
. 2 . . . . . . 6
. 3 . . 8 . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
287439615543617928619528473154873269896152734372964581468791352721345896935286147 #1 Hard (722)
2-String Kite: 3 in r5c8,r7c6 (connected by r7c7,r8c8) => r5c6<>3
Empty Rectangle: 4 in b9 (r38c5) => r3c8<>4
Naked Single: r3c8=7
Hidden Single: r2c6=7
Hidden Single: r4c5=7
Hidden Single: r5c7=7
Hidden Single: r3c6=8
Hidden Single: r9c9=7
Hidden Single: r8c1=7
Hidden Single: r7c9=2
Naked Single: r7c5=9
Naked Single: r8c5=4
Full House: r3c5=2
Hidden Single: r9c1=9
Naked Single: r9c8=4
Naked Single: r1c8=1
Hidden Single: r6c6=4
Hidden Single: r3c1=6
Hidden Single: r1c7=6
Locked Candidates Type 1 (Pointing): 5 in b2 => r89c4<>5
Naked Single: r9c4=2
Hidden Single: r6c3=2
Hidden Single: r5c6=2
Locked Candidates Type 1 (Pointing): 1 in b7 => r5c3<>1
Hidden Single: r5c4=1
Naked Single: r4c6=3
Full House: r6c4=9
Naked Single: r8c4=3
Naked Single: r8c8=9
Full House: r5c8=3
Naked Single: r8c7=8
Full House: r7c7=3
Naked Single: r5c3=6
Full House: r5c2=9
Naked Single: r6c7=5
Naked Single: r9c3=5
Full House: r9c6=6
Naked Single: r4c2=5
Naked Single: r3c7=4
Full House: r2c7=9
Full House: r3c4=5
Full House: r1c4=4
Naked Single: r6c9=1
Full House: r4c9=9
Full House: r4c1=1
Full House: r6c1=3
Full House: r2c1=5
Naked Single: r8c3=1
Full House: r8c6=5
Full House: r7c6=1
Naked Single: r1c2=8
Full House: r1c9=5
Full House: r2c9=8
Naked Single: r7c3=8
Full House: r2c3=3
Full House: r2c2=4
Full House: r7c2=6
|
normal_sudoku_62
|
1..897....3...1.7.7....6.8...1...5.8..2....3.8...5.2.4......3..25.1....63.4..2...
|
145897623638521479729346185491273568562418937873659214916785342257134896384962751
|
Basic 9x9 Sudoku 62
|
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 9 7 . . .
. 3 . . . 1 . 7 .
7 . . . . 6 . 8 .
. . 1 . . . 5 . 8
. . 2 . . . . 3 .
8 . . . 5 . 2 . 4
. . . . . . 3 . .
2 5 . 1 . . . . 6
3 . 4 . . 2 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
145897623638521479729346185491273568562418937873659214916785342257134896384962751 #1 Unfair (1430)
Hidden Single: r1c6=7
Hidden Single: r2c3=8
Hidden Single: r5c1=5
Hidden Single: r6c8=1
Hidden Single: r5c5=1
Hidden Single: r6c3=3
Naked Single: r6c6=9
Hidden Single: r1c9=3
Hidden Single: r7c6=5
Hidden Single: r5c6=8
Locked Candidates Type 1 (Pointing): 7 in b4 => r79c2<>7
Locked Candidates Type 1 (Pointing): 7 in b6 => r5c24<>7
Naked Triple: 6,7,9 in r7c13,r8c3 => r79c2<>6, r79c2<>9
Locked Candidates Type 1 (Pointing): 6 in b7 => r7c45<>6
Hidden Triple: 2,3,5 in r234c4 => r234c4<>4, r4c4<>6, r4c4<>7
Locked Candidates Type 1 (Pointing): 4 in b2 => r478c5<>4
2-String Kite: 6 in r2c1,r4c8 (connected by r1c8,r2c7) => r4c1<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r1c2<>6
W-Wing: 9/4 in r4c1,r8c8 connected by 4 in r48c6 => r4c8<>9
Naked Single: r4c8=6
Hidden Single: r9c5=6
Locked Candidates Type 1 (Pointing): 9 in b6 => r5c2<>9
Locked Candidates Type 2 (Claiming): 9 in c8 => r79c9,r89c7<>9
XY-Chain: 9 9- r8c8 -4- r8c6 -3- r4c6 -4- r5c4 -6- r6c4 -7- r9c4 -9 => r9c8<>9
Naked Single: r9c8=5
Hidden Single: r9c4=9
Hidden Single: r1c3=5
Naked Single: r3c3=9
Naked Single: r8c3=7
Full House: r7c3=6
Naked Single: r7c1=9
Naked Single: r4c1=4
Full House: r2c1=6
Naked Single: r4c6=3
Full House: r8c6=4
Naked Single: r5c2=6
Naked Single: r4c4=2
Naked Single: r7c4=7
Naked Single: r8c7=8
Naked Single: r8c8=9
Full House: r8c5=3
Full House: r7c5=8
Naked Single: r5c4=4
Naked Single: r6c2=7
Full House: r6c4=6
Full House: r4c5=7
Full House: r4c2=9
Naked Single: r2c4=5
Full House: r3c4=3
Naked Single: r7c2=1
Full House: r9c2=8
Naked Single: r7c9=2
Full House: r7c8=4
Full House: r1c8=2
Naked Single: r2c9=9
Naked Single: r1c2=4
Full House: r1c7=6
Full House: r3c2=2
Naked Single: r2c7=4
Full House: r2c5=2
Full House: r3c5=4
Naked Single: r5c9=7
Full House: r5c7=9
Naked Single: r3c7=1
Full House: r3c9=5
Full House: r9c9=1
Full House: r9c7=7
|
normal_sudoku_555
|
2..1.46......5..121..2..3.46...41..3..3.624.....3......81.....9.....7...3..4..2..
|
238194657946753812157286394625841973793562481814379526481625739562937148379418265
|
Basic 9x9 Sudoku 555
|
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 6 . .
. . . . 5 . . 1 2
1 . . 2 . . 3 . 4
6 . . . 4 1 . . 3
. . 3 . 6 2 4 . .
. . . 3 . . . . .
. 8 1 . . . . . 9
. . . . . 7 . . .
3 . . 4 . . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
238194657946753812157286394625841973793562481814379526481625739562937148379418265 #1 Extreme (17788) bf
Hidden Single: r2c9=2
Hidden Single: r7c5=2
Hidden Pair: 3,4 in r78c8 => r78c8<>5, r78c8<>6, r7c8<>7, r8c8<>8
Locked Candidates Type 2 (Claiming): 6 in r7 => r8c4,r9c6<>6
Brute Force: r6c1=8
Locked Candidates Type 1 (Pointing): 8 in b5 => r28c4<>8
Forcing Net Contradiction in r5 => r7c4=6
r7c4<>6 r7c4=5 (r8c4<>5 r8c4=9 r8c1<>9) (r7c1<>5) r7c7<>5 r7c7=7 r7c1<>7 r7c1=4 r8c1<>4 r8c1=5 r5c1<>5
r7c4<>6 r7c4=5 (r7c7<>5 r7c7=7 r6c7<>7) (r8c4<>5 r8c4=9 r4c4<>9) (r8c4<>5 r8c4=9 r5c4<>9) (r7c6<>5) r9c6<>5 r6c6=5 (r6c7<>5) r6c6<>9 r6c5=9 r6c7<>9 r6c7=1 r5c9<>1 r5c2=1 r5c2<>5
r7c4<>6 r7c4=5 r5c4<>5
r7c4<>6 r7c4=5 (r7c7<>5) (r9c6<>5 r6c6=5 r6c7<>5) (r8c4<>5 r8c4=9 r8c1<>9) (r7c1<>5) r7c7<>5 r7c7=7 r7c1<>7 r7c1=4 r8c1<>4 r8c1=5 r8c7<>5 r4c7=5 r5c8<>5
r7c4<>6 r7c4=5 (r7c7<>5) (r9c6<>5 r6c6=5 r6c7<>5) (r8c4<>5 r8c4=9 r8c1<>9) (r7c1<>5) r7c7<>5 r7c7=7 r7c1<>7 r7c1=4 r8c1<>4 r8c1=5 r8c7<>5 r4c7=5 r5c9<>5
Discontinuous Nice Loop: 7 r1c5 -7- r6c5 -9- r6c6 -5- r7c6 -3- r2c6 =3= r1c5 => r1c5<>7
Discontinuous Nice Loop: 7 r2c2 -7- r2c4 -9- r8c4 -5- r7c6 -3- r2c6 =3= r2c2 => r2c2<>7
Forcing Chain Contradiction in r2c1 => r2c2<>9
r2c2=9 r2c2<>3 r2c6=3 r7c6<>3 r7c8=3 r7c8<>4 r7c1=4 r2c1<>4
r2c2=9 r2c4<>9 r2c4=7 r2c1<>7
r2c2=9 r2c1<>9
Forcing Net Contradiction in r7c8 => r2c1<>7
r2c1=7 r2c4<>7 (r2c4=9 r8c4<>9 r8c4=5 r8c7<>5) (r2c4=9 r2c7<>9) r3c5=7 r6c5<>7 r6c5=9 (r6c6<>9 r6c6=5 r6c7<>5) r6c7<>9 r4c7=9 r4c7<>5 r7c7=5 r7c7<>7 r7c1=7 r2c1<>7
Forcing Net Contradiction in r5c2 => r2c2<>6
r2c2=6 (r2c2<>4) r2c2<>3 r2c6=3 r1c5<>3 r8c5=3 r8c8<>3 r8c8=4 r8c2<>4 r6c2=4 r6c2<>1 r5c2=1
r2c2=6 r2c2<>3 r2c6=3 r7c6<>3 (r7c6=5 r6c6<>5 r6c6=9 r5c4<>9) (r7c6=5 r6c6<>5 r6c6=9 r6c7<>9) r7c8=3 r7c8<>4 r7c1=4 r2c1<>4 r2c1=9 (r5c1<>9) r2c7<>9 r4c7=9 r5c8<>9 r5c2=9
Forcing Net Contradiction in c3 => r1c5<>8
r1c5=8 r1c5<>3 r8c5=3 r7c6<>3 r7c6=5 (r6c6<>5 r6c6=9 r6c5<>9 r6c5=7 r6c9<>7) r7c7<>5 r7c7=7 (r9c9<>7) r7c1<>7 r5c1=7 r5c9<>7 r1c9=7 r1c3<>7
r1c5=8 r1c5<>3 r1c2=3 r2c2<>3 r2c6=3 r2c6<>6 r2c3=6 r2c3<>7
r1c5=8 (r3c5<>8) (r3c6<>8) (r2c6<>8) r1c5<>3 r1c2=3 r2c2<>3 r2c6=3 r2c6<>6 r2c3=6 r2c3<>8 r2c7=8 r3c8<>8 r3c3=8 r3c3<>7
r1c5=8 r1c5<>3 r8c5=3 r7c6<>3 r7c6=5 r7c7<>5 r7c7=7 r7c1<>7 r5c1=7 r4c3<>7
r1c5=8 r1c5<>3 r1c2=3 r2c2<>3 r2c2=4 r6c2<>4 r6c3=4 r6c3<>7
r1c5=8 r1c5<>3 r1c2=3 r2c2<>3 (r2c2=4 r2c1<>4 r2c1=9 r1c3<>9) (r2c2=4 r2c1<>4 r2c1=9 r3c3<>9) (r2c2=4 r2c1<>4 r2c1=9 r2c7<>9) r2c6=3 (r2c6<>6 r2c3=6 r2c3<>9) r7c6<>3 r7c6=5 r6c6<>5 r6c6=9 (r6c3<>9) r6c7<>9 r4c7=9 r4c3<>9 r9c3=9 r9c3<>7
Forcing Net Contradiction in r6c8 => r2c3<>7
r2c3=7 r2c4<>7 (r2c4=9 r8c4<>9 r8c4=5 r8c7<>5 r8c7=1 r6c7<>1) (r2c4=9 r5c4<>9) (r2c4=9 r8c4<>9 r8c4=5 r8c1<>5 r8c1=9 r5c1<>9) (r2c4=9 r2c7<>9) r3c5=7 r6c5<>7 r6c5=9 r6c7<>9 r4c7=9 r5c8<>9 r5c2=9 r5c2<>1 r5c9=1 r6c9<>1 r6c2=1 (r6c2<>2) r6c2<>4 r6c3=4 r6c3<>2 r6c8=2
r2c3=7 r2c4<>7 (r2c4=9 r8c4<>9 r8c4=5 r8c9<>5) (r2c4=9 r8c4<>9 r8c4=5 r8c7<>5 r8c7=1 r8c9<>1) (r2c4=9 r8c4<>9 r8c4=5 r8c7<>5 r8c7=1 r8c5<>1) (r2c4=9 r8c4<>9 r8c4=5 r8c7<>5 r8c7=1 r6c7<>1) r3c5=7 r6c5<>7 r6c5=9 (r8c5<>9) (r6c7<>9) r6c6<>9 r6c6=5 r6c7<>5 r6c7=7 r6c5<>7 r6c5=9 (r8c5<>9) (r6c7<>9) r1c5<>9 r1c5=3 r8c5<>3 r8c5=8 r8c9<>8 r8c9=6 r6c9<>6 r6c8=6
2-String Kite: 7 in r2c7,r6c5 (connected by r2c4,r3c5) => r6c7<>7
Forcing Chain Contradiction in c9 => r9c8<>5
r9c8=5 r13c8<>5 r1c9=5 r1c9<>7
r9c8=5 r7c7<>5 r7c7=7 r7c1<>7 r5c1=7 r5c9<>7
r9c8=5 r7c7<>5 r7c7=7 r2c7<>7 r2c4=7 r3c5<>7 r6c5=7 r6c9<>7
r9c8=5 r7c7<>5 r7c7=7 r9c9<>7
Forcing Net Contradiction in r5c2 => r2c4=7
r2c4<>7 (r2c7=7 r7c7<>7 r7c7=5 r6c7<>5) r3c5=7 r6c5<>7 r6c5=9 r6c7<>9 r6c7=1 r5c9<>1 r5c2=1
r2c4<>7 r3c5=7 (r6c5<>7 r6c5=9 r6c7<>9 r4c7=9 r5c8<>9) r2c4<>7 r2c4=9 (r5c4<>9) (r2c1<>9 r2c1=4 r8c1<>4) r8c4<>9 r8c4=5 r8c1<>5 r8c1=9 r5c1<>9 r5c2=9
Hidden Single: r6c5=7
Skyscraper: 7 in r4c7,r5c1 (connected by r7c17) => r4c23,r5c89<>7
Finned X-Wing: 7 c39 r19 fr3c3 => r1c2<>7
Discontinuous Nice Loop: 2 r6c2 -2- r6c8 =2= r4c8 =7= r4c7 -7- r7c7 =7= r7c1 -7- r5c1 =7= r5c2 =1= r6c2 => r6c2<>2
Discontinuous Nice Loop: 5/6/9 r6c8 =2= r6c3 =4= r6c2 =1= r5c2 =7= r5c1 -7- r7c1 =7= r7c7 -7- r4c7 =7= r4c8 =2= r6c8 => r6c8<>5, r6c8<>6, r6c8<>9
Naked Single: r6c8=2
Hidden Single: r6c9=6
Hidden Single: r9c8=6
Hidden Pair: 2,6 in r8c23 => r8c23<>4, r8c23<>5, r8c23<>9
Locked Candidates Type 1 (Pointing): 4 in b7 => r2c1<>4
Naked Single: r2c1=9
Naked Single: r2c7=8
Hidden Single: r1c3=8
Locked Candidates Type 1 (Pointing): 7 in b1 => r3c8<>7
Locked Candidates Type 1 (Pointing): 9 in b3 => r45c8<>9
Locked Candidates Type 1 (Pointing): 9 in b7 => r9c56<>9
Locked Candidates Type 1 (Pointing): 8 in b9 => r5c9<>8
Hidden Rectangle: 5/8 in r4c48,r5c48 => r4c4<>5
W-Wing: 1/5 in r5c9,r8c7 connected by 5 in r58c4 => r6c7,r89c9<>1
Hidden Single: r6c2=1
Hidden Single: r8c7=1
Hidden Single: r5c9=1
Hidden Single: r9c5=1
Hidden Single: r6c3=4
Naked Single: r2c3=6
Naked Single: r2c6=3
Full House: r2c2=4
Naked Single: r8c3=2
Naked Single: r1c5=9
Naked Single: r7c6=5
Naked Single: r8c2=6
Naked Single: r3c5=8
Full House: r3c6=6
Full House: r8c5=3
Naked Single: r6c6=9
Full House: r9c6=8
Full House: r8c4=9
Full House: r6c7=5
Naked Single: r7c7=7
Full House: r4c7=9
Naked Single: r8c8=4
Naked Single: r4c4=8
Full House: r5c4=5
Naked Single: r5c8=8
Full House: r4c8=7
Naked Single: r7c1=4
Full House: r7c8=3
Naked Single: r9c9=5
Full House: r8c9=8
Full House: r8c1=5
Full House: r5c1=7
Full House: r1c9=7
Full House: r5c2=9
Naked Single: r4c3=5
Full House: r4c2=2
Naked Single: r1c8=5
Full House: r1c2=3
Full House: r3c8=9
Naked Single: r9c2=7
Full House: r3c2=5
Full House: r3c3=7
Full House: r9c3=9
|
normal_sudoku_5186
|
.9....3.75.....1.474.1...2..3.2..7......53.4.9....8....7.4....1....8.2..6.9......
|
291845367563972184748136529836294715127653948954718632372469851415387296689521473
|
Basic 9x9 Sudoku 5186
|
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
5 . . . . . 1 . 4
7 4 . 1 . . . 2 .
. 3 . 2 . . 7 . .
. . . . 5 3 . 4 .
9 . . . . 8 . . .
. 7 . 4 . . . . 1
. . . . 8 . 2 . .
6 . 9 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
291845367563972184748136529836294715127653948954718632372469851415387296689521473 #1 Extreme (27440) bf
Locked Candidates Type 1 (Pointing): 3 in b1 => r78c3<>3
Locked Candidates Type 1 (Pointing): 4 in b7 => r8c8<>4
Hidden Rectangle: 6/7 in r5c34,r6c34 => r5c3<>6
Brute Force: r5c8=4
Hidden Single: r9c7=4
Locked Candidates Type 2 (Claiming): 1 in r5 => r4c13,r6c23<>1
Discontinuous Nice Loop: 2 r5c3 -2- r5c9 =2= r6c9 =3= r6c8 =1= r6c5 =4= r6c3 =7= r5c3 => r5c3<>2
Forcing Net Verity => r2c4<>7
r6c5=7 (r6c5<>4 r6c3=4 r8c3<>4) r6c4<>7 r6c4=6 r6c7<>6 r6c7=5 (r6c2<>5) (r4c8<>5) r4c9<>5 r4c3=5 r8c3<>5 r8c3=1 (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 r6c2<>2 r6c2=6 r6c4<>6 r6c4=7 r2c4<>7
r6c5<>7 r56c4=7 r2c4<>7
Forcing Net Contradiction in r7c7 => r6c5<>6
r6c5=6 (r6c5<>4 r6c3=4 r8c3<>4) r6c7<>6 r6c7=5 (r6c2<>5) (r4c8<>5) r4c9<>5 r4c3=5 r8c3<>5 r8c3=1 (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 r6c2<>2 r6c2=6 r6c5<>6
Forcing Net Contradiction in r7c7 => r6c5<>7
r6c5=7 (r6c5<>4 r6c3=4 r8c3<>4) r6c4<>7 r6c4=6 r6c7<>6 r6c7=5 (r6c2<>5) (r4c8<>5) r4c9<>5 r4c3=5 r8c3<>5 r8c3=1 (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 r6c2<>2 r6c2=6 r6c4<>6 r6c4=7 r6c5<>7
Locked Candidates Type 1 (Pointing): 7 in b5 => r89c4<>7
Forcing Net Contradiction in c9 => r6c8<>5
r6c8=5 (r4c9<>5 r4c3=5 r8c3<>5) r6c8<>1 r6c5=1 r6c5<>4 r6c3=4 r8c3<>4 r8c3=1 (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 r5c9<>2
r6c8=5 r6c8<>3 r6c9=3 r6c9<>2
Forcing Net Contradiction in r5c2 => r6c8<>6
r6c8=6 (r6c7<>6 r6c7=5 r4c9<>5 r4c3=5 r8c3<>5) r6c8<>1 r6c5=1 r6c5<>4 r6c3=4 r8c3<>4 r8c3=1 r89c2<>1 r5c2=1
r6c8=6 (r6c2<>6) (r6c3<>6) r6c7<>6 r6c7=5 (r4c8<>5) r4c9<>5 r4c3=5 r4c3<>6 r5c2=6
Forcing Net Verity => r6c9<>5
r8c3=1 (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 (r6c2<>2) r6c3<>2 r6c9=2 r6c9<>5
r8c3=4 r6c3<>4 r6c5=4 r6c5<>1 r6c8=1 r6c8<>3 r6c9=3 r6c9<>5
r8c3=5 (r8c2<>5) r9c2<>5 r6c2=5 r6c9<>5
Forcing Net Verity => r6c9<>6
r8c3=1 (r8c2<>1 r8c2=5 r6c2<>5) (r1c3<>1 r1c1=1 r5c1<>1) r8c3<>4 r8c1=4 r4c1<>4 r4c1=8 r5c1<>8 r5c1=2 r6c2<>2 r6c2=6 r6c9<>6
r8c3=4 r6c3<>4 r6c5=4 r6c5<>1 r6c8=1 r6c8<>3 r6c9=3 r6c9<>6
r8c3=5 (r8c2<>5) r9c2<>5 r6c2=5 r6c7<>5 r6c7=6 r6c9<>6
Brute Force: r5c7=9
Locked Pair: 6,7 in r56c4 => r128c4,r4c56<>6
Skyscraper: 9 in r2c4,r3c9 (connected by r8c49) => r2c8,r3c56<>9
Hidden Single: r3c9=9
Uniqueness Test 4: 6/7 in r5c34,r6c34 => r6c3<>6
Sue de Coq: r4c89 - {1568} (r4c156 - {1489}, r6c7 - {56}) => r5c9<>6, r4c3<>4, r4c3<>8
AIC: 8 8- r1c4 -5- r1c8 =5= r3c7 =8= r3c3 -8 => r1c13<>8
Discontinuous Nice Loop: 6 r2c3 -6- r2c8 -8- r3c7 =8= r3c3 =3= r2c3 => r2c3<>6
Grouped AIC: 5/8 5- r1c8 =5= r3c7 -5- r6c7 -6- r4c89 =6= r4c3 -6- r56c2 =6= r2c2 -6- r2c8 -8- r2c4 =8= r1c4 -8 => r1c4<>5, r1c8<>8
Naked Single: r1c4=8
Locked Candidates Type 1 (Pointing): 5 in b2 => r789c6<>5
Finned Swordfish: 5 c249 r489 fr6c2 => r4c3<>5
Naked Single: r4c3=6
Hidden Single: r2c2=6
Naked Single: r2c8=8
Hidden Single: r8c9=6
Hidden Single: r6c7=6
Naked Single: r3c7=5
Full House: r1c8=6
Full House: r7c7=8
Naked Single: r6c4=7
Naked Single: r3c6=6
Naked Single: r5c4=6
Naked Single: r3c5=3
Full House: r3c3=8
Naked Single: r2c4=9
Hidden Single: r1c6=5
Hidden Single: r9c2=8
Hidden Single: r5c3=7
Hidden Single: r7c5=6
Hidden Single: r2c3=3
Hidden Single: r1c5=4
Naked Single: r6c5=1
Naked Single: r4c5=9
Full House: r4c6=4
Naked Single: r6c8=3
Naked Single: r4c1=8
Naked Single: r6c9=2
Naked Single: r4c9=5
Full House: r4c8=1
Full House: r5c9=8
Full House: r9c9=3
Naked Single: r6c2=5
Full House: r6c3=4
Naked Single: r9c4=5
Full House: r8c4=3
Naked Single: r8c2=1
Full House: r5c2=2
Full House: r5c1=1
Naked Single: r9c8=7
Naked Single: r8c1=4
Naked Single: r8c3=5
Naked Single: r1c1=2
Full House: r1c3=1
Full House: r7c3=2
Full House: r7c1=3
Naked Single: r9c5=2
Full House: r2c5=7
Full House: r9c6=1
Full House: r2c6=2
Naked Single: r8c8=9
Full House: r7c8=5
Full House: r7c6=9
Full House: r8c6=7
|
normal_sudoku_283
|
.89...6..14..8......597..4...4.9..2.95...8..7..37...9.5.......1..1..598...8.19...
|
289154673147386259635972148714593826956428317823761594592837461371645982468219735
|
Basic 9x9 Sudoku 283
|
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 . . . 6 . .
1 4 . . 8 . . . .
. . 5 9 7 . . 4 .
. . 4 . 9 . . 2 .
9 5 . . . 8 . . 7
. . 3 7 . . . 9 .
5 . . . . . . . 1
. . 1 . . 5 9 8 .
. . 8 . 1 9 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
289154673147386259635972148714593826956428317823761594592837461371645982468219735 #1 Extreme (2032)
Hidden Single: r5c1=9
Hidden Single: r2c9=9
Hidden Single: r7c4=8
Hidden Single: r7c2=9
Hidden Single: r7c6=7
Hidden Single: r2c3=7
Hidden Single: r1c8=7
Hidden Single: r9c7=7
Hidden Single: r5c8=1
Hidden Single: r3c7=1
Hidden Single: r3c9=8
Locked Candidates Type 1 (Pointing): 6 in b1 => r3c6<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r89c9<>6
Empty Rectangle: 4 in b6 (r7c57) => r6c5<>4
Discontinuous Nice Loop: 5 r2c7 -5- r2c8 -3- r7c8 -6- r7c3 -2- r7c7 =2= r2c7 => r2c7<>5
Locked Candidates Type 2 (Claiming): 5 in c7 => r46c9<>5
Naked Triple: 3,4,6 in r46c9,r5c7 => r4c7<>3, r6c7<>4
Simple Colors Trap: 4 (r1c6,r6c9,r7c7) / (r5c7,r6c6,r7c5) => r1c5<>4
Naked Triple: 2,3,5 in r1c159 => r1c46<>2, r1c46<>3, r1c4<>5
Finned Swordfish: 2 c347 r257 fr8c4 fr9c4 => r7c5<>2
AIC: 6 6- r4c9 =6= r6c9 =4= r6c6 -4- r1c6 -1- r1c4 =1= r4c4 =5= r2c4 -5- r2c8 -3- r7c8 -6- r7c3 =6= r5c3 -6 => r4c12<>6
AIC: 6 6- r5c3 -2- r7c3 =2= r7c7 =4= r5c7 -4- r6c9 -6 => r6c12<>6
Hidden Single: r5c3=6
Full House: r7c3=2
Hidden Single: r2c7=2
Locked Candidates Type 1 (Pointing): 2 in b4 => r6c56<>2
Hidden Single: r3c6=2
Hidden Single: r1c1=2
Naked Single: r6c1=8
Naked Single: r4c1=7
Naked Single: r6c7=5
Naked Single: r4c2=1
Full House: r6c2=2
Naked Single: r4c7=8
Naked Single: r6c5=6
Naked Single: r4c6=3
Naked Single: r6c9=4
Full House: r6c6=1
Naked Single: r2c6=6
Full House: r1c6=4
Naked Single: r4c4=5
Full House: r4c9=6
Full House: r5c7=3
Full House: r7c7=4
Naked Single: r1c4=1
Naked Single: r2c4=3
Full House: r1c5=5
Full House: r2c8=5
Full House: r1c9=3
Naked Single: r7c5=3
Full House: r7c8=6
Full House: r9c8=3
Naked Single: r8c9=2
Full House: r9c9=5
Naked Single: r9c2=6
Naked Single: r8c5=4
Full House: r5c5=2
Full House: r5c4=4
Naked Single: r3c2=3
Full House: r3c1=6
Full House: r8c2=7
Naked Single: r9c1=4
Full House: r8c1=3
Full House: r8c4=6
Full House: r9c4=2
|
normal_sudoku_575
|
..72...3.2.......438...9.....1.5.....6.9...8...3..67....2.9...51..3...2.....246..
|
957248136216573894384619572891457263765932481423186759672891345148365927539724618
|
Basic 9x9 Sudoku 575
|
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 2 . . . 3 .
2 . . . . . . . 4
3 8 . . . 9 . . .
. . 1 . 5 . . . .
. 6 . 9 . . . 8 .
. . 3 . . 6 7 . .
. . 2 . 9 . . . 5
1 . . 3 . . . 2 .
. . . . 2 4 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
957248136216573894384619572891457263765932481423186759672891345148365927539724618 #1 Extreme (26646) bf
Hidden Single: r9c5=2
Locked Candidates Type 1 (Pointing): 8 in b4 => r79c1<>8
2-String Kite: 6 in r1c1,r8c5 (connected by r7c1,r8c3) => r1c5<>6
Grouped Discontinuous Nice Loop: 8 r9c4 -8- r9c3 =8= r8c3 =6= r7c1 -6- r1c1 =6= r1c9 =8= r12c7 -8- r7c7 =8= r7c46 -8- r9c4 => r9c4<>8
Forcing Net Contradiction in c7 => r4c2<>4
r4c2=4 (r8c2<>4) (r4c8<>4) r5c3<>4 r5c3=5 (r6c1<>5) r6c2<>5 r6c8=5 r6c8<>4 r7c8=4 (r7c1<>4 r1c1=4 r1c1<>9) (r7c1<>4 r1c1=4 r1c1<>6 r1c9=6 r1c9<>9) r8c7<>4 r8c3=4 (r8c3<>9) r8c3<>8 r9c3=8 r9c3<>9 r2c3=9 r1c2<>9 r1c7=9
r4c2=4 (r8c2<>4) (r4c8<>4) r5c3<>4 r5c3=5 (r6c1<>5) r6c2<>5 r6c8=5 r6c8<>4 r7c8=4 (r8c7<>4) r8c7<>4 r8c3=4 (r8c3<>8 r9c3=8 r9c9<>8) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c7<>8 r8c7=9
Forcing Net Contradiction in c7 => r5c5<>4
r5c5=4 (r5c3<>4 r5c3=5 r3c3<>5) (r4c4<>4) r6c4<>4 r3c4=4 r3c3<>4 r3c3=6 (r2c3<>6 r2c3=9 r1c1<>9) (r2c3<>6 r2c3=9 r1c2<>9) r1c1<>6 r1c9=6 r1c9<>9 r1c7=9
r5c5=4 (r5c3<>4) (r4c4<>4) r6c4<>4 r3c4=4 r3c3<>4 r8c3=4 (r8c7<>4) (r8c3<>8 r9c3=8 r9c9<>8) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c7<>8 r8c7=9
Forcing Net Contradiction in b9 => r6c2<>4
r6c2=4 (r8c2<>4) (r5c1<>4) r5c3<>4 r5c7=4 (r8c7<>4) r8c7<>4 r8c3=4 (r8c3<>8 r9c3=8 r9c9<>8) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c7<>8 r8c7=9
r6c2=4 (r8c2<>4) (r5c1<>4) r5c3<>4 (r5c3=5 r6c1<>5 r6c8=5 r6c8<>9) r5c7=4 r8c7<>4 r8c3=4 (r3c3<>4 r3c3=6 r2c3<>6 r2c3=9 r2c8<>9) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r4c9<>6 r4c8=6 r4c8<>9 r9c8=9
Forcing Net Contradiction in c7 => r8c3<>4
r8c3=4 (r8c2<>4 r1c2=4 r1c2<>9) (r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>9) (r8c3<>9) r8c3<>8 r9c3=8 r9c3<>9 r2c3=9 r1c1<>9 r1c7=9
r8c3=4 (r8c7<>4) (r8c3<>8 r9c3=8 r9c9<>8) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c7<>8 r8c7=9
Brute Force: r5c5=3
Hidden Single: r2c6=3
Forcing Net Contradiction in c8 => r6c8<>1
r6c8=1 (r6c8<>5 r5c7=5 r5c1<>5) (r6c8<>5) r5c9<>1 r5c9=2 r6c9<>2 r6c2=2 r6c2<>5 r6c1=5 (r9c1<>5) r5c3<>5 r5c3=4 r5c1<>4 r5c1=7 r9c1<>7 r9c1=9 (r8c3<>9) r9c3<>9 r2c3=9 r2c8<>9
r6c8=1 (r6c9<>1) r5c9<>1 r5c9=2 r6c9<>2 r6c9=9 r4c8<>9
r6c8=1 r6c8<>9
r6c8=1 (r6c8<>5) r5c9<>1 (r5c6=1 r5c6<>7 r5c1=7 r9c1<>7) r5c9=2 r6c9<>2 r6c2=2 r6c2<>5 r6c1=5 r9c1<>5 r9c1=9 r9c8<>9
Forcing Net Contradiction in r8c7 => r1c9<>1
r1c9=1 (r6c9<>1 r5c7=1 r5c6<>1 r7c6=1 r7c6<>8) r1c9<>6 r1c1=6 r7c1<>6 r7c4=6 r7c4<>8 r7c7=8 (r8c9<>8) r9c9<>8 r1c9=8 r1c9<>1
Forcing Net Contradiction in b7 => r8c3<>5
r8c3=5 (r8c3<>9) (r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c9<>9) (r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r7c1<>4 r1c1=4 r1c1<>9) (r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>9) (r8c3<>9) r8c3<>8 r9c3=8 r9c3<>9 r2c3=9 r1c2<>9 r1c7=9 r8c7<>9 r8c2=9
r8c3=5 (r8c6<>5) (r8c3<>8 r9c3=8 r9c9<>8) r8c3<>6 r8c5=6 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r1c9<>8 r8c9=8 r8c6<>8 r8c6=7 (r5c6<>7 r5c1=7 r9c1<>7) r8c6<>5 r1c6=5 (r2c4<>5) r3c4<>5 r9c4=5 r9c1<>5 r9c1=9
Forcing Net Contradiction in r3 => r2c2<>5
r2c2=5 (r8c2<>5 r8c6=5 r1c6<>5 r1c7=5 r3c8<>5 r3c4=5 r3c4<>4) (r8c2<>5 r8c6=5 r1c6<>5) r2c2<>1 r1c2=1 (r1c5<>1) r1c6<>1 r1c6=8 r1c5<>8 r1c5=4 r3c5<>4 r3c3=4 r3c3<>6
r2c2=5 (r3c3<>5) (r1c1<>5) (r1c2<>5) r8c2<>5 r8c6=5 r1c6<>5 r1c7=5 (r3c7<>5) r3c8<>5 r3c4=5 r3c4<>6
r2c2=5 (r8c2<>5 r8c6=5 r1c6<>5) r2c2<>1 r1c2=1 r1c6<>1 r1c6=8 (r7c6<>8) (r2c4<>8) r2c5<>8 r2c7=8 r7c7<>8 r7c4=8 r7c4<>6 r23c4=6 r3c5<>6
r2c2=5 (r8c2<>5 r8c6=5 r1c6<>5) r2c2<>1 r1c2=1 r1c6<>1 r1c6=8 (r7c6<>8) (r2c4<>8) r2c5<>8 r2c7=8 r7c7<>8 r7c4=8 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r3c8<>6
r2c2=5 (r8c2<>5 r8c6=5 r1c6<>5) r2c2<>1 r1c2=1 r1c6<>1 r1c6=8 (r7c6<>8) (r2c4<>8) r2c5<>8 r2c7=8 r7c7<>8 r7c4=8 r7c4<>6 r7c1=6 r1c1<>6 r1c9=6 r3c9<>6
Forcing Net Contradiction in r1c1 => r6c2<>5
r6c2=5 (r1c2<>5) (r5c3<>5 r5c7=5 r1c7<>5) r8c2<>5 r8c6=5 r1c6<>5 r1c1=5 (r1c1<>6 r7c1=6 r7c1<>4) r3c3<>5 r3c3=6 r3c3<>4 r5c3=4 (r4c1<>4) (r5c1<>4) (r3c3<>4) r6c1<>4 r1c1=4
r6c2=5 (r1c2<>5) (r5c3<>5 r5c7=5 r1c7<>5) r8c2<>5 r8c6=5 r1c6<>5 r1c1=5
Forcing Net Contradiction in r8 => r1c1<>5
r1c1=5 (r6c1<>5 r6c8=5 r6c8<>4) r1c1<>6 r1c9=6 r4c9<>6 r4c8=6 r4c8<>4 r7c8=4 r8c7<>4 r8c2=4 r8c2<>7
r1c1=5 r1c1<>6 r7c1=6 r8c3<>6 r8c5=6 r8c5<>7
r1c1=5 r1c6<>5 r8c6=5 r8c6<>7
r1c1=5 (r1c1<>6 r1c9=6 r1c9<>8) (r9c1<>5) (r1c6<>5 r8c6=5 r9c4<>5) (r5c1<>5) r6c1<>5 r6c8=5 r5c7<>5 r5c3=5 r9c3<>5 r9c2=5 r9c2<>3 r9c9=3 r9c9<>8 r8c9=8 r8c9<>7
Forcing Chain Contradiction in r1c5 => r2c7<>1
r2c7=1 r2c2<>1 r1c2=1 r1c5<>1
r2c7=1 r2c2<>1 r1c2=1 r1c2<>5 r23c3=5 r5c3<>5 r5c3=4 r3c3<>4 r1c12=4 r1c5<>4
r2c7=1 r2c7<>8 r1c79=8 r1c5<>8
Forcing Net Verity => r2c2=1
r4c7=4 (r8c7<>4 r8c2=4 r8c2<>5) r4c7<>3 r4c9=3 r9c9<>3 r9c2=3 r9c2<>5 r1c2=5 r1c2<>1 r2c2=1
r4c8=4 r4c8<>6 r4c9=6 (r1c9<>6 r1c1=6 r3c3<>6 r8c3=6 r8c3<>9) r4c9<>3 r9c9=3 r9c9<>8 r9c3=8 r9c3<>9 r2c3=9 r2c2<>9 r2c2=1
r5c7=4 r5c3<>4 r5c3=5 (r2c3<>5) r3c3<>5 r1c2=5 r1c2<>1 r2c2=1
r6c8=4 r6c8<>5 r6c1=5 (r9c1<>5) (r5c1<>5) r5c3<>5 r5c3=4 r5c1<>4 r5c1=7 r9c1<>7 r9c1=9 (r8c3<>9) r9c3<>9 r2c3=9 r2c2<>9 r2c2=1
Forcing Net Verity => r1c2<>9
r4c7=4 (r8c7<>4 r8c2=4 r8c2<>5) r4c7<>3 r4c9=3 r9c9<>3 r9c2=3 r9c2<>5 r1c2=5 r1c2<>9
r4c8=4 r4c8<>6 r4c9=6 (r1c9<>6 r1c1=6 r3c3<>6 r8c3=6 r8c3<>9) r4c9<>3 r9c9=3 r9c9<>8 r9c3=8 r9c3<>9 r2c3=9 r1c2<>9
r5c7=4 r5c3<>4 r5c3=5 (r2c3<>5) r3c3<>5 r1c2=5 r1c2<>9
r6c8=4 r6c8<>5 r6c1=5 (r9c1<>5) (r5c1<>5) r5c3<>5 r5c3=4 r5c1<>4 r5c1=7 r9c1<>7 r9c1=9 (r8c3<>9) r9c3<>9 r2c3=9 r1c2<>9
Grouped Discontinuous Nice Loop: 5 r2c3 -5- r1c2 -4- r78c2 =4= r7c1 =6= r1c1 =9= r2c3 => r2c3<>5
Forcing Net Contradiction in c8 => r1c1<>4
r1c1=4 r1c1<>9 r2c3=9 r2c8<>9
r1c1=4 r1c1<>6 r1c9=6 r4c9<>6 r4c8=6 r4c8<>9
r1c1=4 (r6c1<>4) (r4c1<>4) (r1c1<>9 r2c3=9 r8c3<>9 r8c3=8 r8c7<>8) (r1c1<>9) r1c1<>6 r1c9=6 (r4c9<>6 r4c8=6 r4c8<>4) r1c9<>9 r1c7=9 r8c7<>9 r8c7=4 r4c7<>4 r4c4=4 (r6c4<>4) r6c5<>4 r6c8=4 r6c8<>9
r1c1=4 (r6c1<>4) (r4c1<>4) (r1c1<>9 r2c3=9 r8c3<>9 r8c3=8 r8c7<>8) (r1c1<>9) r1c1<>6 r1c9=6 (r4c9<>6 r4c8=6 r4c8<>4) r1c9<>9 r1c7=9 r8c7<>9 r8c7=4 r4c7<>4 r4c4=4 (r6c4<>4) r6c5<>4 r6c8=4 r6c8<>5 r6c1=5 (r5c1<>5) r5c3<>5 (r9c3=5 r9c1<>5) r5c3=4 r5c1<>4 r5c1=7 r9c1<>7 r9c1=9 r9c8<>9
Naked Pair: 6,9 in r1c1,r2c3 => r3c3<>6
Naked Pair: 4,5 in r35c3 => r9c3<>5
2-String Kite: 5 in r3c3,r6c8 (connected by r5c3,r6c1) => r3c8<>5
2-String Kite: 6 in r2c3,r7c4 (connected by r7c1,r8c3) => r2c4<>6
Forcing Chain Contradiction in c8 => r7c2<>4
r7c2=4 r7c2<>3 r7c7=3 r4c7<>3 r4c9=3 r4c9<>6 r4c8=6 r4c8<>4
r7c2=4 r7c1<>4 r456c1=4 r5c3<>4 r5c3=5 r5c7<>5 r6c8=5 r6c8<>4
r7c2=4 r7c8<>4
Forcing Chain Contradiction in r8c7 => r2c7<>9
r2c7=9 r2c3<>9 r2c3=6 r8c3<>6 r7c1=6 r7c1<>4 r8c2=4 r8c7<>4
r2c7=9 r2c3<>9 r2c3=6 r1c1<>6 r1c9=6 r1c9<>8 r12c7=8 r8c7<>8
r2c7=9 r8c7<>9
Forcing Chain Contradiction in r9 => r7c4<>7
r7c4=7 r7c4<>6 r7c1=6 r1c1<>6 r1c1=9 r9c1<>9
r7c4=7 r7c4<>6 r7c1=6 r1c1<>6 r1c1=9 r2c3<>9 r89c3=9 r9c2<>9
r7c4=7 r7c2<>7 r7c2=3 r7c7<>3 r9c9=3 r9c9<>8 r9c3=8 r9c3<>9
r7c4=7 r7c4<>6 r7c1=6 r1c1<>6 r1c1=9 r2c3<>9 r2c8=9 r9c8<>9
r7c4=7 r7c2<>7 r7c2=3 r7c7<>3 r9c9=3 r9c9<>9
Forcing Chain Contradiction in r8c7 => r8c3<>9
r8c3=9 r8c3<>6 r7c1=6 r7c1<>4 r8c2=4 r8c7<>4
r8c3=9 r8c3<>6 r2c3=6 r1c1<>6 r1c9=6 r1c9<>8 r12c7=8 r8c7<>8
r8c3=9 r8c7<>9
Forcing Chain Verity => r9c9<>9
r1c2=5 r1c2<>4 r8c2=4 r8c2<>9 r8c79=9 r9c9<>9
r8c2=5 r8c2<>9 r8c79=9 r9c9<>9
r9c2=5 r9c2<>3 r9c9=3 r9c9<>9
Forcing Net Verity => r6c2=2
r5c7=1 r5c9<>1 r5c9=2 r6c9<>2 r6c2=2
r5c7=2 r6c9<>2 r6c2=2
r5c7=4 (r6c8<>4 r7c8=4 r7c1<>4) (r5c1<>4) r5c3<>4 r5c3=5 (r6c1<>5 r6c8=5 r6c8<>9) r5c1<>5 r5c1=7 r7c1<>7 r7c1=6 (r7c1<>4 r8c2=4 r8c7<>4 r8c7=9 r4c7<>9) r1c1<>6 r1c1=9 (r6c1<>9) (r4c1<>9) r2c3<>9 (r2c8=9 r4c8<>9) r9c3=9 r9c3<>8 r9c9=8 r9c9<>3 r4c9=3 r4c9<>9 r4c2=9 r6c2<>9 r6c9=9 r6c9<>2 r6c2=2
r5c7=5 (r2c7<>5 r2c7=8 r2c4<>8) r6c8<>5 r2c8=5 r2c4<>5 r2c4=7 (r2c5<>7) r3c5<>7 r8c5=7 r8c6<>7 r8c6=8 r7c6<>8 r7c7=8 r2c7<>8 r2c7=5 (r5c7<>5) r3c7<>5 r3c3=5 (r3c4<>5) (r1c2<>5 r1c6=5 r8c6<>5) r5c3<>5 (r5c3=4 r6c1<>4 r7c1=4 r7c1<>6 r7c4=6 r7c4<>8) r5c1=5 r5c1<>7 r5c6=7 r5c6<>2 r4c6=2 r4c2<>2 r6c2=2
Discontinuous Nice Loop: 9 r4c7 -9- r4c2 -7- r7c2 -3- r7c7 =3= r4c7 => r4c7<>9
Discontinuous Nice Loop: 5 r1c7 -5- r1c2 -4- r8c2 =4= r8c7 =9= r1c7 => r1c7<>5
X-Wing: 5 r18 c26 => r9c2<>5
Naked Triple: 3,7,9 in r479c2 => r8c2<>7, r8c2<>9
Locked Candidates Type 1 (Pointing): 9 in b7 => r9c8<>9
Finned Swordfish: 9 r168 c179 fr6c8 => r4c9<>9
Grouped AIC: 7 7- r5c1 =7= r5c6 =1= r5c79 -1- r6c9 -9- r46c8 =9= r2c8 -9- r2c3 =9= r9c3 =8= r9c9 =3= r9c2 -3- r7c2 -7 => r4c2,r79c1<>7
Naked Single: r4c2=9
Hidden Pair: 5,9 in r26c8 => r2c8<>6, r2c8<>7, r6c8<>4
Locked Candidates Type 1 (Pointing): 7 in b3 => r3c45<>7
X-Wing: 6 r28 c35 => r3c5<>6
Naked Triple: 1,4,8 in r136c5 => r28c5<>8
XY-Chain: 1 1- r3c5 -4- r3c3 -5- r1c2 -4- r8c2 -5- r9c1 -9- r1c1 -6- r2c3 -9- r2c8 -5- r6c8 -9- r6c9 -1 => r3c9,r6c5<>1
Locked Candidates Type 2 (Claiming): 1 in c5 => r1c6,r3c4<>1
XY-Chain: 8 8- r1c6 -5- r1c2 -4- r8c2 -5- r9c1 -9- r1c1 -6- r2c3 -9- r2c8 -5- r2c7 -8 => r1c79,r2c4<>8
Hidden Single: r2c7=8
Locked Candidates Type 2 (Claiming): 8 in r7 => r8c6<>8
Naked Pair: 6,9 in r1c19 => r1c7<>9
Naked Single: r1c7=1
Hidden Single: r8c7=9
Hidden Single: r3c5=1
Hidden Single: r8c2=4
Naked Single: r1c2=5
Naked Single: r7c1=6
Naked Single: r1c6=8
Naked Single: r3c3=4
Naked Single: r1c1=9
Full House: r2c3=6
Naked Single: r8c3=8
Naked Single: r1c5=4
Full House: r1c9=6
Naked Single: r5c3=5
Full House: r9c3=9
Naked Single: r9c1=5
Naked Single: r2c5=7
Naked Single: r8c9=7
Naked Single: r6c5=8
Full House: r8c5=6
Full House: r8c6=5
Naked Single: r3c8=7
Naked Single: r2c4=5
Full House: r2c8=9
Full House: r3c4=6
Naked Single: r3c9=2
Full House: r3c7=5
Naked Single: r9c8=1
Naked Single: r6c1=4
Naked Single: r6c8=5
Naked Single: r4c9=3
Naked Single: r5c9=1
Naked Single: r7c8=4
Full House: r4c8=6
Naked Single: r9c4=7
Naked Single: r5c1=7
Full House: r4c1=8
Naked Single: r6c4=1
Full House: r6c9=9
Full House: r9c9=8
Full House: r7c7=3
Full House: r9c2=3
Full House: r7c2=7
Naked Single: r4c4=4
Full House: r7c4=8
Full House: r7c6=1
Naked Single: r5c6=2
Full House: r4c6=7
Full House: r4c7=2
Full House: r5c7=4
|
normal_sudoku_2808
|
.6..8......95.6....3.4..5....2....7.....7.1621..8..3.4..319..........943....2..8.
|
561287439429536718738419526392641875854973162176852394683194257215768943947325681
|
Basic 9x9 Sudoku 2808
|
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 . . . .
. . 9 5 . 6 . . .
. 3 . 4 . . 5 . .
. . 2 . . . . 7 .
. . . . 7 . 1 6 2
1 . . 8 . . 3 . 4
. . 3 1 9 . . . .
. . . . . . 9 4 3
. . . . 2 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
561287439429536718738419526392641875854973162176852394683194257215768943947325681 #1 Easy (384)
Naked Single: r6c7=3
Naked Single: r3c5=1
Naked Single: r4c7=8
Naked Single: r2c5=3
Hidden Single: r3c9=6
Hidden Single: r6c6=2
Hidden Single: r1c4=2
Hidden Single: r4c5=4
Hidden Single: r9c9=1
Hidden Single: r4c6=1
Hidden Single: r1c8=3
Hidden Single: r2c9=8
Hidden Single: r1c3=1
Hidden Single: r2c8=1
Hidden Single: r8c2=1
Hidden Single: r1c1=5
Hidden Single: r8c1=2
Hidden Single: r1c7=4
Hidden Single: r3c8=2
Naked Single: r2c7=7
Full House: r1c9=9
Full House: r1c6=7
Full House: r3c6=9
Naked Single: r7c8=5
Full House: r6c8=9
Full House: r4c9=5
Full House: r7c9=7
Naked Single: r2c1=4
Full House: r2c2=2
Naked Single: r9c7=6
Full House: r7c7=2
Naked Single: r4c2=9
Hidden Single: r7c1=6
Naked Single: r4c1=3
Full House: r4c4=6
Naked Single: r5c1=8
Naked Single: r6c5=5
Full House: r8c5=6
Naked Single: r8c4=7
Naked Single: r3c1=7
Full House: r3c3=8
Full House: r9c1=9
Naked Single: r5c6=3
Full House: r5c4=9
Full House: r9c4=3
Naked Single: r6c2=7
Full House: r6c3=6
Naked Single: r8c3=5
Full House: r8c6=8
Naked Single: r5c3=4
Full House: r5c2=5
Full House: r9c3=7
Naked Single: r9c2=4
Full House: r7c2=8
Full House: r7c6=4
Full House: r9c6=5
|
normal_sudoku_429
|
8....2..7..5.1.2...4...7.3..2...45.....29..6...1.5......7..93...3.62..4.2.4.....8
|
813462957675913284942587631326874519758291463491356872587149326139628745264735198
|
Basic 9x9 Sudoku 429
|
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 . . . . 2 . . 7
. . 5 . 1 . 2 . .
. 4 . . . 7 . 3 .
. 2 . . . 4 5 . .
. . . 2 9 . . 6 .
. . 1 . 5 . . . .
. . 7 . . 9 3 . .
. 3 . 6 2 . . 4 .
2 . 4 . . . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
813462957675913284942587631326874519758291463491356872587149326139628745264735198 #1 Extreme (3510)
Hidden Single: r1c6=2
Hidden Single: r8c7=7
Hidden Single: r3c3=2
Locked Candidates Type 1 (Pointing): 5 in b2 => r79c4<>5
Locked Candidates Type 2 (Claiming): 7 in r5 => r46c1,r6c2<>7
Hidden Pair: 5,7 in r5c12 => r5c1<>3, r5c1<>4, r5c2<>8
Hidden Single: r6c1=4
2-String Kite: 8 in r6c2,r8c6 (connected by r7c2,r8c3) => r6c6<>8
Sashimi Swordfish: 8 r358 c367 fr3c4 fr3c5 => r2c6<>8
Naked Pair: 3,6 in r26c6 => r59c6<>3
Hidden Pair: 3,7 in r9c45 => r9c4<>1
Skyscraper: 3 in r4c1,r6c6 (connected by r2c16) => r4c45<>3
Locked Candidates Type 1 (Pointing): 3 in b5 => r6c9<>3
Sue de Coq: r46c4 - {1378} (r9c4 - {37}, r5c6 - {18}) => r4c5<>8, r12c4<>3
Finned Swordfish: 8 c257 r367 fr5c7 => r6c8<>8
Sashimi Swordfish: 8 r248 c348 fr8c6 => r7c4<>8
Discontinuous Nice Loop: 1/5/6 r7c2 =8= r7c5 =4= r1c5 =3= r1c3 -3- r5c3 -8- r8c3 =8= r7c2 => r7c2<>1, r7c2<>5, r7c2<>6
Naked Single: r7c2=8
Naked Single: r7c5=4
Naked Single: r8c3=9
Naked Single: r7c4=1
Naked Single: r9c6=5
Naked Single: r8c6=8
Naked Single: r5c6=1
Hidden Single: r3c5=8
Hidden Single: r5c2=5
Naked Single: r5c1=7
Hidden Single: r2c8=8
Hidden Single: r2c2=7
Naked Pair: 3,6 in r1c35 => r1c27<>6
X-Wing: 6 c35 r14 => r4c1<>6
2-String Kite: 6 in r3c7,r7c1 (connected by r7c9,r9c7) => r3c1<>6
Locked Candidates Type 2 (Claiming): 6 in r3 => r2c9<>6
Naked Pair: 1,9 in r1c2,r3c1 => r2c1<>9
XY-Wing: 1/6/9 in r69c2,r9c8 => r6c8<>9
XYZ-Wing: 1/4/9 in r1c27,r2c9 => r1c8<>9
W-Wing: 5/1 in r1c8,r8c9 connected by 1 in r4c89 => r3c9,r7c8<>5
Naked Single: r7c8=2
Naked Single: r6c8=7
Hidden Single: r3c4=5
Hidden Single: r1c8=5
Hidden Single: r6c9=2
Naked Triple: 1,3,9 in r4c189 => r4c3<>3
2-String Kite: 9 in r3c1,r6c7 (connected by r4c1,r6c2) => r3c7<>9
W-Wing: 6/1 in r3c7,r9c2 connected by 1 in r1c27 => r9c7<>6
Hidden Single: r9c2=6
Naked Single: r6c2=9
Full House: r1c2=1
Naked Single: r7c1=5
Full House: r7c9=6
Full House: r8c1=1
Full House: r8c9=5
Naked Single: r4c1=3
Naked Single: r6c7=8
Naked Single: r3c1=9
Full House: r2c1=6
Full House: r1c3=3
Naked Single: r5c3=8
Full House: r4c3=6
Naked Single: r5c7=4
Full House: r5c9=3
Naked Single: r6c4=3
Full House: r6c6=6
Full House: r2c6=3
Naked Single: r3c9=1
Full House: r3c7=6
Naked Single: r1c5=6
Naked Single: r4c5=7
Full House: r4c4=8
Full House: r9c5=3
Full House: r9c4=7
Naked Single: r1c7=9
Full House: r1c4=4
Full House: r2c9=4
Full House: r4c9=9
Full House: r9c7=1
Full House: r2c4=9
Full House: r4c8=1
Full House: r9c8=9
|
normal_sudoku_4890
|
2.....1....6.2...4.7.5...6...7.3..9.6..9.25...9...5..11....87....8.4.....6.3...1.
|
235496187916827354874513962527134896681972543493685271149268735358741629762359418
|
Basic 9x9 Sudoku 4890
|
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 . .
. . 6 . 2 . . . 4
. 7 . 5 . . . 6 .
. . 7 . 3 . . 9 .
6 . . 9 . 2 5 . .
. 9 . . . 5 . . 1
1 . . . . 8 7 . .
. . 8 . 4 . . . .
. 6 . 3 . . . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
235496187916827354874513962527134896681972543493685271149268735358741629762359418 #1 Extreme (11130) bf
X-Wing: 1 c35 r35 => r35c6,r5c2<>1
Finned Swordfish: 5 r248 c128 fr8c9 => r7c8<>5
Brute Force: r5c6=2
Finned Swordfish: 2 r349 c279 fr9c3 => r78c2<>2
Hidden Single: r4c2=2
Hidden Single: r2c2=1
Hidden Single: r5c3=1
Hidden Single: r4c1=5
Hidden Single: r3c5=1
Hidden Single: r2c8=5
Locked Candidates Type 1 (Pointing): 7 in b3 => r1c456<>7
Swordfish: 8 c258 r156 => r1c49,r5c9,r6c147<>8
Hidden Single: r5c2=8
Naked Single: r5c5=7
Naked Single: r5c9=3
Full House: r5c8=4
Hidden Single: r1c9=7
Hidden Single: r6c8=7
Hidden Single: r9c7=4
Hidden Single: r6c7=2
Hidden Single: r6c5=8
Hidden Single: r1c8=8
Hidden Single: r9c9=8
Naked Single: r4c9=6
Full House: r4c7=8
Hidden Single: r3c9=2
Hidden Single: r2c4=8
Hidden Single: r6c4=6
Naked Single: r1c4=4
Naked Single: r7c4=2
Naked Single: r4c4=1
Full House: r4c6=4
Full House: r8c4=7
Naked Single: r7c8=3
Full House: r8c8=2
Naked Single: r9c6=9
Naked Single: r3c6=3
Naked Single: r9c1=7
Naked Single: r9c5=5
Full House: r9c3=2
Naked Single: r1c6=6
Naked Single: r2c6=7
Full House: r1c5=9
Full House: r7c5=6
Full House: r8c6=1
Naked Single: r3c7=9
Full House: r2c7=3
Full House: r8c7=6
Full House: r2c1=9
Naked Single: r3c3=4
Full House: r3c1=8
Naked Single: r8c1=3
Full House: r6c1=4
Full House: r6c3=3
Naked Single: r8c2=5
Full House: r8c9=9
Full House: r7c9=5
Naked Single: r1c3=5
Full House: r1c2=3
Full House: r7c2=4
Full House: r7c3=9
|
normal_sudoku_6349
|
5......8..318.....8.7...4.1.1.....3.38.....577.5.....44....75.....69.7.8.....4..3
|
542716389931842675867953421619475832384269157725138964498327516253691748176584293
|
Basic 9x9 Sudoku 6349
|
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.
|
5 . . . . . . 8 .
. 3 1 8 . . . . .
8 . 7 . . . 4 . 1
. 1 . . . . . 3 .
3 8 . . . . . 5 7
7 . 5 . . . . . 4
4 . . . . 7 5 . .
. . . 6 9 . 7 . 8
. . . . . 4 . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
542716389931842675867953421619475832384269157725138964498327516253691748176584293 #1 Extreme (15822) bf
Hidden Single: r3c1=8
Hidden Single: r1c2=4
Hidden Single: r2c9=5
Hidden Single: r2c8=7
Hidden Single: r9c2=7
Hidden Single: r2c5=4
Hidden Single: r8c8=4
Hidden Single: r1c7=3
Hidden Single: r8c2=5
Locked Candidates Type 1 (Pointing): 8 in b8 => r46c5<>8
Brute Force: r5c6=9
Forcing Net Contradiction in c3 => r3c5<>6
r3c5=6 (r1c5<>6) (r1c6<>6) r2c6<>6 r2c6=2 (r1c4<>2) (r1c5<>2) r1c6<>2 r1c6=1 (r1c4<>1) r1c5<>1 r1c5=7 r1c4<>7 r1c4=9 r1c3<>9
r3c5=6 (r1c5<>6) (r1c6<>6) r2c6<>6 r2c6=2 (r1c5<>2) r1c6<>2 r1c6=1 r1c5<>1 r1c5=7 r4c5<>7 r4c4=7 r4c4<>4 r4c3=4 r4c3<>9
r3c5=6 (r1c6<>6) r2c6<>6 r2c6=2 (r8c6<>2) r1c6<>2 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>9
r3c5=6 (r1c6<>6) r2c6<>6 r2c6=2 (r8c6<>2) r1c6<>2 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>8 r7c5=8 r9c5<>8 r9c3=8 r9c3<>9
Forcing Net Contradiction in c3 => r3c6<>2
r3c6=2 (r1c4<>2) (r1c5<>2) (r1c6<>2) r2c6<>2 r2c6=6 (r1c5<>6) r1c6<>6 r1c6=1 (r1c4<>1) r1c5<>1 r1c5=7 r1c4<>7 r1c4=9 r1c3<>9
r3c6=2 (r1c5<>2) (r1c6<>2) r2c6<>2 r2c6=6 (r1c5<>6) r1c6<>6 r1c6=1 r1c5<>1 r1c5=7 r4c5<>7 r4c4=7 r4c4<>4 r4c3=4 r4c3<>9
r3c6=2 (r8c6<>2) (r1c6<>2) r2c6<>2 r2c6=6 r1c6<>6 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>9
r3c6=2 (r8c6<>2) (r1c6<>2) r2c6<>2 r2c6=6 r1c6<>6 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>8 r7c5=8 r9c5<>8 r9c3=8 r9c3<>9
Forcing Net Contradiction in c3 => r3c6<>6
r3c6=6 (r1c5<>6) (r1c6<>6) r2c6<>6 r2c6=2 (r1c4<>2) (r1c5<>2) r1c6<>2 r1c6=1 (r1c4<>1) r1c5<>1 r1c5=7 r1c4<>7 r1c4=9 r1c3<>9
r3c6=6 (r1c5<>6) (r1c6<>6) r2c6<>6 r2c6=2 (r1c5<>2) r1c6<>2 r1c6=1 r1c5<>1 r1c5=7 r4c5<>7 r4c4=7 r4c4<>4 r4c3=4 r4c3<>9
r3c6=6 (r1c6<>6) r2c6<>6 r2c6=2 (r8c6<>2) r1c6<>2 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>9
r3c6=6 (r1c6<>6) r2c6<>6 r2c6=2 (r8c6<>2) r1c6<>2 r1c6=1 r8c6<>1 r8c6=3 (r7c4<>3) r7c5<>3 r7c3=3 r7c3<>8 r7c5=8 r9c5<>8 r9c3=8 r9c3<>9
Forcing Net Contradiction in r9 => r3c2<>9
r3c2=9 (r3c2<>6 r3c8=6 r1c9<>6 r1c9=2 r1c3<>2 r1c3=6 r2c1<>6) (r3c2<>6 r3c8=6 r1c9<>6 r1c9=2 r4c9<>2) (r6c2<>9) r2c1<>9 r2c7=9 r6c7<>9 r6c8=9 r4c9<>9 r4c9=6 r4c1<>6 r9c1=6
r3c2=9 (r1c3<>9) (r2c1<>9 r2c7=9 r1c9<>9) r3c2<>6 r3c8=6 (r9c8<>6) r1c9<>6 r1c9=2 r1c3<>2 r1c3=6 r9c3<>6 r9c7=6
Finned Franken Swordfish: 9 c29b1 r147 fr2c1 fr6c2 => r4c1<>9
Forcing Net Verity => r2c1=9
r7c2=2 (r7c9<>2) (r3c2<>2 r3c2=6 r1c3<>6) (r8c1<>2) r8c3<>2 r8c6=2 r2c6<>2 r2c6=6 (r1c5<>6) r1c6<>6 r1c9=6 r7c9<>6 r7c9=9 (r4c9<>9) r7c2<>9 r6c2=9 r4c3<>9 r4c7=9 r2c7<>9 r2c1=9
r7c2=6 r3c2<>6 r3c8=6 r3c8<>9 r3c4=9 r1c4<>9 r1c9=9 r2c7<>9 r2c1=9
r7c2=9 r9c1<>9 r2c1=9
W-Wing: 2/6 in r1c3,r2c7 connected by 6 in r3c28 => r1c9<>2
Sashimi X-Wing: 2 c19 r47 fr8c1 fr9c1 => r7c23<>2
Turbot Fish: 2 r2c7 =2= r3c8 -2- r3c2 =2= r6c2 => r6c7<>2
W-Wing: 6/2 in r1c3,r4c1 connected by 2 in r36c2 => r45c3<>6
Skyscraper: 6 in r2c6,r5c5 (connected by r25c7) => r1c5,r46c6<>6
W-Wing: 9/6 in r1c9,r7c2 connected by 6 in r3c28 => r7c9<>9
Hidden Rectangle: 2/4 in r4c34,r5c34 => r4c4<>2
Sashimi Swordfish: 6 c139 r147 fr9c1 fr9c3 => r7c2<>6
Naked Single: r7c2=9
Hidden Single: r4c3=9
Hidden Single: r1c9=9
Hidden Single: r4c4=4
Hidden Single: r5c3=4
Hidden Single: r3c4=9
Hidden Single: r4c5=7
Hidden Single: r1c4=7
Hidden Single: r9c4=5
Hidden Single: r4c6=5
Naked Single: r3c6=3
Hidden Single: r3c5=5
Hidden Single: r4c7=8
Hidden Single: r6c6=8
Hidden Single: r8c3=3
Remote Pair: 2/6 r3c8 -6- r3c2 -2- r6c2 -6- r4c1 -2- r4c9 -6- r7c9 => r79c8<>2, r79c8<>6
Naked Single: r7c8=1
Naked Single: r9c8=9
Hidden Single: r6c7=9
Hidden Single: r5c7=1
Naked Single: r5c4=2
Full House: r5c5=6
Naked Single: r7c4=3
Full House: r6c4=1
Full House: r6c5=3
Remote Pair: 6/2 r1c3 -2- r3c2 -6- r6c2 -2- r4c1 -6- r4c9 -2- r6c8 -6- r3c8 -2- r2c7 -6- r9c7 -2- r7c9 => r9c1<>2, r7c3,r9c1<>6
Naked Single: r7c3=8
Naked Single: r9c1=1
Naked Single: r7c5=2
Full House: r7c9=6
Full House: r4c9=2
Full House: r9c7=2
Full House: r4c1=6
Full House: r8c1=2
Full House: r8c6=1
Full House: r9c5=8
Full House: r1c5=1
Full House: r6c8=6
Full House: r2c7=6
Full House: r9c3=6
Full House: r6c2=2
Full House: r3c8=2
Full House: r2c6=2
Full House: r1c3=2
Full House: r3c2=6
Full House: r1c6=6
|
normal_sudoku_3455
|
7....1.25.1.24.8.7..8..541...3.....1..6...2..............18.5...825.41..5....7.4.
|
749831625615249837238765419853472961976318254124956783467183592382594176591627348
|
Basic 9x9 Sudoku 3455
|
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 . . . . 1 . 2 5
. 1 . 2 4 . 8 . 7
. . 8 . . 5 4 1 .
. . 3 . . . . . 1
. . 6 . . . 2 . .
. . . . . . . . .
. . . 1 8 . 5 . .
. 8 2 5 . 4 1 . .
5 . . . . 7 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
749831625615249837238765419853472961976318254124956783467183592382594176591627348 #1 Extreme (30026) bf
Hidden Single: r3c8=1
Hidden Single: r1c4=8
Hidden Single: r2c3=5
Hidden Single: r9c3=1
Hidden Single: r8c8=7
Hidden Single: r9c9=8
Hidden Single: r9c5=2
Hidden Single: r7c9=2
Brute Force: r5c6=8
Brute Force: r5c5=1
Hidden Single: r6c1=1
Hidden Single: r6c8=8
Hidden Single: r4c1=8
Hidden Single: r3c1=2
Almost Locked Set XY-Wing: A=r4c25678 {245679}, B=r5c1489 {34579}, C=r13579c2 {345679}, X,Y=4,5, Z=7 => r4c4<>7
Forcing Chain Contradiction in r6c3 => r5c4<>4
r5c4=4 r5c9<>4 r6c9=4 r6c3<>4
r5c4=4 r5c4<>7 r5c2=7 r6c3<>7
r5c4=4 r5c1<>4 r5c1=9 r6c3<>9
Forcing Net Contradiction in c6 => r4c4=4
r4c4<>4 (r6c4=4 r6c4<>3) r4c2=4 (r5c1<>4 r5c1=9 r5c8<>9) (r4c2<>5) r4c2<>2 r4c6=2 r6c6<>2 r6c2=2 r6c2<>5 (r6c5=5 r6c5<>3) r5c2=5 r5c8<>5 r5c8=3 (r6c7<>3) r6c9<>3 r6c6=3
r4c4<>4 r4c2=4 (r1c2<>4 r1c3=4 r7c3<>4 r7c1=4 r7c1<>3) (r4c2<>2 r4c6=2 r6c6<>2 r6c2=2 r6c2<>5 r5c2=5 r5c8<>5 r5c8=3 r7c8<>3) (r6c3<>4) r5c1<>4 r5c1=9 r6c3<>9 r6c3=7 r7c3<>7 r7c2=7 r7c2<>3 r7c6=3
Forcing Net Contradiction in r1 => r4c2<>9
r4c2=9 (r6c3<>9) r5c1<>9 r5c1=4 (r7c1<>4) r6c3<>4 r6c3=7 r7c3<>7 r7c2=7 r7c2<>4 r7c3=4 r1c3<>4 r1c2=4 r1c2<>6
r4c2=9 (r4c2<>2 r4c6=2 r6c6<>2 r6c2=2 r6c2<>5 r6c5=5 r4c5<>5) (r4c5<>9) (r6c3<>9) r5c1<>9 r5c1=4 r6c3<>4 r6c3=7 r5c2<>7 r5c4=7 r4c5<>7 r4c5=6 r1c5<>6
r4c2=9 (r4c2<>2 r4c6=2 r6c6<>2 r6c2=2 r6c2<>5 r6c5=5 r6c5<>6) (r4c2<>2 r4c6=2 r6c6<>2 r6c2=2 r6c2<>5 r6c5=5 r4c5<>5) (r4c5<>9) (r6c3<>9) r5c1<>9 r5c1=4 r6c3<>4 (r6c9=4 r6c9<>6) r6c3=7 r5c2<>7 r5c4=7 r4c5<>7 r4c5=6 (r6c4<>6) r6c6<>6 r6c7=6 r1c7<>6
Forcing Net Contradiction in r7 => r6c7<>3
r6c7=3 (r6c6<>3) (r1c7<>3) (r9c7<>3) (r5c8<>3) r5c9<>3 r5c4=3 r9c4<>3 r9c2=3 r1c2<>3 r1c5=3 r2c6<>3 r7c6=3
r6c7=3 (r9c7<>3) (r5c8<>3) r5c9<>3 r5c4=3 r9c4<>3 r9c2=3 (r7c1<>3) r7c2<>3 r7c8=3
Forcing Chain Contradiction in c5 => r8c9<>3
r8c9=3 r9c7<>3 r1c7=3 r1c5<>3
r8c9=3 r56c9<>3 r5c8=3 r5c8<>5 r5c2=5 r5c2<>7 r5c4=7 r3c4<>7 r3c5=7 r3c5<>3
r8c9=3 r56c9<>3 r5c8=3 r5c8<>5 r5c2=5 r6c2<>5 r6c5=5 r6c5<>3
r8c9=3 r8c5<>3
Finned Franken Swordfish: 3 r18b9 c257 fr7c8 fr8c1 => r7c2<>3
Forcing Net Contradiction in c1 => r5c9<>9
r5c9=9 (r8c9<>9 r8c9=6 r3c9<>6 r3c9=3 r2c8<>3) (r8c9<>9 r8c9=6 r7c8<>6) (r5c9<>3) r5c1<>9 r5c1=4 (r6c2<>4) r6c3<>4 r6c9=4 r6c9<>3 r5c8=3 r7c8<>3 r7c8=9 r2c8<>9 r2c8=6 r2c1<>6
r5c9=9 (r5c1<>9 r5c1=4 r6c3<>4 r6c9=4 r6c9<>3 r5c8=3 r7c8<>3) (r3c9<>9) r8c9<>9 r8c9=6 r3c9<>6 r3c9=3 (r2c8<>3) (r3c2<>3) r1c7<>3 r9c7=3 r9c2<>3 r1c2=3 r2c1<>3 r2c6=3 r7c6<>3 r7c1=3 r7c1<>6
r5c9=9 r8c9<>9 r8c9=6 r8c1<>6
Forcing Net Contradiction in b8 => r3c9<>3
r3c9=3 (r1c7<>3 r9c7=3 r7c8<>3) r5c9<>3 r5c9=4 r5c1<>4 r7c1=4 r7c1<>3 r7c6=3
r3c9=3 r8c5=3
Locked Candidates Type 2 (Claiming): 3 in c9 => r5c8<>3
Naked Pair: 6,9 in r38c9 => r6c9<>6, r6c9<>9
Almost Locked Set XZ-Rule: A=r5c128 {4579}, B=r1379c2 {34679}, X=7, Z=4 => r6c2<>4
Forcing Net Verity => r1c7<>9
r8c1=6 (r8c1<>3 r8c5=3 r1c5<>3) (r2c1<>6) r8c9<>6 r3c9=6 r2c8<>6 r2c6=6 r1c5<>6 r1c5=9 r1c7<>9
r8c5=6 (r9c4<>6) (r8c5<>3 r8c1=3 r9c2<>3) (r1c5<>6) r8c9<>6 r3c9=6 r1c7<>6 r1c2=6 r9c2<>6 r9c2=9 r9c4<>9 r9c4=3 r9c7<>3 r1c7=3 r1c7<>9
r8c9=6 r3c9<>6 r3c9=9 r1c7<>9
Discontinuous Nice Loop: 6 r7c8 -6- r8c9 -9- r3c9 =9= r2c8 =3= r7c8 => r7c8<>6
Finned Franken Swordfish: 9 r18b3 c159 fr1c2 fr1c3 fr2c8 => r2c1<>9
Almost Locked Set XZ-Rule: A=r2c1,r3c2 {369}, B=r1c7,r3c9 {369}, X=9, Z=3 => r1c2<>3
2-String Kite: 3 in r3c2,r8c5 (connected by r8c1,r9c2) => r3c5<>3
Multi Colors 1: 3 (r1c5,r2c8,r9c7) / (r1c7,r7c8), (r8c1) / (r8c5) => r7c1<>3
Forcing Chain Contradiction in c4 => r5c8=5
r5c8<>5 r5c8=9 r2c8<>9 r2c6=9 r3c4<>9
r5c8<>5 r5c8=9 r5c4<>9
r5c8<>5 r5c8=9 r4c78<>9 r4c56=9 r6c4<>9
r5c8<>5 r5c8=9 r46c7<>9 r9c7=9 r9c4<>9
Naked Triple: 4,7,9 in r5c12,r6c3 => r46c2<>7, r6c2<>9
Discontinuous Nice Loop: 6 r4c7 -6- r4c8 =6= r2c8 -6- r2c1 -3- r3c2 =3= r3c4 =7= r3c5 -7- r4c5 =7= r4c7 => r4c7<>6
Forcing Chain Contradiction in b8 => r4c8=6
r4c8<>6 r4c8=9 r2c8<>9 r2c6=9 r7c6<>9
r4c8<>6 r2c8=6 r2c1<>6 r2c1=3 r8c1<>3 r8c5=3 r8c5<>9
r4c8<>6 r4c8=9 r46c7<>9 r9c7=9 r9c4<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r9c7<>9
XY-Wing: 3/9/6 in r2c18,r3c9 => r3c2<>6
Finned X-Wing: 6 r27 c16 fr7c2 => r8c1<>6
2-String Kite: 6 in r1c7,r8c5 (connected by r8c9,r9c7) => r1c5<>6
W-Wing: 3/9 in r2c8,r8c1 connected by 9 in r38c9 => r2c1<>3
Naked Single: r2c1=6
Hidden Single: r8c1=3
Hidden Single: r3c2=3
Hidden Single: r1c7=6
Naked Single: r3c9=9
Full House: r2c8=3
Full House: r2c6=9
Full House: r7c8=9
Naked Single: r9c7=3
Full House: r8c9=6
Full House: r8c5=9
Naked Single: r1c5=3
Naked Single: r4c6=2
Naked Single: r7c1=4
Full House: r5c1=9
Naked Single: r9c4=6
Full House: r7c6=3
Full House: r9c2=9
Full House: r6c6=6
Naked Single: r4c2=5
Naked Single: r7c3=7
Full House: r7c2=6
Naked Single: r3c4=7
Full House: r3c5=6
Naked Single: r1c2=4
Full House: r1c3=9
Full House: r6c3=4
Naked Single: r4c5=7
Full House: r4c7=9
Full House: r6c5=5
Full House: r6c7=7
Naked Single: r6c2=2
Full House: r5c2=7
Naked Single: r5c4=3
Full House: r5c9=4
Full House: r6c9=3
Full House: r6c4=9
|
normal_sudoku_1967
|
.6.....7....24.56.4....7..1.147....8..3..4...7...8...43....1..5.59.........59.2..
|
865139472137248569492657831914762358583914726726385914378421695259876143641593287
|
Basic 9x9 Sudoku 1967
|
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 . . . . . 7 .
. . . 2 4 . 5 6 .
4 . . . . 7 . . 1
. 1 4 7 . . . . 8
. . 3 . . 4 . . .
7 . . . 8 . . . 4
3 . . . . 1 . . 5
. 5 9 . . . . . .
. . . 5 9 . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
865139472137248569492657831914762358583914726726385914378421695259876143641593287 #1 Extreme (18182) bf
Hidden Single: r2c5=4
Hidden Single: r1c7=4
Locked Candidates Type 1 (Pointing): 1 in b2 => r1c13<>1
Locked Candidates Type 1 (Pointing): 8 in b3 => r3c234<>8
Forcing Net Contradiction in r4 => r2c6<>9
r2c6=9 (r2c1<>9) (r2c2<>9) r2c9<>9 r2c9=3 r2c2<>3 r3c2=3 r3c2<>9 r1c1=9 r4c1<>9
r2c6=9 r4c6<>9
r2c6=9 (r2c9<>9) (r2c1<>9) (r2c2<>9) r2c9<>9 r2c9=3 r2c2<>3 r3c2=3 r3c2<>9 r1c1=9 r1c9<>9 r5c9=9 r4c7<>9
r2c6=9 (r2c9<>9) (r2c1<>9) (r2c2<>9) r2c9<>9 r2c9=3 r2c2<>3 r3c2=3 r3c2<>9 r1c1=9 r1c9<>9 r5c9=9 r4c8<>9
Forcing Net Contradiction in c5 => r1c6<>8
r1c6=8 (r8c6<>8) (r9c6<>8) r2c6<>8 r2c6=3 (r8c6<>3) r9c6<>3 r9c6=6 (r7c5<>6) r8c6<>6 r8c6=2 r7c5<>2 r7c5=7
r1c6=8 (r1c6<>3) r2c6<>8 r2c6=3 (r9c6<>3 r9c6=6 r9c9<>6) (r1c4<>3) r1c5<>3 r1c9=3 r9c9<>3 r9c9=7 (r8c7<>7) r8c9<>7 r8c5=7
Forcing Net Contradiction in r4c8 => r2c1<>8
r2c1=8 r2c6<>8 r2c6=3 (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 r1c9<>2 r5c9=2 r4c8<>2
r2c1=8 r2c6<>8 r2c6=3 (r9c6<>3) (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 r9c9<>3 r9c8=3 r4c8<>3
r2c1=8 r2c6<>8 r2c6=3 (r1c6<>3) (r2c9<>3 r2c9=9 r3c7<>9) (r2c9<>3 r2c9=9 r3c8<>9) (r3c4<>3) (r3c5<>3) (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 (r3c7<>3) r3c8<>3 r3c2=3 r3c2<>9 r3c4=9 r1c6<>9 r1c6=5 (r6c6<>5) r3c5<>5 r3c3=5 r6c3<>5 r6c8=5 r4c8<>5
r2c1=8 (r5c1<>8 r5c2=8 r5c2<>9) r2c6<>8 r2c6=3 (r2c9<>3 r2c9=9 r2c2<>9) (r3c4<>3) (r3c5<>3) (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 (r3c7<>3) r3c8<>3 r3c2=3 r3c2<>9 (r3c4=9 r1c6<>9) r6c2=9 r6c6<>9 r4c6=9 r4c8<>9
Forcing Net Contradiction in r8c6 => r2c2<>8
r2c2=8 (r5c2<>8 r5c1=8 r8c1<>8) (r5c2<>8 r5c1=8 r9c1<>8) r2c2<>7 r2c3=7 r2c3<>1 r2c1=1 (r8c1<>1) r9c1<>1 r9c1=6 r8c1<>6 r8c1=2 r8c6<>2
r2c2=8 r2c6<>8 r2c6=3 r8c6<>3
r2c2=8 (r2c2<>7 r2c3=7 r2c3<>1 r2c1=1 r9c1<>1 r9c1=6 r9c9<>6) r2c6<>8 r2c6=3 (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 r1c9<>2 r5c9=2 r5c9<>6 r8c9=6 r8c6<>6
r2c2=8 (r2c6<>8 r2c6=3 r9c6<>3) (r5c2<>8 r5c1=8 r9c1<>8) r2c2<>7 r2c3=7 r2c3<>1 r2c1=1 r9c1<>1 r9c1=6 r9c6<>6 r9c6=8 r8c6<>8
Forcing Net Contradiction in r7 => r2c6=8
r2c6<>8 r2c3=8 (r2c3<>7) r2c3<>1 r9c3=1 r9c3<>7 r7c3=7 r7c3<>6
r2c6<>8 (r2c6=3 r8c6<>3) (r2c6=3 r1c6<>3 r1c9=3 r9c9<>3 r9c8=3 r8c7<>3) (r2c6=3 r1c6<>3 r1c9=3 r9c9<>3 r9c8=3 r8c8<>3) (r2c6=3 r1c6<>3 r1c9=3 r8c9<>3) r2c3=8 (r2c3<>1 r9c3=1 r9c3<>7) r2c3<>7 r2c2=7 r9c2<>7 r9c9=7 (r8c7<>7) r8c9<>7 r8c5=7 r8c5<>3 r8c4=3 r8c4<>4 r7c4=4 r7c4<>6
r2c6<>8 r2c6=3 (r2c9<>3 r2c9=9 r3c7<>9) (r2c9<>3 r2c9=9 r3c8<>9) (r3c4<>3) (r3c5<>3) (r1c4<>3) (r1c5<>3) r1c6<>3 r1c9=3 (r3c7<>3) r3c8<>3 r3c2=3 r3c2<>9 r3c4=9 r3c4<>6 r3c5=6 r7c5<>6
r2c6<>8 (r2c6=3 r1c6<>3 r1c9=3 r8c9<>3) (r2c6=3 r2c9<>3 r2c9=9 r2c2<>9 r2c2=7 r9c2<>7) r2c3=8 r2c3<>1 r9c3=1 r9c3<>7 r9c9=7 r8c9<>7 r8c9=6 r7c7<>6
Hidden Pair: 4,8 in r78c4 => r78c4<>6, r8c4<>3
Forcing Net Contradiction in r5 => r1c3<>2
r1c3=2 (r6c3<>2) r3c3<>2 r3c3=5 r6c3<>5 r6c3=6 r5c1<>6
r1c3=2 (r3c3<>2 r3c3=5 r6c3<>5 r6c3=6 r7c3<>6) (r3c3<>2 r3c3=5 r6c3<>5 r6c3=6 r6c7<>6) r1c9<>2 r5c9=2 (r5c9<>6) r5c9<>7 r5c7=7 r5c7<>6 r4c7=6 r7c7<>6 r7c5=6 r3c5<>6 r3c4=6 r5c4<>6
r1c3=2 (r3c3<>2 r3c3=5 r6c3<>5 r6c3=6 r7c3<>6) (r3c3<>2 r3c3=5 r6c3<>5 r6c3=6 r6c7<>6) r1c9<>2 r5c9=2 (r5c9<>6) r5c9<>7 r5c7=7 r5c7<>6 r4c7=6 r7c7<>6 r7c5=6 r5c5<>6
r1c3=2 r1c9<>2 r5c9=2 r5c9<>7 r5c7=7 r5c7<>6
r1c3=2 r1c9<>2 r5c9=2 r5c9<>6
Forcing Net Contradiction in b5 => r5c2<>2
r5c2=2 (r5c2<>8 r5c1=8 r1c1<>8 r1c3=8 r1c3<>5 r6c3=5 r4c1<>5) (r5c2<>8 r5c1=8 r5c1<>5) (r3c2<>2) r5c9<>2 r1c9=2 r3c8<>2 r3c3=2 r3c3<>5 r3c5=5 (r4c5<>5) r5c5<>5 r5c8=5 r4c8<>5 r4c6=5 r4c6<>9
r5c2=2 (r5c9<>2 r1c9=2 r1c9<>9) (r3c2<>2) r6c2<>2 r6c2=9 r3c2<>9 r3c2=3 r2c2<>3 r2c9=3 r2c9<>9 r5c9=9 r5c4<>9
r5c2=2 r6c2<>2 r6c2=9 r6c4<>9
r5c2=2 r6c2<>2 r6c2=9 r6c6<>9
Forcing Net Contradiction in b9 => r7c2<>8
r7c2=8 (r9c3<>8 r9c8=8 r9c8<>1) r7c4<>8 r7c4=4 r8c4<>4 r8c8=4 r8c8<>1 r8c7=1 r8c7<>3
r7c2=8 r7c4<>8 r7c4=4 r8c4<>4 r8c8=4 r8c8<>3
r7c2=8 (r7c2<>7) (r9c1<>8) (r9c2<>8) r9c3<>8 r9c8=8 r9c8<>4 r9c2=4 r9c2<>7 r2c2=7 r2c2<>3 r2c9=3 r8c9<>3
r7c2=8 (r9c1<>8) (r9c2<>8) r9c3<>8 r9c8=8 r9c8<>3
r7c2=8 (r7c2<>7) (r9c1<>8) (r9c2<>8) r9c3<>8 r9c8=8 r9c8<>4 r9c2=4 r9c2<>7 r2c2=7 r2c2<>3 r2c9=3 r9c9<>3
Forcing Net Contradiction in r7c7 => r5c2=8
r5c2<>8 r5c2=9 (r5c9<>9) (r3c2<>9) r6c2<>9 r6c2=2 r3c2<>2 r3c2=3 r2c2<>3 r2c9=3 r2c9<>9 r1c9=9 r1c9<>2 r5c9=2 r5c9<>6 r456c7=6 r7c7<>6
r5c2<>8 r5c2=9 (r5c9<>9) (r3c2<>9) r6c2<>9 r6c2=2 r3c2<>2 r3c2=3 r2c2<>3 r2c9=3 r2c9<>9 r1c9=9 r1c9<>2 r5c9=2 r5c9<>7 r5c7=7 r7c7<>7
r5c2<>8 r9c2=8 r9c2<>4 r7c2=4 r7c4<>4 r7c4=8 r7c7<>8
r5c2<>8 r9c2=8 r9c2<>4 (r9c8=4 r7c8<>4) r7c2=4 r7c4<>4 r7c4=8 r7c8<>8 r7c8=9 r7c7<>9
Forcing Net Contradiction in r1c6 => r9c3<>8
r9c3=8 (r9c3<>7) r9c3<>1 r2c3=1 r2c3<>7 r2c2=7 r9c2<>7 r9c9=7 (r8c7<>7) r8c9<>7 r8c5=7 r8c5<>3 r89c6=3 r1c6<>3
r9c3=8 r1c3<>8 r1c3=5 r1c6<>5
r9c3=8 (r9c3<>1 r2c3=1 r2c1<>1 r2c1=9 r4c1<>9) (r9c3<>1 r2c3=1 r2c1<>1 r2c1=9 r2c9<>9) r1c3<>8 r1c1=8 r1c1<>2 r1c9=2 r1c9<>9 r5c9=9 (r4c7<>9) r4c8<>9 r4c6=9 r1c6<>9
Brute Force: r5c9=6
Hidden Single: r1c9=2
Hidden Single: r5c7=7
Hidden Single: r2c9=9
Naked Single: r2c1=1
Naked Single: r2c3=7
Full House: r2c2=3
Hidden Single: r9c3=1
Locked Candidates Type 1 (Pointing): 3 in b3 => r3c45<>3
Locked Candidates Type 2 (Claiming): 3 in c9 => r8c78,r9c8<>3
Naked Pair: 2,9 in r36c2 => r7c2<>2
2-String Kite: 6 in r6c3,r9c6 (connected by r7c3,r9c1) => r6c6<>6
W-Wing: 8/4 in r7c4,r9c8 connected by 4 in r8c48 => r7c78<>8
XY-Chain: 6 6- r7c7 -9- r7c8 -4- r9c8 -8- r9c1 -6 => r7c3<>6
Hidden Single: r6c3=6
Hidden Single: r3c4=6
Naked Single: r3c5=5
Naked Single: r3c3=2
Naked Single: r3c2=9
Naked Single: r7c3=8
Full House: r1c3=5
Full House: r1c1=8
Naked Single: r6c2=2
Naked Single: r7c4=4
Naked Single: r9c1=6
Naked Single: r7c2=7
Full House: r9c2=4
Full House: r8c1=2
Naked Single: r7c8=9
Naked Single: r8c4=8
Naked Single: r9c6=3
Naked Single: r9c8=8
Full House: r9c9=7
Full House: r8c9=3
Naked Single: r7c7=6
Full House: r7c5=2
Naked Single: r1c6=9
Naked Single: r8c6=6
Full House: r8c5=7
Naked Single: r3c8=3
Full House: r3c7=8
Naked Single: r8c7=1
Full House: r8c8=4
Naked Single: r5c5=1
Naked Single: r6c6=5
Full House: r4c6=2
Naked Single: r1c5=3
Full House: r1c4=1
Full House: r4c5=6
Naked Single: r5c4=9
Full House: r6c4=3
Naked Single: r6c8=1
Full House: r6c7=9
Full House: r4c7=3
Naked Single: r4c8=5
Full House: r4c1=9
Full House: r5c1=5
Full House: r5c8=2
|
normal_sudoku_4712
|
.....3..4......8.96..8...2.....7...82.65.49...1.6...5...21...8.15......386...7...
|
728913564541762839693845721935271648286534917417698352372159486159486273864327195
|
Basic 9x9 Sudoku 4712
|
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 . . 4
. . . . . . 8 . 9
6 . . 8 . . . 2 .
. . . . 7 . . . 8
2 . 6 5 . 4 9 . .
. 1 . 6 . . . 5 .
. . 2 1 . . . 8 .
1 5 . . . . . . 3
8 6 . . . 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
728913564541762839693845721935271648286534917417698352372159486159486273864327195 #1 Extreme (26572) bf
Brute Force: r5c3=6
Hidden Single: r7c9=6
Hidden Pair: 6,8 in r8c56 => r8c56<>2, r8c5<>4, r8c56<>9
Grouped Discontinuous Nice Loop: 2 r6c5 -2- r6c9 -7- r5c89 =7= r5c2 =8= r1c2 =2= r2c2 -2- r2c6 =2= r46c6 -2- r6c5 => r6c5<>2
Forcing Chain Verity => r5c2<>3
r2c6=2 r2c2<>2 r1c2=2 r1c2<>8 r5c2=8 r5c2<>3
r4c6=2 r4c6<>1 r5c5=1 r5c5<>8 r5c2=8 r5c2<>3
r6c6=2 r6c9<>2 r6c9=7 r5c89<>7 r5c2=7 r5c2<>3
Forcing Chain Contradiction in r4 => r6c7<>2
r6c7=2 r8c7<>2 r8c4=2 r4c4<>2
r6c7=2 r6c9<>2 r6c9=7 r5c9<>7 r5c9=1 r5c5<>1 r4c6=1 r4c6<>2
r6c7=2 r4c7<>2
Forcing Chain Verity => r6c7<>7
r2c6=2 r2c2<>2 r1c2=2 r1c2<>8 r5c2=8 r5c2<>7 r5c89=7 r6c7<>7
r4c6=2 r4c6<>1 r5c5=1 r5c9<>1 r5c9=7 r6c7<>7
r6c6=2 r6c9<>2 r6c9=7 r6c7<>7
Forcing Chain Contradiction in r3 => r1c3<>7
r1c3=7 r3c2<>7
r1c3=7 r3c3<>7
r1c3=7 r1c3<>8 r1c2=8 r5c2<>8 r5c5=8 r5c5<>3 r5c8=3 r2c8<>3 r3c7=3 r3c7<>7
r1c3=7 r1c3<>8 r1c2=8 r5c2<>8 r5c2=7 r5c8<>7 r56c9=7 r3c9<>7
Forcing Chain Contradiction in r4 => r8c7<>4
r8c7=4 r8c7<>2 r8c4=2 r4c4<>2
r8c7=4 r6c7<>4 r6c7=3 r5c8<>3 r5c5=3 r5c5<>1 r4c6=1 r4c6<>2
r8c7=4 r46c7<>4 r4c8=4 r4c8<>6 r4c7=6 r4c7<>2
Forcing Chain Contradiction in r7c7 => r1c3<>9
r1c3=9 r1c3<>8 r1c2=8 r5c2<>8 r5c5=8 r5c5<>3 r5c8=3 r6c7<>3 r6c7=4 r7c7<>4
r1c3=9 r89c3<>9 r7c12=9 r7c6<>9 r7c6=5 r7c7<>5
r1c3=9 r1c3<>8 r1c2=8 r5c2<>8 r5c2=7 r5c89<>7 r6c9=7 r6c9<>2 r9c9=2 r8c7<>2 r8c7=7 r7c7<>7
Forcing Net Contradiction in c6 => r1c3=8
r1c3<>8 r6c3=8 r6c6<>8
r1c3<>8 r1c2=8 r5c2<>8 (r5c5=8 r5c5<>3 r5c8=3 r6c7<>3 r6c7=4 r7c7<>4) r5c2=7 (r6c1<>7) r6c3<>7 r6c9=7 r6c9<>2 r9c9=2 r8c7<>2 r8c7=7 r7c7<>7 r7c7=5 (r7c6<>5) r9c9<>5 r3c9=5 r3c6<>5 r2c6=5 r2c6<>6 r8c6=6 r8c6<>8
Hidden Single: r5c2=8
Locked Candidates Type 1 (Pointing): 7 in b4 => r6c9<>7
Naked Single: r6c9=2
Forcing Chain Contradiction in r3 => r1c2<>7
r1c2=7 r3c2<>7
r1c2=7 r3c3<>7
r1c2=7 r1c2<>2 r2c2=2 r2c6<>2 r4c6=2 r4c6<>1 r5c5=1 r5c5<>3 r5c8=3 r2c8<>3 r3c7=3 r3c7<>7
r1c2=7 r1c2<>2 r2c2=2 r2c6<>2 r4c6=2 r4c6<>1 r5c5=1 r5c9<>1 r5c9=7 r3c9<>7
Forcing Net Contradiction in c3 => r4c6<>9
r4c6=9 (r3c6<>9) r7c6<>9 r7c6=5 r3c6<>5 r3c6=1 r3c3<>1 r2c3=1 r2c3<>3
r4c6=9 (r6c6<>9 r6c6=8 r6c5<>8 r6c5=3 r6c7<>3) r4c6<>1 r5c5=1 r5c5<>3 r5c8=3 r4c7<>3 r3c7=3 r3c3<>3
r4c6=9 (r4c6<>1 r5c5=1 r5c9<>1 r5c9=7 r3c9<>7 r3c9=5 r3c3<>5) (r3c6<>9) r7c6<>9 r7c6=5 r3c6<>5 r3c6=1 r3c3<>1 r2c3=1 r2c3<>5 r4c3=5 r4c3<>3
r4c6=9 (r6c5<>9) r6c6<>9 r6c6=8 r6c5<>8 r6c5=3 r6c3<>3
r4c6=9 r4c6<>2 r4c4=2 r4c4<>3 r9c4=3 r9c3<>3
Forcing Net Contradiction in c8 => r6c3<>9
r6c3=9 (r6c3<>4) r6c3<>7 r6c1=7 r6c1<>4 r6c7=4 r4c8<>4
r6c3=9 (r8c3<>9) (r4c1<>9) (r4c2<>9) r4c3<>9 r4c4=9 r8c4<>9 r8c8=9 r8c8<>4
r6c3=9 (r9c3<>9) (r4c1<>9) (r4c2<>9) r4c3<>9 r4c4=9 r4c4<>3 r9c4=3 r9c3<>3 r9c3=4 r9c8<>4
Brute Force: r4c8=4
Naked Single: r6c7=3
Hidden Single: r4c7=6
Hidden Single: r2c8=3
Hidden Single: r5c5=3
Hidden Single: r4c6=1
Hidden Single: r1c8=6
Hidden Single: r9c4=3
Hidden Single: r4c4=2
Hidden Single: r2c6=2
Hidden Single: r8c7=2
Hidden Single: r9c5=2
Hidden Single: r1c2=2
Hidden Single: r2c5=6
Naked Single: r8c5=8
Naked Single: r6c5=9
Full House: r6c6=8
Naked Single: r8c6=6
Hidden Single: r2c3=1
Hidden Single: r2c1=5
Hidden Single: r4c3=5
Hidden Single: r3c3=3
Locked Candidates Type 1 (Pointing): 4 in b1 => r7c2<>4
Locked Candidates Type 1 (Pointing): 5 in b8 => r7c7<>5
Locked Candidates Type 2 (Claiming): 9 in c3 => r7c12<>9
Hidden Single: r7c6=9
Full House: r3c6=5
Naked Single: r8c4=4
Full House: r7c5=5
Naked Single: r1c5=1
Full House: r3c5=4
Naked Single: r2c4=7
Full House: r1c4=9
Full House: r2c2=4
Naked Single: r1c1=7
Full House: r1c7=5
Full House: r3c2=9
Naked Single: r6c1=4
Full House: r6c3=7
Naked Single: r4c2=3
Full House: r4c1=9
Full House: r7c1=3
Full House: r7c2=7
Full House: r7c7=4
Naked Single: r8c3=9
Full House: r8c8=7
Full House: r9c3=4
Naked Single: r9c7=1
Full House: r3c7=7
Full House: r3c9=1
Naked Single: r5c8=1
Full House: r9c8=9
Full House: r9c9=5
Full House: r5c9=7
|
normal_sudoku_4181
|
.83...9.54...932.....5.8.34......32...9.345.88..2.5.4.318.......6.8.........5....
|
783462915451793286692518734145689327279134568836275149318947652567821493924356871
|
Basic 9x9 Sudoku 4181
|
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 3 . . . 9 . 5
4 . . . 9 3 2 . .
. . . 5 . 8 . 3 4
. . . . . . 3 2 .
. . 9 . 3 4 5 . 8
8 . . 2 . 5 . 4 .
3 1 8 . . . . . .
. 6 . 8 . . . . .
. . . . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
783462915451793286692518734145689327279134568836275149318947652567821493924356871 #1 Extreme (14194) bf
Hidden Single: r3c8=3
Hidden Single: r2c8=8
Hidden Single: r6c2=3
Hidden Single: r6c9=9
Hidden Single: r4c5=8
Hidden Single: r9c7=8
Hidden Single: r9c4=3
Hidden Single: r7c8=5
Hidden Single: r8c9=3
Locked Candidates Type 2 (Claiming): 9 in r7 => r89c6<>9
Locked Candidates Type 2 (Claiming): 4 in r9 => r8c3<>4
Brute Force: r5c4=1
Skyscraper: 1 in r2c9,r6c7 (connected by r26c3) => r3c7,r4c9<>1
Hidden Single: r6c7=1
Naked Triple: 2,6,7 in r5c12,r6c3 => r4c13<>6, r4c123<>7
Forcing Chain Verity => r2c9<>7
r2c3=6 r2c3<>1 r2c9=1 r2c9<>7
r3c3=6 r3c7<>6 r3c7=7 r2c9<>7
r6c3=6 r6c3<>7 r6c5=7 r4c46<>7 r4c9=7 r2c9<>7
Discontinuous Nice Loop: 7 r3c5 -7- r3c7 =7= r1c8 -7- r5c8 -6- r5c1 =6= r6c3 =7= r6c5 -7- r3c5 => r3c5<>7
Discontinuous Nice Loop: 6 r9c8 -6- r5c8 -7- r1c8 =7= r3c7 =6= r7c7 -6- r9c8 => r9c8<>6
Forcing Chain Contradiction in r2 => r3c7=7
r3c7<>7 r3c7=6 r1c8<>6 r5c8=6 r5c1<>6 r6c3=6 r2c3<>6
r3c7<>7 r1c8=7 r1c456<>7 r2c4=7 r2c4<>6
r3c7<>7 r3c7=6 r2c9<>6
Naked Single: r8c7=4
Full House: r7c7=6
Hidden Single: r9c6=6
Locked Candidates Type 1 (Pointing): 1 in b8 => r8c8<>1
2-String Kite: 6 in r1c8,r4c4 (connected by r4c9,r5c8) => r1c4<>6
X-Wing: 6 c49 r24 => r2c3<>6
W-Wing: 7/6 in r2c4,r6c3 connected by 6 in r4c4,r6c5 => r2c3<>7
W-Wing: 1/5 in r2c3,r4c1 connected by 5 in r8c13 => r13c1,r4c3<>1
Hidden Single: r4c1=1
Hidden Single: r8c1=5
Hidden Single: r8c8=9
Empty Rectangle: 7 in b4 (r59c8) => r9c3<>7
Hidden Rectangle: 4/7 in r1c45,r7c45 => r7c5<>7
Hidden Rectangle: 2/9 in r3c12,r9c12 => r9c1<>2
Hidden Rectangle: 7/9 in r4c46,r7c46 => r7c4<>7
XY-Chain: 7 7- r2c4 -6- r2c9 -1- r2c3 -5- r4c3 -4- r9c3 -2- r8c3 -7- r6c3 -6- r6c5 -7 => r1c5,r4c4<>7
Locked Candidates Type 2 (Claiming): 7 in c4 => r1c6<>7
X-Wing: 7 r47 c69 => r8c6,r9c9<>7
Naked Pair: 1,2 in r18c6 => r7c6<>2
XY-Chain: 2 2- r1c6 -1- r1c8 -6- r5c8 -7- r4c9 -6- r4c4 -9- r7c4 -4- r7c5 -2 => r13c5,r8c6<>2
Naked Single: r8c6=1
Naked Single: r1c6=2
W-Wing: 7/6 in r1c1,r2c4 connected by 6 in r1c8,r2c9 => r1c4,r2c2<>7
Naked Single: r1c4=4
Naked Single: r2c2=5
Naked Single: r7c4=9
Naked Single: r2c3=1
Naked Single: r4c2=4
Naked Single: r4c4=6
Full House: r2c4=7
Full House: r2c9=6
Full House: r1c8=1
Naked Single: r7c6=7
Full House: r4c6=9
Full House: r6c5=7
Full House: r6c3=6
Naked Single: r4c3=5
Full House: r4c9=7
Full House: r5c8=6
Full House: r9c8=7
Naked Single: r1c5=6
Full House: r1c1=7
Full House: r3c5=1
Naked Single: r7c9=2
Full House: r7c5=4
Full House: r8c5=2
Full House: r9c9=1
Full House: r8c3=7
Naked Single: r3c3=2
Full House: r9c3=4
Naked Single: r9c1=9
Full House: r9c2=2
Naked Single: r5c1=2
Full House: r3c1=6
Full House: r3c2=9
Full House: r5c2=7
|
normal_sudoku_2944
|
57........2..7......3..57.2..5..19....17.36.44..8....1..651....9...3.1.......9..6
|
579124863624378519813965742365241987281793654497856231736512498948637125152489376
|
Basic 9x9 Sudoku 2944
|
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 7 . . . . . . .
. 2 . . 7 . . . .
. . 3 . . 5 7 . 2
. . 5 . . 1 9 . .
. . 1 7 . 3 6 . 4
4 . . 8 . . . . 1
. . 6 5 1 . . . .
9 . . . 3 . 1 . .
. . . . . 9 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
579124863624378519813965742365241987281793654497856231736512498948637125152489376 #1 Extreme (24518) bf
Almost Locked Set XZ-Rule: A=r1c345679 {1234689}, B=r34589c4 {124679}, X=1, Z=6 => r2c4<>6
Brute Force: r5c4=7
Locked Candidates Type 1 (Pointing): 9 in b5 => r13c5<>9
Naked Triple: 2,4,6 in r4c45,r6c6 => r56c5<>2, r6c5<>6
Naked Triple: 2,4,6 in r489c4 => r1c4<>2, r123c4<>4, r13c4<>6
Finned X-Wing: 7 r69 c38 fr9c1 => r8c3<>7
Forcing Net Contradiction in c3 => r9c2<>8
r9c2=8 (r5c2<>8 r5c2=9 r6c3<>9) (r8c3<>8) (r9c2<>1 r3c2=1 r3c2<>4) (r9c2<>4) r9c2<>5 r8c2=5 r8c2<>4 r7c2=4 r8c3<>4 r8c3=2 r6c3<>2 r6c3=7
r9c2=8 (r9c3<>8) (r8c3<>8) (r9c2<>1 r3c2=1 r3c2<>4) (r9c2<>4) r9c2<>5 r8c2=5 r8c2<>4 r7c2=4 (r9c3<>4) r8c3<>4 r8c3=2 r9c3<>2 r9c3=7
Forcing Net Contradiction in r1c8 => r9c8<>2
r9c8=2 (r5c8<>2 r5c1=2 r6c3<>2) (r9c3<>2) (r9c5<>2) r9c4<>2 r9c4=4 (r9c3<>4) r9c5<>4 r9c5=8 r9c3<>8 r9c3=7 r6c3<>7 r6c3=9 (r5c2<>9) r6c2<>9 r3c2=9 r3c4<>9 r3c4=1 r1c4<>1 r1c8=1
r9c8=2 (r9c7<>2 r6c7=2 r6c6<>2 r6c6=6 r1c6<>6) r9c4<>2 r9c4=4 (r9c5<>4 r9c5=8 r3c5<>8) r4c4<>4 r4c5=4 r3c5<>4 r3c5=6 r1c5<>6 r1c8=6
Brute Force: r5c5=9
Naked Single: r5c2=8
Naked Single: r6c5=5
Naked Single: r5c1=2
Full House: r5c8=5
Discontinuous Nice Loop: 2 r8c4 -2- r8c3 =2= r9c3 =7= r6c3 =9= r6c2 =6= r6c6 -6- r8c6 =6= r8c4 => r8c4<>2
Grouped Discontinuous Nice Loop: 6 r2c6 -6- r6c6 =6= r6c2 =9= r3c2 -9- r3c4 -1- r1c4 =1= r1c8 =6= r1c56 -6- r2c6 => r2c6<>6
Almost Locked Set XY-Wing: A=r9c345 {2478}, B=r467c2 {3469}, C=r6c3 {79}, X,Y=7,9, Z=4 => r9c2<>4
Almost Locked Set Chain: 248- r9c345 {2478} -7- r2379c1 {13678} -3- r78c2 {345} -5- r7c789,r8c89,r9c8 {2345789} -248 => r9c7<>2, r9c7<>4, r9c7<>8
Forcing Chain Contradiction in r3c8 => r6c6=6
r6c6<>6 r6c2=6 r6c2<>9 r3c2=9 r3c4<>9 r3c4=1 r3c8<>1
r6c6<>6 r6c6=2 r6c7<>2 r7c7=2 r7c7<>4 r12c7=4 r3c8<>4
r6c6<>6 r6c2=6 r6c2<>9 r3c2=9 r3c4<>9 r3c4=1 r3c12<>1 r2c1=1 r2c1<>6 r2c8=6 r3c8<>6
r6c6<>6 r6c6=2 r6c7<>2 r7c7=2 r7c7<>8 r12c7=8 r3c8<>8
r6c6<>6 r6c2=6 r6c2<>9 r3c2=9 r3c8<>9
Hidden Single: r8c4=6
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c8<>2
Uniqueness Test 1: 2/4 in r4c45,r9c45 => r9c5<>2, r9c5<>4
Naked Single: r9c5=8
Turbot Fish: 8 r3c8 =8= r3c1 -8- r7c1 =8= r8c3 => r8c8<>8
Finned Swordfish: 8 r347 c189 fr7c7 => r8c9<>8
Hidden Single: r8c3=8
Hidden Single: r9c3=2
Naked Single: r9c4=4
Naked Single: r4c4=2
Full House: r4c5=4
Naked Single: r3c5=6
Full House: r1c5=2
Hidden Single: r6c3=7
Hidden Single: r1c8=6
Hidden Single: r4c2=6
Naked Single: r4c1=3
Full House: r6c2=9
Naked Single: r7c1=7
Naked Single: r7c6=2
Full House: r8c6=7
Naked Single: r9c1=1
Naked Single: r8c9=5
Naked Single: r3c1=8
Full House: r2c1=6
Naked Single: r8c2=4
Full House: r8c8=2
Naked Single: r9c7=3
Naked Single: r3c2=1
Naked Single: r7c2=3
Full House: r9c2=5
Full House: r9c8=7
Naked Single: r6c8=3
Full House: r6c7=2
Naked Single: r3c4=9
Full House: r3c8=4
Naked Single: r4c8=8
Full House: r4c9=7
Naked Single: r1c7=8
Naked Single: r7c8=9
Full House: r2c8=1
Naked Single: r1c6=4
Full House: r2c6=8
Naked Single: r2c7=5
Full House: r7c7=4
Full House: r7c9=8
Naked Single: r2c4=3
Full House: r1c4=1
Naked Single: r1c3=9
Full House: r1c9=3
Full House: r2c9=9
Full House: r2c3=4
|
normal_sudoku_314
|
.9.2....1..6....3.71...86..67..3....85.9.......148756..6...18......4..761.......2
|
593264781486719235712358694679135428854926317321487569267591843935842176148673952
|
Basic 9x9 Sudoku 314
|
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
. . 6 . . . . 3 .
7 1 . . . 8 6 . .
6 7 . . 3 . . . .
8 5 . 9 . . . . .
. . 1 4 8 7 5 6 .
. 6 . . . 1 8 . .
. . . . 4 . . 7 6
1 . . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
593264781486719235712358694679135428854926317321487569267591843935842176148673952 #1 Unfair (952)
Naked Single: r6c4=4
Hidden Single: r9c4=6
Hidden Single: r8c7=1
Hidden Single: r8c4=8
Locked Candidates Type 1 (Pointing): 4 in b4 => r1379c3<>4
Locked Candidates Type 2 (Claiming): 4 in r3 => r1c78,r2c79<>4
Naked Single: r1c7=7
Hidden Single: r5c9=7
Locked Candidates Type 2 (Claiming): 2 in r6 => r45c3<>2
Naked Pair: 2,3 in r68c2 => r2c2<>2, r9c2<>3
Hidden Pair: 1,7 in r2c45 => r2c45<>5, r2c5<>9
Skyscraper: 3 in r7c9,r8c2 (connected by r6c29) => r7c13<>3
Finned Swordfish: 3 r159 c367 fr1c1 => r3c3<>3
Hidden Single: r3c4=3
Hidden Single: r7c9=3
Naked Single: r6c9=9
Hidden Single: r5c7=3
Naked Single: r5c3=4
Naked Single: r4c3=9
Locked Candidates Type 1 (Pointing): 5 in b9 => r13c8<>5
Naked Single: r1c8=8
Naked Single: r2c9=5
Naked Single: r3c9=4
Full House: r4c9=8
Hidden Single: r9c3=8
Naked Single: r9c2=4
Naked Single: r2c2=8
Naked Single: r9c7=9
Naked Single: r2c7=2
Full House: r3c8=9
Full House: r4c7=4
Naked Single: r9c8=5
Full House: r7c8=4
Naked Single: r2c1=4
Naked Single: r3c5=5
Full House: r3c3=2
Naked Single: r9c5=7
Full House: r9c6=3
Naked Single: r2c6=9
Naked Single: r1c5=6
Naked Single: r2c5=1
Full House: r2c4=7
Full House: r1c6=4
Naked Single: r7c4=5
Full House: r4c4=1
Naked Single: r5c5=2
Full House: r7c5=9
Full House: r8c6=2
Naked Single: r7c3=7
Full House: r7c1=2
Naked Single: r4c8=2
Full House: r4c6=5
Full House: r5c6=6
Full House: r5c8=1
Naked Single: r8c2=3
Full House: r6c2=2
Full House: r6c1=3
Naked Single: r8c3=5
Full House: r1c3=3
Full House: r1c1=5
Full House: r8c1=9
|
normal_sudoku_6627
|
.4.7....2..5....7.....3.4..8...1..2..9.28.7.......3.69.2.6.1.4...83.....1...5....
|
349768152685124973712539486873916524496285731251473869527691348968347215134852697
|
Basic 9x9 Sudoku 6627
|
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 . . . . 2
. . 5 . . . . 7 .
. . . . 3 . 4 . .
8 . . . 1 . . 2 .
. 9 . 2 8 . 7 . .
. . . . . 3 . 6 9
. 2 . 6 . 1 . 4 .
. . 8 3 . . . . .
1 . . . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
349768152685124973712539486873916524496285731251473869527691348968347215134852697 #1 Extreme (11344) bf
Brute Force: r5c5=8
Hidden Single: r6c7=8
Hidden Single: r7c9=8
Locked Candidates Type 1 (Pointing): 6 in b5 => r123c6<>6
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c3<>1
XYZ-Wing: 3/5/9 in r47c7,r9c8 => r9c7<>3
Discontinuous Nice Loop: 9 r9c4 -9- r4c4 =9= r4c6 =7= r6c5 -7- r7c5 -9- r9c4 => r9c4<>9
Almost Locked Set XY-Wing: A=r1c1357 {13569}, B=r9c8 {39}, C=r47c7 {359}, X,Y=5,9, Z=3 => r1c8<>3
Finned Swordfish: 3 r157 c137 fr5c8 fr5c9 => r4c7<>3
Naked Single: r4c7=5
Hidden Single: r7c1=5
Hidden Single: r5c6=5
Naked Single: r6c4=4
Naked Single: r4c4=9
Naked Single: r6c5=7
Full House: r4c6=6
Naked Single: r9c4=8
Naked Single: r6c1=2
Naked Single: r7c5=9
Naked Single: r2c4=1
Full House: r3c4=5
Naked Single: r6c3=1
Full House: r6c2=5
Naked Single: r1c5=6
Naked Single: r7c7=3
Full House: r7c3=7
Naked Single: r9c8=9
Naked Single: r8c2=6
Naked Single: r9c2=3
Naked Single: r2c2=8
Naked Single: r4c2=7
Full House: r3c2=1
Naked Single: r9c3=4
Full House: r8c1=9
Naked Single: r3c8=8
Naked Single: r3c9=6
Naked Single: r4c3=3
Full House: r4c9=4
Naked Single: r1c1=3
Naked Single: r2c7=9
Naked Single: r2c9=3
Naked Single: r3c1=7
Naked Single: r9c9=7
Naked Single: r1c3=9
Naked Single: r5c3=6
Full House: r3c3=2
Full House: r2c1=6
Full House: r5c1=4
Full House: r3c6=9
Naked Single: r1c7=1
Full House: r1c8=5
Full House: r1c6=8
Naked Single: r5c9=1
Full House: r5c8=3
Full House: r8c8=1
Full House: r8c9=5
Naked Single: r9c6=2
Full House: r9c7=6
Full House: r8c7=2
Naked Single: r2c6=4
Full House: r2c5=2
Full House: r8c5=4
Full House: r8c6=7
|
normal_sudoku_1171
|
..5...1.2.7.2...59......74...763......4.2....1..9..2.......24.1.21498.755.....9..
|
635749182478216359912853746297635814864127593153984267789562431321498675546371928
|
Basic 9x9 Sudoku 1171
|
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.
|
. . 5 . . . 1 . 2
. 7 . 2 . . . 5 9
. . . . . . 7 4 .
. . 7 6 3 . . . .
. . 4 . 2 . . . .
1 . . 9 . . 2 . .
. . . . . 2 4 . 1
. 2 1 4 9 8 . 7 5
5 . . . . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
635749182478216359912853746297635814864127593153984267789562431321498675546371928 #1 Extreme (8014)
Hidden Single: r5c5=2
Hidden Single: r4c1=2
Hidden Single: r9c8=2
Hidden Single: r3c3=2
Hidden Single: r3c2=1
Hidden Single: r9c2=4
Hidden Single: r7c1=7
Hidden Single: r7c3=9
Naked Triple: 3,6,8 in r167c8 => r45c8<>8, r5c8<>3, r5c8<>6
Sashimi X-Wing: 8 r47 c28 fr4c7 fr4c9 => r6c8<>8
Discontinuous Nice Loop: 8 r2c5 -8- r6c5 =8= r5c4 =1= r9c4 -1- r9c5 =1= r2c5 => r2c5<>8
Almost Locked Set XY-Wing: A=r2c1367 {13468}, B=r37c5 {568}, C=r456c6,r6c5 {14578}, X,Y=1,8, Z=6 => r2c5<>6
Forcing Net Verity => r4c9=4
r5c7=3 (r5c2<>3) (r2c7<>3) r8c7<>3 (r8c1=3 r7c2<>3) r8c7=6 r2c7<>6 r2c7=8 r1c8<>8 r1c8=3 r1c2<>3 r6c2=3 (r6c3<>3) r6c8<>3 r6c8=6 (r1c8<>6) r6c3<>6 r6c3=8 r9c3<>8 r9c9=8 r4c9<>8 r4c9=4
r5c7=5 r4c7<>5 r4c7=8 r4c9<>8 r4c9=4
r5c7=6 (r5c2<>6) (r2c7<>6) r8c7<>6 (r8c1=6 r7c2<>6) r8c7=3 r2c7<>3 r2c7=8 r1c8<>8 r1c8=6 r1c2<>6 r6c2=6 (r6c3<>6) r6c8<>6 r6c8=3 (r1c8<>3) r6c3<>3 r6c3=8 r9c3<>8 r9c9=8 r4c9<>8 r4c9=4
r5c7=8 r4c9<>8 r4c9=4
Sashimi X-Wing: 8 r24 c27 fr2c1 fr2c3 => r1c2<>8
Forcing Net Contradiction in c3 => r1c1<>3
r1c1=3 r2c3<>3
r1c1=3 (r1c8<>3) r8c1<>3 r8c7=3 r7c8<>3 r6c8=3 r6c3<>3
r1c1=3 (r2c3<>3) (r2c3<>3) (r1c8<>3) r8c1<>3 r8c7=3 (r2c7<>3 r2c6=3 r3c6<>3 r3c9=3 r5c9<>3 r5c2=3 r7c2<>3 r7c2=8 r4c2<>8 r4c7=8 r4c7<>5 r5c7=5 r5c4<>5) (r2c7<>3 r2c6=3 r3c6<>3 r3c9=3 r3c9<>8) (r2c7<>3 r2c6=3 r3c6<>3 r3c9=3 r5c9<>3 r5c2=3 r7c2<>3 r7c2=8 r6c2<>8) (r2c7<>3) r7c8<>3 r6c8=3 r6c3<>3 r9c3=3 r9c3<>8 r9c9=8 r7c8<>8 r1c8=8 r2c7<>8 r2c7=6 r2c3<>6 r2c3=8 (r3c1<>8) (r6c3<>8) r9c3<>8 r9c9=8 r6c9<>8 r6c5=8 r3c5<>8 r3c4=8 r3c4<>5 r7c4=5 r7c4<>3 r9c46=3 r9c3<>3
Forcing Net Contradiction in r8 => r1c8<>3
r1c8=3 (r1c2<>3) (r6c8<>3 r6c8=6 r6c3<>6) r1c8<>8 r7c8=8 r9c9<>8 r9c3=8 r6c3<>8 r6c3=3 (r5c2<>3) r6c2<>3 r7c2=3 r8c1<>3 r8c1=6
r1c8=3 (r6c8<>3 r6c8=6 r5c7<>6) (r6c8<>3 r6c8=6 r6c3<>6) r1c8<>8 r7c8=8 r9c9<>8 r9c3=8 r9c3<>6 r2c3=6 r2c7<>6 r8c7=6
Turbot Fish: 3 r3c9 =3= r2c7 -3- r8c7 =3= r8c1 => r3c1<>3
Discontinuous Nice Loop: 3 r5c7 -3- r6c8 =3= r7c8 =8= r7c2 -8- r4c2 =8= r4c7 =5= r5c7 => r5c7<>3
Sashimi Swordfish: 3 c378 r269 fr7c8 fr8c7 => r9c9<>3
Discontinuous Nice Loop: 8 r3c9 -8- r9c9 -6- r8c7 -3- r2c7 =3= r3c9 => r3c9<>8
W-Wing: 6/3 in r3c9,r8c1 connected by 3 in r28c7 => r3c1<>6
Multi Colors 1: 8 (r1c8,r7c2,r9c9) / (r2c7,r7c8,r9c3), (r4c2) / (r4c7) => r5c27,r6c2<>8
Discontinuous Nice Loop: 6 r7c2 -6- r8c1 -3- r8c7 =3= r7c8 =8= r7c2 => r7c2<>6
Discontinuous Nice Loop: 5 r5c4 -5- r5c7 =5= r4c7 =8= r4c2 -8- r7c2 -3- r7c4 -5- r5c4 => r5c4<>5
Grouped Discontinuous Nice Loop: 6 r1c5 -6- r7c5 =6= r7c8 =3= r6c8 -3- r56c9 =3= r3c9 =6= r3c56 -6- r1c5 => r1c5<>6
Grouped Discontinuous Nice Loop: 6 r1c6 -6- r1c8 -8- r2c7 =8= r2c13 -8- r3c1 -9- r3c6 =9= r1c6 => r1c6<>6
Grouped Discontinuous Nice Loop: 6 r2c1 -6- r2c6 =6= r3c56 -6- r3c9 -3- r2c7 =3= r8c7 =6= r8c1 -6- r2c1 => r2c1<>6
Grouped Discontinuous Nice Loop: 6 r5c1 -6- r8c1 -3- r8c7 =3= r2c7 -3- r2c13 =3= r1c2 =6= r56c2 -6- r5c1 => r5c1<>6
Grouped Discontinuous Nice Loop: 3 r6c2 -3- r6c8 =3= r7c8 -3- r8c7 =3= r2c7 -3- r2c13 =3= r1c2 -3- r6c2 => r6c2<>3
Almost Locked Set Chain: 5- r6c2 {56} -6- r6c38 {368} -8- r9c3456 {13678} -6- r9c9 {68} -8- r5c79,r6c89 {35678} -5 => r5c2<>5
Forcing Chain Contradiction in r3c4 => r1c6=9
r1c6<>9 r3c6=9 r3c1<>9 r3c1=8 r2c13<>8 r2c7=8 r2c7<>3 r3c9=3 r3c4<>3
r1c6<>9 r3c6=9 r3c1<>9 r3c1=8 r2c13<>8 r2c7=8 r4c7<>8 r4c2=8 r7c2<>8 r7c2=3 r7c4<>3 r7c4=5 r3c4<>5
r1c6<>9 r3c6=9 r3c1<>9 r3c1=8 r3c4<>8
Hidden Single: r3c1=9
Locked Candidates Type 2 (Claiming): 8 in r3 => r1c45<>8
XY-Wing: 3/6/8 in r1c28,r7c2 => r7c8<>8
Hidden Single: r7c2=8
Hidden Single: r1c8=8
Hidden Single: r9c9=8
Hidden Single: r4c7=8
Hidden Single: r5c7=5
Locked Candidates Type 2 (Claiming): 6 in r1 => r2c3<>6
Remote Pair: 3/6 r2c7 -6- r8c7 -3- r8c1 -6- r9c3 => r2c3<>3
Naked Single: r2c3=8
Hidden Single: r5c1=8
Hidden Single: r6c5=8
Hidden Single: r3c4=8
Hidden Single: r6c6=4
Hidden Single: r7c4=5
Naked Single: r7c5=6
Full House: r7c8=3
Full House: r8c7=6
Full House: r2c7=3
Full House: r8c1=3
Full House: r3c9=6
Full House: r9c3=6
Full House: r6c3=3
Naked Single: r3c5=5
Full House: r3c6=3
Naked Single: r6c8=6
Naked Single: r2c1=4
Full House: r1c1=6
Full House: r1c2=3
Naked Single: r6c9=7
Full House: r6c2=5
Full House: r5c9=3
Naked Single: r1c4=7
Full House: r1c5=4
Naked Single: r2c5=1
Full House: r2c6=6
Full House: r9c5=7
Naked Single: r4c2=9
Full House: r5c2=6
Naked Single: r5c4=1
Full House: r9c4=3
Full House: r9c6=1
Naked Single: r4c8=1
Full House: r4c6=5
Full House: r5c6=7
Full House: r5c8=9
|
normal_sudoku_1950
|
5....72....845..6..6.....5.6...1..42.....4.76......1..4..9.1...2....64...36.4...9
|
513867294928453761764192358697315842351284976842679135475921683289536417136748529
|
Basic 9x9 Sudoku 1950
|
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 . . . . 7 2 . .
. . 8 4 5 . . 6 .
. 6 . . . . . 5 .
6 . . . 1 . . 4 2
. . . . . 4 . 7 6
. . . . . . 1 . .
4 . . 9 . 1 . . .
2 . . . . 6 4 . .
. 3 6 . 4 . . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
513867294928453761764192358697315842351284976842679135475921683289536417136748529 #1 Extreme (29838) bf
Hidden Single: r9c5=4
Hidden Single: r7c7=6
Brute Force: r5c4=2
Hidden Pair: 2,4 in r6c23 => r6c23<>5, r6c23<>7, r6c2<>8, r6c23<>9, r6c3<>3
Grouped Discontinuous Nice Loop: 5 r4c4 -5- r8c4 =5= r9c46 -5- r9c7 =5= r45c7 -5- r6c9 =5= r6c46 -5- r4c4 => r4c4<>5
Forcing Net Verity => r2c1<>1
r1c2=1 r2c1<>1
r1c2=4 r6c2<>4 r6c2=2 r2c2<>2 r2c6=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 r2c1<>1
r1c2=9 (r1c5<>9) (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 (r6c5<>9) r6c1<>9 r5c1=9 r5c5<>9 r3c5=9 r3c5<>2 r7c5=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 r2c1<>1
Discontinuous Nice Loop: 1 r3c9 -1- r2c9 =1= r2c2 =2= r3c3 =4= r3c9 => r3c9<>1
Forcing Net Contradiction in c7 => r2c2<>7
r2c2=7 (r3c1<>7) (r3c3<>7) r2c2<>2 r2c6=2 (r3c5<>2) r3c6<>2 r3c3=2 r3c3<>4 r3c9=4 r3c9<>7 r3c7=7
r2c2=7 (r4c2<>7) (r2c1<>7) (r3c1<>7) r2c2<>2 r2c6=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 (r9c1<>7) r9c1<>7 r6c1=7 r4c3<>7 r4c4=7 r9c4<>7 r9c7=7
Forcing Net Verity => r3c1<>1
r1c2=1 r3c1<>1
r1c2=4 r6c2<>4 r6c2=2 r2c2<>2 r2c6=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 r3c1<>1
r1c2=9 (r1c5<>9) (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 (r6c5<>9) r6c1<>9 r5c1=9 r5c5<>9 r3c5=9 r3c5<>2 r7c5=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 r3c1<>1
Forcing Net Contradiction in r8c3 => r3c4<>3
r3c4=3 r3c4<>1 r3c3=1 (r1c2<>1) r3c3<>2 r6c3=2 r6c2<>2 r6c2=4 r1c2<>4 r1c2=9 (r8c2<>9 r8c3=9 r4c3<>9 r4c6=9 r2c6<>9) r1c2<>4 r6c2=4 r6c2<>2 r2c2=2 r2c6<>2 r2c6=3 r3c4<>3
Forcing Net Contradiction in b1 => r4c4<>7
r4c4=7 (r9c4<>7) (r6c4<>7) r6c5<>7 r6c1=7 (r2c1<>7) r9c1<>7 r9c7=7 r2c7<>7 r2c9=7 r2c9<>1 r2c2=1 r2c2<>2
r4c4=7 (r6c4<>7) r6c5<>7 r6c1=7 (r2c1<>7) r3c1<>7 r3c3=7 r3c3<>2
Locked Candidates Type 1 (Pointing): 7 in b5 => r6c1<>7
Hidden Pair: 6,7 in r6c45 => r6c45<>3, r6c4<>5, r6c45<>8, r6c5<>9
Locked Candidates Type 1 (Pointing): 5 in b5 => r9c6<>5
Forcing Net Verity => r8c2<>1
r1c2=1 r8c2<>1
r1c2=4 r6c2<>4 r6c2=2 r2c2<>2 r2c6=2 r9c6<>2 r9c8=2 r9c8<>1 r9c1=1 r8c2<>1
r1c2=9 (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 r6c1<>9 r5c1=9 r5c1<>1 r9c1=1 r8c2<>1
Forcing Net Contradiction in c7 => r3c4=1
r3c4<>1 r3c3=1 (r1c2<>1) r3c3<>2 r6c3=2 r6c2<>2 (r2c2=2 r2c2<>9) r6c2=4 r1c2<>4 r1c2=9 (r2c1<>9) (r4c2<>9) (r1c8<>9 r6c8=9 r4c7<>9) r8c2<>9 r8c3=9 r4c3<>9 r4c6=9 r2c6<>9 r2c7=9 r2c7<>3
r3c4<>1 r3c3=1 (r1c2<>1) r3c3<>2 r6c3=2 r6c2<>2 (r2c2=2 r2c6<>2 r2c6=3 r2c1<>3) r6c2=4 r1c2<>4 (r1c3=4 r1c3<>3 r5c3=3 r5c1<>3) r1c2=9 (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 r6c1<>9 r5c1=9 (r5c1<>8) r5c1<>1 r9c1=1 r9c1<>8 r6c1=8 r6c1<>3 r3c1=3 r3c7<>3
r3c4<>1 r3c4=8 r4c4<>8 r4c4=3 r4c7<>3
r3c4<>1 (r3c4=8 r4c4<>8 r4c4=3 r4c3<>3) r3c3=1 (r3c3<>3) (r3c3<>4 r3c9=4 r1c9<>4) r3c3<>2 r6c3=2 r6c2<>2 r6c2=4 r1c2<>4 r1c3=4 r1c3<>3 r5c3=3 r5c7<>3
Forcing Net Contradiction in c7 => r1c2<>9
r1c2=9 (r8c2<>9 r8c3=9 r4c3<>9 r4c6=9 r2c6<>9) r1c2<>4 r6c2=4 r6c2<>2 r2c2=2 r2c6<>2 r2c6=3 r2c7<>3
r1c2=9 (r1c2<>4 r6c2=4 r6c2<>2 r2c2=2 r2c6<>2 r2c6=3 r2c1<>3) (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 r6c1<>9 r5c1=9 (r5c1<>3) (r5c1<>8) r5c1<>1 r9c1=1 r9c1<>8 r6c1=8 r6c1<>3 r3c1=3 r3c7<>3
r1c2=9 (r8c2<>9 r8c3=9 r4c3<>9 r4c6=9 r4c6<>5 r6c6=5 r6c9<>5) (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 r6c1<>9 r5c1=9 (r5c1<>8) r5c1<>1 r9c1=1 r9c1<>8 r6c1=8 r6c9<>8 r6c9=3 r4c7<>3
r1c2=9 (r8c2<>9 r8c3=9 r4c3<>9 r4c6=9 r4c6<>5 r6c6=5 r6c9<>5) (r2c1<>9) (r3c1<>9) r1c8<>9 r6c8=9 r6c1<>9 r5c1=9 (r5c1<>8) r5c1<>1 r9c1=1 r9c1<>8 r6c1=8 r6c9<>8 r6c9=3 r5c7<>3
Forcing Net Contradiction in r9c7 => r9c7<>8
r9c7=8 (r9c1<>8) (r9c8<>8) r9c6<>8 r9c6=2 r9c8<>2 r9c8=1 r9c1<>1 r5c1=1 r5c1<>8 r6c1=8 r6c89<>8 r45c7=8 r9c7<>8
Forcing Net Contradiction in r9c8 => r3c3<>7
r3c3=7 (r2c1<>7) r3c1<>7 r9c1=7 r9c1<>1 r9c8=1
r3c3=7 (r2c1<>7) r3c1<>7 r9c1=7 (r9c1<>1 r5c1=1 r5c1<>8 r6c1=8 r6c6<>8) (r9c4<>7) r9c7<>7 r9c7=5 (r4c7<>5 r4c6=5 r4c6<>8 r4c7=8 r5c7<>8 r5c5=8 r5c5<>9) (r4c7<>5 r4c6=5 r6c6<>5) r9c4<>5 r9c4=8 r4c4<>8 r4c4=3 r6c6<>3 r6c6=9 r6c8<>9 r1c8=9 r1c5<>9 r3c5=9 r3c5<>2 r7c5=2 r9c6<>2 r9c8=2
Locked Candidates Type 1 (Pointing): 7 in b1 => r9c1<>7
Naked Triple: 1,2,8 in r9c168 => r9c4<>8
Brute Force: r5c5=8
Naked Single: r4c4=3
Locked Candidates Type 1 (Pointing): 9 in b5 => r23c6<>9
Locked Candidates Type 1 (Pointing): 3 in b8 => r13c5<>3
Finned Swordfish: 3 c167 r235 fr6c1 => r5c3<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r23c1<>3
Locked Pair: 7,9 in r23c1 => r13c3,r2c2,r56c1<>9
Naked Triple: 1,2,4 in r126c2 => r5c2<>1
Locked Candidates Type 2 (Claiming): 1 in c2 => r1c3<>1
XYZ-Wing: 5/7/9 in r47c3,r5c2 => r5c3<>5
Hidden Rectangle: 3/4 in r1c39,r3c39 => r3c9<>3
Sashimi Swordfish: 8 c167 r349 fr6c1 => r4c2<>8
Hidden Single: r4c7=8
Hidden Single: r6c1=8
Naked Single: r9c1=1
Naked Single: r5c1=3
Hidden Single: r5c3=1
Locked Candidates Type 2 (Claiming): 3 in c7 => r1c89,r2c9<>3
Hidden Single: r1c3=3
Skyscraper: 8 in r3c9,r9c8 (connected by r39c6) => r1c8,r78c9<>8
Hidden Pair: 4,8 in r13c9 => r1c9<>1, r3c9<>7
XY-Wing: 1/7/9 in r1c8,r2c19 => r2c7<>9
Hidden Single: r2c1=9
Full House: r3c1=7
XY-Wing: 2/9/3 in r2c6,r3c57 => r2c7,r3c6<>3
Naked Single: r2c7=7
Naked Single: r2c9=1
Naked Single: r9c7=5
Naked Single: r1c8=9
Naked Single: r2c2=2
Full House: r2c6=3
Naked Single: r5c7=9
Full House: r3c7=3
Full House: r5c2=5
Naked Single: r9c4=7
Naked Single: r1c5=6
Naked Single: r6c8=3
Full House: r6c9=5
Naked Single: r3c3=4
Full House: r1c2=1
Naked Single: r6c2=4
Naked Single: r6c4=6
Naked Single: r8c5=3
Naked Single: r1c4=8
Full House: r1c9=4
Full House: r3c9=8
Full House: r8c4=5
Naked Single: r6c5=7
Naked Single: r6c6=9
Full House: r6c3=2
Full House: r4c6=5
Naked Single: r7c5=2
Full House: r3c5=9
Full House: r3c6=2
Full House: r9c6=8
Full House: r9c8=2
Naked Single: r8c9=7
Full House: r7c9=3
Naked Single: r7c8=8
Full House: r8c8=1
Naked Single: r8c3=9
Full House: r8c2=8
Naked Single: r7c2=7
Full House: r4c2=9
Full House: r4c3=7
Full House: r7c3=5
|
normal_sudoku_1490
|
6.4.....9..5.9..6.3...6...2.6.1.73.......6.5...3.4....4.6..92.3.52..46..9......4.
|
624758139715293468398461572569127384247836951183945726476589213852314697931672845
|
Basic 9x9 Sudoku 1490
|
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 . 4 . . . . . 9
. . 5 . 9 . . 6 .
3 . . . 6 . . . 2
. 6 . 1 . 7 3 . .
. . . . . 6 . 5 .
. . 3 . 4 . . . .
4 . 6 . . 9 2 . 3
. 5 2 . . 4 6 . .
9 . . . . . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
624758139715293468398461572569127384247836951183945726476589213852314697931672845 #1 Extreme (25070) bf
Hidden Single: r1c1=6
Hidden Single: r5c2=4
Hidden Single: r1c8=3
Hidden Single: r9c9=5
Hidden Single: r9c2=3
Hidden Single: r6c9=6
Hidden Single: r9c4=6
Hidden Single: r8c8=9
Hidden Single: r4c9=4
Hidden Single: r2c6=3
Hidden Single: r4c3=9
Hidden Single: r3c2=9
Brute Force: r5c5=3
Hidden Single: r8c4=3
Brute Force: r5c4=8
Hidden Single: r5c1=2
Hidden Single: r5c7=9
Hidden Single: r6c4=9
Locked Candidates Type 2 (Claiming): 2 in c4 => r1c56<>2
Forcing Net Verity => r1c2<>8
r1c2=7 r1c2<>8
r1c4=7 r1c4<>2 r1c2=2 r1c2<>8
r1c5=7 (r1c4<>7) (r2c4<>7) r3c4<>7 r7c4=7 r7c4<>5 r7c5=5 (r7c5<>8) r4c5<>5 r4c5=2 r4c8<>2 r4c8=8 r7c8<>8 r7c2=8 r1c2<>8
r1c7=7 (r1c7<>1) (r2c9<>7) (r3c8<>7) (r3c7<>7) (r3c8<>7) r1c7<>5 r3c7=5 (r3c7<>1) r3c7<>4 r3c4=4 r3c4<>7 r3c3=7 (r3c3<>8 r9c3=8 r8c1<>8) (r3c3<>8 r9c3=8 r7c2<>8) r5c3<>7 r5c9=7 r6c8<>7 r7c8=7 r7c8<>8 r7c5=8 r8c5<>8 (r8c5=1 r1c5<>1) r8c9=8 r2c9<>8 r2c9=1 (r3c8<>1) r5c9<>1 r5c3=1 r3c3<>1 r3c6=1 r1c6<>1 r1c2=1 r1c2<>8
Finned Franken Swordfish: 8 c29b6 r267 fr4c8 fr8c9 => r7c8<>8
Forcing Net Verity => r7c4=5
r9c3=1 (r9c3<>8 r3c3=8 r3c8<>8) (r7c2<>1) (r8c1<>1) r5c3<>1 r5c9=1 r8c9<>1 r8c5=1 r7c5<>1 r7c8=1 r3c8<>1 r3c8=7 (r2c9<>7 r8c9=7 r9c7<>7) r6c8<>7 r6c7=7 r5c9<>7 r5c3=7 (r6c1<>7) (r6c2<>7) r9c3<>7 r9c5=7 r7c4<>7 r7c4=5
r9c3=7 (r8c1<>7) r5c3<>7 r5c9=7 r8c9<>7 r8c5=7 r7c4<>7 r7c4=5
r9c3=8 r7c2<>8 r7c5=8 r7c5<>5 r7c4=5
Locked Candidates Type 1 (Pointing): 7 in b8 => r1c5<>7
Hidden Rectangle: 2/7 in r1c24,r2c24 => r2c2<>7
Hidden Rectangle: 4/7 in r2c47,r3c47 => r2c7<>7
Forcing Chain Contradiction in r2 => r9c5<>8
r9c5=8 r9c3<>8 r3c3=8 r2c1<>8
r9c5=8 r9c3<>8 r3c3=8 r2c2<>8
r9c5=8 r9c5<>2 r9c6=2 r6c6<>2 r6c6=5 r3c6<>5 r3c7=5 r3c7<>4 r2c7=4 r2c7<>8
r9c5=8 r9c7<>8 r8c9=8 r2c9<>8
Forcing Net Contradiction in r2c7 => r2c7=4
r2c7<>4 r2c4=4 r3c4<>4 (r3c4=7 r1c4<>7) r3c7=4 r3c7<>5 r3c6=5 (r6c6<>5 r6c6=2 r9c6<>2 r9c5=2 r9c5<>7) (r6c6<>5 r6c1=5 r6c1<>7) (r1c5<>5) r1c6<>5 r1c7=5 r1c7<>7 r1c2=7 r2c1<>7 r8c1=7 r8c5<>7 r7c5=7 (r7c8<>7 r7c8=1 r3c8<>1) r7c5<>8 r7c2=8 r9c3<>8 r3c3=8 r3c8<>8 r3c8=7 r3c4<>7 r3c4=4 r2c4<>4 r2c7=4
Hidden Single: r3c4=4
Uniqueness Test 4: 2/7 in r1c24,r2c24 => r1c2<>7
Turbot Fish: 7 r2c1 =7= r3c3 -7- r5c3 =7= r5c9 => r2c9<>7
XYZ-Wing: 1/2/8 in r12c2,r2c9 => r2c1<>1
Skyscraper: 1 in r2c2,r5c3 (connected by r25c9) => r3c3,r6c2<>1
Locked Candidates Type 1 (Pointing): 1 in b1 => r7c2<>1
Naked Pair: 7,8 in r2c1,r3c3 => r2c2<>8
Skyscraper: 8 in r2c9,r4c8 (connected by r24c1) => r3c8<>8
Locked Candidates Type 2 (Claiming): 8 in c8 => r6c7<>8
Naked Pair: 1,7 in r5c9,r6c7 => r6c8<>1, r6c8<>7
Swordfish: 8 c367 r139 => r1c5<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r9c6<>8
2-String Kite: 1 in r5c9,r8c1 (connected by r5c3,r6c1) => r8c9<>1
2-String Kite: 1 in r6c7,r9c3 (connected by r5c3,r6c1) => r9c7<>1
Hidden Single: r7c8=1
Naked Single: r3c8=7
Naked Single: r3c3=8
Naked Single: r2c1=7
Naked Single: r2c4=2
Full House: r1c4=7
Naked Single: r2c2=1
Full House: r1c2=2
Full House: r2c9=8
Naked Single: r8c9=7
Full House: r5c9=1
Full House: r9c7=8
Full House: r5c3=7
Full House: r9c3=1
Naked Single: r6c7=7
Naked Single: r6c2=8
Full House: r7c2=7
Full House: r8c1=8
Full House: r7c5=8
Full House: r8c5=1
Naked Single: r9c6=2
Full House: r9c5=7
Naked Single: r4c1=5
Full House: r6c1=1
Naked Single: r6c8=2
Full House: r6c6=5
Full House: r4c5=2
Full House: r1c5=5
Full House: r4c8=8
Naked Single: r3c6=1
Full House: r1c6=8
Full House: r1c7=1
Full House: r3c7=5
|
normal_sudoku_2918
|
6.5...12.4......6...2.....515.8.97..2..5..6...4.......5....7..47..1..2....1..657.
|
685934127419725368372618495156849732238571649947362851563287914794153286821496573
|
Basic 9x9 Sudoku 2918
|
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 . 5 . . . 1 2 .
4 . . . . . . 6 .
. . 2 . . . . . 5
1 5 . 8 . 9 7 . .
2 . . 5 . . 6 . .
. 4 . . . . . . .
5 . . . . 7 . . 4
7 . . 1 . . 2 . .
. . 1 . . 6 5 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
685934127419725368372618495156849732238571649947362851563287914794153286821496573 #1 Extreme (13552) bf
Hidden Single: r4c2=5
Hidden Single: r3c7=4
Hidden Single: r7c8=1
Hidden Single: r8c3=4
Hidden Single: r8c9=6
Hidden Single: r6c8=5
Hidden Single: r7c2=6
Hidden Single: r9c2=2
Brute Force: r5c3=8
Skyscraper: 8 in r8c8,r9c1 (connected by r3c18) => r8c2,r9c9<>8
Hidden Single: r9c1=8
2-String Kite: 7 in r2c3,r5c5 (connected by r5c2,r6c3) => r2c5<>7
2-String Kite: 8 in r3c8,r7c5 (connected by r7c7,r8c8) => r3c5<>8
Finned X-Wing: 7 r35 c25 fr3c4 => r1c5<>7
Sashimi Swordfish: 9 c137 r267 fr3c1 => r2c2<>9
Finned Franken Swordfish: 3 c17b7 r267 fr3c1 fr8c2 => r2c2<>3
Forcing Chain Contradiction in c8 => r6c9<>3
r6c9=3 r6c1<>3 r3c1=3 r3c8<>3
r6c9=3 r4c8<>3
r6c9=3 r5c8<>3
r6c9=3 r6c9<>8 r6c7=8 r7c7<>8 r8c8=8 r8c8<>3
Forcing Chain Contradiction in c8 => r6c9<>9
r6c9=9 r6c1<>9 r3c1=9 r3c8<>9
r6c9=9 r5c8<>9
r6c9=9 r6c9<>8 r6c7=8 r7c7<>8 r8c8=8 r8c8<>9
Forcing Net Verity => r3c1=3
r1c2=3 (r8c2<>3 r8c2=9 r8c8<>9) (r2c3<>3) r3c1<>3 (r3c1=9 r3c8<>9) r6c1=3 (r6c7<>3) (r4c3<>3) r6c3<>3 r7c3=3 r7c7<>3 r2c7=3 r3c8<>3 r3c8=8 (r2c9<>8 r6c9=8 r6c7<>8) r8c8<>8 r8c8=3 r4c8<>3 r4c8=4 r5c8<>4 r5c8=9 (r5c8<>3) r6c7<>9 r6c7=3 r6c1<>3 r3c1=3
r2c3=3 (r1c2<>3) (r3c2<>3) (r7c3<>3 r7c3=9 r6c3<>9 r6c7=9 r2c7<>9 r2c7=8 r3c8<>8 r3c8=3 r1c9<>3) (r2c9<>3) (r3c1<>3 r3c1=9 r3c8<>9) (r3c1<>3 r6c1=3 r5c2<>3) r2c3<>7 r6c3=7 r5c2<>7 r5c2=9 r5c8<>9 r8c8=9 r8c8<>8 r3c8=8 r3c8<>3 r2c7=3 r2c3<>3 r3c1=3
r3c1=3 r3c1=3
r3c2=3 (r6c9=8 r6c7<>8) (r8c2<>3 r8c2=9 r8c8<>9) (r3c8<>3) r3c1<>3 r3c1=9 r3c8<>9 r3c8=8 r8c8<>8 r8c8=3 r4c8<>3 r4c8=4 r5c8<>4 r5c8=9 (r5c8<>3) r6c7<>9 r6c7=3 r6c1<>3 r3c1=3
Full House: r6c1=9
X-Wing: 9 c37 r27 => r2c459,r7c45<>9
W-Wing: 3/9 in r8c2,r9c9 connected by 9 in r7c37 => r8c8<>3
Locked Candidates Type 2 (Claiming): 3 in c8 => r45c9,r6c7<>3
Naked Single: r4c9=2
Naked Single: r6c7=8
Naked Single: r6c9=1
Naked Single: r5c9=9
Naked Single: r9c9=3
Naked Single: r7c7=9
Full House: r2c7=3
Full House: r8c8=8
Naked Single: r7c3=3
Full House: r8c2=9
Naked Single: r3c8=9
Naked Single: r4c3=6
Naked Single: r7c4=2
Full House: r7c5=8
Naked Single: r6c3=7
Full House: r2c3=9
Full House: r5c2=3
Naked Single: r2c4=7
Naked Single: r5c8=4
Full House: r4c8=3
Full House: r4c5=4
Naked Single: r2c9=8
Full House: r1c9=7
Naked Single: r3c4=6
Naked Single: r5c6=1
Full House: r5c5=7
Naked Single: r9c5=9
Full House: r9c4=4
Naked Single: r2c2=1
Naked Single: r1c2=8
Full House: r3c2=7
Naked Single: r3c5=1
Full House: r3c6=8
Naked Single: r6c4=3
Full House: r1c4=9
Naked Single: r1c5=3
Full House: r1c6=4
Naked Single: r6c6=2
Full House: r6c5=6
Naked Single: r8c5=5
Full House: r2c5=2
Full House: r2c6=5
Full House: r8c6=3
|
normal_sudoku_379
|
.3..1.8...68...4..5....8..3.5...3..89......2...67.......5..9..6....712.....4..18.
|
239514867168937452547268913452193678971685324386742591815329746694871235723456189
|
Basic 9x9 Sudoku 379
|
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 . . 1 . 8 . .
. 6 8 . . . 4 . .
5 . . . . 8 . . 3
. 5 . . . 3 . . 8
9 . . . . . . 2 .
. . 6 7 . . . . .
. . 5 . . 9 . . 6
. . . . 7 1 2 . .
. . . 4 . . 1 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
239514867168937452547268913452193678971685324386742591815329746694871235723456189 #1 Extreme (20218) bf
Hidden Single: r1c7=8
Locked Candidates Type 2 (Claiming): 5 in c7 => r56c9,r6c8<>5
Brute Force: r5c6=5
Hidden Single: r6c7=5
2-String Kite: 3 in r6c1,r7c7 (connected by r5c7,r6c8) => r7c1<>3
Empty Rectangle: 9 in b5 (r34c7) => r3c5<>9
Grouped Discontinuous Nice Loop: 3 r8c1 -3- r9c13 =3= r9c5 =5= r8c4 =6= r8c1 => r8c1<>3
Almost Locked Set XZ-Rule: A=r8c2389 {34589}, B=r1247c1 {12478}, X=8, Z=4 => r8c1<>4
Almost Locked Set XY-Wing: A=r7c457 {2378}, B=r4c13,r5c23,r6c2 {123478}, C=r345c7 {3679}, X,Y=3,7, Z=8 => r7c2<>8
Almost Locked Set XY-Wing: A=r9c12369 {235679}, B=r4c13,r5c23,r6c2 {123478}, C=r8c2389 {34589}, X,Y=5,8, Z=3 => r8c3<>3
Locked Candidates Type 1 (Pointing): 3 in b7 => r9c5<>3
Almost Locked Set XY-Wing: A=r6c25689 {123489}, B=r1247c1 {12478}, C=r8c12389 {345689}, X,Y=3,8, Z=1,2,4 => r6c1<>1, r6c1<>2, r6c1<>4
Almost Locked Set Chain: 4- r7c78 {347} -3- r8c2389 {34589} -8- r4c13,r5c23,r6c2 {123478} -3- r4c78,r5c79,r6c9 {134679} -4 => r6c8<>4
Forcing Chain Contradiction in r8 => r9c5=5
r9c5<>5 r8c4=5 r8c4<>6 r8c1=6 r8c1<>8
r9c5<>5 r8c4=5 r8c4<>3 r8c8=3 r6c8<>3 r6c1=3 r6c1<>8 r78c1=8 r8c2<>8
r9c5<>5 r8c4=5 r8c4<>8
Forcing Chain Contradiction in r8c2 => r7c8<>3
r7c8=3 r7c8<>4 r7c12=4 r8c2<>4
r7c8=3 r6c8<>3 r6c1=3 r6c1<>8 r78c1=8 r8c2<>8
r7c8=3 r7c8<>4 r7c12=4 r8c3<>4 r8c3=9 r8c2<>9
Forcing Net Contradiction in r4 => r2c6=7
r2c6<>7 (r1c6=7 r1c1<>7) r2c6=2 r2c9<>2 r1c9=2 r1c1<>2 r1c1=4 r4c1<>4
r2c6<>7 (r1c6=7 r1c3<>7) (r1c6=7 r1c1<>7) r2c6=2 r2c9<>2 r1c9=2 (r1c3<>2) r1c1<>2 r1c1=4 r1c3<>4 r1c3=9 r8c3<>9 r8c3=4 r4c3<>4
r2c6<>7 r2c6=2 r6c6<>2 r6c6=4 r4c5<>4
r2c6<>7 (r1c6=7 r1c3<>7) (r1c6=7 r1c1<>7) r2c6=2 r2c9<>2 r1c9=2 (r1c3<>2) r1c1<>2 r1c1=4 (r7c1<>4) r1c3<>4 r1c3=9 r8c3<>9 r8c3=4 r7c2<>4 r7c8=4 r4c8<>4
Forcing Chain Contradiction in r2c9 => r2c5<>2
r2c5=2 r2c1<>2 r2c1=1 r2c9<>1
r2c5=2 r2c9<>2
r2c5=2 r2c5<>3 r2c4=3 r8c4<>3 r8c8=3 r8c8<>5 r8c9=5 r2c9<>5
r2c5=2 r2c5<>3 r2c4=3 r8c4<>3 r8c8=3 r8c8<>9 r89c9=9 r2c9<>9
Forcing Net Contradiction in c1 => r8c1=6
r8c1<>6 r8c1<>6
r8c1<>6 (r8c1=8 r6c1<>8 r6c1=3 r9c1<>3 r9c3=3 r9c3<>7) r8c4=6 (r9c6<>6 r9c6=2 r6c6<>2 r6c6=4 r6c9<>4) r8c4<>3 r8c8=3 r8c8<>5 r8c9=5 r8c9<>4 r5c9=4 r5c9<>7 r5c3=7 (r3c3<>7) (r4c1<>7) (r4c3<>7) r5c3<>3 r5c7=3 (r5c7<>7) r7c7<>3 r7c7=7 (r9c9<>7) (r3c7<>7) (r9c9<>7 r9c2=7 r5c2<>7) r4c7<>7 r4c8=7 r3c8<>7 r3c2=7 r9c2<>7 r9c1=7 r9c1<>6
Hidden Single: r9c6=6
Locked Candidates Type 1 (Pointing): 2 in b8 => r7c12<>2
Almost Locked Set XZ-Rule: A=r1c1369 {24579}, B=r2c189 {1259}, X=5, Z=9 => r1c8<>9
Forcing Chain Contradiction in r3 => r3c2<>1
r3c2=1 r3c2<>4
r3c2=1 r3c2<>9 r89c2=9 r8c3<>9 r8c3=4 r3c3<>4
r3c2=1 r2c1<>1 r2c1=2 r2c9<>2 r1c9=2 r1c6<>2 r1c6=4 r3c5<>4
Forcing Chain Contradiction in r3 => r7c2<>4
r7c2=4 r3c2<>4
r7c2=4 r7c2<>1 r7c1=1 r2c1<>1 r3c3=1 r3c3<>4
r7c2=4 r7c2<>1 r7c1=1 r2c1<>1 r2c1=2 r2c9<>2 r1c9=2 r1c6<>2 r1c6=4 r3c5<>4
Forcing Net Verity => r1c8=6
r6c2=1 (r5c2<>1) r7c2<>1 (r7c2=7 r7c8<>7 r7c8=4 r4c8<>4) (r7c2=7 r7c8<>7 r7c8=4 r4c8<>4) (r7c2=7 r5c2<>7) r7c1=1 r7c1<>8 r6c1=8 r5c2<>8 r5c2=4 (r3c2<>4 r3c2=9 r1c3<>9) (r4c1<>4) (r4c1<>4) r4c3<>4 r4c5=4 r6c6<>4 r1c6=4 r1c1<>4 r7c1=4 r7c8<>4 r8c8=4 r7c8<>4 r7c8=7 r9c9<>7 r9c9=9 r1c9<>9 r1c4=9 r1c4<>6 r1c8=6
r6c2=2 (r9c2<>2) (r3c2<>2) r6c6<>2 r1c6=2 (r3c4<>2) r3c5<>2 r3c3=2 r9c3<>2 r9c1=2 (r9c1<>3 r6c1=3 r6c8<>3) r2c1<>2 r2c1=1 (r2c8<>1) r3c3<>1 r3c8=1 r6c8<>1 r6c8=9 r2c8<>9 r2c8=5 (r1c8<>5) r1c9<>5 r1c4=5 r1c4<>6 r1c8=6
r6c2=4 (r3c2<>4) r6c6<>4 r1c6=4 r3c5<>4 r3c3=4 r8c3<>4 r8c3=9 (r1c3<>9) (r9c2<>9) r9c3<>9 r9c9=9 r1c9<>9 r1c4=9 r1c4<>6 r1c8=6
r6c2=8 (r6c1<>8 r6c1=3 r5c3<>3 r5c7=3 r5c7<>6) (r5c2<>8) r8c2<>8 r8c4=8 r5c4<>8 r5c5=8 r5c5<>6 r5c4=6 r1c4<>6 r1c8=6
Grouped Discontinuous Nice Loop: 4 r5c3 -4- r8c3 -9- r1c3 =9= r3c23 -9- r3c7 -7- r7c7 -3- r5c7 =3= r5c3 => r5c3<>4
Grouped Discontinuous Nice Loop: 4 r8c2 -4- r8c3 -9- r1c3 =9= r3c23 -9- r3c7 -7- r7c7 -3- r8c8 =3= r8c4 =8= r8c2 => r8c2<>4
Grouped Discontinuous Nice Loop: 4 r4c3 -4- r8c3 -9- r89c2 =9= r3c2 =4= r56c2 -4- r4c3 => r4c3<>4
Sashimi Swordfish: 4 r347 c158 fr3c2 fr3c3 => r1c1<>4
Sue de Coq: r13c3 - {12479} (r8c3 - {49}, r12c1 - {127}) => r3c2<>2, r3c2<>7, r9c3<>9
AIC: 9 9- r8c3 -4- r1c3 =4= r1c6 =2= r6c6 -2- r6c2 =2= r9c2 =9= r9c9 -9 => r8c89,r9c2<>9
Hidden Single: r9c9=9
Locked Candidates Type 1 (Pointing): 7 in b9 => r7c12<>7
Naked Single: r7c2=1
Locked Candidates Type 2 (Claiming): 1 in r6 => r4c8,r5c9<>1
Empty Rectangle: 7 in b1 (r15c9) => r5c3<>7
Continuous Nice Loop: 2/7 9= r1c3 =4= r1c6 =2= r6c6 -2- r6c2 =2= r9c2 =7= r5c2 -7- r5c9 =7= r1c9 =5= r1c4 =9= r1c3 =4 => r1c349,r6c5<>2, r1c3,r5c7<>7
Hidden Single: r2c9=2
Naked Single: r2c1=1
Hidden Single: r6c9=1
Hidden Single: r3c8=1
Naked Pair: 4,9 in r1c3,r3c2 => r3c3<>4, r3c3<>9
Naked Triple: 3,5,9 in r12c4,r2c5 => r3c4<>9
Skyscraper: 2 in r1c1,r6c2 (connected by r16c6) => r4c1<>2
Swordfish: 2 r347 c345 => r9c3<>2
Skyscraper: 7 in r1c1,r5c2 (connected by r15c9) => r4c1<>7
Naked Single: r4c1=4
Naked Single: r7c1=8
Naked Single: r6c1=3
Naked Single: r8c2=9
Naked Single: r5c3=1
Naked Single: r6c8=9
Naked Single: r3c2=4
Naked Single: r8c3=4
Naked Single: r2c8=5
Naked Single: r4c8=7
Naked Single: r1c3=9
Naked Single: r8c9=5
Naked Single: r1c9=7
Full House: r5c9=4
Full House: r3c7=9
Naked Single: r8c8=3
Full House: r7c8=4
Full House: r7c7=7
Full House: r8c4=8
Naked Single: r4c3=2
Naked Single: r4c7=6
Full House: r5c7=3
Naked Single: r1c4=5
Naked Single: r1c1=2
Full House: r3c3=7
Full House: r1c6=4
Full House: r9c1=7
Full House: r9c3=3
Full House: r6c6=2
Full House: r9c2=2
Naked Single: r5c4=6
Naked Single: r6c2=8
Full House: r5c2=7
Full House: r5c5=8
Full House: r6c5=4
Naked Single: r4c5=9
Full House: r4c4=1
Naked Single: r3c4=2
Full House: r3c5=6
Naked Single: r2c5=3
Full House: r2c4=9
Full House: r7c4=3
Full House: r7c5=2
|
normal_sudoku_2780
|
5.218...46....91......7...2.29.5.4.3.......56.....4.....3..2....41.....8...3.79..
|
592186734637429185418573692129658473374291856856734219963812547741965328285347961
|
Basic 9x9 Sudoku 2780
|
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.
|
5 . 2 1 8 . . . 4
6 . . . . 9 1 . .
. . . . 7 . . . 2
. 2 9 . 5 . 4 . 3
. . . . . . . 5 6
. . . . . 4 . . .
. . 3 . . 2 . . .
. 4 1 . . . . . 8
. . . 3 . 7 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
592186734637429185418573692129658473374291856856734219963812547741965328285347961 #1 Medium (834)
Hidden Single: r1c3=2
Hidden Single: r7c4=8
Hidden Single: r6c9=9
Locked Triple: 5,6,9 in r8c456 => r7c5,r8c1<>9, r8c7<>5, r79c5,r8c78<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r6c45<>6
Hidden Single: r8c5=6
Naked Single: r8c6=5
Naked Single: r8c4=9
Hidden Single: r5c5=9
Locked Pair: 3,6 in r13c6 => r3c4,r4c6<>6, r2c5,r5c6<>3
Hidden Single: r4c4=6
Hidden Single: r6c5=3
Hidden Single: r2c5=2
Locked Candidates Type 1 (Pointing): 1 in b6 => r79c8<>1
Naked Triple: 4,7,8 in r235c3 => r6c3<>7, r69c3<>8
Hidden Pair: 5,6 in r6c23 => r6c2<>1, r6c2<>7, r6c2<>8
Hidden Pair: 3,4 in r35c1 => r35c1<>1, r35c1<>8, r3c1<>9, r5c1<>7
Hidden Single: r3c2=1
Hidden Single: r7c1=9
Hidden Single: r5c6=1
Naked Single: r4c6=8
Hidden Single: r3c8=9
Hidden Single: r1c2=9
Locked Candidates Type 1 (Pointing): 7 in b1 => r2c89<>7
Naked Single: r2c9=5
Naked Single: r2c4=4
Naked Single: r9c9=1
Full House: r7c9=7
Naked Single: r3c4=5
Naked Single: r9c5=4
Full House: r7c5=1
Hidden Single: r7c7=5
Naked Single: r7c2=6
Full House: r7c8=4
Naked Single: r6c2=5
Naked Single: r9c3=5
Naked Single: r6c3=6
Naked Single: r9c2=8
Naked Single: r9c1=2
Full House: r8c1=7
Full House: r9c8=6
Naked Single: r4c1=1
Full House: r4c8=7
Naked Single: r6c1=8
Naked Single: r1c8=3
Naked Single: r6c7=2
Naked Single: r1c6=6
Full House: r1c7=7
Full House: r3c6=3
Naked Single: r2c8=8
Full House: r3c7=6
Naked Single: r8c8=2
Full House: r6c8=1
Full House: r5c7=8
Full House: r6c4=7
Full House: r8c7=3
Full House: r5c4=2
Naked Single: r3c1=4
Full House: r3c3=8
Full House: r5c1=3
Naked Single: r2c3=7
Full House: r2c2=3
Full House: r5c2=7
Full House: r5c3=4
|
normal_sudoku_6896
|
.68..9..2.......7..1.....4.8..39...6..3267.....2..8.....69.2517..9..6.837...5....
|
568479132924183675317625948845391726193267854672548391486932517259716483731854269
|
Basic 9x9 Sudoku 6896
|
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 . . 9 . . 2
. . . . . . . 7 .
. 1 . . . . . 4 .
8 . . 3 9 . . . 6
. . 3 2 6 7 . . .
. . 2 . . 8 . . .
. . 6 9 . 2 5 1 7
. . 9 . . 6 . 8 3
7 . . . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
568479132924183675317625948845391726193267854672548391486932517259716483731854269 #1 Unfair (1322)
Naked Single: r7c8=1
Hidden Single: r6c1=6
Hidden Single: r9c8=6
Hidden Single: r3c3=7
Hidden Single: r4c8=2
Locked Candidates Type 2 (Claiming): 9 in c8 => r5c79,r6c79<>9
Naked Triple: 1,4,5 in r6c459 => r6c27<>4, r6c28<>5, r6c7<>1
2-String Kite: 5 in r1c8,r6c4 (connected by r5c8,r6c9) => r1c4<>5
Turbot Fish: 5 r2c3 =5= r4c3 -5- r4c6 =5= r6c4 => r2c4<>5
XYZ-Wing: 3/4/5 in r17c1,r2c3 => r2c1<>4
Sashimi Swordfish: 1 c369 r249 fr5c9 fr6c9 => r4c7<>1
Sashimi Swordfish: 4 c369 r249 fr5c9 fr6c9 => r4c7<>4
Naked Single: r4c7=7
Naked Single: r6c7=3
Naked Single: r1c7=1
Naked Single: r6c8=9
Naked Single: r5c8=5
Full House: r1c8=3
Naked Single: r6c2=7
Hidden Single: r1c1=5
Naked Single: r2c3=4
Naked Single: r9c3=1
Full House: r4c3=5
Naked Single: r4c2=4
Full House: r4c6=1
Naked Single: r5c2=9
Full House: r5c1=1
Naked Single: r6c5=4
Full House: r6c4=5
Full House: r6c9=1
Naked Single: r1c5=7
Full House: r1c4=4
Naked Single: r8c5=1
Naked Single: r9c4=8
Naked Single: r8c4=7
Naked Single: r3c4=6
Full House: r2c4=1
Naked Single: r7c5=3
Full House: r9c6=4
Naked Single: r7c1=4
Full House: r7c2=8
Naked Single: r9c9=9
Naked Single: r8c1=2
Naked Single: r9c7=2
Full House: r8c7=4
Full House: r8c2=5
Full House: r9c2=3
Full House: r2c2=2
Naked Single: r5c7=8
Full House: r5c9=4
Naked Single: r2c5=8
Full House: r3c5=2
Naked Single: r3c7=9
Full House: r2c7=6
Naked Single: r2c9=5
Full House: r3c9=8
Naked Single: r3c1=3
Full House: r2c1=9
Full House: r2c6=3
Full House: r3c6=5
|
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