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_2172
|
.3.....6.9.85.........39.8..826..7.949......6.7.....2.82.97.41..54.168.....4....7
|
237841965948562371561739284182653749495287136673194528826975413754316892319428657
|
Basic 9x9 Sudoku 2172
|
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 .
9 . 8 5 . . . . .
. . . . 3 9 . 8 .
. 8 2 6 . . 7 . 9
4 9 . . . . . . 6
. 7 . . . . . 2 .
8 2 . 9 7 . 4 1 .
. 5 4 . 1 6 8 . .
. . . 4 . . . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
237841965948562371561739284182653749495287136673194528826975413754316892319428657 #1 Easy (254)
Naked Single: r8c2=5
Hidden Single: r1c7=9
Hidden Single: r6c5=9
Hidden Single: r9c3=9
Hidden Single: r2c5=6
Hidden Single: r7c3=6
Naked Single: r9c2=1
Naked Single: r2c2=4
Full House: r3c2=6
Naked Single: r9c1=3
Full House: r8c1=7
Naked Single: r9c8=5
Naked Single: r5c8=3
Naked Single: r7c9=3
Full House: r7c6=5
Naked Single: r2c8=7
Naked Single: r4c8=4
Full House: r8c8=9
Naked Single: r8c9=2
Full House: r8c4=3
Full House: r9c7=6
Naked Single: r4c5=5
Naked Single: r2c9=1
Naked Single: r4c1=1
Full House: r4c6=3
Naked Single: r2c6=2
Full House: r2c7=3
Naked Single: r5c3=5
Naked Single: r9c6=8
Full House: r9c5=2
Naked Single: r5c7=1
Naked Single: r6c1=6
Full House: r6c3=3
Naked Single: r5c5=8
Full House: r1c5=4
Naked Single: r5c6=7
Full House: r5c4=2
Naked Single: r6c7=5
Full House: r3c7=2
Full House: r6c9=8
Naked Single: r6c4=1
Full House: r6c6=4
Full House: r1c6=1
Naked Single: r1c9=5
Full House: r3c9=4
Naked Single: r3c1=5
Full House: r1c1=2
Naked Single: r3c4=7
Full House: r1c4=8
Full House: r1c3=7
Full House: r3c3=1
|
normal_sudoku_6127
|
....5179...968...1...7....8.....86.....9...7.3.2.7.8..5....7.8....19..569.6...1..
|
638451792759682341241739568497318625185926473362574819513267984874193256926845137
|
Basic 9x9 Sudoku 6127
|
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 7 9 .
. . 9 6 8 . . . 1
. . . 7 . . . . 8
. . . . . 8 6 . .
. . . 9 . . . 7 .
3 . 2 . 7 . 8 . .
5 . . . . 7 . 8 .
. . . 1 9 . . 5 6
9 . 6 . . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
638451792759682341241739568497318625185926473362574819513267984874193256926845137 #1 Extreme (22648) bf
Hidden Single: r3c4=7
Hidden Single: r9c4=8
Hidden Single: r3c6=9
Hidden Single: r3c8=6
Hidden Single: r9c9=7
Hidden Single: r7c7=9
Hidden Single: r7c5=6
Hidden Single: r9c6=5
Locked Candidates Type 1 (Pointing): 5 in b3 => r5c7<>5
Brute Force: r5c2=8
Almost Locked Set XZ-Rule: A=r1c1349 {23468}, B=r2345c1 {12467}, X=6, Z=2 => r1c2<>2
Brute Force: r5c1=1
Hidden Single: r4c5=1
Hidden Single: r6c8=1
Hidden Single: r5c6=6
Naked Single: r6c6=4
Naked Single: r6c4=5
Naked Single: r6c9=9
Full House: r6c2=6
Hidden Single: r1c1=6
Hidden Single: r4c2=9
Hidden Single: r1c3=8
Hidden Single: r8c1=8
Locked Candidates Type 1 (Pointing): 5 in b4 => r3c3<>5
Locked Candidates Type 1 (Pointing): 2 in b7 => r23c2<>2
Turbot Fish: 2 r1c9 =2= r1c4 -2- r4c4 =2= r5c5 => r5c9<>2
Hidden Rectangle: 4/5 in r4c39,r5c39 => r4c9<>4
Discontinuous Nice Loop: 2 r3c7 -2- r3c1 -4- r3c5 =4= r1c4 =2= r1c9 -2- r3c7 => r3c7<>2
Grouped Discontinuous Nice Loop: 3 r8c2 -3- r1c2 -4- r23c1 =4= r4c1 =7= r4c3 -7- r8c3 =7= r8c2 => r8c2<>3
Finned Franken Swordfish: 2 c68b5 r249 fr5c5 fr8c6 => r9c5<>2
Jellyfish: 2 r1479 c2489 => r2c8,r8c2<>2
W-Wing: 3/4 in r1c2,r9c5 connected by 4 in r17c4 => r9c2<>3
2-String Kite: 3 in r2c6,r9c8 (connected by r8c6,r9c5) => r2c8<>3
Naked Single: r2c8=4
Locked Candidates Type 1 (Pointing): 4 in b6 => r5c3<>4
Naked Single: r5c3=5
Hidden Single: r4c9=5
Remote Pair: 3/2 r5c5 -2- r4c4 -3- r4c8 -2- r9c8 => r9c5<>3
Naked Single: r9c5=4
Naked Single: r9c2=2
Full House: r9c8=3
Full House: r4c8=2
Naked Single: r4c4=3
Full House: r5c5=2
Full House: r3c5=3
Naked Single: r7c4=2
Full House: r1c4=4
Full House: r2c6=2
Full House: r8c6=3
Naked Single: r3c7=5
Naked Single: r7c9=4
Full House: r8c7=2
Naked Single: r1c2=3
Full House: r1c9=2
Full House: r2c7=3
Full House: r5c9=3
Full House: r5c7=4
Naked Single: r2c1=7
Full House: r2c2=5
Naked Single: r7c2=1
Full House: r7c3=3
Naked Single: r4c1=4
Full House: r3c1=2
Full House: r4c3=7
Naked Single: r3c2=4
Full House: r3c3=1
Full House: r8c3=4
Full House: r8c2=7
|
normal_sudoku_1856
|
.43.2.97.98......4.....41..3..172...4.1.9...6..9..6..3...2.........3786.7.....3..
|
143628975985713624627954138368172459471395286259846713834261597592437861716589342
|
Basic 9x9 Sudoku 1856
|
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 . 2 . 9 7 .
9 8 . . . . . . 4
. . . . . 4 1 . .
3 . . 1 7 2 . . .
4 . 1 . 9 . . . 6
. . 9 . . 6 . . 3
. . . 2 . . . . .
. . . . 3 7 8 6 .
7 . . . . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
143628975985713624627954138368172459471395286259846713834261597592437861716589342 #1 Hard (1086)
Hidden Single: r1c2=4
Hidden Single: r3c4=9
Hidden Single: r6c8=1
Hidden Single: r2c7=6
Hidden Single: r7c9=7
Hidden Single: r7c2=3
Hidden Single: r1c1=1
Hidden Single: r3c8=3
Hidden Single: r2c4=7
Hidden Single: r1c4=6
Hidden Single: r3c3=7
Hidden Single: r2c6=3
Hidden Single: r5c4=3
Hidden Single: r2c5=1
Hidden Single: r7c6=1
Hidden Single: r7c8=9
Hidden Single: r9c6=9
Hidden Single: r4c9=9
Hidden Single: r8c2=9
Hidden Single: r8c9=1
Hidden Single: r9c2=1
Locked Candidates Type 1 (Pointing): 4 in b5 => r6c7<>4
Locked Candidates Type 1 (Pointing): 2 in b9 => r9c3<>2
Locked Candidates Type 2 (Claiming): 2 in c7 => r5c8<>2
Naked Pair: 5,8 in r5c68 => r5c27<>5
Naked Pair: 4,5 in r47c7 => r6c7<>5
Remote Pair: 5/8 r1c9 -8- r1c6 -5- r5c6 -8- r5c8 => r2c8<>5
Naked Single: r2c8=2
Full House: r2c3=5
Hidden Single: r8c3=2
Naked Single: r8c1=5
Full House: r8c4=4
Hidden Single: r9c9=2
Hidden Single: r6c5=4
Remote Pair: 5/8 r5c8 -8- r5c6 -5- r6c4 -8- r9c4 => r9c8<>5
Naked Single: r9c8=4
Full House: r7c7=5
Naked Single: r4c7=4
Hidden Single: r7c3=4
Skyscraper: 8 in r6c4,r7c5 (connected by r67c1) => r9c4<>8
Naked Single: r9c4=5
Full House: r6c4=8
Full House: r5c6=5
Full House: r1c6=8
Full House: r1c9=5
Full House: r3c5=5
Full House: r3c9=8
Naked Single: r6c1=2
Naked Single: r5c8=8
Full House: r4c8=5
Naked Single: r3c1=6
Full House: r3c2=2
Full House: r7c1=8
Full House: r7c5=6
Full House: r9c3=6
Full House: r9c5=8
Full House: r4c3=8
Full House: r4c2=6
Naked Single: r5c2=7
Full House: r5c7=2
Full House: r6c7=7
Full House: r6c2=5
|
normal_sudoku_2867
|
....87..19..2.....285..1..3..3.9..2.........7....36.4.6.75...8..4.......31...2..5
|
436987251971253864285641793753498126864125937192736548627514389548379612319862475
|
Basic 9x9 Sudoku 2867
|
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 7 . . 1
9 . . 2 . . . . .
2 8 5 . . 1 . . 3
. . 3 . 9 . . 2 .
. . . . . . . . 7
. . . . 3 6 . 4 .
6 . 7 5 . . . 8 .
. 4 . . . . . . .
3 1 . . . 2 . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
436987251971253864285641793753498126864125937192736548627514389548379612319862475 #1 Medium (644)
Naked Single: r7c1=6
Naked Single: r1c1=4
Naked Single: r1c3=6
Naked Single: r1c2=3
Naked Single: r2c3=1
Full House: r2c2=7
Naked Single: r1c4=9
Naked Single: r1c8=5
Full House: r1c7=2
Naked Single: r2c8=6
Hidden Single: r8c1=5
Hidden Single: r5c5=2
Hidden Single: r5c3=4
Hidden Single: r8c4=3
Hidden Single: r2c6=3
Hidden Single: r2c5=5
Hidden Single: r7c7=3
Hidden Single: r5c8=3
Hidden Single: r7c5=1
Hidden Single: r8c8=1
Locked Candidates Type 1 (Pointing): 4 in b2 => r3c7<>4
Locked Candidates Type 1 (Pointing): 7 in b5 => r9c4<>7
Locked Candidates Type 1 (Pointing): 8 in b7 => r6c3<>8
Naked Pair: 1,8 in r5c14 => r5c67<>8, r5c7<>1
Naked Single: r5c6=5
Naked Triple: 6,8,9 in r46c9,r5c7 => r4c7<>6, r46c7<>8, r6c7<>9
Hidden Single: r2c7=8
Full House: r2c9=4
Hidden Single: r9c7=4
Hidden Single: r7c6=4
Naked Single: r4c6=8
Full House: r8c6=9
Naked Single: r4c9=6
Naked Single: r5c4=1
Naked Single: r4c2=5
Naked Single: r5c7=9
Naked Single: r8c9=2
Naked Single: r5c1=8
Full House: r5c2=6
Naked Single: r6c4=7
Full House: r4c4=4
Naked Single: r4c7=1
Full House: r4c1=7
Full House: r6c1=1
Naked Single: r3c7=7
Full House: r3c8=9
Full House: r9c8=7
Naked Single: r6c9=8
Full House: r7c9=9
Full House: r6c7=5
Full House: r8c7=6
Full House: r7c2=2
Full House: r6c2=9
Full House: r6c3=2
Naked Single: r8c3=8
Full House: r8c5=7
Full House: r9c3=9
Naked Single: r3c4=6
Full House: r3c5=4
Full House: r9c5=6
Full House: r9c4=8
|
normal_sudoku_5370
|
........9..5..4..88..1..4..4.....8.73.9...1...78.26..4.347.....7....15...812437.6
|
247538619915674328863192475426915837359487162178326954634759281792861543581243796
|
Basic 9x9 Sudoku 5370
|
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
. . 5 . . 4 . . 8
8 . . 1 . . 4 . .
4 . . . . . 8 . 7
3 . 9 . . . 1 . .
. 7 8 . 2 6 . . 4
. 3 4 7 . . . . .
7 . . . . 1 5 . .
. 8 1 2 4 3 7 . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
247538619915674328863192475426915837359487162178326954634759281792861543581243796 #1 Hard (984)
Naked Single: r6c3=8
Naked Single: r9c8=9
Full House: r9c1=5
Naked Single: r7c7=2
Naked Single: r6c1=1
Naked Single: r7c9=1
Naked Single: r8c9=3
Naked Single: r7c8=8
Full House: r8c8=4
Hidden Single: r1c2=4
Hidden Single: r4c5=1
Hidden Single: r5c4=4
Hidden Single: r6c7=9
Hidden Single: r1c8=1
Hidden Single: r2c2=1
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c56<>5
Locked Candidates Type 1 (Pointing): 3 in b5 => r12c4<>3
Locked Candidates Type 1 (Pointing): 3 in b6 => r23c8<>3
Locked Candidates Type 1 (Pointing): 6 in b6 => r23c8<>6
Locked Candidates Type 2 (Claiming): 2 in c1 => r13c3,r3c2<>2
Naked Pair: 2,6 in r48c3 => r13c3<>6
Naked Pair: 5,9 in r47c6 => r15c6<>5, r3c6<>9
Naked Triple: 3,5,9 in r4c46,r6c4 => r5c5<>5
Naked Triple: 2,5,7 in r3c689 => r3c35<>7
Naked Single: r3c3=3
Naked Single: r1c3=7
Naked Pair: 6,9 in r2c4,r3c5 => r1c45,r2c5<>6, r2c5<>9
Skyscraper: 6 in r3c2,r7c1 (connected by r37c5) => r12c1,r8c2<>6
Naked Single: r1c1=2
Naked Single: r1c6=8
Naked Single: r2c1=9
Full House: r3c2=6
Full House: r7c1=6
Naked Single: r1c4=5
Naked Single: r5c6=7
Naked Single: r2c4=6
Naked Single: r3c5=9
Naked Single: r8c3=2
Full House: r4c3=6
Full House: r8c2=9
Naked Single: r1c5=3
Full House: r1c7=6
Full House: r2c7=3
Naked Single: r6c4=3
Full House: r6c8=5
Naked Single: r3c6=2
Full House: r2c5=7
Full House: r2c8=2
Naked Single: r5c5=8
Naked Single: r7c5=5
Full House: r8c5=6
Full House: r8c4=8
Full House: r4c4=9
Full House: r7c6=9
Full House: r4c6=5
Naked Single: r5c9=2
Full House: r3c9=5
Full House: r3c8=7
Naked Single: r4c8=3
Full House: r5c8=6
Full House: r4c2=2
Full House: r5c2=5
|
normal_sudoku_349
|
48.2..3.6.6.7....8....4.5.2.9....6..1...63..5356.8..2...7..54.....8...53.........
|
481259376265731948973648512798512634142963785356487129827395461619874253534126897
|
Basic 9x9 Sudoku 349
|
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 . 2 . . 3 . 6
. 6 . 7 . . . . 8
. . . . 4 . 5 . 2
. 9 . . . . 6 . .
1 . . . 6 3 . . 5
3 5 6 . 8 . . 2 .
. . 7 . . 5 4 . .
. . . 8 . . . 5 3
. . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
481259376265731948973648512798512634142963785356487129827395461619874253534126897 #1 Extreme (2746)
Hidden Single: r6c3=6
Hidden Single: r1c8=7
Hidden Single: r4c4=5
Hidden Single: r2c8=4
Hidden Single: r3c6=8
Hidden Single: r4c8=3
Hidden Single: r3c4=6
Hidden Single: r2c5=3
Hidden Single: r1c5=5
Locked Candidates Type 1 (Pointing): 1 in b2 => r4689c6<>1
Locked Candidates Type 1 (Pointing): 9 in b2 => r689c6<>9
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c13<>2
Locked Candidates Type 1 (Pointing): 9 in b5 => r79c4<>9
Locked Candidates Type 1 (Pointing): 8 in b6 => r5c3<>8
Naked Pair: 1,9 in r2c67 => r2c13<>9, r2c3<>1
Hidden Pair: 6,8 in r7c18 => r7c1<>2, r7c18<>9, r7c8<>1
Empty Rectangle: 1 in b1 (r39c8) => r9c3<>1
W-Wing: 9/1 in r2c7,r7c9 connected by 1 in r39c8 => r89c7<>9
Uniqueness Test 4: 2/5 in r2c13,r9c13 => r9c13<>2
XY-Chain: 9 9- r2c7 -1- r3c8 -9- r3c1 -7- r4c1 -8- r7c1 -6- r7c8 -8- r5c8 -9 => r3c8,r56c7<>9
Naked Single: r3c8=1
Full House: r2c7=9
Naked Single: r2c6=1
Full House: r1c6=9
Full House: r1c3=1
Sue de Coq: r6c46 - {1479} (r6c7 - {17}, r5c4 - {49}) => r4c6<>4, r6c9<>1, r6c9<>7
2-String Kite: 7 in r6c6,r9c9 (connected by r4c9,r6c7) => r9c6<>7
XY-Chain: 1 1- r6c7 -7- r6c6 -4- r6c9 -9- r7c9 -1 => r4c9,r89c7<>1
Hidden Single: r4c5=1
Hidden Single: r6c7=1
Hidden Single: r8c2=1
Hidden Single: r4c6=2
Hidden Single: r6c6=7
Locked Candidates Type 1 (Pointing): 4 in b5 => r9c4<>4
XY-Chain: 2 2- r5c3 -4- r5c4 -9- r6c4 -4- r6c9 -9- r7c9 -1- r7c4 -3- r7c2 -2 => r5c2,r8c3<>2
Hidden Single: r5c3=2
Naked Single: r2c3=5
Full House: r2c1=2
Hidden Single: r9c1=5
Naked Triple: 4,6,9 in r8c136 => r8c5<>9
Locked Candidates Type 2 (Claiming): 9 in r8 => r9c3<>9
XY-Chain: 7 7- r3c2 -3- r3c3 -9- r8c3 -4- r4c3 -8- r4c1 -7 => r3c1,r5c2<>7
Naked Single: r3c1=9
Naked Single: r5c2=4
Naked Single: r3c3=3
Full House: r3c2=7
Naked Single: r8c1=6
Naked Single: r4c3=8
Full House: r4c1=7
Full House: r7c1=8
Full House: r4c9=4
Naked Single: r5c4=9
Full House: r6c4=4
Full House: r6c9=9
Naked Single: r8c6=4
Full House: r9c6=6
Naked Single: r9c3=4
Full House: r8c3=9
Naked Single: r7c8=6
Naked Single: r5c8=8
Full House: r5c7=7
Full House: r9c8=9
Naked Single: r7c9=1
Full House: r9c9=7
Naked Single: r8c7=2
Full House: r8c5=7
Full House: r9c7=8
Naked Single: r7c4=3
Full House: r9c4=1
Naked Single: r9c5=2
Full House: r7c5=9
Full House: r7c2=2
Full House: r9c2=3
|
normal_sudoku_3358
|
.3.......4....9.85..5.......8...61...6.7.892.7...4..6..5...4...9..8...46....9.2.1
|
638257419472169385195483672384926157561738924729541863256314798913872546847695231
|
Basic 9x9 Sudoku 3358
|
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 . . . . 9 . 8 5
. . 5 . . . . . .
. 8 . . . 6 1 . .
. 6 . 7 . 8 9 2 .
7 . . . 4 . . 6 .
. 5 . . . 4 . . .
9 . . 8 . . . 4 6
. . . . 9 . 2 . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
638257419472169385195483672384926157561738924729541863256314798913872546847695231 #1 Extreme (40264) bf
Locked Candidates Type 1 (Pointing): 4 in b6 => r13c9<>4
Locked Candidates Type 1 (Pointing): 8 in b9 => r7c13<>8
Hidden Rectangle: 3/8 in r6c79,r7c79 => r7c7<>3
Brute Force: r5c2=6
Hidden Single: r9c2=4
Hidden Rectangle: 3/4 in r4c39,r5c39 => r4c3<>3
Brute Force: r5c1=5
Forcing Chain Contradiction in c6 => r8c3<>1
r8c3=1 r7c1<>1 r13c1=1 r2c23<>1 r2c45=1 r1c6<>1
r8c3=1 r7c1<>1 r13c1=1 r2c23<>1 r2c45=1 r3c6<>1
r8c3=1 r5c3<>1 r5c5=1 r6c6<>1
r8c3=1 r8c6<>1
Forcing Net Contradiction in c6 => r4c4<>3
r4c4=3 (r4c5<>3) r4c1<>3 r4c1=2 r4c5<>2 r4c5=5 r1c5<>5 r1c6=5
r4c4=3 (r4c5<>3) r4c1<>3 r4c1=2 r4c5<>2 r4c5=5 (r8c5<>5) r4c8<>5 r9c8=5 r8c7<>5 r8c6=5
Brute Force: r4c9=7
Hidden Single: r4c3=4
Hidden Single: r5c9=4
Hidden Single: r4c4=9
2-String Kite: 5 in r4c5,r8c7 (connected by r4c8,r6c7) => r8c5<>5
Simple Colors Trap: 5 (r1c5,r4c8,r8c7) / (r4c5,r6c7,r8c6,r9c8) => r1c6<>5
Forcing Chain Verity => r1c5<>1
r8c2=1 r7c1<>1 r13c1=1 r2c23<>1 r2c45=1 r1c5<>1
r8c5=1 r1c5<>1
r8c6=1 r8c6<>5 r8c7=5 r6c7<>5 r4c8=5 r4c5<>5 r1c5=5 r1c5<>1
Forcing Chain Verity => r3c5<>1
r8c2=1 r7c1<>1 r13c1=1 r2c23<>1 r2c45=1 r3c5<>1
r8c5=1 r3c5<>1
r8c6=1 r8c6<>5 r8c7=5 r6c7<>5 r4c8=5 r4c5<>5 r1c5=5 r1c5<>8 r3c5=8 r3c5<>1
Forcing Chain Contradiction in r8 => r3c5<>3
r3c5=3 r5c5<>3 r5c3=3 r8c3<>3
r3c5=3 r8c5<>3
r3c5=3 r3c5<>8 r1c5=8 r1c5<>5 r4c5=5 r4c8<>5 r9c8=5 r8c7<>5 r8c6=5 r8c6<>3
r3c5=3 r2c45<>3 r2c7=3 r8c7<>3
Forcing Net Contradiction in r4c8 => r1c3<>1
r1c3=1 (r3c1<>1 r7c1=1 r8c2<>1) r5c3<>1 r5c5=1 r8c5<>1 r8c6=1 (r8c6<>3) r8c6<>5 r8c7=5 r8c7<>3 r8c5=3 (r4c5<>3) r5c5<>3 r5c3=3 (r8c3<>3) r4c1<>3 r4c8=3
r1c3=1 (r3c1<>1 r7c1=1 r8c2<>1) r5c3<>1 r5c5=1 r8c5<>1 r8c6=1 r8c6<>5 r8c7=5 r9c8<>5 r4c8=5
Forcing Net Contradiction in r7c8 => r1c5<>2
r1c5=2 (r4c5<>2 r4c1=2 r6c2<>2) r1c9<>2 r1c9=9 r1c3<>9 r6c3=9 r6c2<>9 r6c2=1 (r8c2<>1) r5c3<>1 r5c5=1 r8c5<>1 r8c6=1 r8c6<>5 r8c7=5 r9c8<>5 r4c8=5 r4c5<>5 r1c5=5 r1c5<>2
Forcing Net Contradiction in r4c8 => r2c3<>1
r2c3=1 (r3c1<>1 r7c1=1 r8c2<>1) r5c3<>1 r5c5=1 r8c5<>1 r8c6=1 (r8c6<>3) r8c6<>5 r8c7=5 r8c7<>3 r8c5=3 (r4c5<>3) r5c5<>3 r5c3=3 (r8c3<>3) r4c1<>3 r4c8=3
r2c3=1 (r3c1<>1 r7c1=1 r8c2<>1) r5c3<>1 r5c5=1 r8c5<>1 r8c6=1 r8c6<>5 r8c7=5 r9c8<>5 r4c8=5
Forcing Net Verity => r5c3=1
r4c5=3 (r5c5<>3 r5c5=1 r8c5<>1) (r5c5<>3 r5c5=1 r7c5<>1) (r5c5<>3 r5c5=1 r8c5<>1) (r8c5<>3) (r5c5<>3 r5c3=3 r8c3<>3) r4c8<>3 r4c8=5 r6c7<>5 r8c7=5 r8c7<>3 r8c6=3 r8c6<>1 r8c2=1 (r7c1<>1) r7c3<>1 r7c4=1 (r2c4<>1) r8c6<>1 r8c2=1 (r7c1<>1) r2c2<>1 r2c5=1 r5c5<>1 r5c3=1
r5c5=3 r5c3<>3 r5c3=1
r6c4=3 (r5c5<>3 r5c5=1 r8c5<>1) (r5c5<>3 r5c5=1 r7c5<>1) (r5c5<>3 r5c5=1 r8c5<>1) (r6c7<>3) r6c9<>3 r6c9=8 r6c7<>8 r6c7=5 r8c7<>5 r8c6=5 r8c6<>1 r8c2=1 (r7c1<>1) r7c3<>1 r7c4=1 (r2c4<>1) r8c6<>1 r8c2=1 (r7c1<>1) r2c2<>1 r2c5=1 r5c5<>1 r5c3=1
r6c6=3 (r5c5<>3 r5c5=1 r8c5<>1) (r5c5<>3 r5c5=1 r7c5<>1) (r5c5<>3 r5c5=1 r8c5<>1) (r6c7<>3) r6c9<>3 r6c9=8 r6c7<>8 r6c7=5 r8c7<>5 r8c6=5 r8c6<>1 r8c2=1 (r7c1<>1) r7c3<>1 r7c4=1 (r2c4<>1) r8c6<>1 r8c2=1 (r7c1<>1) r2c2<>1 r2c5=1 r5c5<>1 r5c3=1
Full House: r5c5=3
Almost Locked Set XY-Wing: A=r8c235 {1237}, B=r12367c7 {345678}, C=r6c2346 {12359}, X,Y=3,5, Z=7 => r8c7<>7
Forcing Chain Contradiction in r1 => r3c5<>7
r3c5=7 r3c5<>8 r1c5=8 r1c5<>5 r4c5=5 r4c5<>2 r4c1=2 r4c1<>3 r6c3=3 r6c3<>9 r1c3=9 r1c3<>7
r3c5=7 r1c5<>7
r3c5=7 r1c6<>7
r3c5=7 r3c5<>8 r1c5=8 r1c5<>5 r1c4=5 r1c4<>4 r1c7=4 r1c7<>7
r3c5=7 r3c5<>8 r1c5=8 r1c5<>5 r4c5=5 r4c8<>5 r6c7=5 r6c7<>8 r7c7=8 r7c7<>7 r123c7=7 r1c8<>7
Forcing Chain Contradiction in c6 => r9c1<>3
r9c1=3 r4c1<>3 r4c8=3 r4c8<>5 r9c8=5 r8c7<>5 r8c7=3 r2c7<>3 r2c4=3 r3c6<>3
r9c1=3 r4c1<>3 r4c8=3 r4c8<>5 r9c8=5 r8c7<>5 r8c7=3 r8c6<>3
r9c1=3 r9c6<>3
Forcing Chain Contradiction in r9c4 => r1c5=5
r1c5<>5 r4c5=5 r4c8<>5 r9c8=5 r8c7<>5 r8c7=3 r2c7<>3 r2c4=3 r9c4<>3
r1c5<>5 r1c4=5 r9c4<>5
r1c5<>5 r4c5=5 r4c5<>2 r4c1=2 r4c1<>3 r6c3=3 r6c3<>9 r1c3=9 r1c3<>8 r9c3=8 r9c1<>8 r9c1=6 r9c4<>6
Naked Single: r4c5=2
Naked Single: r4c1=3
Full House: r4c8=5
Hidden Single: r3c5=8
Hidden Single: r8c7=5
Uniqueness Test 4: 3/8 in r6c79,r7c79 => r7c9<>3
Locked Candidates Type 1 (Pointing): 3 in b9 => r3c8<>3
Hidden Rectangle: 6/8 in r1c13,r9c13 => r1c3<>6
Empty Rectangle: 6 in b1 (r27c5) => r7c1<>6
Finned Swordfish: 2 r267 c234 fr7c1 => r8c23<>2
Hidden Single: r8c6=2
Hidden Single: r8c3=3
Continuous Nice Loop: 3/7 9= r7c8 =3= r7c4 -3- r2c4 =3= r2c7 -3- r6c7 -8- r6c9 =8= r7c9 =9= r7c8 =3 => r3c47,r9c4<>3, r7c8<>7
Discontinuous Nice Loop: 1 r3c2 -1- r8c2 =1= r7c1 =2= r7c3 -2- r6c3 -9- r6c2 =9= r3c2 => r3c2<>1
Discontinuous Nice Loop: 1 r7c4 -1- r6c4 -5- r6c6 =5= r9c6 =3= r7c4 => r7c4<>1
Locked Candidates Type 1 (Pointing): 1 in b8 => r2c5<>1
Discontinuous Nice Loop: 2/7 r3c2 =9= r6c2 =2= r6c3 -2- r7c3 =2= r7c1 =1= r8c2 -1- r2c2 =1= r2c4 -1- r6c4 -5- r9c4 -6- r9c1 -8- r9c3 =8= r1c3 =9= r3c2 => r3c2<>2, r3c2<>7
Naked Single: r3c2=9
Naked Single: r6c2=2
Full House: r6c3=9
Continuous Nice Loop: 2/3/6 2= r2c4 =1= r2c2 -1- r8c2 =1= r7c1 =2= r7c3 -2- r2c3 =2= r2c4 =1 => r1c3<>2, r2c4<>3, r2c4<>6
Hidden Single: r2c7=3
Naked Single: r3c9=2
Naked Single: r6c7=8
Full House: r6c9=3
Naked Single: r1c9=9
Full House: r7c9=8
Naked Single: r7c7=7
Naked Single: r9c8=3
Full House: r7c8=9
Hidden Single: r7c4=3
Hidden Single: r3c6=3
Hidden Single: r3c8=7
Full House: r1c8=1
Naked Single: r1c6=7
Naked Single: r1c3=8
Naked Single: r2c5=6
Naked Single: r9c6=5
Full House: r6c6=1
Full House: r6c4=5
Naked Single: r7c5=1
Full House: r8c5=7
Full House: r9c4=6
Full House: r8c2=1
Full House: r2c2=7
Naked Single: r7c1=2
Full House: r7c3=6
Naked Single: r9c1=8
Full House: r9c3=7
Full House: r2c3=2
Full House: r2c4=1
Naked Single: r1c1=6
Full House: r3c1=1
Naked Single: r3c4=4
Full House: r1c4=2
Full House: r1c7=4
Full House: r3c7=6
|
normal_sudoku_5490
|
..583.2..4....9..8.891......1...5...9..41......3.7.6....6....25.2....3...9..2..76
|
675834291431259768289167543714685932962413857853972614346798125127546389598321476
|
Basic 9x9 Sudoku 5490
|
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 8 3 . 2 . .
4 . . . . 9 . . 8
. 8 9 1 . . . . .
. 1 . . . 5 . . .
9 . . 4 1 . . . .
. . 3 . 7 . 6 . .
. . 6 . . . . 2 5
. 2 . . . . 3 . .
. 9 . . 2 . . 7 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
675834291431259768289167543714685932962413857853972614346798125127546389598321476 #1 Extreme (3020)
Hidden Single: r3c3=9
Locked Candidates Type 1 (Pointing): 5 in b7 => r6c1<>5
Naked Pair: 2,8 in r6c16 => r6c49<>2, r6c8<>8
Naked Single: r6c4=9
X-Wing: 2 r36 c16 => r4c1,r5c6<>2
Discontinuous Nice Loop: 6/7 r2c2 =3= r7c2 =4= r6c2 =5= r5c2 =6= r5c6 =3= r4c4 =2= r2c4 -2- r2c3 =2= r3c1 =3= r2c2 => r2c2<>6, r2c2<>7
Naked Single: r2c2=3
AIC: 4 4- r4c3 =4= r6c2 =5= r5c2 =6= r5c6 =3= r4c4 -3- r7c4 -7- r7c2 -4 => r6c2,r89c3<>4
Naked Single: r6c2=5
Hidden Single: r7c2=4
Hidden Single: r4c3=4
Skyscraper: 4 in r8c5,r9c7 (connected by r3c57) => r8c89,r9c6<>4
Hidden Single: r9c7=4
Turbot Fish: 1 r1c1 =1= r2c3 -1- r2c7 =1= r7c7 => r7c1<>1
Finned X-Wing: 8 r69 c16 fr9c3 => r78c1<>8
Naked Pair: 3,7 in r7c14 => r7c6<>3, r7c6<>7
Discontinuous Nice Loop: 1 r1c8 -1- r6c8 =1= r6c9 -1- r8c9 -9- r1c9 =9= r1c8 => r1c8<>1
Discontinuous Nice Loop: 5 r2c4 -5- r2c5 -6- r4c5 -8- r6c6 -2- r3c6 =2= r2c4 => r2c4<>5
Locked Candidates Type 1 (Pointing): 5 in b2 => r8c5<>5
Discontinuous Nice Loop: 7 r3c1 -7- r1c2 -6- r5c2 =6= r5c6 =3= r4c4 =2= r2c4 -2- r2c3 =2= r3c1 => r3c1<>7
Almost Locked Set XZ-Rule: A=r4c5 {68}, B=r579c6 {1368}, X=6, Z=8 => r6c6<>8
Naked Single: r6c6=2
Naked Single: r6c1=8
Hidden Single: r3c1=2
Hidden Single: r2c4=2
Hidden Single: r4c9=2
Hidden Single: r5c3=2
Locked Candidates Type 1 (Pointing): 6 in b1 => r1c68<>6
Locked Candidates Type 1 (Pointing): 7 in b2 => r8c6<>7
Swordfish: 7 c269 r135 => r1c1,r35c7<>7
Naked Single: r3c7=5
Naked Single: r5c7=8
Hidden Single: r2c5=5
Hidden Single: r5c8=5
Hidden Single: r4c5=8
Naked Single: r7c5=9
Naked Single: r7c7=1
Naked Single: r2c7=7
Full House: r4c7=9
Naked Single: r7c6=8
Naked Single: r8c9=9
Full House: r8c8=8
Naked Single: r2c3=1
Full House: r2c8=6
Naked Single: r4c8=3
Naked Single: r1c1=6
Full House: r1c2=7
Full House: r5c2=6
Full House: r4c1=7
Full House: r4c4=6
Full House: r5c6=3
Full House: r5c9=7
Naked Single: r8c3=7
Full House: r9c3=8
Naked Single: r3c8=4
Naked Single: r1c6=4
Naked Single: r7c1=3
Full House: r7c4=7
Naked Single: r9c6=1
Naked Single: r8c4=5
Full House: r9c4=3
Full House: r9c1=5
Full House: r8c1=1
Naked Single: r1c8=9
Full House: r1c9=1
Full House: r3c9=3
Full House: r6c8=1
Full House: r6c9=4
Naked Single: r3c5=6
Full House: r3c6=7
Full House: r8c6=6
Full House: r8c5=4
|
normal_sudoku_2356
|
..9548.71872.9..........893..5...4.7..893....1.7.2........5.3.99.1.8...5...6...2.
|
369548271872193654514762893295816437648937512137425986786251349921384765453679128
|
Basic 9x9 Sudoku 2356
|
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 5 4 8 . 7 1
8 7 2 . 9 . . . .
. . . . . . 8 9 3
. . 5 . . . 4 . 7
. . 8 9 3 . . . .
1 . 7 . 2 . . . .
. . . . 5 . 3 . 9
9 . 1 . 8 . . . 5
. . . 6 . . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
369548271872193654514762893295816437648937512137425986786251349921384765453679128 #1 Hard (544)
Hidden Single: r1c6=8
Hidden Single: r1c7=2
Hidden Single: r5c6=7
Hidden Single: r6c7=9
Hidden Single: r4c2=9
Hidden Single: r9c6=9
Hidden Single: r3c2=1
Hidden Single: r9c3=3
Hidden Single: r5c9=2
Hidden Single: r6c6=5
Hidden Single: r4c1=2
Hidden Single: r3c1=5
Hidden Single: r9c2=5
Hidden Single: r6c4=4
Hidden Single: r4c8=3
Hidden Single: r1c1=3
Full House: r1c2=6
Full House: r3c3=4
Full House: r7c3=6
Naked Single: r5c2=4
Naked Single: r6c2=3
Full House: r5c1=6
Naked Single: r8c2=2
Full House: r7c2=8
Hidden Single: r9c9=8
Naked Single: r6c9=6
Full House: r2c9=4
Full House: r6c8=8
Hidden Single: r4c4=8
Hidden Single: r9c1=4
Full House: r7c1=7
Locked Candidates Type 1 (Pointing): 6 in b3 => r2c6<>6
Bivalue Universal Grave + 1 => r7c6<>2, r7c6<>4
Naked Single: r7c6=1
Naked Single: r2c6=3
Naked Single: r4c6=6
Full House: r4c5=1
Naked Single: r7c4=2
Full House: r7c8=4
Naked Single: r9c5=7
Full House: r3c5=6
Full House: r9c7=1
Naked Single: r2c4=1
Naked Single: r8c6=4
Full House: r3c6=2
Full House: r3c4=7
Full House: r8c4=3
Naked Single: r8c8=6
Full House: r8c7=7
Naked Single: r5c7=5
Full House: r2c7=6
Full House: r2c8=5
Full House: r5c8=1
|
normal_sudoku_1917
|
1...9..5...4..86.998........4...3.....38214..8...6.3.2..8..25.6...7......5....2..
|
136294758724518639985637124241973865563821497879465312398142576412756983657389241
|
Basic 9x9 Sudoku 1917
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . . . 9 . . 5 .
. . 4 . . 8 6 . 9
9 8 . . . . . . .
. 4 . . . 3 . . .
. . 3 8 2 1 4 . .
8 . . . 6 . 3 . 2
. . 8 . . 2 5 . 6
. . . 7 . . . . .
. 5 . . . . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
136294758724518639985637124241973865563821497879465312398142576412756983657389241 #1 Extreme (11066) bf
Brute Force: r5c6=1
2-String Kite: 9 in r5c2,r8c7 (connected by r4c7,r5c8) => r8c2<>9
Finned Franken Swordfish: 9 r57b5 c248 fr6c6 => r6c28<>9
Naked Pair: 1,7 in r6c28 => r6c3<>1, r6c36<>7
Hidden Single: r4c5=7
Locked Candidates Type 2 (Claiming): 7 in c7 => r13c9,r23c8<>7
Locked Candidates Type 2 (Claiming): 7 in r2 => r1c23,r3c3<>7
Hidden Single: r9c3=7
Hidden Single: r7c8=7
Naked Single: r6c8=1
Naked Single: r6c2=7
Hidden Single: r5c9=7
Hidden Single: r4c3=1
Hidden Single: r2c1=7
Hidden Single: r5c1=5
Naked Single: r6c3=9
Naked Single: r5c2=6
Full House: r4c1=2
Full House: r5c8=9
Naked Single: r4c7=8
Naked Single: r1c7=7
Naked Single: r4c8=6
Full House: r4c9=5
Full House: r4c4=9
Naked Single: r3c7=1
Full House: r8c7=9
Hidden Single: r3c3=5
Hidden Single: r7c2=9
Hidden Single: r1c9=8
Hidden Single: r3c6=7
Hidden Single: r9c6=9
Hidden Single: r1c3=6
Full House: r8c3=2
Naked Single: r1c6=4
Naked Single: r3c5=3
Naked Single: r6c6=5
Full House: r6c4=4
Full House: r8c6=6
Naked Single: r1c4=2
Full House: r1c2=3
Full House: r2c2=2
Full House: r8c2=1
Naked Single: r3c9=4
Naked Single: r3c4=6
Full House: r3c8=2
Full House: r2c8=3
Naked Single: r8c9=3
Full House: r9c9=1
Naked Single: r8c1=4
Naked Single: r9c4=3
Naked Single: r7c1=3
Full House: r9c1=6
Naked Single: r8c8=8
Full House: r8c5=5
Full House: r9c8=4
Full House: r9c5=8
Naked Single: r7c4=1
Full House: r2c4=5
Full House: r2c5=1
Full House: r7c5=4
|
normal_sudoku_223
|
2.7....5.....5.3.145...6..27.318........9...7.4672.89..1......6..5......8..419...
|
237841659689257341451936782793185264528694137146723895314578926975362418862419573
|
Basic 9x9 Sudoku 223
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . 7 . . . . 5 .
. . . . 5 . 3 . 1
4 5 . . . 6 . . 2
7 . 3 1 8 . . . .
. . . . 9 . . . 7
. 4 6 7 2 . 8 9 .
. 1 . . . . . . 6
. . 5 . . . . . .
8 . . 4 1 9 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
237841659689257341451936782793185264528694137146723895314578926975362418862419573 #1 Easy (322)
Naked Single: r6c2=4
Naked Single: r9c3=2
Hidden Single: r1c2=3
Naked Single: r1c5=4
Hidden Single: r5c4=6
Hidden Single: r4c2=9
Hidden Single: r3c3=1
Naked Single: r5c3=8
Naked Single: r2c3=9
Full House: r7c3=4
Naked Single: r5c2=2
Naked Single: r2c1=6
Full House: r2c2=8
Naked Single: r2c4=2
Naked Single: r2c6=7
Full House: r2c8=4
Naked Single: r3c5=3
Naked Single: r7c5=7
Full House: r8c5=6
Naked Single: r8c2=7
Full House: r9c2=6
Hidden Single: r6c1=1
Full House: r5c1=5
Hidden Single: r1c6=1
Hidden Single: r1c7=6
Hidden Single: r7c4=5
Hidden Single: r4c8=6
Hidden Single: r8c4=3
Naked Single: r8c1=9
Full House: r7c1=3
Hidden Single: r4c7=2
Naked Single: r7c7=9
Naked Single: r3c7=7
Naked Single: r3c8=8
Full House: r1c9=9
Full House: r3c4=9
Full House: r1c4=8
Naked Single: r9c7=5
Naked Single: r7c8=2
Full House: r7c6=8
Full House: r8c6=2
Naked Single: r9c9=3
Full House: r9c8=7
Naked Single: r8c8=1
Full House: r5c8=3
Naked Single: r6c9=5
Full House: r6c6=3
Naked Single: r8c7=4
Full House: r5c7=1
Full House: r5c6=4
Full House: r4c9=4
Full House: r8c9=8
Full House: r4c6=5
|
normal_sudoku_4466
|
..2.849.5.8.9.3......25.83.49.8.......53...8.3...425...........2.....1.......972.
|
632184975587963241941257836496875312725391684318642597153728469279436158864519723
|
Basic 9x9 Sudoku 4466
|
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 . 8 4 9 . 5
. 8 . 9 . 3 . . .
. . . 2 5 . 8 3 .
4 9 . 8 . . . . .
. . 5 3 . . . 8 .
3 . . . 4 2 5 . .
. . . . . . . . .
2 . . . . . 1 . .
. . . . . 9 7 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
632184975587963241941257836496875312725391684318642597153728469279436158864519723 #1 Extreme (13142) bf
Hidden Single: r1c5=8
Hidden Single: r2c1=5
Hidden Single: r1c2=3
Hidden Single: r6c3=8
Hidden Single: r4c6=5
Hidden Single: r5c2=2
Hidden Single: r5c5=9
Hidden Single: r7c5=2
Naked Triple: 1,6,7 in r4c358 => r4c79<>6, r4c9<>1, r4c9<>7
Brute Force: r6c4=6
Skyscraper: 6 in r1c1,r4c3 (connected by r14c8) => r23c3,r5c1<>6
Hidden Single: r4c3=6
Naked Pair: 1,7 in r5c16 => r5c9<>1, r5c9<>7
Forcing Chain Contradiction in r3c6 => r1c1<>1
r1c1=1 r5c1<>1 r5c6=1 r3c6<>1
r1c1=1 r1c1<>6 r3c12=6 r3c6<>6
r1c1=1 r1c4<>1 r1c4=7 r3c6<>7
Skyscraper: 1 in r1c4,r4c5 (connected by r14c8) => r2c5<>1
2-String Kite: 1 in r5c1,r9c5 (connected by r4c5,r5c6) => r9c1<>1
Grouped Discontinuous Nice Loop: 7 r7c6 -7- r5c6 -1- r3c6 =1= r1c4 =7= r78c4 -7- r7c6 => r7c6<>7
Grouped Discontinuous Nice Loop: 7 r8c6 -7- r5c6 -1- r3c6 =1= r1c4 =7= r78c4 -7- r8c6 => r8c6<>7
Turbot Fish: 7 r3c6 =7= r5c6 -7- r5c1 =7= r6c2 => r3c2<>7
Almost Locked Set XY-Wing: A=r6c2 {17}, B=r14c8 {167}, C=r15c1 {167}, X,Y=1,6, Z=7 => r6c8<>7
Forcing Chain Contradiction in r3c6 => r1c1=6
r1c1<>6 r1c1=7 r1c4<>7 r1c4=1 r3c6<>1
r1c1<>6 r3c12=6 r3c6<>6
r1c1<>6 r1c1=7 r5c1<>7 r5c6=7 r3c6<>7
Naked Single: r9c1=8
Naked Pair: 1,7 in r14c8 => r26c8<>1, r2c8<>7
Naked Single: r6c8=9
Hidden Pair: 8,9 in r78c9 => r78c9<>3, r78c9<>4, r78c9<>6
Remote Pair: 7/1 r1c4 -1- r1c8 -7- r4c8 -1- r4c5 => r2c5<>7
Naked Single: r2c5=6
Naked Single: r2c8=4
Naked Single: r2c7=2
Naked Single: r4c7=3
Naked Single: r4c9=2
Hidden Single: r3c9=6
Naked Single: r5c9=4
Naked Single: r5c7=6
Full House: r7c7=4
Naked Single: r9c9=3
Naked Single: r9c5=1
Naked Single: r4c5=7
Full House: r4c8=1
Full House: r5c6=1
Full House: r8c5=3
Full House: r6c9=7
Full House: r5c1=7
Full House: r6c2=1
Naked Single: r9c3=4
Naked Single: r1c8=7
Full House: r2c9=1
Full House: r1c4=1
Full House: r3c6=7
Full House: r2c3=7
Naked Single: r3c2=4
Naked Single: r9c4=5
Full House: r9c2=6
Naked Single: r8c3=9
Naked Single: r7c4=7
Full House: r8c4=4
Naked Single: r3c3=1
Full House: r3c1=9
Full House: r7c1=1
Full House: r7c3=3
Naked Single: r8c9=8
Full House: r7c9=9
Naked Single: r7c2=5
Full House: r8c2=7
Naked Single: r8c6=6
Full House: r7c6=8
Full House: r7c8=6
Full House: r8c8=5
|
normal_sudoku_5562
|
.7..4......1..6.....3...25..4963.1..6.79.1.......7.6....671..4.....63.1..3.4.9...
|
975342861281596437463187259849635172657921384312874695526718943794263518138459726
|
Basic 9x9 Sudoku 5562
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . 4 . . . .
. . 1 . . 6 . . .
. . 3 . . . 2 5 .
. 4 9 6 3 . 1 . .
6 . 7 9 . 1 . . .
. . . . 7 . 6 . .
. . 6 7 1 . . 4 .
. . . . 6 3 . 1 .
. 3 . 4 . 9 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
975342861281596437463187259849635172657921384312874695526718943794263518138459726 #1 Extreme (13978) bf
Hidden Single: r4c4=6
Hidden Single: r3c2=6
Hidden Single: r3c6=7
Hidden Single: r6c1=3
Hidden Single: r9c1=1
Hidden Single: r6c2=1
Hidden Single: r6c6=4
Hidden Single: r8c3=4
Hidden Single: r8c1=7
Hidden Rectangle: 1/8 in r1c49,r3c49 => r1c9<>8
Brute Force: r5c2=5
Locked Candidates Type 1 (Pointing): 5 in b6 => r789c9<>5
Skyscraper: 5 in r1c3,r2c5 (connected by r9c35) => r1c46,r2c1<>5
Grouped Discontinuous Nice Loop: 9 r2c8 -9- r6c8 =9= r6c9 =5= r6c4 -5- r4c6 =5= r7c6 -5- r7c1 =5= r1c1 =9= r1c789 -9- r2c8 => r2c8<>9
Forcing Chain Contradiction in r1c3 => r4c6<>2
r4c6=2 r4c1<>2 r6c3=2 r1c3<>2
r4c6=2 r4c6<>5 r7c6=5 r7c1<>5 r1c1=5 r1c3<>5
r4c6=2 r1c6<>2 r1c6=8 r1c3<>8
Discontinuous Nice Loop: 8 r6c8 -8- r6c3 =8= r4c1 -8- r4c6 -5- r4c9 =5= r6c9 =9= r6c8 => r6c8<>8
Discontinuous Nice Loop: 8 r6c9 -8- r6c3 =8= r4c1 -8- r4c6 -5- r4c9 =5= r6c9 => r6c9<>8
Finned Franken Swordfish: 2 c36b5 r169 fr5c5 fr7c6 => r9c5<>2
Discontinuous Nice Loop: 8 r9c9 -8- r9c5 -5- r2c5 =5= r2c4 =3= r1c4 =1= r1c9 =6= r9c9 => r9c9<>8
Forcing Chain Contradiction in r1c3 => r4c6=5
r4c6<>5 r4c6=8 r1c6<>8 r1c6=2 r1c3<>2
r4c6<>5 r7c6=5 r7c1<>5 r1c1=5 r1c3<>5
r4c6<>5 r4c6=8 r4c1<>8 r6c3=8 r1c3<>8
Hidden Single: r6c9=5
Hidden Single: r6c8=9
W-Wing: 8/2 in r1c6,r6c4 connected by 2 in r25c5 => r123c4<>8
Naked Single: r3c4=1
Hidden Single: r1c9=1
Hidden Single: r1c8=6
Hidden Single: r9c9=6
Turbot Fish: 2 r4c1 =2= r6c3 -2- r9c3 =2= r9c8 => r4c8<>2
Sashimi Swordfish: 2 c258 r259 fr7c2 fr8c2 => r9c3<>2
Hidden Single: r9c8=2
Hidden Single: r9c7=7
Skyscraper: 8 in r6c4,r9c5 (connected by r69c3) => r5c5,r8c4<>8
Naked Single: r5c5=2
Full House: r6c4=8
Full House: r6c3=2
Full House: r4c1=8
Naked Single: r4c8=7
Full House: r4c9=2
Hidden Single: r2c9=7
Skyscraper: 8 in r7c6,r9c3 (connected by r1c36) => r7c2,r9c5<>8
Naked Single: r9c5=5
Full House: r9c3=8
Full House: r1c3=5
Naked Single: r8c4=2
Full House: r7c6=8
Full House: r1c6=2
Naked Single: r1c4=3
Full House: r2c4=5
Naked Single: r8c2=9
Naked Single: r1c1=9
Full House: r1c7=8
Naked Single: r7c2=2
Full House: r2c2=8
Full House: r7c1=5
Naked Single: r8c9=8
Full House: r8c7=5
Naked Single: r3c1=4
Full House: r2c1=2
Naked Single: r2c8=3
Full House: r5c8=8
Naked Single: r2c5=9
Full House: r2c7=4
Full House: r3c9=9
Full House: r3c5=8
Naked Single: r5c7=3
Full House: r5c9=4
Full House: r7c9=3
Full House: r7c7=9
|
normal_sudoku_4474
|
..2..7.1...7.4.....9.6....5...2.....3.6.91..2.2....59..6.5....38...1.4.......8...
|
682957314537142968491683275749265831356891742128734596264579183875316429913428657
|
Basic 9x9 Sudoku 4474
|
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 . 1 .
. . 7 . 4 . . . .
. 9 . 6 . . . . 5
. . . 2 . . . . .
3 . 6 . 9 1 . . 2
. 2 . . . . 5 9 .
. 6 . 5 . . . . 3
8 . . . 1 . 4 . .
. . . . . 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
682957314537142968491683275749265831356891742128734596264579183875316429913428657 #1 Extreme (19470) bf
Locked Candidates Type 1 (Pointing): 3 in b6 => r4c56<>3
2-String Kite: 5 in r1c5,r5c2 (connected by r4c5,r5c6) => r1c2<>5
Empty Rectangle: 2 in b2 (r8c68) => r3c8<>2
Discontinuous Nice Loop: 6 r9c8 -6- r9c5 =6= r8c6 =2= r8c8 =5= r9c8 => r9c8<>6
Brute Force: r5c6=1
Hidden Single: r2c4=1
Hidden Single: r5c2=5
Locked Candidates Type 1 (Pointing): 5 in b1 => r9c1<>5
Hidden Pair: 5,6 in r12c1 => r1c1<>4
Empty Rectangle: 1 in b6 (r49c2) => r9c9<>1
Locked Candidates Type 1 (Pointing): 1 in b9 => r4c7<>1
AIC: 7/8 7- r3c8 =7= r3c7 -7- r5c7 -8- r7c7 =8= r7c8 -8 => r7c8<>7, r3c8<>8
Grouped Discontinuous Nice Loop: 7 r8c8 -7- r8c2 -3- r12c2 =3= r3c3 -3- r3c6 -2- r8c6 =2= r8c8 => r8c8<>7
Almost Locked Set XY-Wing: A=r8c2469 {23679}, B=r3467c3 {13489}, C=r3c6 {23}, X,Y=2,3, Z=9 => r8c3<>9
Forcing Chain Contradiction in r3c7 => r7c8=8
r7c8<>8 r7c8=2 r8c8<>2 r8c6=2 r2c6<>2 r2c78=2 r3c7<>2
r7c8<>8 r7c8=2 r8c8<>2 r8c6=2 r3c6<>2 r3c6=3 r3c7<>3
r7c8<>8 r7c7=8 r5c7<>8 r5c7=7 r3c7<>7
r7c8<>8 r7c7=8 r3c7<>8
Finned Franken Swordfish: 8 r35b4 c357 fr4c2 fr5c4 => r4c5<>8
Forcing Chain Contradiction in r4c6 => r1c9<>6
r1c9=6 r1c9<>4 r3c8=4 r5c8<>4 r5c4=4 r4c6<>4
r1c9=6 r1c1<>6 r1c1=5 r1c5<>5 r4c5=5 r4c6<>5
r1c9=6 r6c9<>6 r4c789=6 r4c6<>6
Forcing Chain Contradiction in r7 => r4c5<>7
r4c5=7 r4c2<>7 r46c1=7 r7c1<>7
r4c5=7 r7c5<>7
r4c5=7 r5c4<>7 r5c78=7 r46c9<>7 r89c9=7 r7c7<>7
Discontinuous Nice Loop: 6 r4c7 -6- r4c5 -5- r1c5 =5= r1c1 =6= r1c7 -6- r4c7 => r4c7<>6
Grouped Discontinuous Nice Loop: 6 r2c9 -6- r2c1 -5- r2c6 =5= r4c6 -5- r4c5 -6- r4c8 =6= r46c9 -6- r2c9 => r2c9<>6
Almost Locked Set XZ-Rule: A=r4c56 {456}, B=r4c78,r5c78 {34678}, X=6, Z=4 => r4c9<>4
Grouped Discontinuous Nice Loop: 9 r1c9 -9- r1c4 =9= r2c6 =5= r4c6 -5- r4c5 -6- r4c89 =6= r6c9 =4= r1c9 => r1c9<>9
Almost Locked Set XY-Wing: A=r1c2459 {34589}, B=r4c78,r5c78 {34678}, C=r4c5 {56}, X,Y=5,6, Z=8 => r1c7<>8
Almost Locked Set XY-Wing: A=r1c29 {348}, B=r13c5,r23c6 {23589}, C=r2c29 {389}, X,Y=3,9, Z=8 => r1c4<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r6c5<>8
Almost Locked Set XY-Wing: A=r2c2 {38}, B=r4c79,r5c78,r6c9 {134678}, C=r289c9 {6789}, X,Y=6,8, Z=3 => r2c7<>3
Almost Locked Set XY-Wing: A=r123467c1 {1245679}, B=r189c4 {3479}, C=r7c5 {27}, X,Y=2,7, Z=4 => r9c1<>4
Forcing Chain Contradiction in r8 => r1c4=9
r1c4<>9 r1c7=9 r2c9<>9 r2c9=8 r2c2<>8 r2c2=3 r8c2<>3
r1c4<>9 r1c4=3 r3c6<>3 r3c6=2 r8c6<>2 r8c8=2 r8c8<>5 r8c3=5 r8c3<>3
r1c4<>9 r1c4=3 r8c4<>3
r1c4<>9 r2c6=9 r2c6<>5 r4c6=5 r4c5<>5 r4c5=6 r9c5<>6 r8c6=6 r8c6<>3
Naked Pair: 3,7 in r8c24 => r8c36<>3, r8c9<>7
Naked Single: r8c3=5
Hidden Single: r9c8=5
Discontinuous Nice Loop: 3 r2c6 -3- r2c2 -8- r2c9 -9- r8c9 -6- r8c6 =6= r9c5 -6- r4c5 -5- r4c6 =5= r2c6 => r2c6<>3
Empty Rectangle: 3 in b2 (r39c3) => r9c5<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r6c4<>3
Discontinuous Nice Loop: 6 r2c7 -6- r2c1 -5- r2c6 =5= r4c6 -5- r4c5 -6- r9c5 =6= r8c6 =9= r8c9 -9- r2c9 =9= r2c7 => r2c7<>6
Discontinuous Nice Loop: 7 r9c1 -7- r8c2 =7= r8c4 -7- r7c5 -2- r7c1 =2= r9c1 => r9c1<>7
Grouped Discontinuous Nice Loop: 4 r4c8 -4- r5c8 =4= r5c4 -4- r9c4 =4= r7c6 =9= r8c6 -9- r8c9 -6- r46c9 =6= r4c8 => r4c8<>4
Grouped Discontinuous Nice Loop: 7 r9c2 -7- r9c9 =7= r46c9 -7- r5c78 =7= r5c4 -7- r8c4 =7= r8c2 -7- r9c2 => r9c2<>7
Grouped Discontinuous Nice Loop: 7 r9c4 -7- r9c9 =7= r46c9 -7- r5c78 =7= r5c4 -7- r9c4 => r9c4<>7
Discontinuous Nice Loop: 4 r9c2 -4- r9c4 -3- r8c4 -7- r8c2 =7= r4c2 =1= r9c2 => r9c2<>4
Skyscraper: 4 in r4c2,r6c9 (connected by r1c29) => r6c13<>4
Locked Candidates Type 1 (Pointing): 4 in b4 => r4c6<>4
Locked Pair: 5,6 in r4c56 => r4c89,r6c56<>6
Hidden Single: r6c9=6
Naked Single: r8c9=9
Naked Single: r2c9=8
Naked Single: r9c9=7
Naked Single: r1c9=4
Full House: r4c9=1
Naked Single: r2c2=3
Naked Single: r1c2=8
Naked Single: r8c2=7
Naked Single: r9c2=1
Full House: r4c2=4
Naked Single: r8c4=3
Naked Single: r9c4=4
Hidden Single: r5c8=4
Hidden Single: r2c7=9
Hidden Single: r7c6=9
Naked Single: r7c3=4
Naked Single: r3c3=1
Naked Single: r7c1=2
Naked Single: r3c1=4
Naked Single: r6c3=8
Naked Single: r7c5=7
Full House: r7c7=1
Naked Single: r9c1=9
Full House: r9c3=3
Full House: r4c3=9
Naked Single: r6c4=7
Full House: r5c4=8
Full House: r5c7=7
Naked Single: r6c5=3
Naked Single: r4c1=7
Full House: r6c1=1
Full House: r6c6=4
Naked Single: r4c8=3
Full House: r4c7=8
Naked Single: r1c5=5
Naked Single: r3c8=7
Naked Single: r1c1=6
Full House: r1c7=3
Full House: r2c1=5
Naked Single: r2c6=2
Full House: r2c8=6
Full House: r3c7=2
Full House: r8c8=2
Full House: r8c6=6
Full House: r9c7=6
Full House: r9c5=2
Naked Single: r4c5=6
Full House: r3c5=8
Full House: r3c6=3
Full House: r4c6=5
|
normal_sudoku_2729
|
.638..1.....3.4867.8...2.3.6...47..2..1....7....2..5...7..6...8.....8.5...25..7..
|
463879125219354867587612439658147392321985674794236581975463218146728953832591746
|
Basic 9x9 Sudoku 2729
|
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 8 . . 1 . .
. . . 3 . 4 8 6 7
. 8 . . . 2 . 3 .
6 . . . 4 7 . . 2
. . 1 . . . . 7 .
. . . 2 . . 5 . .
. 7 . . 6 . . . 8
. . . . . 8 . 5 .
. . 2 5 . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
463879125219354867587612439658147392321985674794236581975463218146728953832591746 #1 Medium (486)
Hidden Single: r2c8=6
Hidden Single: r3c4=6
Naked Single: r5c4=9
Naked Single: r4c4=1
Naked Single: r7c4=4
Full House: r8c4=7
Hidden Single: r8c5=2
Hidden Single: r8c3=6
Hidden Single: r9c1=8
Hidden Single: r9c9=6
Hidden Single: r1c8=2
Hidden Single: r7c7=2
Hidden Single: r5c7=6
Hidden Single: r5c5=8
Naked Single: r6c5=3
Naked Single: r5c6=5
Full House: r6c6=6
Naked Single: r1c6=9
Hidden Single: r9c5=9
Locked Candidates Type 1 (Pointing): 9 in b3 => r3c13<>9
Locked Candidates Type 1 (Pointing): 3 in b9 => r8c12<>3
Naked Pair: 5,9 in r27c3 => r34c3<>5, r46c3<>9
Naked Single: r4c3=8
Naked Single: r4c8=9
Naked Single: r4c7=3
Full House: r4c2=5
Naked Single: r7c8=1
Naked Single: r5c9=4
Naked Single: r7c6=3
Full House: r9c6=1
Naked Single: r9c8=4
Full House: r6c8=8
Full House: r6c9=1
Full House: r9c2=3
Naked Single: r1c9=5
Naked Single: r8c7=9
Full House: r3c7=4
Full House: r3c9=9
Full House: r8c9=3
Naked Single: r5c2=2
Full House: r5c1=3
Naked Single: r1c5=7
Full House: r1c1=4
Naked Single: r3c3=7
Naked Single: r8c1=1
Full House: r8c2=4
Naked Single: r6c3=4
Naked Single: r3c1=5
Full House: r3c5=1
Full House: r2c5=5
Naked Single: r6c2=9
Full House: r2c2=1
Full House: r6c1=7
Naked Single: r2c3=9
Full House: r2c1=2
Full House: r7c1=9
Full House: r7c3=5
|
normal_sudoku_570
|
.384.....69..85.3.27.......71..5.48...97..62..46...........8..3.2..1...6...6.2.98
|
138467952694285731275193864712356489389741625546829317961578243823914576457632198
|
Basic 9x9 Sudoku 570
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 8 4 . . . . .
6 9 . . 8 5 . 3 .
2 7 . . . . . . .
7 1 . . 5 . 4 8 .
. . 9 7 . . 6 2 .
. 4 6 . . . . . .
. . . . . 8 . . 3
. 2 . . 1 . . . 6
. . . 6 . 2 . 9 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
138467952694285731275193864712356489389741625546829317961578243823914576457632198 #1 Easy (228)
Naked Single: r4c2=1
Naked Single: r4c9=9
Naked Single: r9c2=5
Naked Single: r5c2=8
Full House: r7c2=6
Hidden Single: r6c4=8
Hidden Single: r6c7=3
Naked Single: r6c1=5
Naked Single: r1c1=1
Naked Single: r5c1=3
Full House: r4c3=2
Naked Single: r2c3=4
Full House: r3c3=5
Naked Single: r5c5=4
Naked Single: r9c1=4
Naked Single: r4c4=3
Full House: r4c6=6
Naked Single: r5c6=1
Full House: r5c9=5
Naked Single: r7c1=9
Full House: r8c1=8
Naked Single: r6c6=9
Full House: r6c5=2
Naked Single: r7c4=5
Naked Single: r7c5=7
Naked Single: r1c6=7
Naked Single: r3c6=3
Full House: r8c6=4
Naked Single: r8c4=9
Full House: r9c5=3
Naked Single: r7c3=1
Naked Single: r1c9=2
Naked Single: r3c4=1
Full House: r2c4=2
Naked Single: r7c7=2
Full House: r7c8=4
Naked Single: r9c3=7
Full House: r8c3=3
Full House: r9c7=1
Naked Single: r3c9=4
Naked Single: r3c8=6
Naked Single: r2c7=7
Full House: r2c9=1
Full House: r6c9=7
Full House: r6c8=1
Naked Single: r1c8=5
Full House: r8c8=7
Full House: r8c7=5
Naked Single: r3c5=9
Full House: r1c5=6
Full House: r1c7=9
Full House: r3c7=8
|
normal_sudoku_1313
|
.7.9.....1....7..5..2.6....8...135...4..86.1....2...387....8.5..6......1..4.9.7..
|
678952143139847625452361879827413596943586217516279438791628354265734981384195762
|
Basic 9x9 Sudoku 1313
|
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 . . . . .
1 . . . . 7 . . 5
. . 2 . 6 . . . .
8 . . . 1 3 5 . .
. 4 . . 8 6 . 1 .
. . . 2 . . . 3 8
7 . . . . 8 . 5 .
. 6 . . . . . . 1
. . 4 . 9 . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
678952143139847625452361879827413596943586217516279438791628354265734981384195762 #1 Extreme (19306) bf
Brute Force: r5c6=6
Hidden Single: r6c6=9
Discontinuous Nice Loop: 4 r3c4 -4- r3c1 =4= r1c1 =6= r6c1 -6- r6c7 -4- r6c5 =4= r4c4 -4- r3c4 => r3c4<>4
Discontinuous Nice Loop: 4 r3c7 -4- r3c1 =4= r1c1 =6= r6c1 -6- r6c7 -4- r3c7 => r3c7<>4
Forcing Chain Contradiction in c8 => r3c9<>4
r3c9=4 r1c8<>4
r3c9=4 r2c8<>4
r3c9=4 r3c8<>4
r3c9=4 r3c1<>4 r1c1=4 r1c1<>6 r6c1=6 r6c7<>6 r6c7=4 r4c8<>4
r3c9=4 r2c78<>4 r2c45=4 r13c6<>4 r8c6=4 r8c8<>4
Forcing Chain Verity => r7c5<>4
r1c9=4 r2c78<>4 r2c45=4 r13c6<>4 r8c6=4 r7c5<>4
r4c9=4 r4c4<>4 r6c5=4 r7c5<>4
r7c9=4 r7c5<>4
Forcing Chain Contradiction in r8c4 => r1c7<>4
r1c7=4 r1c7<>1 r1c6=1 r1c6<>2 r12c5=2 r7c5<>2 r7c5=3 r8c4<>3
r1c7=4 r2c78<>4 r2c45=4 r13c6<>4 r8c6=4 r8c4<>4
r1c7=4 r6c7<>4 r6c5=4 r6c5<>5 r5c4=5 r8c4<>5
r1c7=4 r6c7<>4 r6c5=4 r6c5<>7 r8c5=7 r8c4<>7
Forcing Net Contradiction in c6 => r3c4<>5
r3c4=5 r1c6<>5
r3c4=5 r3c6<>5
r3c4=5 r5c4<>5 r5c4=7 (r4c4<>7 r4c4=4 r7c4<>4) (r4c4<>7 r4c4=4 r8c4<>4) r8c4<>7 r8c5=7 r8c5<>4 r8c6=4 r8c6<>5
r3c4=5 (r3c2<>5) r5c4<>5 r6c5=5 r6c2<>5 r9c2=5 r9c6<>5
Forcing Net Contradiction in r3 => r7c4<>4
r7c4=4 r4c4<>4 r4c4=7 r4c8<>7 r3c8=7 r3c8<>4 r3c1=4
r7c4=4 (r7c4<>6 r9c4=6 r9c4<>1 r3c4=1 r3c6<>1) r4c4<>4 (r6c5=4 r6c5<>5) r4c4=7 r8c4<>7 r8c5=7 r8c5<>5 r1c5=5 r3c6<>5 r3c6=4
Locked Candidates Type 1 (Pointing): 4 in b8 => r8c78<>4
Forcing Net Contradiction in c1 => r7c7<>2
r7c7=2 (r5c7<>2 r5c7=9 r4c9<>9) (r5c7<>2 r5c7=9 r5c9<>9) r7c7<>4 r7c9=4 r7c9<>9 r3c9=9 r3c1<>9
r7c7=2 r5c7<>2 r5c7=9 r5c1<>9
r7c7=2 (r5c7<>2 r5c7=9 r4c8<>9) (r5c7<>2 r5c7=9 r4c9<>9) (r5c7<>2 r5c7=9 r5c9<>9) r7c7<>4 r7c9=4 r7c9<>9 r3c9=9 (r2c8<>9) r3c8<>9 r8c8=9 r8c1<>9
Forcing Net Verity => r1c7<>6
r7c7=3 r7c5<>3 r7c5=2 (r8c6<>2) r9c6<>2 r1c6=2 r1c6<>1 r1c7=1 r1c7<>6
r7c7=4 r6c7<>4 r6c7=6 r1c7<>6
r7c7=6 r1c7<>6
r7c7=9 (r7c7<>4 r7c9=4 r7c9<>2) r5c7<>9 r5c7=2 (r4c8<>2) r4c9<>2 r4c2=2 r7c2<>2 r7c5=2 (r8c6<>2) r9c6<>2 r1c6=2 r1c6<>1 r1c7=1 r1c7<>6
Forcing Net Contradiction in r7c7 => r2c7<>4
r2c7=4 (r2c7<>2) (r2c7<>6) r6c7<>4 r6c7=6 (r4c8<>6) r4c9<>6 r4c3=6 r2c3<>6 r2c8=6 r2c8<>2 r2c5=2 r7c5<>2 r7c5=3 r7c7<>3
r2c7=4 r7c7<>4
r2c7=4 r6c7<>4 r6c7=6 r7c7<>6
r2c7=4 (r3c8<>4 r4c8=4 r4c8<>7 r3c8=7 r3c8<>9) (r3c8<>4 r4c8=4 r4c8<>9) (r2c7<>6) r6c7<>4 r6c7=6 (r4c8<>6) r4c9<>6 r4c3=6 r2c3<>6 r2c8=6 r2c8<>9 r8c8=9 r7c7<>9
Forcing Chain Contradiction in r2 => r8c4<>4
r8c4=4 r4c4<>4 r6c5=4 r6c7<>4 r6c7=6 r6c1<>6 r1c1=6 r2c3<>6
r8c4=4 r4c4<>4 r6c5=4 r6c7<>4 r6c7=6 r2c7<>6
r8c4=4 r8c6<>4 r13c6=4 r2c45<>4 r2c8=4 r2c8<>6
Forcing Chain Contradiction in r8c4 => r7c9<>2
r7c9=2 r7c5<>2 r7c5=3 r8c4<>3
r7c9=2 r7c9<>4 r7c7=4 r6c7<>4 r6c5=4 r6c5<>5 r5c4=5 r8c4<>5
r7c9=2 r7c9<>4 r7c7=4 r6c7<>4 r6c5=4 r6c5<>7 r8c5=7 r8c4<>7
Forcing Chain Contradiction in c4 => r7c9<>6
r7c9=6 r7c9<>4 r7c7=4 r6c7<>4 r6c5=4 r4c4<>4 r2c4=4 r2c4<>8 r3c4=8 r3c4<>1
r7c9=6 r7c9<>4 r7c7=4 r6c7<>4 r6c5=4 r6c5<>7 r6c3=7 r6c3<>1 r7c3=1 r7c4<>1
r7c9=6 r7c4<>6 r9c4=6 r9c4<>1
Forcing Chain Contradiction in r1 => r9c2<>2
r9c2=2 r9c2<>8 r8c3=8 r1c3<>8
r9c2=2 r7c2<>2 r7c5=2 r12c5<>2 r1c6=2 r1c6<>1 r1c7=1 r1c7<>8
r9c2=2 r9c2<>8 r9c8=8 r1c8<>8
Forcing Net Contradiction in r4 => r4c4=4
r4c4<>4 r4c4=7 (r8c4<>7) r5c4<>7 r5c4=5 r8c4<>5 r8c4=3 r7c5<>3 r7c5=2 r7c2<>2 r4c2=2
r4c4<>4 (r4c4=7 r8c4<>7) r6c5=4 r6c5<>5 r5c4=5 r8c4<>5 r8c4=3 r7c5<>3 r7c5=2 r7c2<>2 r4c2=2 r4c8<>2 r4c9=2
Hidden Single: r6c7=4
Hidden Single: r7c9=4
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c3<>6
Finned Franken Swordfish: 9 c19b9 r358 fr4c9 fr7c7 => r5c7<>9
Naked Single: r5c7=2
Hidden Single: r4c2=2
Hidden Single: r7c5=2
Hidden Single: r2c8=2
Hidden Single: r1c6=2
Hidden Single: r9c9=2
Hidden Single: r8c1=2
Hidden Single: r2c5=4
Hidden Single: r1c7=1
Hidden Single: r8c6=4
Locked Candidates Type 1 (Pointing): 3 in b9 => r23c7<>3
Skyscraper: 8 in r1c3,r9c2 (connected by r19c8) => r23c2,r8c3<>8
Hidden Single: r9c2=8
Naked Single: r9c8=6
Hidden Single: r4c9=6
Naked Single: r1c9=3
Naked Single: r1c5=5
Naked Single: r3c6=1
Full House: r9c6=5
Naked Single: r6c5=7
Full House: r5c4=5
Full House: r8c5=3
Naked Single: r9c1=3
Full House: r9c4=1
Naked Single: r8c4=7
Full House: r7c4=6
Naked Single: r5c1=9
Naked Single: r4c3=7
Full House: r4c8=9
Full House: r5c9=7
Full House: r5c3=3
Full House: r3c9=9
Naked Single: r8c8=8
Naked Single: r3c7=8
Naked Single: r1c8=4
Full House: r3c8=7
Full House: r2c7=6
Naked Single: r8c7=9
Full House: r7c7=3
Full House: r8c3=5
Naked Single: r3c4=3
Full House: r2c4=8
Naked Single: r1c1=6
Full House: r1c3=8
Naked Single: r3c2=5
Full House: r3c1=4
Full House: r6c1=5
Naked Single: r2c3=9
Full House: r2c2=3
Naked Single: r6c2=1
Full House: r6c3=6
Full House: r7c3=1
Full House: r7c2=9
|
normal_sudoku_2621
|
16.......4.39......296....4.3..9.2......579.6........13.....61...2.694..6.4.1...2
|
167584329453972168829631754736198245281457936945326871398245617512769483674813592
|
Basic 9x9 Sudoku 2621
|
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 . . . . . . .
4 . 3 9 . . . . .
. 2 9 6 . . . . 4
. 3 . . 9 . 2 . .
. . . . 5 7 9 . 6
. . . . . . . . 1
3 . . . . . 6 1 .
. . 2 . 6 9 4 . .
6 . 4 . 1 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
167584329453972168829631754736198245281457936945326871398245617512769483674813592 #1 Extreme (24534) bf
Hidden Single: r7c7=6
Hidden Single: r2c8=6
Hidden Single: r6c1=9
Hidden Single: r8c2=1
Hidden Single: r1c8=2
Hidden Single: r5c1=2
Hidden Single: r1c9=9
Hidden Single: r9c8=9
Hidden Single: r7c2=9
Hidden Single: r8c9=3
Locked Candidates Type 1 (Pointing): 1 in b2 => r4c6<>1
Hidden Rectangle: 1/8 in r4c34,r5c34 => r4c4<>8
Brute Force: r5c3=1
Hidden Single: r4c4=1
Brute Force: r5c4=4
Naked Single: r5c2=8
Full House: r5c8=3
Hidden Single: r4c8=4
Hidden Single: r6c2=4
Finned Franken Swordfish: 5 c29b4 r247 fr6c3 fr9c2 => r7c3<>5
W-Wing: 7/5 in r2c2,r4c1 connected by 5 in r8c1,r9c2 => r3c1<>7
Sashimi Swordfish: 7 c129 r247 fr8c1 fr9c2 => r7c3<>7
Naked Single: r7c3=8
Hidden Single: r3c1=8
Discontinuous Nice Loop: 5 r1c7 -5- r3c8 -7- r3c5 -3- r3c7 =3= r1c7 => r1c7<>5
Forcing Chain Contradiction in r9c7 => r2c9<>5
r2c9=5 r2c2<>5 r9c2=5 r9c7<>5
r2c9=5 r7c9<>5 r7c9=7 r9c7<>7
r2c9=5 r2c9<>8 r12c7=8 r9c7<>8
Skyscraper: 5 in r7c9,r8c1 (connected by r4c19) => r8c8<>5
Discontinuous Nice Loop: 7 r4c3 -7- r1c3 =7= r2c2 -7- r2c9 -8- r4c9 =8= r4c6 =6= r4c3 => r4c3<>7
Grouped Discontinuous Nice Loop: 7 r9c4 -7- r9c2 -5- r9c7 =5= r7c9 =7= r7c45 -7- r9c4 => r9c4<>7
Turbot Fish: 7 r1c3 =7= r2c2 -7- r9c2 =7= r9c7 => r1c7<>7
Forcing Chain Contradiction in r9c7 => r1c7=3
r1c7<>3 r1c7=8 r2c9<>8 r2c9=7 r7c9<>7 r7c9=5 r9c7<>5
r1c7<>3 r1c7=8 r2c9<>8 r2c9=7 r2c2<>7 r9c2=7 r9c7<>7
r1c7<>3 r1c7=8 r9c7<>8
Locked Candidates Type 1 (Pointing): 8 in b3 => r2c56<>8
Discontinuous Nice Loop: 7 r1c5 -7- r1c3 -5- r4c3 -6- r4c6 -8- r6c5 =8= r1c5 => r1c5<>7
Discontinuous Nice Loop: 2 r7c5 -2- r2c5 -7- r2c9 -8- r4c9 =8= r4c6 -8- r6c5 =8= r1c5 =4= r7c5 => r7c5<>2
Grouped AIC: 4/8 8- r1c5 =8= r6c5 -8- r4c6 =8= r4c9 -8- r2c9 -7- r3c78 =7= r3c5 -7- r7c5 -4- r7c6 =4= r1c6 -4 => r1c5<>4, r1c6<>8
Naked Single: r1c5=8
Hidden Single: r1c6=4
Hidden Single: r7c5=4
Locked Candidates Type 1 (Pointing): 7 in b8 => r1c4<>7
Naked Single: r1c4=5
Full House: r1c3=7
Full House: r2c2=5
Full House: r9c2=7
Full House: r8c1=5
Full House: r4c1=7
W-Wing: 5/8 in r4c9,r9c7 connected by 8 in r2c79 => r6c7,r7c9<>5
Naked Single: r7c9=7
Naked Single: r2c9=8
Full House: r4c9=5
Naked Single: r7c4=2
Full House: r7c6=5
Naked Single: r8c8=8
Full House: r8c4=7
Full House: r9c7=5
Naked Single: r4c3=6
Full House: r4c6=8
Full House: r6c3=5
Naked Single: r6c8=7
Full House: r3c8=5
Full House: r6c7=8
Naked Single: r6c4=3
Full House: r9c4=8
Full House: r9c6=3
Naked Single: r6c5=2
Full House: r6c6=6
Naked Single: r3c6=1
Full House: r2c6=2
Naked Single: r2c5=7
Full House: r2c7=1
Full House: r3c7=7
Full House: r3c5=3
|
normal_sudoku_6660
|
.7...3..21.56..7..8..71.....8.9....6..7..631..6..3.2...1...9..3....4..51..4...82.
|
679853142145692738832714695483921576257486319961537284518279463726348951394165827
|
Basic 9x9 Sudoku 6660
|
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
1 . 5 6 . . 7 . .
8 . . 7 1 . . . .
. 8 . 9 . . . . 6
. . 7 . . 6 3 1 .
. 6 . . 3 . 2 . .
. 1 . . . 9 . . 3
. . . . 4 . . 5 1
. . 4 . . . 8 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
679853142145692738832714695483921576257486319961537284518279463726348951394165827 #1 Unfair (1732)
Hidden Single: r2c1=1
Hidden Single: r1c7=1
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c6<>5
Sashimi X-Wing: 5 c26 r59 fr4c6 fr6c6 => r5c45<>5
Discontinuous Nice Loop: 3 r8c1 -3- r8c4 =3= r9c4 =1= r9c6 -1- r4c6 =1= r4c3 =3= r4c1 -3- r8c1 => r8c1<>3
Almost Locked Set XZ-Rule: A=r4c578 {2457}, B=r5c45 {248}, X=2, Z=4 => r4c6,r5c9<>4
Finned Swordfish: 4 c269 r236 fr5c2 => r6c1<>4
Sue de Coq: r5c12 - {2459} (r5c45 - {248}, r6c1 - {59}) => r4c1<>5, r6c3<>9, r5c9<>8
Naked Single: r6c3=1
Hidden Single: r4c6=1
Hidden Single: r9c4=1
Hidden Single: r8c4=3
Locked Candidates Type 1 (Pointing): 8 in b6 => r6c46<>8
Skyscraper: 5 in r5c2,r6c6 (connected by r9c26) => r6c1<>5
Naked Single: r6c1=9
Hidden Single: r5c9=9
Naked Single: r9c9=7
Naked Single: r9c6=5
Naked Single: r9c5=6
Naked Single: r9c1=3
Full House: r9c2=9
Naked Single: r8c2=2
Hidden Single: r8c7=9
Hidden Single: r7c1=5
Hidden Single: r5c2=5
Hidden Single: r4c3=3
Hidden Single: r3c3=2
Naked Single: r3c6=4
Naked Single: r3c2=3
Full House: r2c2=4
Naked Single: r3c9=5
Naked Single: r6c6=7
Naked Single: r1c1=6
Full House: r1c3=9
Naked Single: r2c9=8
Full House: r6c9=4
Naked Single: r3c7=6
Full House: r3c8=9
Naked Single: r8c6=8
Full House: r2c6=2
Naked Single: r8c1=7
Full House: r8c3=6
Full House: r7c3=8
Naked Single: r1c8=4
Full House: r2c8=3
Full House: r2c5=9
Naked Single: r4c7=5
Full House: r7c7=4
Full House: r7c8=6
Naked Single: r4c8=7
Full House: r6c8=8
Full House: r6c4=5
Naked Single: r7c4=2
Full House: r7c5=7
Naked Single: r4c5=2
Full House: r4c1=4
Full House: r5c1=2
Naked Single: r1c4=8
Full House: r1c5=5
Full House: r5c5=8
Full House: r5c4=4
|
normal_sudoku_1078
|
...7..19.....182.7.7.2.9.485........3.7...8...2...4..99.4.2...1.......75.8.9.1...
|
832745196495618237671239548549863712367192854128574369954327681213486975786951423
|
Basic 9x9 Sudoku 1078
|
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 9 .
. . . . 1 8 2 . 7
. 7 . 2 . 9 . 4 8
5 . . . . . . . .
3 . 7 . . . 8 . .
. 2 . . . 4 . . 9
9 . 4 . 2 . . . 1
. . . . . . . 7 5
. 8 . 9 . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
832745196495618237671239548549863712367192854128574369954327681213486975786951423 #1 Extreme (6972)
Hidden Single: r2c9=7
Hidden Single: r7c6=7
Hidden Single: r9c1=7
Hidden Single: r7c8=8
Hidden Single: r8c7=9
Locked Candidates Type 1 (Pointing): 4 in b4 => r12c2<>4
Locked Candidates Type 1 (Pointing): 2 in b9 => r9c3<>2
Locked Candidates Type 1 (Pointing): 4 in b9 => r9c5<>4
Naked Triple: 3,5,6 in r7c4,r8c6,r9c5 => r8c45<>3, r8c45<>6
Naked Triple: 3,5,6 in r1c269 => r1c135<>6, r1c35<>3, r1c35<>5
Naked Single: r1c5=4
Naked Single: r8c5=8
Naked Single: r8c4=4
Hidden Single: r2c1=4
Skyscraper: 5 in r1c6,r7c4 (connected by r17c2) => r2c4<>5
Forcing Net Verity => r1c6=5
r9c5=3 (r9c9<>3 r7c7=3 r3c7<>3) (r8c6<>3 r8c6=6 r1c6<>6) (r9c9<>3 r7c7=3 r7c2<>3) r9c5<>5 r9c3=5 r7c2<>5 r7c2=6 r1c2<>6 r1c9=6 r3c7<>6 r3c7=5 r3c5<>5 r1c6=5
r9c5=5 r3c5<>5 r1c6=5
r9c5=6 (r9c9<>6 r7c7=6 r3c7<>6) (r8c6<>6 r8c6=3 r1c6<>3) (r9c9<>6 r7c7=6 r7c2<>6) r9c5<>5 r9c3=5 r7c2<>5 r7c2=3 r1c2<>3 r1c9=3 r3c7<>3 r3c7=5 r3c5<>5 r1c6=5
Finned Franken Swordfish: 3 r17b2 c247 fr1c9 fr3c5 => r3c7<>3
W-Wing: 6/3 in r1c2,r2c4 connected by 3 in r3c35 => r2c23<>6
Sashimi Swordfish: 6 r127 c247 fr1c9 fr2c8 => r3c7<>6
Naked Single: r3c7=5
Naked Pair: 3,6 in r2c48 => r2c23<>3
Almost Locked Set XY-Wing: A=r5c24689 {124569}, B=r39c5 {356}, C=r134689c3 {1235689}, X,Y=5,9, Z=6 => r5c5<>6
Finned Franken Swordfish: 6 c16b2 r368 fr2c4 fr4c6 fr5c6 => r6c4<>6
Forcing Chain Verity => r4c4<>3
r3c3=3 r3c5<>3 r2c4=3 r4c4<>3
r8c3=3 r8c6<>3 r4c6=3 r4c4<>3
r9c3=3 r9c3<>5 r2c3=5 r2c3<>9 r4c3=9 r4c3<>8 r4c4=8 r4c4<>3
Forcing Chain Contradiction in r7c2 => r4c4<>6
r4c4=6 r45c6<>6 r8c6=6 r8c6<>3 r8c23=3 r7c2<>3
r4c4=6 r4c4<>8 r4c3=8 r4c3<>9 r2c3=9 r2c3<>5 r2c2=5 r7c2<>5
r4c4=6 r2c4<>6 r2c8=6 r1c9<>6 r1c2=6 r7c2<>6
Forcing Chain Contradiction in r6 => r6c5<>6
r6c5=6 r45c6<>6 r8c6=6 r8c6<>3 r4c6=3 r6c4<>3
r6c5=6 r6c5<>3
r6c5=6 r6c5<>7 r6c7=7 r6c7<>3
r6c5=6 r3c5<>6 r3c5=3 r2c4<>3 r2c8=3 r6c8<>3
Forcing Chain Contradiction in r9c5 => r7c2<>3
r7c2=3 r7c7<>3 r9c789=3 r9c5<>3
r7c2=3 r7c2<>5 r7c4=5 r9c5<>5
r7c2=3 r1c2<>3 r1c2=6 r3c13<>6 r3c5=6 r9c5<>6
Skyscraper: 3 in r2c8,r7c7 (connected by r27c4) => r9c8<>3
2-String Kite: 3 in r4c6,r7c7 (connected by r7c4,r8c6) => r4c7<>3
Multi Colors 1: 3 (r1c2,r2c8,r3c5) / (r1c9,r2c4,r3c3,r8c2), (r4c6) / (r8c6) => r4c58,r6c5<>3
Swordfish: 3 r267 c478 => r9c7<>3
W-Wing: 6/3 in r2c4,r8c6 connected by 3 in r39c5 => r7c4<>6
Skyscraper: 6 in r1c9,r7c7 (connected by r17c2) => r9c9<>6
Turbot Fish: 6 r1c9 =6= r2c8 -6- r2c4 =6= r5c4 => r5c9<>6
W-Wing: 2/6 in r5c6,r9c8 connected by 6 in r8c6,r9c5 => r5c8<>2
XY-Wing: 3/5/6 in r7c24,r8c6 => r8c123<>6
Hidden Single: r8c6=6
Naked Single: r5c6=2
Full House: r4c6=3
Naked Single: r5c9=4
Hidden Single: r9c7=4
Hidden Single: r4c2=4
Locked Candidates Type 2 (Claiming): 3 in r8 => r9c3<>3
Skyscraper: 6 in r4c5,r6c1 (connected by r3c15) => r4c3<>6
2-String Kite: 6 in r2c8,r4c5 (connected by r2c4,r3c5) => r4c8<>6
Empty Rectangle: 6 in b4 (r7c27) => r6c7<>6
W-Wing: 6/3 in r1c2,r7c7 connected by 3 in r19c9 => r7c2<>6
Naked Single: r7c2=5
Naked Single: r2c2=9
Naked Single: r7c4=3
Full House: r7c7=6
Full House: r9c5=5
Naked Single: r9c3=6
Naked Single: r2c3=5
Naked Single: r2c4=6
Full House: r2c8=3
Full House: r3c5=3
Full House: r1c9=6
Naked Single: r4c7=7
Full House: r6c7=3
Naked Single: r9c8=2
Full House: r9c9=3
Full House: r4c9=2
Naked Single: r5c5=9
Naked Single: r6c5=7
Full House: r4c5=6
Naked Single: r3c3=1
Full House: r3c1=6
Naked Single: r1c2=3
Naked Single: r4c8=1
Naked Single: r6c3=8
Naked Single: r8c2=1
Full House: r5c2=6
Naked Single: r4c4=8
Full House: r4c3=9
Full House: r6c1=1
Naked Single: r1c3=2
Full House: r1c1=8
Full House: r8c1=2
Full House: r8c3=3
Naked Single: r5c8=5
Full House: r5c4=1
Full House: r6c4=5
Full House: r6c8=6
|
normal_sudoku_6659
|
.3.4.16.8498.6..15....5.43.........69......8.7..8...4.6.1..5..384.6.3......1.....
|
235491678498367215167258439583724196924516387716839542671945823842673951359182764
|
Basic 9x9 Sudoku 6659
|
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 . 1 6 . 8
4 9 8 . 6 . . 1 5
. . . . 5 . 4 3 .
. . . . . . . . 6
9 . . . . . . 8 .
7 . . 8 . . . 4 .
6 . 1 . . 5 . . 3
8 4 . 6 . 3 . . .
. . . 1 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
235491678498367215167258439583724196924516387716839542671945823842673951359182764 #1 Extreme (3998)
Hidden Single: r2c1=4
Hidden Single: r3c6=8
Hidden Single: r4c2=8
Hidden Single: r7c5=4
Hidden Single: r9c9=4
Hidden Single: r9c8=6
Hidden Single: r2c4=3
Hidden Single: r7c7=8
Hidden Single: r9c5=8
Skyscraper: 9 in r1c5,r7c4 (connected by r17c8) => r3c4,r8c5<>9
Hidden Single: r3c9=9
Hidden Single: r1c5=9
Finned X-Wing: 7 c59 r58 fr4c5 => r5c46<>7
Grouped Discontinuous Nice Loop: 5 r5c3 -5- r6c23 =5= r6c7 =9= r6c6 =6= r5c6 =4= r5c3 => r5c3<>5
Forcing Chain Contradiction in r9c6 => r6c7<>2
r6c7=2 r2c7<>2 r2c6=2 r9c6<>2
r6c7=2 r56c9<>2 r8c9=2 r8c5<>2 r8c5=7 r9c6<>7
r6c7=2 r6c7<>9 r6c6=9 r9c6<>9
Forcing Chain Contradiction in r9 => r7c4<>2
r7c4=2 r7c2<>2 r7c2=7 r9c2<>7
r7c4=2 r7c2<>2 r7c2=7 r9c3<>7
r7c4=2 r7c4<>9 r9c6=9 r9c6<>7
r7c4=2 r3c4<>2 r3c4=7 r2c6<>7 r2c7=7 r9c7<>7
Turbot Fish: 2 r2c7 =2= r2c6 -2- r9c6 =2= r8c5 => r8c7<>2
Sashimi X-Wing: 2 r17 c28 fr1c1 fr1c3 => r3c2<>2
Grouped Discontinuous Nice Loop: 2 r4c7 -2- r2c7 =2= r2c6 -2- r9c6 =2= r8c5 -2- r8c9 =2= r56c9 -2- r4c7 => r4c7<>2
Grouped Discontinuous Nice Loop: 7 r4c6 -7- r2c6 -2- r9c6 =2= r8c5 =7= r45c5 -7- r4c6 => r4c6<>7
Grouped Discontinuous Nice Loop: 2 r5c7 -2- r2c7 =2= r2c6 -2- r9c6 =2= r8c5 -2- r8c9 =2= r56c9 -2- r5c7 => r5c7<>2
Almost Locked Set XZ-Rule: A=r17c8 {279}, B=r7c4,r8c5 {279}, X=9, Z=2 => r8c8<>2
Forcing Chain Contradiction in c2 => r1c8=7
r1c8<>7 r1c3=7 r3c2<>7
r1c8<>7 r1c8=2 r7c8<>2 r7c2=2 r7c2<>7
r1c8<>7 r2c7=7 r2c6<>7 r9c6=7 r9c2<>7
Full House: r2c7=2
Full House: r2c6=7
Full House: r3c4=2
Naked Single: r3c1=1
Naked Single: r5c4=5
W-Wing: 7/2 in r7c2,r8c5 connected by 2 in r7c8,r8c9 => r7c4,r8c3<>7
Naked Single: r7c4=9
Full House: r4c4=7
Naked Single: r7c8=2
Full House: r7c2=7
Naked Single: r9c6=2
Full House: r8c5=7
Naked Single: r3c2=6
Full House: r3c3=7
Naked Single: r9c2=5
Naked Single: r8c9=1
Naked Single: r9c1=3
Naked Single: r6c9=2
Full House: r5c9=7
Naked Single: r9c3=9
Full House: r8c3=2
Full House: r9c7=7
Naked Single: r6c2=1
Full House: r5c2=2
Naked Single: r1c3=5
Full House: r1c1=2
Full House: r4c1=5
Naked Single: r6c5=3
Naked Single: r4c8=9
Full House: r8c8=5
Full House: r8c7=9
Naked Single: r5c5=1
Full House: r4c5=2
Naked Single: r6c3=6
Naked Single: r4c6=4
Naked Single: r6c7=5
Full House: r6c6=9
Full House: r5c6=6
Naked Single: r5c7=3
Full House: r4c7=1
Full House: r4c3=3
Full House: r5c3=4
|
normal_sudoku_877
|
.....1.3..9.36.8.72..7..1.....8..9...5.1...46....49.851..2......6..8.57...7513...
|
578421639491365827236798154624857913859132746713649285145276398362984571987513462
|
Basic 9x9 Sudoku 877
|
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 .
. 9 . 3 6 . 8 . 7
2 . . 7 . . 1 . .
. . . 8 . . 9 . .
. 5 . 1 . . . 4 6
. . . . 4 9 . 8 5
1 . . 2 . . . . .
. 6 . . 8 . 5 7 .
. . 7 5 1 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
578421639491365827236798154624857913859132746713649285145276398362984571987513462 #1 Easy (218)
Naked Single: r5c4=1
Naked Single: r8c6=4
Naked Single: r6c4=6
Naked Single: r8c4=9
Full House: r1c4=4
Naked Single: r7c5=7
Full House: r7c6=6
Naked Single: r8c1=3
Naked Single: r7c8=9
Naked Single: r6c1=7
Naked Single: r8c3=2
Full House: r8c9=1
Hidden Single: r2c3=1
Naked Single: r6c3=3
Naked Single: r6c7=2
Full House: r6c2=1
Naked Single: r1c7=6
Naked Single: r4c8=1
Naked Single: r4c9=3
Full House: r5c7=7
Naked Single: r3c8=5
Naked Single: r9c7=4
Full House: r7c7=3
Naked Single: r5c6=2
Naked Single: r2c8=2
Full House: r9c8=6
Naked Single: r3c5=9
Naked Single: r3c6=8
Naked Single: r7c9=8
Full House: r9c9=2
Naked Single: r9c2=8
Full House: r9c1=9
Naked Single: r2c6=5
Full House: r1c5=2
Full House: r2c1=4
Full House: r4c6=7
Naked Single: r4c5=5
Full House: r5c5=3
Naked Single: r1c9=9
Full House: r3c9=4
Naked Single: r7c2=4
Full House: r7c3=5
Naked Single: r1c2=7
Naked Single: r5c1=8
Full House: r5c3=9
Naked Single: r3c2=3
Full House: r3c3=6
Full House: r4c2=2
Naked Single: r4c1=6
Full House: r1c1=5
Full House: r1c3=8
Full House: r4c3=4
|
normal_sudoku_681
|
5..9.......6..5.8..3..1...7....8.41..4..2387.........3...2...6..1..4.7.8..9...2..
|
527938641196475382834612957352789416641523879978164523483297165215346798769851234
|
Basic 9x9 Sudoku 681
|
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 . . 9 . . . . .
. . 6 . . 5 . 8 .
. 3 . . 1 . . . 7
. . . . 8 . 4 1 .
. 4 . . 2 3 8 7 .
. . . . . . . . 3
. . . 2 . . . 6 .
. 1 . . 4 . 7 . 8
. . 9 . . . 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
527938641196475382834612957352789416641523879978164523483297165215346798769851234 #1 Extreme (20706) bf
Brute Force: r5c5=2
2-String Kite: 9 in r6c5,r8c8 (connected by r7c5,r8c6) => r6c8<>9
Empty Rectangle: 9 in b1 (r5c19) => r2c9<>9
Empty Rectangle: 9 in b6 (r67c5) => r7c9<>9
Locked Candidates Type 2 (Claiming): 9 in c9 => r6c7<>9
Discontinuous Nice Loop: 6 r6c6 -6- r6c7 -5- r3c7 =5= r3c8 =9= r8c8 -9- r8c6 -6- r6c6 => r6c6<>6
Grouped Discontinuous Nice Loop: 6 r1c6 -6- r8c6 -9- r8c8 =9= r3c8 =5= r3c7 =6= r1c79 -6- r1c6 => r1c6<>6
Forcing Chain Contradiction in c5 => r3c8<>2
r3c8=2 r3c8<>5 r3c7=5 r3c7<>6 r1c79=6 r1c5<>6
r3c8=2 r3c8<>5 r3c7=5 r6c7<>5 r6c7=6 r6c5<>6
r3c8=2 r3c8<>9 r8c8=9 r8c6<>9 r8c6=6 r9c5<>6
Forcing Chain Contradiction in c5 => r3c8<>4
r3c8=4 r3c8<>5 r3c7=5 r3c7<>6 r1c79=6 r1c5<>6
r3c8=4 r3c8<>5 r3c7=5 r6c7<>5 r6c7=6 r6c5<>6
r3c8=4 r3c8<>9 r8c8=9 r8c6<>9 r8c6=6 r9c5<>6
Forcing Chain Contradiction in r8 => r6c1<>2
r6c1=2 r8c1<>2 r8c3=2 r8c3<>5
r6c1=2 r6c8<>2 r6c8=5 r6c5<>5 r456c4=5 r8c4<>5
r6c1=2 r6c8<>2 r6c8=5 r8c8<>5
Forcing Chain Contradiction in c5 => r6c3<>2
r6c3=2 r6c8<>2 r6c8=5 r6c7<>5 r6c7=6 r3c7<>6 r1c79=6 r1c5<>6
r6c3=2 r6c8<>2 r6c8=5 r6c7<>5 r6c7=6 r6c5<>6
r6c3=2 r8c3<>2 r8c1=2 r8c1<>6 r8c46=6 r9c5<>6
Forcing Chain Contradiction in c5 => r6c5<>5
r6c5=5 r6c7<>5 r6c7=6 r3c7<>6 r1c79=6 r1c5<>6
r6c5=5 r6c5<>6
r6c5=5 r6c5<>9 r7c5=9 r8c6<>9 r8c6=6 r9c5<>6
Locked Candidates Type 1 (Pointing): 5 in b5 => r89c4<>5
Grouped Discontinuous Nice Loop: 1 r2c9 -1- r2c1 =1= r1c3 -1- r5c3 -5- r8c3 =5= r8c8 =9= r7c7 =1= r12c7 -1- r2c9 => r2c9<>1
Almost Locked Set XZ-Rule: A=r8c1468 {23569}, B=r279c9 {1245}, X=5, Z=2 => r2c1<>2
Skyscraper: 2 in r2c9,r6c8 (connected by r26c2) => r1c8,r4c9<>2
Hidden Single: r6c8=2
Almost Locked Set XY-Wing: A=r6c12357 {156789}, B=r8c1346 {23569}, C=r5c3 {15}, X,Y=1,5, Z=9 => r6c6<>9
Almost Locked Set XY-Wing: A=r1c23,r2c2,r3c13 {124789}, B=r12c5,r2c4 {3467}, C=r1c789,r2c9 {12346}, X,Y=1,6, Z=4 => r2c1<>4
Discontinuous Nice Loop: 4 r3c6 -4- r2c4 =4= r2c9 =2= r1c9 -2- r1c6 =2= r3c6 => r3c6<>4
Grouped Discontinuous Nice Loop: 3 r2c4 -3- r8c4 -6- r8c6 -9- r8c8 =9= r7c7 =3= r12c7 -3- r1c8 -4- r2c9 =4= r2c4 => r2c4<>3
Locked Candidates Type 1 (Pointing): 3 in b2 => r79c5<>3
Grouped Discontinuous Nice Loop: 3 r8c1 -3- r7c13 =3= r7c7 =9= r8c8 =5= r8c3 =2= r8c1 => r8c1<>3
Grouped Discontinuous Nice Loop: 3 r8c3 -3- r7c13 =3= r7c7 =9= r8c8 =5= r8c3 => r8c3<>3
Forcing Chain Contradiction in r4 => r2c4=4
r2c4<>4 r2c9=4 r1c8<>4 r1c8=3 r12c7<>3 r7c7=3 r7c7<>9 r8c8=9 r8c8<>5 r8c3=5 r8c3<>2 r8c1=2 r4c1<>2
r2c4<>4 r2c9=4 r2c9<>2 r2c2=2 r4c2<>2
r2c4<>4 r2c9=4 r1c8<>4 r1c8=3 r12c7<>3 r7c7=3 r7c3<>3 r4c3=3 r4c3<>2
Naked Single: r2c9=2
Hidden Single: r6c6=4
Locked Candidates Type 1 (Pointing): 4 in b3 => r1c3<>4
Locked Candidates Type 1 (Pointing): 1 in b5 => r9c4<>1
Discontinuous Nice Loop: 6 r6c4 -6- r6c7 -5- r3c7 =5= r3c8 -5- r8c8 =5= r8c3 -5- r5c3 -1- r5c4 =1= r6c4 => r6c4<>6
Forcing Chain Contradiction in r5 => r6c4=1
r6c4<>1 r5c4=1 r5c3<>1 r5c3=5 r8c3<>5 r8c3=2 r8c1<>2 r8c1=6 r5c1<>6
r6c4<>1 r5c4=1 r5c4<>6
r6c4<>1 r5c4=1 r5c3<>1 r5c3=5 r8c3<>5 r8c8=5 r3c8<>5 r3c7=5 r6c7<>5 r6c7=6 r5c9<>6
Finned Swordfish: 5 r368 c378 fr6c2 => r45c3<>5
Naked Single: r5c3=1
Hidden Single: r2c1=1
Naked Triple: 2,7,8 in r1c236 => r1c5<>7
Empty Rectangle: 7 in b5 (r2c25) => r4c2<>7
Grouped Discontinuous Nice Loop: 9 r4c2 -9- r2c2 -7- r2c5 -3- r1c5 -6- r1c9 =6= r13c7 -6- r6c7 -5- r6c23 =5= r4c2 => r4c2<>9
Discontinuous Nice Loop: 7 r7c5 -7- r2c5 =7= r2c2 =9= r6c2 -9- r6c5 =9= r7c5 => r7c5<>7
XY-Chain: 5 5- r7c5 -9- r8c6 -6- r8c1 -2- r8c3 -5 => r7c23<>5
Discontinuous Nice Loop: 7 r9c5 -7- r2c5 =7= r2c2 =9= r6c2 -9- r6c5 =9= r7c5 =5= r9c5 => r9c5<>7
Naked Triple: 5,6,9 in r79c5,r8c6 => r7c6<>9, r89c4,r9c6<>6
Naked Single: r8c4=3
Naked Pair: 5,9 in r38c8 => r9c8<>5
XY-Wing: 6/9/5 in r8c68,r9c5 => r9c9<>5
AIC: 6 6- r5c1 -9- r5c9 =9= r4c9 -9- r4c6 =9= r8c6 -9- r8c8 -5- r8c3 =5= r6c3 -5- r6c7 -6 => r5c9,r6c12<>6
Skyscraper: 6 in r5c4,r8c6 (connected by r58c1) => r4c6<>6
2-String Kite: 6 in r1c9,r6c5 (connected by r4c9,r6c7) => r1c5<>6
Naked Single: r1c5=3
Naked Single: r1c8=4
Naked Single: r2c5=7
Naked Single: r9c8=3
Naked Single: r2c2=9
Full House: r2c7=3
Locked Candidates Type 1 (Pointing): 6 in b2 => r3c7<>6
Locked Candidates Type 1 (Pointing): 7 in b5 => r4c13<>7
Swordfish: 6 r358 c146 => r4c14,r9c1<>6
Hidden Pair: 5,6 in r9c25 => r9c2<>7, r9c2<>8
W-Wing: 5/6 in r6c7,r9c2 connected by 6 in r4c29 => r6c2<>5
Naked Pair: 7,8 in r67c2 => r1c2<>7, r1c2<>8
Naked Single: r1c2=2
Naked Single: r1c6=8
Naked Single: r1c3=7
Naked Single: r3c4=6
Full House: r3c6=2
Naked Single: r5c4=5
Naked Single: r4c4=7
Full House: r9c4=8
Naked Single: r5c9=9
Full House: r5c1=6
Naked Single: r4c6=9
Full House: r6c5=6
Naked Single: r4c2=5
Naked Single: r8c1=2
Naked Single: r8c6=6
Naked Single: r6c7=5
Full House: r4c9=6
Naked Single: r9c5=5
Full House: r7c5=9
Naked Single: r6c3=8
Naked Single: r9c2=6
Naked Single: r4c1=3
Full House: r4c3=2
Naked Single: r8c3=5
Full House: r8c8=9
Full House: r3c8=5
Naked Single: r3c7=9
Naked Single: r1c9=1
Full House: r1c7=6
Full House: r7c7=1
Naked Single: r3c3=4
Full House: r3c1=8
Full House: r7c3=3
Naked Single: r6c2=7
Full House: r6c1=9
Full House: r7c2=8
Naked Single: r9c9=4
Full House: r7c9=5
Naked Single: r7c6=7
Full House: r7c1=4
Full House: r9c1=7
Full House: r9c6=1
|
normal_sudoku_2622
|
5....3...1....7...4.72...36...124...8.5..6.12.1....49.2.6.3..71951......7..6..8..
|
528963147163547289497281536379124658845396712612758493286435971951872364734619825
|
Basic 9x9 Sudoku 2622
|
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 . . . . 3 . . .
1 . . . . 7 . . .
4 . 7 2 . . . 3 6
. . . 1 2 4 . . .
8 . 5 . . 6 . 1 2
. 1 . . . . 4 9 .
2 . 6 . 3 . . 7 1
9 5 1 . . . . . .
7 . . 6 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
528963147163547289497281536379124658845396712612758493286435971951872364734619825 #1 Medium (374)
Naked Single: r3c1=4
Hidden Single: r5c2=4
Naked Single: r7c2=8
Naked Single: r9c2=3
Full House: r9c3=4
Naked Single: r3c2=9
Hidden Single: r6c3=2
Naked Single: r1c3=8
Naked Single: r2c3=3
Full House: r4c3=9
Hidden Single: r6c1=6
Full House: r4c1=3
Full House: r4c2=7
Hidden Single: r7c4=4
Naked Single: r1c4=9
Hidden Single: r5c5=9
Locked Triple: 2,7,8 in r8c456 => r8c78,r9c6<>2
Hidden Single: r8c6=2
Hidden Single: r9c8=2
Naked Single: r1c8=4
Naked Single: r1c9=7
Naked Single: r8c8=6
Naked Single: r8c7=3
Naked Single: r5c7=7
Full House: r5c4=3
Naked Single: r8c9=4
Hidden Single: r2c5=4
Hidden Single: r4c7=6
Hidden Single: r6c9=3
Hidden Single: r2c2=6
Full House: r1c2=2
Naked Single: r1c7=1
Full House: r1c5=6
Naked Single: r3c7=5
Naked Single: r2c8=8
Full House: r4c8=5
Full House: r4c9=8
Naked Single: r7c7=9
Full House: r2c7=2
Full House: r2c9=9
Full House: r2c4=5
Full House: r7c6=5
Full House: r9c9=5
Naked Single: r6c6=8
Naked Single: r9c5=1
Full House: r9c6=9
Full House: r3c6=1
Full House: r3c5=8
Naked Single: r6c4=7
Full House: r6c5=5
Full House: r8c5=7
Full House: r8c4=8
|
normal_sudoku_4369
|
9...4...8..8..3.5....8..7..86..3...1..3..8.6.2.5..6.8...2.8...6.5...2...3..6...2.
|
921745638748963152536821749864237591193458267275196483412589376659372814387614925
|
Basic 9x9 Sudoku 4369
|
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
. . 8 . . 3 . 5 .
. . . 8 . . 7 . .
8 6 . . 3 . . . 1
. . 3 . . 8 . 6 .
2 . 5 . . 6 . 8 .
. . 2 . 8 . . . 6
. 5 . . . 2 . . .
3 . . 6 . . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
921745638748963152536821749864237591193458267275196483412589376659372814387614925 #1 Extreme (30600) bf
Hidden Single: r5c6=8
Hidden Single: r3c1=5
Hidden Single: r8c7=8
Hidden Single: r9c2=8
X-Wing: 5 c59 r59 => r5c47,r9c67<>5
Brute Force: r5c4=4
Brute Force: r5c5=5
Hidden Single: r4c7=5
Hidden Single: r9c9=5
Hidden Single: r4c4=2
Locked Candidates Type 1 (Pointing): 1 in b5 => r6c2<>1
Naked Triple: 1,7,9 in r689c5 => r23c5<>1, r2c5<>7, r23c5<>9
Discontinuous Nice Loop: 2 r2c2 -2- r2c5 -6- r2c7 =6= r1c7 =2= r1c2 -2- r2c2 => r2c2<>2
Hidden Pair: 2,3 in r13c2 => r13c2<>1, r1c2<>7, r3c2<>4
Finned Swordfish: 4 r348 c389 fr8c1 => r9c3<>4
Forcing Chain Contradiction in r4 => r8c4<>7
r8c4=7 r9c56<>7 r9c3=7 r4c3<>7
r8c4=7 r12c4<>7 r1c6=7 r4c6<>7
r8c4=7 r8c9<>7 r78c8=7 r4c8<>7
Forcing Net Contradiction in r7 => r1c4<>1
r1c4=1 (r3c6<>1 r3c6=9 r4c6<>9 r4c6=7 r4c8<>7) (r6c4<>1 r6c5=1 r6c5<>9 r6c4=9 r6c7<>9) (r1c8<>1 r1c8=3 r7c8<>3) r1c4<>5 r1c6=5 r7c6<>5 r7c4=5 r7c4<>3 r7c7=3 r6c7<>3 r6c7=4 r4c8<>4 r4c8=9 (r5c7<>9) r5c9<>9 r5c2=9 r7c2<>9
r1c4=1 r1c4<>5 r1c6=5 r7c6<>5 r7c4=5 r7c4<>9
r1c4=1 r3c6<>1 r3c6=9 r7c6<>9
r1c4=1 (r1c8<>1 r1c8=3 r7c8<>3) r1c4<>5 r1c6=5 r7c6<>5 r7c4=5 r7c4<>3 r7c7=3 r7c7<>9
r1c4=1 (r3c6<>1 r3c6=9 r4c6<>9 r4c6=7 r4c8<>7) (r6c4<>1 r6c5=1 r6c5<>9 r6c4=9 r6c7<>9) (r1c8<>1 r1c8=3 r7c8<>3) r1c4<>5 r1c6=5 r7c6<>5 r7c4=5 r7c4<>3 r7c7=3 r6c7<>3 r6c7=4 r4c8<>4 r4c8=9 r7c8<>9
Hidden Rectangle: 5/7 in r1c46,r7c46 => r7c6<>7
Forcing Net Contradiction in r6c7 => r2c7<>4
r2c7=4 (r2c7<>6 r1c7=6 r1c7<>2 r1c2=2 r3c2<>2 r3c2=3 r3c9<>3) (r2c9<>4) (r3c9<>4) (r3c8<>4) r3c9<>4 r3c3=4 r4c3<>4 r4c8=4 r6c9<>4 r8c9=4 r8c9<>3 r6c9=3 r6c7<>3
r2c7=4 r6c7<>4
r2c7=4 (r2c7<>1) r2c7<>6 r1c7=6 (r1c7<>1) (r1c7<>3) r1c7<>2 r1c2=2 r1c2<>3 r1c8=3 r1c8<>1 r3c8=1 r3c6<>1 r3c6=9 r4c6<>9 r6c45=9 r6c7<>9
Forcing Net Verity => r3c9<>3
r8c1=4 r8c1<>6 (r2c1=6 r2c5<>6 r2c5=2 r3c5<>2) r8c3=6 r1c3<>6 r1c7=6 r1c7<>2 r1c2=2 r3c2<>2 r3c9=2 r3c9<>3
r8c3=4 (r3c3<>4) r4c3<>4 r4c8=4 r3c8<>4 r3c9=4 r3c9<>3
r8c8=4 (r3c8<>4) r4c8<>4 r4c3=4 r3c3<>4 r3c9=4 r3c9<>3
r8c9=4 (r7c7<>4) r9c7<>4 r6c7=4 r6c7<>3 r6c9=3 r3c9<>3
Forcing Chain Contradiction in r6c7 => r9c6<>1
r9c6=1 r9c6<>4 r7c6=4 r7c6<>5 r7c4=5 r7c4<>3 r8c4=3 r8c9<>3 r6c9=3 r6c7<>3
r9c6=1 r9c6<>4 r9c7=4 r6c7<>4
r9c6=1 r3c6<>1 r3c6=9 r4c6<>9 r6c45=9 r6c7<>9
Forcing Chain Contradiction in r6c7 => r9c6<>9
r9c6=9 r9c6<>4 r7c6=4 r7c6<>5 r7c4=5 r7c4<>3 r8c4=3 r8c9<>3 r6c9=3 r6c7<>3
r9c6=9 r9c6<>4 r9c7=4 r6c7<>4
r9c6=9 r4c6<>9 r6c45=9 r6c7<>9
Forcing Net Verity => r1c2=2
r4c8=7 (r4c8<>4 r4c3=4 r3c3<>4) r4c6<>7 r4c6=9 r3c6<>9 r3c6=1 r3c3<>1 r3c3=6 r1c3<>6 r1c7=6 r1c7<>2 r1c2=2
r5c9=7 r5c9<>2 r5c7=2 r1c7<>2 r1c2=2
r6c9=7 (r6c5<>7 r4c6=7 r1c6<>7) r6c9<>3 (r6c7=3 r7c7<>3) r8c9=3 r7c8<>3 r7c4=3 r7c4<>5 r7c6=5 r1c6<>5 r1c6=1 r1c8<>1 r1c8=3 r1c2<>3 r1c2=2
Naked Single: r3c2=3
Forcing Net Contradiction in r7c7 => r9c6=4
r9c6<>4 (r9c7=4 r6c7<>4) r7c6=4 r7c6<>5 r7c4=5 r7c4<>3 r8c4=3 (r8c9<>3) r8c9<>3 r6c9=3 (r6c9<>4 r6c2=4 r4c3<>4 r4c8=4 r4c8<>7 r78c8=7 r8c9<>7) r6c7<>3 r6c7=9 (r7c7<>9) (r5c7<>9) r5c9<>9 r5c2=9 r4c3<>9 (r56c2=9 r7c2<>9) r4c6=9 (r7c6<>9) (r4c8<>9) r3c6<>9 r2c4=9 r7c4<>9 r7c8=9 r8c9<>9 r8c9=4 r9c7<>4 r9c6=4
Forcing Net Verity => r1c7<>1
r7c2=9 (r8c3<>9) r9c3<>9 r4c3=9 (r4c6<>9 r3c6=9 r3c8<>9) r4c3<>4 r4c8=4 r3c8<>4 r3c8=1 r1c7<>1
r7c4=9 (r2c4<>9 r3c6=9 r3c6<>1) r7c4<>5 r7c6=5 r7c6<>1 r1c6=1 r1c7<>1
r7c6=9 (r3c6<>9 r3c6=1 r3c3<>1) (r4c6<>9 r4c6=7 r4c3<>7) (r7c2<>9) (r8c5<>9) r9c5<>9 r6c5=9 r6c2<>9 r5c2=9 r4c3<>9 r4c3=4 r3c3<>4 r3c3=6 r1c3<>6 r1c7=6 r1c7<>1
r7c7=9 r9c7<>9 r9c7=1 r1c7<>1
r7c8=9 r9c7<>9 r9c7=1 r1c7<>1
Forcing Net Contradiction in r7c7 => r2c1<>1
r2c1=1 (r7c1<>1) r5c1<>1 r5c1=7 (r6c2<>7) r7c1<>7 r7c1=4 r7c7<>4 r6c7=4 (r4c8<>4 r4c3=4 r3c3<>4) r6c2<>4 r6c2=9 (r6c4<>9) r6c5<>9 r4c6=9 (r4c6<>7 r1c6=7 r1c3<>7) r3c6<>9 r3c6=1 r3c3<>1 r3c3=6 r1c3<>6 r1c3=1 r2c1<>1
Forcing Net Contradiction in r4 => r2c4<>1
r2c4=1 r3c6<>1 r3c6=9 r4c6<>9 r4c6=7
r2c4=1 (r1c6<>1) r3c6<>1 r7c6=1 (r7c2<>1 r5c2=1 r5c1<>1 r5c1=7 r5c9<>7) r7c6<>5 r7c4=5 r7c4<>3 r8c4=3 r8c9<>3 r6c9=3 r6c9<>7 r8c9=7 (r7c8<>7) r8c8<>7 r4c8=7
Locked Candidates Type 1 (Pointing): 1 in b2 => r7c6<>1
Forcing Chain Contradiction in r9c3 => r3c3<>1
r3c3=1 r9c3<>1
r3c3=1 r3c6<>1 r3c6=9 r2c4<>9 r2c4=7 r1c46<>7 r1c3=7 r9c3<>7
r3c3=1 r2c2<>1 r2c7=1 r9c7<>1 r9c7=9 r9c3<>9
Forcing Chain Contradiction in c1 => r1c7=6
r1c7<>6 r1c3=6 r3c3<>6 r3c3=4 r2c1<>4
r1c7<>6 r1c3=6 r3c3<>6 r3c3=4 r4c3<>4 r4c8=4 r6c7<>4 r7c7=4 r7c1<>4
r1c7<>6 r1c3=6 r8c3<>6 r8c1=6 r8c1<>4
Hidden Single: r1c8=3
Naked Triple: 1,2,9 in r259c7 => r67c7<>9, r7c7<>1
Turbot Fish: 1 r1c3 =1= r2c2 -1- r2c7 =1= r9c7 => r9c3<>1
Simple Colors Trap: 1 (r1c3,r2c7,r3c6,r9c5) / (r1c6,r2c2,r3c8,r8c3,r9c7) => r8c45<>1
Discontinuous Nice Loop: 4/7/9 r6c9 =3= r6c7 -3- r7c7 =3= r7c4 =1= r9c5 -1- r9c7 =1= r2c7 -1- r3c8 =1= r3c6 =9= r2c4 -9- r8c4 -3- r8c9 =3= r6c9 => r6c9<>4, r6c9<>7, r6c9<>9
Naked Single: r6c9=3
Naked Single: r6c7=4
Naked Single: r7c7=3
Hidden Single: r8c4=3
Hidden Single: r4c3=4
Naked Single: r3c3=6
Naked Single: r3c5=2
Naked Single: r2c5=6
Hidden Single: r8c1=6
Locked Candidates Type 1 (Pointing): 4 in b1 => r2c9<>4
Locked Candidates Type 1 (Pointing): 9 in b4 => r7c2<>9
Locked Candidates Type 1 (Pointing): 4 in b7 => r7c8<>4
Swordfish: 1 r138 c368 => r7c8<>1
Naked Pair: 7,9 in r47c8 => r38c8<>9, r8c8<>7
Skyscraper: 9 in r3c9,r4c8 (connected by r34c6) => r5c9<>9
Uniqueness Test 6: 2/9 in r2c79,r5c79 => r2c7,r5c9<>2
Naked Single: r5c9=7
Naked Single: r4c8=9
Full House: r4c6=7
Full House: r5c7=2
Naked Single: r5c1=1
Full House: r5c2=9
Full House: r6c2=7
Naked Single: r7c8=7
Naked Single: r7c1=4
Full House: r2c1=7
Naked Single: r7c2=1
Full House: r2c2=4
Full House: r1c3=1
Naked Single: r2c4=9
Naked Single: r1c6=5
Full House: r1c4=7
Full House: r3c6=1
Full House: r7c6=9
Full House: r7c4=5
Full House: r6c4=1
Full House: r6c5=9
Naked Single: r2c7=1
Full House: r2c9=2
Full House: r9c7=9
Naked Single: r3c8=4
Full House: r3c9=9
Full House: r8c9=4
Full House: r8c8=1
Naked Single: r8c5=7
Full House: r8c3=9
Full House: r9c3=7
Full House: r9c5=1
|
normal_sudoku_3374
|
1.6.8...3...6...2...9.......9.74..3.3.2..8..447.3..1..5.38....1.87.15....14.3....
|
126984753835671429749523618691742835352168974478359162563897241287415396914236587
|
Basic 9x9 Sudoku 3374
|
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 . 8 . . . 3
. . . 6 . . . 2 .
. . 9 . . . . . .
. 9 . 7 4 . . 3 .
3 . 2 . . 8 . . 4
4 7 . 3 . . 1 . .
5 . 3 8 . . . . 1
. 8 7 . 1 5 . . .
. 1 4 . 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
126984753835671429749523618691742835352168974478359162563897241287415396914236587 #1 Unfair (1548)
Naked Single: r8c3=7
Hidden Single: r3c8=1
Hidden Single: r2c6=1
Hidden Single: r8c7=3
Hidden Single: r5c4=1
Hidden Single: r4c3=1
Hidden Single: r2c2=3
Hidden Single: r3c6=3
Hidden Single: r2c7=4
Locked Candidates Type 1 (Pointing): 5 in b5 => r23c5<>5
Locked Candidates Type 2 (Claiming): 5 in r4 => r5c78,r6c89<>5
Empty Rectangle: 9 in b5 (r2c59) => r6c9<>9
W-Wing: 2/6 in r4c6,r7c2 connected by 6 in r4c1,r5c2 => r7c6<>2
Finned Swordfish: 6 c258 r567 fr8c8 fr9c8 => r7c7<>6
Finned Swordfish: 7 r157 c678 fr7c5 => r9c6<>7
Locked Candidates Type 1 (Pointing): 7 in b8 => r7c78<>7
Naked Triple: 2,6,9 in r9c146 => r9c79<>2, r9c789<>6, r9c789<>9
Naked Triple: 2,6,9 in r469c6 => r1c6<>2, r17c6<>9, r7c6<>6
Turbot Fish: 9 r1c4 =9= r2c5 -9- r2c9 =9= r8c9 => r8c4<>9
Sashimi X-Wing: 9 r27 c59 fr7c7 fr7c8 => r8c9<>9
Hidden Single: r2c9=9
Naked Single: r2c5=7
Naked Single: r1c6=4
Naked Single: r2c1=8
Full House: r2c3=5
Full House: r6c3=8
Naked Single: r3c5=2
Naked Single: r7c6=7
Naked Single: r4c1=6
Full House: r5c2=5
Naked Single: r1c2=2
Naked Single: r3c1=7
Full House: r3c2=4
Full House: r7c2=6
Naked Single: r3c4=5
Full House: r1c4=9
Naked Single: r4c6=2
Naked Single: r7c5=9
Naked Single: r9c4=2
Full House: r8c4=4
Full House: r9c6=6
Full House: r6c6=9
Naked Single: r5c5=6
Full House: r6c5=5
Naked Single: r7c7=2
Full House: r7c8=4
Naked Single: r9c1=9
Full House: r8c1=2
Naked Single: r6c8=6
Full House: r6c9=2
Naked Single: r8c9=6
Full House: r8c8=9
Naked Single: r3c9=8
Full House: r3c7=6
Naked Single: r5c8=7
Full House: r5c7=9
Naked Single: r4c9=5
Full House: r4c7=8
Full House: r9c9=7
Naked Single: r1c8=5
Full House: r1c7=7
Full House: r9c7=5
Full House: r9c8=8
|
normal_sudoku_1663
|
....3.8...15...6..........41.3....4..7..1.....94..71.59..5...7..37..4....5.1..9.3
|
649735821715248639328691754163859247572416398894327165981563472237984516456172983
|
Basic 9x9 Sudoku 1663
|
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 . 8 . .
. 1 5 . . . 6 . .
. . . . . . . . 4
1 . 3 . . . . 4 .
. 7 . . 1 . . . .
. 9 4 . . 7 1 . 5
9 . . 5 . . . 7 .
. 3 7 . . 4 . . .
. 5 . 1 . . 9 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
649735821715248639328691754163859247572416398894327165981563472237984516456172983 #1 Extreme (22976) bf
Hidden Single: r4c1=1
Hidden Single: r5c4=4
Hidden Single: r2c5=4
Hidden Single: r7c3=1
Hidden Single: r9c5=7
Hidden Single: r9c1=4
Hidden Single: r7c7=4
Hidden Single: r7c6=3
Hidden Single: r5c1=5
Hidden Single: r6c4=3
Hidden Single: r1c2=4
Brute Force: r4c6=9
Hidden Single: r4c5=5
Naked Triple: 2,6,8 in r259c6 => r13c6<>2, r13c6<>6, r3c6<>8
Uniqueness Test 3: 1/5 in r1c68,r3c68 => r8c8<>2, r8c8<>6, r8c8<>8
Empty Rectangle: 6 in b9 (r59c6) => r5c9<>6
W-Wing: 5/1 in r1c6,r8c8 connected by 1 in r3c68 => r1c8<>5
Hidden Single: r1c6=5
Naked Single: r3c6=1
Hidden Rectangle: 2/5 in r3c78,r8c78 => r3c8<>2
Forcing Net Verity => r3c2<>6
r4c2=6 r3c2<>6
r4c4=6 (r1c4<>6) r3c4<>6 r3c5=6 r3c2<>6
r4c9=6 (r6c8<>6) (r5c8<>6) r6c8<>6 r9c8=6 (r9c3<>6) r9c6<>6 r5c6=6 r6c5<>6 r6c1=6 r8c1<>6 r7c2=6 r3c2<>6
Brute Force: r4c9=7
Naked Single: r4c7=2
Naked Single: r5c7=3
Naked Single: r8c7=5
Full House: r3c7=7
Naked Single: r8c8=1
Hidden Single: r3c8=5
Hidden Single: r1c9=1
Hidden Single: r3c1=3
Hidden Single: r2c8=3
Locked Candidates Type 1 (Pointing): 6 in b6 => r9c8<>6
W-Wing: 8/2 in r2c6,r9c8 connected by 2 in r1c8,r2c9 => r9c6<>8
Empty Rectangle: 8 in b6 (r9c38) => r5c3<>8
W-Wing: 6/8 in r4c4,r6c8 connected by 8 in r4c2,r6c1 => r6c5<>6
W-Wing: 2/8 in r3c2,r6c5 connected by 8 in r4c24 => r3c5<>2
XY-Wing: 2/9/8 in r2c69,r5c9 => r5c6<>8
Hidden Single: r2c6=8
Locked Candidates Type 1 (Pointing): 2 in b2 => r8c4<>2
Locked Candidates Type 2 (Claiming): 8 in r5 => r6c8<>8
Naked Single: r6c8=6
X-Wing: 6 r59 c36 => r13c3<>6
Hidden Single: r1c1=6
Hidden Single: r1c4=7
Hidden Single: r2c1=7
Swordfish: 2 r159 c368 => r3c3<>2
Skyscraper: 8 in r4c4,r6c1 (connected by r8c14) => r4c2,r6c5<>8
Naked Single: r4c2=6
Full House: r4c4=8
Naked Single: r6c5=2
Full House: r5c6=6
Full House: r6c1=8
Full House: r5c3=2
Full House: r9c6=2
Full House: r8c1=2
Naked Single: r1c3=9
Full House: r1c8=2
Full House: r2c9=9
Full House: r2c4=2
Naked Single: r9c8=8
Full House: r5c8=9
Full House: r5c9=8
Full House: r9c3=6
Full House: r7c2=8
Full House: r3c3=8
Full House: r3c2=2
Naked Single: r8c9=6
Full House: r7c9=2
Full House: r7c5=6
Naked Single: r8c4=9
Full House: r3c4=6
Full House: r3c5=9
Full House: r8c5=8
|
normal_sudoku_5109
|
76.8......5..9.6....4..6.5.2.7...3...4...2.9.....1..........5.94..5.7.6.6.5..947.
|
769851234352794618184236957217968345548372196936415782871643529493527861625189473
|
Basic 9x9 Sudoku 5109
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 6 . 8 . . . . .
. 5 . . 9 . 6 . .
. . 4 . . 6 . 5 .
2 . 7 . . . 3 . .
. 4 . . . 2 . 9 .
. . . . 1 . . . .
. . . . . . 5 . 9
4 . . 5 . 7 . 6 .
6 . 5 . . 9 4 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
769851234352794618184236957217968345548372196936415782871643529493527861625189473 #1 Extreme (34268) bf
Hidden Single: r7c7=5
Hidden Single: r7c2=7
2-String Kite: 7 in r2c9,r5c5 (connected by r2c4,r3c5) => r5c9<>7
Brute Force: r5c4=3
Forcing Net Contradiction in r7 => r2c9<>3
r2c9=3 (r2c9<>7 r2c4=7 r3c5<>7) (r2c6<>3) (r1c8<>3) r2c8<>3 r7c8=3 r7c6<>3 r1c6=3 r3c5<>3 r3c5=2 r3c2<>2 r89c2=2 r7c3<>2
r2c9=3 (r2c9<>7 r2c4=7 r3c4<>7) (r2c9<>7 r2c4=7 r3c5<>7) (r2c6<>3) (r1c8<>3) r2c8<>3 r7c8=3 r7c6<>3 r1c6=3 r3c5<>3 r3c5=2 r3c4<>2 r3c4=1 r9c4<>1 r9c4=2 r7c4<>2
r2c9=3 (r2c9<>7 r2c4=7 r3c5<>7) (r2c6<>3) (r1c8<>3) r2c8<>3 r7c8=3 r7c6<>3 r1c6=3 r3c5<>3 r3c5=2 r7c5<>2
r2c9=3 (r1c8<>3) r2c8<>3 r7c8=3 r7c8<>2
Brute Force: r5c5=7
Naked Triple: 2,3,8 in r389c5 => r17c5<>2, r17c5<>3, r47c5<>8
Locked Candidates Type 1 (Pointing): 8 in b5 => r7c6<>8
Forcing Net Contradiction in r1c7 => r2c4<>1
r2c4=1 (r2c4<>7 r2c9=7 r6c9<>7 r6c7=7 r6c7<>2) r9c4<>1 r9c4=2 (r9c2<>2) (r8c5<>2) r9c5<>2 r3c5=2 (r3c7<>2) r3c2<>2 r8c2=2 r8c7<>2 r1c7=2
r2c4=1 r9c4<>1 r9c4=2 (r9c2<>2) (r8c5<>2) r9c5<>2 r3c5=2 r3c2<>2 r8c2=2 r8c2<>9 r8c3=9 r1c3<>9 r1c7=9
Forcing Net Contradiction in r3c9 => r3c9<>2
r3c9=2 (r6c9<>2) (r2c8<>2) (r2c9<>2) (r1c7<>2) (r1c8<>2) r1c9<>2 r1c3=2 (r7c3<>2) r2c3<>2 r2c4=2 r7c4<>2 r7c8=2 r6c8<>2 r6c7=2 r6c7<>7 r6c9=7 r2c9<>7 r2c4=7 r2c4<>2 r3c45=2 r3c9<>2
Forcing Net Contradiction in r1c7 => r7c4<>1
r7c4=1 r9c4<>1 r9c4=2 (r3c4<>2 r3c4=7 r2c4<>7 r2c9=7 r6c9<>7 r6c7=7 r6c7<>2) (r9c2<>2) (r8c5<>2) r9c5<>2 r3c5=2 (r3c7<>2) r3c2<>2 r8c2=2 r8c7<>2 r1c7=2
r7c4=1 r9c4<>1 r9c4=2 (r9c2<>2) (r8c5<>2) r9c5<>2 r3c5=2 r3c2<>2 r8c2=2 r8c2<>9 r8c3=9 r1c3<>9 r1c7=9
Forcing Net Verity => r9c9<>1
r7c6=1 (r7c1<>1) (r7c3<>1) r9c4<>1 r9c4=2 (r9c2<>2) (r8c5<>2) r9c5<>2 r3c5=2 r3c2<>2 r8c2=2 (r8c2<>1) r8c2<>9 r8c3=9 r8c3<>1 r9c2=1 r9c9<>1
r9c4=1 r9c9<>1
Brute Force: r5c3=8
Naked Single: r5c7=1
Naked Single: r5c1=5
Full House: r5c9=6
Hidden Single: r6c3=6
Hidden Single: r4c2=1
Hidden Single: r9c4=1
Hidden Single: r4c4=9
Naked Single: r6c4=4
Hidden Single: r4c5=6
Naked Single: r7c5=4
Naked Single: r1c5=5
Naked Single: r7c6=3
Hidden Single: r7c4=6
Hidden Single: r3c5=3
Locked Candidates Type 1 (Pointing): 3 in b9 => r1c9<>3
Naked Pair: 2,8 in r8c57 => r8c239<>2, r8c29<>8
Naked Pair: 3,9 in r68c2 => r3c2<>9, r9c2<>3
Hidden Single: r9c9=3
Naked Single: r8c9=1
Hidden Single: r3c1=1
Naked Single: r7c1=8
Naked Single: r2c1=3
Full House: r6c1=9
Full House: r6c2=3
Naked Single: r7c8=2
Full House: r7c3=1
Full House: r8c7=8
Naked Single: r9c2=2
Full House: r9c5=8
Full House: r8c5=2
Naked Single: r2c3=2
Naked Single: r8c2=9
Full House: r3c2=8
Full House: r1c3=9
Full House: r8c3=3
Naked Single: r6c8=8
Naked Single: r2c4=7
Full House: r3c4=2
Naked Single: r3c9=7
Full House: r3c7=9
Naked Single: r1c7=2
Full House: r6c7=7
Naked Single: r4c8=4
Naked Single: r6c6=5
Full House: r4c6=8
Full House: r4c9=5
Full House: r6c9=2
Naked Single: r1c9=4
Full House: r2c9=8
Naked Single: r2c8=1
Full House: r1c8=3
Full House: r1c6=1
Full House: r2c6=4
|
normal_sudoku_6449
|
8..........14..78..4..5...1..2..9...4..5.3..75.61....8.6....3...........1..7...56
|
857291463921436785643857921372689514418523697596174238765918342284365179139742856
|
Basic 9x9 Sudoku 6449
|
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 4 . . 7 8 .
. 4 . . 5 . . . 1
. . 2 . . 9 . . .
4 . . 5 . 3 . . 7
5 . 6 1 . . . . 8
. 6 . . . . 3 . .
. . . . . . . . .
1 . . 7 . . . 5 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
857291463921436785643857921372689514418523697596174238765918342284365179139742856 #1 Extreme (33184) bf
Brute Force: r5c6=3
Forcing Net Contradiction in r3 => r2c5<>2
r2c5=2 r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c1<>2
r2c5=2 r3c4<>2
r2c5=2 r3c6<>2
r2c5=2 (r9c5<>2) (r6c5<>2 r6c6=2 r9c6<>2) (r2c1<>2) (r2c2<>2) r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c1<>2 r1c2=2 r9c2<>2 r9c7=2 r3c7<>2
r2c5=2 (r9c5<>2) (r6c5<>2 r6c6=2 r9c6<>2) (r2c1<>2) (r2c2<>2) r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c1<>2 r1c2=2 r9c2<>2 r9c7=2 r56c7<>2 r56c8=2 r3c8<>2
Brute Force: r5c5=2
Locked Pair: 4,7 in r6c56 => r4c5,r6c2<>7, r4c5,r6c78<>4
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c78<>6
Locked Candidates Type 1 (Pointing): 8 in b5 => r4c2<>8
Forcing Net Contradiction in r7 => r1c6<>2
r1c6=2 r1c6<>1 r1c5=1 r7c5<>1
r1c6=2 (r9c6<>2) r1c6<>1 r1c5=1 r1c5<>7 r6c5=7 r6c6<>7 (r3c6=7 r3c6<>8 r3c4=8 r7c4<>8) r6c6=4 r9c6<>4 r9c6=8 (r7c5<>8) r7c6<>8 r7c3=8 r7c3<>5 r7c6=5 r7c6<>1
r1c6=2 (r9c6<>2) r1c6<>1 r1c5=1 r1c5<>7 r6c5=7 r6c6<>7 (r3c6=7 r3c6<>8 r3c4=8 r7c4<>8) r6c6=4 r9c6<>4 r9c6=8 (r7c5<>8) r7c6<>8 r7c3=8 (r7c3<>7) r5c3<>8 r5c3=9 r6c2<>9 r6c2=3 r4c1<>3 r4c1=7 r7c1<>7 r7c8=7 r7c8<>1
Forcing Net Contradiction in r7 => r1c6<>6
r1c6=6 r1c6<>1 r1c5=1 r7c5<>1
r1c6=6 (r2c6<>6 r2c6=2 r9c6<>2) r1c6<>1 r1c5=1 r1c5<>7 r6c5=7 r6c6<>7 (r3c6=7 r3c6<>8 r3c4=8 r7c4<>8) r6c6=4 r9c6<>4 r9c6=8 (r7c5<>8) r7c6<>8 r7c3=8 r7c3<>5 r7c6=5 r7c6<>1
r1c6=6 (r2c6<>6 r2c6=2 r9c6<>2) r1c6<>1 r1c5=1 r1c5<>7 r6c5=7 r6c6<>7 (r3c6=7 r3c6<>8 r3c4=8 r7c4<>8) r6c6=4 r9c6<>4 r9c6=8 (r7c5<>8) r7c6<>8 r7c3=8 (r7c3<>7) r5c3<>8 r5c3=9 r6c2<>9 r6c2=3 r4c1<>3 r4c1=7 r7c1<>7 r7c8=7 r7c8<>1
Forcing Net Contradiction in r7c8 => r2c5<>6
r2c5=6 (r2c6<>6 r2c6=2 r9c6<>2) (r2c6<>6 r2c6=2 r2c1<>2) (r2c6<>6 r2c6=2 r2c2<>2) r2c1<>6 r3c1=6 r3c1<>2 r1c2=2 r9c2<>2 r9c7=2 (r3c7<>2) r6c7<>2 r6c7=9 r3c7<>9 r3c7=6 r3c1<>6 r2c1=6 r2c5<>6
Forcing Net Contradiction in c2 => r2c2<>9
r2c2=9 (r6c2<>9 r6c2=3 r4c1<>3) r2c5<>9 r2c5=3 (r2c1<>3) (r1c4<>3) r3c4<>3 r8c4=3 r8c1<>3 r3c1=3 (r3c1<>2) r3c1<>6 r2c1=6 (r2c1<>2) r2c6<>6 r2c6=2 r2c2<>2 r1c2=2
r2c2=9 (r9c2<>9) (r5c2<>9) r6c2<>9 (r6c2=3 r9c2<>3) r5c3=9 r5c3<>8 r5c2=8 r9c2<>8 r9c2=2
Forcing Net Contradiction in r3 => r3c1<>3
r3c1=3 r3c1<>2
r3c1=3 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r3c4<>2
r3c1=3 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r3c6<>2
r3c1=3 (r3c1<>2) r3c1<>6 r2c1=6 (r2c1<>2) r2c6<>6 r2c6=2 (r9c6<>2) r2c2<>2 r1c2=2 r9c2<>2 r9c7=2 r3c7<>2
r3c1=3 (r3c1<>2) r3c1<>6 r2c1=6 (r2c1<>2) r2c6<>6 r2c6=2 (r9c6<>2) r2c2<>2 r1c2=2 r9c2<>2 r9c7=2 r6c7<>2 r6c8=2 r3c8<>2
Forcing Net Contradiction in r3c7 => r2c9<>9
r2c9=9 r2c5<>9 r2c5=3 (r2c1<>3) (r1c4<>3) r3c4<>3 r8c4=3 r8c1<>3 r4c1=3 r6c2<>3 r6c2=9 r6c7<>9 r6c7=2 r3c7<>2
r2c9=9 (r2c9<>3) r2c5<>9 r2c5=3 (r2c2<>3) (r2c1<>3) (r1c4<>3) r3c4<>3 r8c4=3 (r8c2<>3) r8c1<>3 r4c1=3 (r4c2<>3) (r6c2<>3) r4c9<>3 r1c9=3 r1c2<>3 r9c2=3 (r9c2<>2) r6c2<>3 r6c2=9 r6c7<>9 r6c7=2 r9c7<>2 r9c6=2 r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c7<>6
r2c9=9 r3c7<>9
Forcing Chain Contradiction in r9 => r1c2<>9
r1c2=9 r9c2<>9
r1c2=9 r23c1<>9 r78c1=9 r9c3<>9
r1c2=9 r2c1<>9 r2c5=9 r9c5<>9
r1c2=9 r1c9<>9 r78c9=9 r9c7<>9
Forcing Chain Contradiction in r9 => r1c3<>9
r1c3=9 r5c3<>9 r56c2=9 r9c2<>9
r1c3=9 r9c3<>9
r1c3=9 r2c1<>9 r2c5=9 r9c5<>9
r1c3=9 r1c9<>9 r78c9=9 r9c7<>9
Forcing Chain Contradiction in r8 => r8c5<>9
r8c5=9 r2c5<>9 r2c5=3 r13c4<>3 r8c4=3 r8c4<>6
r8c5=9 r8c5<>6
r8c5=9 r2c5<>9 r2c1=9 r2c1<>6 r2c6=6 r8c6<>6
Forcing Net Contradiction in r1c3 => r1c2<>3
r1c2=3 (r3c3<>3) r6c2<>3 r6c8=3 r3c8<>3 r3c4=3 r3c4<>8 r3c6=8 r3c6<>7 r1c56=7 r1c3<>7
r1c2=3 (r1c3<>3) (r2c1<>3) (r2c2<>3) (r3c3<>3) r6c2<>3 r6c8=3 r3c8<>3 r3c4=3 r2c5<>3 r2c9=3 r2c9<>5 r2c2=5 r1c3<>5 r1c3=7
Forcing Net Verity => r1c7<>2
r2c1=9 (r2c1<>3) r2c5<>9 r2c5=3 (r1c4<>3) r3c4<>3 r8c4=3 r8c1<>3 r4c1=3 r6c2<>3 r6c2=9 r6c7<>9 r6c7=2 r1c7<>2
r3c1=9 (r3c1<>2) r3c1<>6 r2c1=6 (r2c1<>2) r2c6<>6 r2c6=2 r2c2<>2 r1c2=2 r1c7<>2
r7c1=9 (r9c2<>9) (r9c3<>9) r2c1<>9 r2c5=9 r9c5<>9 r9c7=9 r6c7<>9 r6c7=2 r1c7<>2
r8c1=9 (r9c2<>9) (r9c3<>9) r2c1<>9 r2c5=9 r9c5<>9 r9c7=9 r6c7<>9 r6c7=2 r1c7<>2
Forcing Net Verity => r1c8<>3
r2c1=3 (r2c1<>9) r2c1<>6 r3c1=6 (r3c8<>6) (r3c7<>6) r3c1<>9 r3c3=9 (r3c8<>9) r3c7<>9 r3c7=2 r3c8<>2 r3c8=3 r1c8<>3
r2c2=3 r6c2<>3 r6c8=3 r1c8<>3
r2c5=3 (r2c9<>3) (r2c1<>3) (r1c4<>3) r3c4<>3 r8c4=3 r8c1<>3 r4c1=3 r4c9<>3 r1c9=3 r1c8<>3
r2c9=3 r1c8<>3
Forcing Net Verity => r1c9<>2
r2c1=9 (r2c1<>3) r2c5<>9 r2c5=3 (r2c9<>3) (r1c4<>3) r3c4<>3 r8c4=3 r8c1<>3 r4c1=3 r4c9<>3 r1c9=3 r1c9<>2
r3c1=9 (r3c1<>2) r3c1<>6 r2c1=6 (r2c1<>2) r2c6<>6 r2c6=2 r2c2<>2 r1c2=2 r1c9<>2
r7c1=9 (r7c9<>9) (r7c4<>9) r2c1<>9 r2c5=9 (r1c4<>9) r3c4<>9 r8c4=9 r8c9<>9 r1c9=9 r1c9<>2
r8c1=9 (r8c9<>9) (r8c4<>9) r2c1<>9 r2c5=9 (r1c4<>9) r3c4<>9 r7c4=9 r7c9<>9 r1c9=9 r1c9<>2
Forcing Chain Contradiction in r3c7 => r8c7<>2
r8c7=2 r3c7<>2
r8c7=2 r78c9<>2 r2c9=2 r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c7<>6
r8c7=2 r6c7<>2 r6c7=9 r3c7<>9
Forcing Chain Contradiction in r3c7 => r9c7<>2
r9c7=2 r3c7<>2
r9c7=2 r78c9<>2 r2c9=2 r2c6<>2 r2c6=6 r2c1<>6 r3c1=6 r3c7<>6
r9c7=2 r6c7<>2 r6c7=9 r3c7<>9
Forcing Chain Contradiction in b1 => r3c1<>7
r3c1=7 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r9c6<>2 r9c2=2 r1c2<>2
r3c1=7 r3c1<>6 r2c1=6 r2c1<>2
r3c1=7 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r2c2<>2
r3c1=7 r3c1<>2
Forcing Chain Contradiction in b1 => r3c1<>9
r3c1=9 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r9c6<>2 r9c2=2 r1c2<>2
r3c1=9 r3c1<>6 r2c1=6 r2c1<>2
r3c1=9 r3c1<>6 r2c1=6 r2c6<>6 r2c6=2 r2c2<>2
r3c1=9 r3c1<>2
AIC: 6 6- r2c6 =6= r2c1 =9= r3c3 =7= r3c6 =8= r3c4 -8- r4c4 -6 => r13c4<>6
Discontinuous Nice Loop: 3 r3c4 -3- r2c5 -9- r2c1 =9= r3c3 =7= r3c6 =8= r3c4 => r3c4<>3
Skyscraper: 3 in r3c3,r6c2 (connected by r36c8) => r2c2<>3
Discontinuous Nice Loop: 3 r2c9 -3- r2c5 -9- r2c1 =9= r3c3 =3= r3c8 -3- r2c9 => r2c9<>3
Naked Pair: 2,5 in r2c29 => r2c16<>2
Naked Single: r2c6=6
Hidden Single: r3c1=6
Locked Candidates Type 1 (Pointing): 2 in b1 => r89c2<>2
Hidden Single: r9c6=2
Naked Pair: 2,9 in r36c7 => r1589c7<>9
2-String Kite: 3 in r2c1,r8c4 (connected by r1c4,r2c5) => r8c1<>3
Skyscraper: 3 in r1c9,r2c1 (connected by r4c19) => r1c3<>3
Naked Triple: 2,5,7 in r1c23,r2c2 => r3c3<>7
Hidden Single: r3c6=7
Naked Single: r1c6=1
Naked Single: r6c6=4
Naked Single: r6c5=7
Hidden Single: r3c4=8
Naked Single: r4c4=6
Full House: r4c5=8
Naked Single: r7c4=9
Naked Single: r8c4=3
Full House: r1c4=2
Naked Single: r9c5=4
Naked Single: r7c5=1
Naked Single: r9c7=8
Naked Single: r8c5=6
Hidden Single: r2c2=2
Naked Single: r2c9=5
Hidden Single: r4c7=5
Locked Candidates Type 1 (Pointing): 9 in b9 => r8c123<>9
Hidden Single: r2c1=9
Full House: r2c5=3
Full House: r1c5=9
Naked Single: r3c3=3
Naked Single: r9c3=9
Full House: r9c2=3
Naked Single: r5c3=8
Naked Single: r6c2=9
Naked Single: r5c2=1
Naked Single: r6c7=2
Full House: r6c8=3
Naked Single: r4c2=7
Full House: r4c1=3
Naked Single: r5c7=6
Full House: r5c8=9
Naked Single: r3c7=9
Full House: r3c8=2
Naked Single: r4c9=4
Full House: r4c8=1
Naked Single: r1c2=5
Full House: r1c3=7
Full House: r8c2=8
Naked Single: r1c7=4
Full House: r8c7=1
Naked Single: r1c9=3
Full House: r1c8=6
Naked Single: r7c9=2
Full House: r8c9=9
Naked Single: r8c6=5
Full House: r7c6=8
Naked Single: r7c1=7
Full House: r8c1=2
Naked Single: r8c3=4
Full House: r7c3=5
Full House: r7c8=4
Full House: r8c8=7
|
normal_sudoku_6721
|
9..1..3....7.5...........726...9..8...3.486....16......4......53...2..4.1..9..8..
|
962187354417352968538469172674291583253748619891635427746813295389526741125974836
|
Basic 9x9 Sudoku 6721
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . . 1 . . 3 . .
. . 7 . 5 . . . .
. . . . . . . 7 2
6 . . . 9 . . 8 .
. . 3 . 4 8 6 . .
. . 1 6 . . . . .
. 4 . . . . . . 5
3 . . . 2 . . 4 .
1 . . 9 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
962187354417352968538469172674291583253748619891635427746813295389526741125974836 #1 Extreme (14594) bf
Locked Candidates Type 1 (Pointing): 9 in b4 => r8c2<>9
Hidden Pair: 1,3 in r23c2 => r2c2<>2, r23c2<>6, r23c2<>8, r3c2<>5
Brute Force: r5c5=4
Hidden Single: r9c6=4
Hidden Single: r7c5=1
Hidden Single: r4c6=1
Locked Candidates Type 1 (Pointing): 5 in b8 => r8c23<>5
Locked Candidates Type 1 (Pointing): 8 in b8 => r23c4<>8
Turbot Fish: 4 r1c9 =4= r1c3 -4- r4c3 =4= r6c1 => r6c9<>4
Grouped Discontinuous Nice Loop: 4 r3c7 -4- r3c4 -3- r4c4 =3= r4c9 =4= r46c7 -4- r3c7 => r3c7<>4
Finned Franken Swordfish: 6 r27b1 c368 fr1c2 fr2c9 => r1c8<>6
Naked Single: r1c8=5
Almost Locked Set XZ-Rule: A=r6c5 {37}, B=r5c89,r6c89 {12379}, X=3, Z=7 => r6c7<>7
Almost Locked Set XY-Wing: A=r679c8 {2369}, B=r4c23,r5c12 {24579}, C=r45689c9 {134679}, X,Y=4,6, Z=9 => r5c8<>9
Forcing Chain Verity => r1c9<>6
r1c2=8 r6c2<>8 r6c1=8 r6c1<>4 r4c3=4 r1c3<>4 r1c9=4 r1c9<>6
r1c3=8 r1c3<>4 r1c9=4 r1c9<>6
r2c1=8 r2c9<>8 r1c9=8 r1c9<>6
r3c1=8 r3c1<>5 r3c3=5 r3c3<>6 r1c23=6 r1c9<>6
r3c3=8 r3c3<>6 r1c23=6 r1c9<>6
Locked Candidates Type 1 (Pointing): 6 in b3 => r2c6<>6
Forcing Chain Contradiction in c1 => r5c8=1
r5c8<>1 r2c8=1 r2c8<>6 r2c9=6 r2c9<>8 r2c1=8 r2c1<>2
r5c8<>1 r5c8=2 r5c1<>2
r5c8<>1 r2c8=1 r2c8<>6 r2c9=6 r2c9<>8 r1c9=8 r1c9<>4 r1c3=4 r4c3<>4 r6c1=4 r6c1<>2
r5c8<>1 r5c8=2 r9c8<>2 r7c78=2 r7c1<>2
Discontinuous Nice Loop: 7 r4c7 -7- r5c9 -9- r5c2 =9= r6c2 =8= r6c1 =4= r6c7 =5= r4c7 => r4c7<>7
Locked Candidates Type 1 (Pointing): 7 in b6 => r89c9<>7
Discontinuous Nice Loop: 6 r9c2 -6- r9c9 -3- r4c9 =3= r4c4 -3- r6c5 -7- r9c5 =7= r9c2 => r9c2<>6
Discontinuous Nice Loop: 6 r9c3 -6- r9c9 -3- r4c9 =3= r4c4 -3- r6c5 -7- r9c5 =7= r9c2 =5= r9c3 => r9c3<>6
Almost Locked Set XZ-Rule: A=r4c23,r5c1 {2457}, B=r456c9,r6c8 {23479}, X=4, Z=2 => r6c12<>2
Almost Locked Set XY-Wing: A=r9c23 {257}, B=r456c9,r6c8 {23479}, C=r4c237 {2457}, X,Y=4,7, Z=2 => r9c8<>2
Locked Pair: 3,6 in r9c89 => r7c8,r9c5<>3, r7c8,r8c9,r9c5<>6
Naked Single: r9c5=7
Naked Single: r6c5=3
Hidden Single: r1c6=7
Hidden Single: r4c9=3
Naked Single: r9c9=6
Naked Single: r9c8=3
Hidden Single: r2c8=6
Locked Pair: 7,9 in r56c9 => r28c9,r6c78<>9
Naked Single: r8c9=1
Naked Single: r6c8=2
Full House: r7c8=9
Naked Single: r6c6=5
Naked Single: r8c7=7
Full House: r7c7=2
Naked Single: r6c7=4
Naked Single: r8c6=6
Naked Single: r4c7=5
Naked Single: r7c6=3
Naked Single: r8c2=8
Naked Single: r3c6=9
Full House: r2c6=2
Naked Single: r7c4=8
Full House: r8c4=5
Full House: r8c3=9
Naked Single: r7c1=7
Full House: r7c3=6
Naked Single: r3c7=1
Full House: r2c7=9
Naked Single: r6c1=8
Naked Single: r3c2=3
Naked Single: r2c1=4
Naked Single: r2c2=1
Naked Single: r3c4=4
Naked Single: r2c4=3
Full House: r2c9=8
Full House: r1c9=4
Naked Single: r3c1=5
Full House: r5c1=2
Naked Single: r3c3=8
Full House: r3c5=6
Full House: r1c5=8
Naked Single: r4c2=7
Naked Single: r4c3=4
Full House: r4c4=2
Full House: r5c4=7
Naked Single: r1c3=2
Full House: r1c2=6
Full House: r9c3=5
Full House: r9c2=2
Naked Single: r6c2=9
Full House: r5c2=5
Full House: r5c9=9
Full House: r6c9=7
|
normal_sudoku_4742
|
..1.4..2.7..6..9.192..15.....7..451.3...7...2.1.5...7.......3.8..315..4......8..6
|
631849725754623981928715634267384519385971462419562873146297358893156247572438196
|
Basic 9x9 Sudoku 4742
|
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 .
7 . . 6 . . 9 . 1
9 2 . . 1 5 . . .
. . 7 . . 4 5 1 .
3 . . . 7 . . . 2
. 1 . 5 . . . 7 .
. . . . . . 3 . 8
. . 3 1 5 . . 4 .
. . . . . 8 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
631849725754623981928715634267384519385971462419562873146297358893156247572438196 #1 Hard (692)
Hidden Single: r3c5=1
Hidden Single: r5c6=1
Hidden Single: r7c1=1
Hidden Single: r9c7=1
Hidden Single: r1c9=5
Hidden Single: r8c7=2
Hidden Single: r9c1=5
Naked Single: r9c8=9
Naked Single: r7c8=5
Full House: r8c9=7
Hidden Single: r6c1=4
Hidden Single: r5c7=4
Hidden Single: r3c9=4
Hidden Single: r4c1=2
Locked Candidates Type 2 (Claiming): 2 in c4 => r7c56,r9c5<>2
Naked Single: r9c5=3
Naked Pair: 6,8 in r1c1,r3c3 => r1c2<>6, r12c2,r2c3<>8
Naked Single: r1c2=3
Naked Pair: 6,9 in r7c5,r8c6 => r7c46<>9, r7c6<>6
Naked Single: r7c6=7
Naked Single: r1c6=9
Naked Single: r8c6=6
Naked Single: r7c5=9
Naked Single: r8c1=8
Full House: r1c1=6
Full House: r8c2=9
Naked Single: r3c3=8
Hidden Single: r9c2=7
Naked Pair: 6,8 in r4c25 => r4c4<>8
Skyscraper: 8 in r1c4,r6c5 (connected by r16c7) => r2c5,r5c4<>8
Naked Single: r2c5=2
Naked Single: r5c4=9
Naked Single: r2c6=3
Full House: r6c6=2
Naked Single: r4c4=3
Naked Single: r2c8=8
Naked Single: r3c4=7
Full House: r1c4=8
Full House: r1c7=7
Naked Single: r4c9=9
Full House: r6c9=3
Naked Single: r5c8=6
Full House: r3c8=3
Full House: r3c7=6
Full House: r6c7=8
Naked Single: r5c3=5
Full House: r5c2=8
Naked Single: r6c5=6
Full House: r4c5=8
Full House: r4c2=6
Full House: r6c3=9
Naked Single: r2c3=4
Full House: r2c2=5
Full House: r7c2=4
Naked Single: r9c3=2
Full House: r7c3=6
Full House: r7c4=2
Full House: r9c4=4
|
normal_sudoku_4857
|
.1..28....23.5...48.5..312......47...5.....42.....59.....3..4...42.8153.........1
|
714628395923157684865493127239814756157936842486275913591362478642781539378549261
|
Basic 9x9 Sudoku 4857
|
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 . . 2 8 . . .
. 2 3 . 5 . . . 4
8 . 5 . . 3 1 2 .
. . . . . 4 7 . .
. 5 . . . . . 4 2
. . . . . 5 9 . .
. . . 3 . . 4 . .
. 4 2 . 8 1 5 3 .
. . . . . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
714628395923157684865493127239814756157936842486275913591362478642781539378549261 #1 Extreme (17012) bf
Hidden Single: r3c8=2
Hidden Single: r9c7=2
Hidden Single: r2c4=1
Hidden Single: r7c1=5
Hidden Single: r9c4=5
Hidden Single: r7c6=2
Hidden Single: r7c3=1
Hidden Single: r9c5=4
Hidden Single: r3c4=4
Brute Force: r5c4=9
Naked Pair: 6,7 in r18c4 => r46c4<>6, r6c4<>7
Finned Franken Swordfish: 9 r28b8 c168 fr7c5 fr8c9 => r7c8<>9
Sashimi Swordfish: 9 r378 c259 fr8c1 => r9c2<>9
Forcing Net Verity => r1c1<>9
r8c1=6 (r8c1<>9 r8c9=9 r3c9<>9) (r1c1<>6) (r2c1<>6) r8c4<>6 r1c4=6 (r1c7<>6) (r2c6<>6) r1c3<>6 r3c2=6 r3c2<>9 r3c5=9 r2c6<>9 r2c6=7 (r2c1<>7) r5c6<>7 r5c6=6 r5c7<>6 r2c7=6 r2c1<>6 r2c1=9 r1c1<>9
r8c1=7 (r8c1<>9 r8c9=9 r9c8<>9) (r2c1<>7) r8c4<>7 r1c4=7 r2c6<>7 r2c8=7 r2c8<>9 r1c8=9 r1c1<>9
r8c1=9 r1c1<>9
Forcing Net Verity => r1c3<>7
r8c1=6 (r8c1<>9 r8c9=9 r3c9<>9) (r1c1<>6) (r2c1<>6) r8c4<>6 r1c4=6 (r2c6<>6) r1c3<>6 r3c2=6 r3c2<>9 r3c5=9 r2c6<>9 r2c6=7 (r5c6<>7 r5c6=6 r5c3<>6) (r5c6<>7 r5c6=6 r5c7<>6) r1c4<>7 r1c4=6 (r2c6<>6) r1c7<>6 r1c7=3 r5c7<>3 r5c7=8 r5c3<>8 r5c3=7 r1c3<>7
r8c4=6 r1c4<>6 r1c4=7 r1c3<>7
r8c9=6 (r8c9<>9 r8c1=9 r2c1<>9) (r3c9<>6) r8c4<>6 r1c4=6 r3c5<>6 r3c2=6 r2c1<>6 r2c1=7 r1c3<>7
Forcing Net Verity => r1c1<>6
r8c1=7 (r8c1<>9) (r8c4<>7 r1c4=7 r1c9<>7 r7c9=7 r7c5<>7 r7c5=9 r9c6<>9) (r8c4<>7 r1c4=7 r2c6<>7 r2c8=7 r2c8<>9) (r2c1<>7 r3c2=7 r3c2<>9) r8c1<>9 r8c9=9 (r9c8<>9) r3c9<>9 r3c5=9 r2c6<>9 r2c1=9 (r9c1<>9) r9c1<>9 r9c3=9 r9c6<>9 r2c6=9 r2c1<>9 r4c1=9 r4c1<>2 r4c4=2 r6c4<>2 r6c1=2 r6c1<>4 r6c3=4 r1c3<>4 r1c1=4 r1c1<>6
r8c4=7 r1c4<>7 r1c4=6 r1c1<>6
r8c9=7 (r8c9<>9 r8c1=9 r2c1<>9) (r7c8<>7) (r9c8<>7) r8c4<>7 r1c4=7 r1c8<>7 r2c8=7 r2c1<>7 r2c1=6 r1c1<>6
Hidden Rectangle: 4/7 in r1c13,r6c13 => r6c3<>7
Forcing Chain Contradiction in r2 => r8c1<>7
r8c1=7 r2c1<>7
r8c1=7 r8c4<>7 r1c4=7 r2c6<>7
r8c1=7 r9c3<>7 r5c3=7 r5c3<>8 r5c7=8 r2c7<>8 r2c8=8 r2c8<>7
Forcing Chain Contradiction in r9c6 => r9c3<>9
r9c3=9 r9c3<>7 r5c3=7 r5c6<>7 r5c6=6 r9c6<>6
r9c3=9 r8c1<>9 r8c1=6 r8c4<>6 r8c4=7 r9c6<>7
r9c3=9 r9c6<>9
Forcing Chain Contradiction in r3 => r9c6<>7
r9c6=7 r9c123<>7 r7c2=7 r3c2<>7
r9c6=7 r5c6<>7 r56c5=7 r3c5<>7
r9c6=7 r8c4<>7 r8c9=7 r3c9<>7
Discontinuous Nice Loop: 6 r3c5 -6- r1c4 -7- r8c4 =7= r7c5 =9= r3c5 => r3c5<>6
Grouped Discontinuous Nice Loop: 7 r5c1 -7- r5c6 -6- r5c7 =6= r12c7 -6- r3c9 =6= r3c2 =7= r12c1 -7- r5c1 => r5c1<>7
Grouped Discontinuous Nice Loop: 7 r9c1 -7- r9c3 =7= r5c3 =8= r5c7 =6= r12c7 -6- r3c9 =6= r3c2 =7= r12c1 -7- r9c1 => r9c1<>7
Finned Franken Swordfish: 6 r38b2 c149 fr2c6 fr3c2 => r2c1<>6
Discontinuous Nice Loop: 7 r3c2 -7- r2c1 -9- r8c1 -6- r8c4 =6= r1c4 -6- r1c3 =6= r3c2 => r3c2<>7
Locked Candidates Type 1 (Pointing): 7 in b1 => r6c1<>7
Skyscraper: 7 in r3c5,r8c4 (connected by r38c9) => r1c4,r7c5<>7
Naked Single: r1c4=6
Naked Single: r1c7=3
Naked Single: r8c4=7
Hidden Single: r3c2=6
Naked Pair: 7,9 in r2c16 => r2c8<>7, r2c8<>9
Naked Triple: 6,7,8 in r5c367 => r5c15<>6, r5c5<>7
Turbot Fish: 9 r1c3 =9= r2c1 -9- r8c1 =9= r8c9 => r1c9<>9
Turbot Fish: 9 r2c1 =9= r1c3 -9- r1c8 =9= r9c8 => r9c1<>9
W-Wing: 6/9 in r7c5,r8c9 connected by 9 in r3c59 => r7c89<>6
Hidden Single: r7c5=6
Full House: r9c6=9
Naked Single: r2c6=7
Full House: r3c5=9
Full House: r5c6=6
Full House: r3c9=7
Naked Single: r2c1=9
Naked Single: r5c7=8
Full House: r2c7=6
Full House: r2c8=8
Naked Single: r1c9=5
Full House: r1c8=9
Naked Single: r1c3=4
Full House: r1c1=7
Naked Single: r8c1=6
Full House: r8c9=9
Naked Single: r5c3=7
Naked Single: r7c8=7
Naked Single: r9c1=3
Naked Single: r7c9=8
Full House: r9c8=6
Full House: r7c2=9
Naked Single: r9c3=8
Full House: r9c2=7
Naked Single: r5c1=1
Full House: r5c5=3
Naked Single: r6c8=1
Full House: r4c8=5
Naked Single: r6c3=6
Full House: r4c3=9
Naked Single: r4c1=2
Full House: r6c1=4
Naked Single: r4c5=1
Full House: r6c5=7
Naked Single: r6c9=3
Full House: r4c9=6
Naked Single: r4c4=8
Full House: r4c2=3
Full House: r6c2=8
Full House: r6c4=2
|
normal_sudoku_999
|
.23.....7...5.8.9..58......59...4.2......53.18.........7.4...8...5867..9..632....
|
423196857617548293958273416591634728762985341834712965379451682245867139186329574
|
Basic 9x9 Sudoku 999
|
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.
|
. 2 3 . . . . . 7
. . . 5 . 8 . 9 .
. 5 8 . . . . . .
5 9 . . . 4 . 2 .
. . . . . 5 3 . 1
8 . . . . . . . .
. 7 . 4 . . . 8 .
. . 5 8 6 7 . . 9
. . 6 3 2 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
423196857617548293958273416591634728762985341834712965379451682245867139186329574 #1 Easy (360)
Hidden Single: r3c3=8
Hidden Single: r6c2=3
Hidden Single: r1c7=8
Hidden Single: r5c5=8
Hidden Single: r9c2=8
Hidden Single: r6c7=9
Hidden Single: r4c5=3
Hidden Single: r7c5=5
Hidden Single: r4c9=8
Hidden Single: r7c3=9
Naked Single: r7c6=1
Full House: r9c6=9
Naked Single: r1c6=6
Naked Single: r6c6=2
Full House: r3c6=3
Hidden Single: r1c8=5
Hidden Single: r5c4=9
Naked Single: r1c4=1
Hidden Single: r2c9=3
Hidden Single: r9c7=5
Naked Single: r9c9=4
Naked Single: r9c1=1
Full House: r9c8=7
Naked Single: r8c2=4
Naked Single: r5c2=6
Full House: r2c2=1
Naked Single: r5c8=4
Naked Single: r6c8=6
Naked Single: r3c8=1
Full House: r8c8=3
Naked Single: r4c7=7
Full House: r6c9=5
Naked Single: r6c4=7
Naked Single: r8c1=2
Full House: r7c1=3
Full House: r8c7=1
Naked Single: r4c3=1
Full House: r4c4=6
Full House: r3c4=2
Full House: r6c5=1
Full House: r6c3=4
Naked Single: r5c1=7
Full House: r5c3=2
Full House: r2c3=7
Naked Single: r3c9=6
Full House: r7c9=2
Full House: r7c7=6
Naked Single: r2c5=4
Naked Single: r3c7=4
Full House: r2c7=2
Full House: r2c1=6
Naked Single: r1c5=9
Full House: r1c1=4
Full House: r3c1=9
Full House: r3c5=7
|
normal_sudoku_1211
|
.8..9..6736.....4.2...13...753.4.9...1..89....4.7.....1.6..........35..1.3......4
|
581294367369578142274613859753142986612389475948756213196427538427835691835961724
|
Basic 9x9 Sudoku 1211
|
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 . . 9 . . 6 7
3 6 . . . . . 4 .
2 . . . 1 3 . . .
7 5 3 . 4 . 9 . .
. 1 . . 8 9 . . .
. 4 . 7 . . . . .
1 . 6 . . . . . .
. . . . 3 5 . . 1
. 3 . . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
581294367369578142274613859753142986612389475948756213196427538427835691835961724 #1 Easy (310)
Naked Single: r1c2=8
Naked Single: r5c1=6
Naked Single: r5c3=2
Hidden Single: r1c7=3
Hidden Single: r3c4=6
Hidden Single: r5c4=3
Naked Single: r5c9=5
Naked Single: r5c8=7
Full House: r5c7=4
Hidden Single: r1c3=1
Hidden Single: r2c7=1
Hidden Single: r8c7=6
Hidden Single: r3c3=4
Naked Single: r1c1=5
Hidden Single: r6c5=5
Hidden Single: r2c9=2
Naked Single: r2c5=7
Naked Single: r2c3=9
Full House: r3c2=7
Naked Single: r2c6=8
Full House: r2c4=5
Naked Single: r7c5=2
Full House: r9c5=6
Naked Single: r6c3=8
Full House: r6c1=9
Naked Single: r7c2=9
Full House: r8c2=2
Naked Single: r6c7=2
Naked Single: r8c3=7
Full House: r9c3=5
Naked Single: r9c1=8
Full House: r8c1=4
Naked Single: r9c7=7
Naked Single: r9c6=1
Naked Single: r6c6=6
Naked Single: r9c4=9
Full House: r9c8=2
Naked Single: r4c6=2
Full House: r4c4=1
Naked Single: r6c9=3
Full House: r6c8=1
Naked Single: r8c4=8
Full House: r8c8=9
Naked Single: r1c6=4
Full House: r1c4=2
Full House: r7c4=4
Full House: r7c6=7
Naked Single: r4c8=8
Full House: r4c9=6
Naked Single: r7c9=8
Full House: r3c9=9
Naked Single: r3c8=5
Full House: r3c7=8
Full House: r7c7=5
Full House: r7c8=3
|
normal_sudoku_5185
|
...8.2...5....1....2..9..81.1...3.29..7...8.....9..1.6.3.2...98....396..4.9......
|
941852367578361942623497581816573429297614835354928176135246798782139654469785213
|
Basic 9x9 Sudoku 5185
|
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 . . .
5 . . . . 1 . . .
. 2 . . 9 . . 8 1
. 1 . . . 3 . 2 9
. . 7 . . . 8 . .
. . . 9 . . 1 . 6
. 3 . 2 . . . 9 8
. . . . 3 9 6 . .
4 . 9 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
941852367578361942623497581816573429297614835354928176135246798782139654469785213 #1 Extreme (16396) bf
Hidden Single: r8c6=9
Locked Candidates Type 1 (Pointing): 2 in b7 => r8c9<>2
Locked Candidates Type 1 (Pointing): 8 in b8 => r9c2<>8
Brute Force: r5c5=1
Hidden Single: r5c1=2
Hidden Single: r6c5=2
Hidden Single: r8c3=2
Hidden Single: r5c2=9
Hidden Single: r1c1=9
Hidden Single: r2c7=9
Hidden Single: r1c3=1
Hidden Single: r2c9=2
Hidden Single: r9c7=2
Hidden Single: r7c1=1
Locked Candidates Type 1 (Pointing): 3 in b4 => r6c8<>3
Locked Candidates Type 1 (Pointing): 6 in b4 => r4c45<>6
Locked Candidates Type 2 (Claiming): 3 in r1 => r2c8,r3c7<>3
Hidden Single: r1c7=3
Finned Swordfish: 6 c258 r129 fr7c5 => r9c46<>6
Forcing Chain Contradiction in c7 => r4c5<>5
r4c5=5 r1c5<>5 r1c89=5 r3c7<>5
r4c5=5 r4c7<>5
r4c5=5 r4c5<>8 r9c5=8 r9c5<>6 r9c2=6 r7c3<>6 r7c3=5 r7c7<>5
Forcing Chain Verity => r7c7<>5
r1c5=5 r1c89<>5 r3c7=5 r7c7<>5
r7c5=5 r7c7<>5
r9c5=5 r9c5<>6 r9c2=6 r7c3<>6 r7c3=5 r7c7<>5
Grouped Discontinuous Nice Loop: 7 r8c8 -7- r7c7 -4- r7c56 =4= r8c4 =1= r8c8 => r8c8<>7
Forcing Chain Verity => r6c6<>5
r7c3=5 r4c3<>5 r6c23=5 r6c6<>5
r7c5=5 r1c5<>5 r1c89=5 r3c7<>5 r4c7=5 r4c3<>5 r6c23=5 r6c6<>5
r7c6=5 r6c6<>5
Forcing Chain Contradiction in r4c4 => r4c3<>5
r4c3=5 r6c23<>5 r6c8=5 r6c8<>7 r4c7=7 r7c7<>7 r7c7=4 r7c56<>4 r8c4=4 r4c4<>4
r4c3=5 r4c4<>5
r4c3=5 r6c23<>5 r6c8=5 r6c8<>7 r6c6=7 r4c4<>7
Locked Candidates Type 1 (Pointing): 5 in b4 => r6c8<>5
Grouped Discontinuous Nice Loop: 5 r8c4 -5- r4c4 =5= r4c7 -5- r3c7 =5= r1c89 -5- r1c5 =5= r79c5 -5- r8c4 => r8c4<>5
Grouped Discontinuous Nice Loop: 5 r9c4 -5- r4c4 =5= r4c7 -5- r3c7 =5= r1c89 -5- r1c5 =5= r79c5 -5- r9c4 => r9c4<>5
Sue de Coq: r7c56 - {4567} (r7c3 - {56}, r89c4 - {147}) => r9c56<>7
Forcing Chain Contradiction in r4c3 => r2c3<>4
r2c3=4 r4c3<>4
r2c3=4 r2c3<>8 r46c3=8 r4c1<>8 r4c1=6 r4c3<>6
r2c3=4 r12c2<>4 r6c2=4 r6c2<>5 r6c3=5 r7c3<>5 r7c3=6 r9c2<>6 r9c5=6 r9c5<>8 r4c5=8 r4c3<>8
Forcing Chain Verity => r2c4<>4
r3c6=7 r3c1<>7 r8c1=7 r8c1<>8 r8c2=8 r2c2<>8 r2c3=8 r2c3<>3 r2c4=3 r2c4<>4
r6c6=7 r6c8<>7 r4c7=7 r7c7<>7 r7c7=4 r7c56<>4 r8c4=4 r2c4<>4
r7c6=7 r7c7<>7 r7c7=4 r7c56<>4 r8c4=4 r2c4<>4
Forcing Chain Contradiction in r6c6 => r3c3<>4
r3c3=4 r4c3<>4 r6c23=4 r6c6<>4
r3c3=4 r4c3<>4 r6c23=4 r6c8<>4 r6c8=7 r6c6<>7
r3c3=4 r12c2<>4 r6c2=4 r6c2<>5 r6c3=5 r7c3<>5 r7c56=5 r9c6<>5 r9c6=8 r6c6<>8
Locked Candidates Type 1 (Pointing): 4 in b1 => r6c2<>4
Hidden Rectangle: 3/6 in r2c34,r3c34 => r2c4<>6
Forcing Chain Contradiction in c5 => r6c8=7
r6c8<>7 r4c7=7 r4c7<>5 r3c7=5 r3c7<>4 r3c46=4 r1c5<>4
r6c8<>7 r4c7=7 r4c7<>5 r3c7=5 r3c7<>4 r3c46=4 r2c5<>4
r6c8<>7 r6c8=4 r6c3<>4 r4c3=4 r4c5<>4
r6c8<>7 r4c7=7 r7c7<>7 r7c7=4 r7c5<>4
X-Wing: 7 c67 r37 => r3c14,r7c5<>7
Hidden Single: r8c1=7
Hidden Single: r8c2=8
Naked Single: r6c2=5
Naked Single: r9c2=6
Full House: r7c3=5
Hidden Single: r2c3=8
Hidden Single: r2c4=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r3c46<>6
Hidden Single: r5c4=6
Hidden Single: r7c6=6
Naked Single: r7c5=4
Full House: r7c7=7
Naked Single: r8c4=1
Naked Single: r9c4=7
Hidden Single: r3c6=7
Naked Single: r2c5=6
Naked Single: r1c5=5
Full House: r3c4=4
Full House: r4c4=5
Naked Single: r2c8=4
Full House: r2c2=7
Full House: r1c2=4
Naked Single: r9c5=8
Full House: r4c5=7
Full House: r9c6=5
Naked Single: r3c7=5
Full House: r4c7=4
Naked Single: r5c6=4
Full House: r6c6=8
Naked Single: r1c8=6
Full House: r1c9=7
Naked Single: r8c8=5
Full House: r8c9=4
Naked Single: r9c9=3
Full House: r5c9=5
Full House: r5c8=3
Full House: r9c8=1
Naked Single: r4c3=6
Full House: r4c1=8
Naked Single: r6c1=3
Full House: r3c1=6
Full House: r3c3=3
Full House: r6c3=4
|
normal_sudoku_4735
|
...36..2....49.....3...8..9.6.8..2.42....45....7....1..4..8...6..1......5.6.4.78.
|
914367825875492631632518479163875294298134567457629318749283156381756942526941783
|
Basic 9x9 Sudoku 4735
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 3 6 . . 2 .
. . . 4 9 . . . .
. 3 . . . 8 . . 9
. 6 . 8 . . 2 . 4
2 . . . . 4 5 . .
. . 7 . . . . 1 .
. 4 . . 8 . . . 6
. . 1 . . . . . .
5 . 6 . 4 . 7 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
914367825875492631632518479163875294298134567457629318749283156381756942526941783 #1 Extreme (25478) bf
Brute Force: r5c6=4
Hidden Single: r6c1=4
Brute Force: r5c5=3
Locked Candidates Type 1 (Pointing): 3 in b4 => r4c8<>3
XY-Wing: 7/8/9 in r4c8,r5c39 => r4c13,r5c8<>9
Grouped Discontinuous Nice Loop: 2 r8c5 -2- r6c5 -5- r6c2 =5= r4c3 =3= r7c3 =2= r7c46 -2- r8c5 => r8c5<>2
Forcing Chain Contradiction in r3 => r7c8<>9
r7c8=9 r7c8<>5 r7c46=5 r8c5<>5 r8c5=7 r8c2<>7 r78c1=7 r3c1<>7
r7c8=9 r4c8<>9 r4c8=7 r4c56<>7 r5c4=7 r3c4<>7
r7c8=9 r7c8<>5 r7c46=5 r8c5<>5 r8c5=7 r3c5<>7
r7c8=9 r4c8<>9 r4c8=7 r3c8<>7
Forcing Chain Contradiction in r8 => r4c8=9
r4c8<>9 r4c8=7 r5c9<>7 r5c9=8 r5c3<>8 r56c2=8 r8c2<>8 r8c1=8 r8c1<>3
r4c8<>9 r6c7=9 r6c7<>3 r6c9=3 r9c9<>3 r9c6=3 r8c6<>3
r4c8<>9 r8c8=9 r8c8<>4 r8c7=4 r8c7<>3
r4c8<>9 r8c8=9 r8c8<>3
r4c8<>9 r6c7=9 r6c7<>3 r6c9=3 r8c9<>3
Locked Candidates Type 1 (Pointing): 7 in b6 => r5c4<>7
Forcing Chain Contradiction in r3 => r6c5=2
r6c5<>2 r6c5=5 r6c2<>5 r4c3=5 r3c3<>5
r6c5<>2 r6c5=5 r8c5<>5 r8c5=7 r78c4<>7 r3c4=7 r3c4<>5
r6c5<>2 r6c5=5 r3c5<>5
r6c5<>2 r6c5=5 r6c2<>5 r4c3=5 r4c3<>3 r7c3=3 r7c8<>3 r7c8=5 r3c8<>5
Finned X-Wing: 2 r37 c34 fr7c6 => r89c4<>2
AIC: 9 9- r8c7 =9= r7c7 =1= r9c9 -1- r9c4 -9 => r8c46<>9
Discontinuous Nice Loop: 2 r7c3 -2- r9c2 -9- r9c4 -1- r5c4 =1= r5c2 -1- r4c1 -3- r4c3 =3= r7c3 => r7c3<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r2c2<>2
Locked Candidates Type 2 (Claiming): 2 in r7 => r89c6<>2
Discontinuous Nice Loop: 8 r5c2 -8- r5c3 -9- r7c3 -3- r4c3 =3= r4c1 =1= r5c2 => r5c2<>8
Discontinuous Nice Loop: 5 r8c8 -5- r7c8 -3- r7c3 -9- r7c7 =9= r8c7 =4= r8c8 => r8c8<>5
Discontinuous Nice Loop: 3 r7c8 -3- r7c3 -9- r9c2 -2- r9c9 =2= r8c9 =5= r7c8 => r7c8<>3
Naked Single: r7c8=5
Grouped AIC: 2 2- r8c9 -3- r6c9 -8- r6c2 =8= r5c3 =9= r56c2 -9- r9c2 -2 => r8c2,r9c9<>2
Hidden Single: r8c9=2
Hidden Single: r9c2=2
Locked Candidates Type 2 (Claiming): 9 in r9 => r7c46<>9
Almost Locked Set XY-Wing: A=r3c1578 {14567}, B=r5689c4 {15679}, C=r8c12578 {345789}, X,Y=5,7, Z=1 => r3c4<>1
Almost Locked Set Chain: 5- r4c156 {1357} -3- r4c3 {35} -5- r12357c3 {234589} -3- r1247c6 {12357} -5 => r6c6<>5
XYZ-Wing: 1/6/9 in r59c4,r6c6 => r6c4<>9
Hidden Rectangle: 5/6 in r6c46,r8c46 => r8c6<>5
Finned Swordfish: 5 r348 c345 fr4c6 => r6c4<>5
Naked Single: r6c4=6
Naked Single: r6c6=9
Naked Single: r5c4=1
Naked Single: r5c2=9
Naked Single: r9c4=9
Naked Single: r5c3=8
Naked Single: r5c9=7
Full House: r5c8=6
Naked Single: r6c2=5
Naked Single: r4c3=3
Full House: r4c1=1
Naked Single: r7c3=9
Hidden Single: r8c6=6
Hidden Single: r3c5=1
Hidden Single: r1c1=9
Hidden Single: r8c7=9
Hidden Single: r8c8=4
Naked Single: r3c8=7
Full House: r2c8=3
Naked Single: r3c1=6
Naked Single: r3c7=4
Hidden Single: r8c1=3
Naked Single: r7c1=7
Full House: r2c1=8
Full House: r8c2=8
Naked Single: r7c4=2
Naked Single: r3c4=5
Full House: r3c3=2
Full House: r8c4=7
Full House: r8c5=5
Full House: r4c5=7
Full House: r4c6=5
Naked Single: r1c6=7
Full House: r2c6=2
Naked Single: r2c3=5
Full House: r1c3=4
Naked Single: r1c2=1
Full House: r2c2=7
Naked Single: r2c9=1
Full House: r2c7=6
Naked Single: r1c7=8
Full House: r1c9=5
Naked Single: r9c9=3
Full House: r6c9=8
Full House: r6c7=3
Full House: r7c7=1
Full House: r9c6=1
Full House: r7c6=3
|
normal_sudoku_1763
|
..12......57..8.24462...938.....2..7.23.....1...19..5.67..8.......71.6........4..
|
381249765957638124462571938196852347523467891748193256679384512234715689815926473
|
Basic 9x9 Sudoku 1763
|
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 . . . . .
. 5 7 . . 8 . 2 4
4 6 2 . . . 9 3 8
. . . . . 2 . . 7
. 2 3 . . . . . 1
. . . 1 9 . . 5 .
6 7 . . 8 . . . .
. . . 7 1 . 6 . .
. . . . . . 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
381249765957638124462571938196852347523467891748193256679384512234715689815926473 #1 Easy (346)
Naked Single: r3c3=2
Naked Single: r3c4=5
Naked Single: r2c7=1
Naked Single: r5c7=8
Naked Single: r3c5=7
Full House: r3c6=1
Naked Single: r4c7=3
Naked Single: r6c7=2
Naked Single: r6c9=6
Naked Single: r7c7=5
Full House: r1c7=7
Naked Single: r1c9=5
Full House: r1c8=6
Hidden Single: r9c5=2
Hidden Single: r9c8=7
Hidden Single: r7c8=1
Hidden Single: r4c4=8
Hidden Single: r6c6=3
Hidden Single: r7c9=2
Hidden Single: r4c3=6
Hidden Single: r8c1=2
Hidden Single: r8c8=8
Hidden Single: r6c1=7
Hidden Single: r5c6=7
Hidden Single: r7c4=3
Hidden Single: r9c6=6
Naked Single: r9c4=9
Naked Single: r2c4=6
Full House: r5c4=4
Naked Single: r7c6=4
Full House: r7c3=9
Full House: r8c6=5
Full House: r1c6=9
Naked Single: r9c9=3
Full House: r8c9=9
Naked Single: r2c5=3
Full House: r1c5=4
Full House: r2c1=9
Naked Single: r4c5=5
Full House: r5c5=6
Naked Single: r5c8=9
Full House: r5c1=5
Full House: r4c8=4
Naked Single: r8c3=4
Full House: r8c2=3
Naked Single: r4c1=1
Full House: r4c2=9
Naked Single: r6c3=8
Full House: r6c2=4
Full House: r9c3=5
Naked Single: r1c2=8
Full House: r1c1=3
Full House: r9c1=8
Full House: r9c2=1
|
normal_sudoku_4976
|
4.....7..3.6.9.....2...4.6....1....76.72.3.45...94.8..........125.8.......3..2.5.
|
415326789376598412928714563842165397697283145531947826784659231259831674163472958
|
Basic 9x9 Sudoku 4976
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . . . . 7 . .
3 . 6 . 9 . . . .
. 2 . . . 4 . 6 .
. . . 1 . . . . 7
6 . 7 2 . 3 . 4 5
. . . 9 4 . 8 . .
. . . . . . . . 1
2 5 . 8 . . . . .
. . 3 . . 2 . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
415326789376598412928714563842165397697283145531947826784659231259831674163472958 #1 Hard (494)
Naked Single: r5c4=2
Naked Single: r5c5=8
Hidden Single: r6c6=7
Hidden Single: r1c5=2
Hidden Single: r6c9=6
Hidden Single: r2c9=2
Hidden Single: r2c7=4
Hidden Single: r3c7=5
Hidden Single: r1c3=5
Hidden Single: r5c7=1
Full House: r5c2=9
Hidden Single: r6c1=5
Naked Single: r4c1=8
Locked Candidates Type 1 (Pointing): 9 in b1 => r3c9<>9
Skyscraper: 8 in r3c3,r9c2 (connected by r39c9) => r12c2,r7c3<>8
Naked Single: r1c2=1
Naked Single: r2c2=7
Naked Single: r6c2=3
Naked Single: r2c4=5
Naked Single: r3c1=9
Full House: r3c3=8
Naked Single: r4c2=4
Naked Single: r6c8=2
Full House: r6c3=1
Full House: r4c3=2
Naked Single: r7c1=7
Full House: r9c1=1
Naked Single: r3c9=3
Naked Single: r3c4=7
Full House: r3c5=1
Naked Single: r2c6=8
Full House: r2c8=1
Naked Single: r1c6=6
Full House: r1c4=3
Naked Single: r4c6=5
Full House: r4c5=6
Naked Single: r7c6=9
Full House: r8c6=1
Naked Single: r9c5=7
Naked Single: r7c3=4
Full House: r8c3=9
Naked Single: r8c5=3
Full House: r7c5=5
Naked Single: r7c4=6
Full House: r9c4=4
Naked Single: r8c9=4
Naked Single: r8c7=6
Full House: r8c8=7
Naked Single: r7c2=8
Full House: r9c2=6
Naked Single: r9c7=9
Full House: r9c9=8
Full House: r1c9=9
Full House: r1c8=8
Naked Single: r7c8=3
Full House: r4c8=9
Full House: r4c7=3
Full House: r7c7=2
|
normal_sudoku_2600
|
....84.......7..9..5.2.....5.....6.9.92..1..464....12.26.95....4.........1.3429.6
|
927184563186573492354269817571428639892631754643795128268957341439816275715342986
|
Basic 9x9 Sudoku 2600
|
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 . . .
. . . . 7 . . 9 .
. 5 . 2 . . . . .
5 . . . . . 6 . 9
. 9 2 . . 1 . . 4
6 4 . . . . 1 2 .
2 6 . 9 5 . . . .
4 . . . . . . . .
. 1 . 3 4 2 9 . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
927184563186573492354269817571428639892631754643795128268957341439816275715342986 #1 Extreme (5112)
Naked Single: r9c5=4
Hidden Single: r4c3=1
Hidden Single: r4c4=4
Hidden Single: r4c5=2
Hidden Single: r8c3=9
Hidden Single: r1c1=9
Hidden Single: r9c3=5
Locked Candidates Type 1 (Pointing): 1 in b8 => r8c89<>1
Hidden Triple: 1,4,6 in r137c8 => r137c8<>3, r1c8<>5, r137c8<>7, r37c8<>8
Hidden Rectangle: 3/9 in r3c56,r6c56 => r3c6<>3
AIC: 3/9 3- r3c5 =3= r2c6 =5= r6c6 =9= r6c5 -9 => r6c5<>3, r3c5<>9
Naked Single: r6c5=9
Hidden Single: r3c6=9
Finned X-Wing: 3 c15 r35 fr2c1 => r3c3<>3
Discontinuous Nice Loop: 1 r3c5 -1- r8c5 -6- r8c6 =6= r2c6 =3= r3c5 => r3c5<>1
Hidden Single: r8c5=1
Grouped Discontinuous Nice Loop: 3 r3c7 -3- r3c5 =3= r5c5 -3- r5c1 =3= r23c1 -3- r1c23 =3= r1c79 -3- r3c7 => r3c7<>3
Grouped Discontinuous Nice Loop: 3 r3c9 -3- r3c5 =3= r5c5 -3- r5c1 =3= r23c1 -3- r1c23 =3= r1c79 -3- r3c9 => r3c9<>3
Finned Franken Swordfish: 7 r49b8 c268 fr8c4 fr9c1 => r8c2<>7
W-Wing: 8/7 in r7c6,r9c8 connected by 7 in r7c3,r9c1 => r7c79<>8
Sashimi Swordfish: 8 r479 c268 fr7c3 fr9c1 => r8c2<>8
Naked Single: r8c2=3
Locked Candidates Type 2 (Claiming): 3 in c8 => r5c7,r6c9<>3
Naked Pair: 7,8 in r7c36 => r7c79<>7
Forcing Chain Contradiction in r5c1 => r4c8<>7
r4c8=7 r4c8<>3 r5c8=3 r5c1<>3
r4c8=7 r9c8<>7 r9c1=7 r5c1<>7
r4c8=7 r4c2<>7 r4c2=8 r5c1<>8
Skyscraper: 7 in r4c2,r7c3 (connected by r47c6) => r6c3<>7
AIC: 8 8- r2c2 =8= r4c2 =7= r5c1 -7- r9c1 -8 => r23c1<>8
Almost Locked Set XY-Wing: A=r2c146 {1356}, B=r167c3 {3678}, C=r1c48 {156}, X,Y=5,6, Z=3 => r2c3<>3
Almost Locked Set XY-Wing: A=r8c789 {2578}, B=r47c6 {378}, C=r13479c8 {134678}, X,Y=3,7, Z=8 => r8c6<>8
Forcing Chain Contradiction in r5c1 => r4c8=3
r4c8<>3 r5c8=3 r5c1<>3
r4c8<>3 r4c8=8 r4c2<>8 r4c2=7 r5c1<>7
r4c8<>3 r4c8=8 r9c8<>8 r9c1=8 r5c1<>8
Naked Pair: 7,8 in r47c6 => r68c6<>7, r6c6<>8
Naked Single: r8c6=6
X-Wing: 3 r35 c15 => r2c1<>3
Naked Single: r2c1=1
Hidden Single: r1c4=1
Naked Single: r1c8=6
Locked Candidates Type 1 (Pointing): 5 in b2 => r2c79<>5
Naked Pair: 3,7 in r1c3,r3c1 => r1c2,r3c3<>7
Naked Single: r1c2=2
Naked Single: r2c2=8
Full House: r4c2=7
Full House: r4c6=8
Naked Single: r7c6=7
Full House: r8c4=8
Naked Single: r7c3=8
Full House: r9c1=7
Full House: r9c8=8
Naked Single: r6c3=3
Full House: r5c1=8
Full House: r3c1=3
Naked Single: r1c3=7
Naked Single: r6c6=5
Full House: r2c6=3
Naked Single: r3c5=6
Full House: r2c4=5
Full House: r5c5=3
Naked Single: r6c4=7
Full House: r5c4=6
Full House: r6c9=8
Naked Single: r2c9=2
Naked Single: r3c3=4
Full House: r2c3=6
Full House: r2c7=4
Naked Single: r3c8=1
Naked Single: r7c7=3
Naked Single: r3c9=7
Full House: r3c7=8
Naked Single: r7c8=4
Full House: r7c9=1
Naked Single: r1c7=5
Full House: r1c9=3
Full House: r8c9=5
Naked Single: r5c7=7
Full House: r5c8=5
Full House: r8c8=7
Full House: r8c7=2
|
normal_sudoku_469
|
41.6.5.3.....7..5..6....4..69...3..2...5.26.8......7..95.1..87....9..32.8.......9
|
419685237283471956765329481698713542347592618521864793952136874176948325834257169
|
Basic 9x9 Sudoku 469
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 1 . 6 . 5 . 3 .
. . . . 7 . . 5 .
. 6 . . . . 4 . .
6 9 . . . 3 . . 2
. . . 5 . 2 6 . 8
. . . . . . 7 . .
9 5 . 1 . . 8 7 .
. . . 9 . . 3 2 .
8 . . . . . . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
419685237283471956765329481698713542347592618521864793952136874176948325834257169 #1 Easy (326)
Naked Single: r7c7=8
Naked Single: r1c9=7
Naked Single: r3c9=1
Naked Single: r2c9=6
Naked Single: r7c9=4
Naked Single: r7c6=6
Naked Single: r8c9=5
Full House: r6c9=3
Naked Single: r9c7=1
Full House: r9c8=6
Naked Single: r4c7=5
Hidden Single: r4c4=7
Hidden Single: r3c8=8
Naked Single: r3c6=9
Hidden Single: r2c6=1
Hidden Single: r6c5=6
Hidden Single: r8c3=6
Hidden Single: r9c5=5
Hidden Single: r2c4=4
Naked Single: r6c4=8
Naked Single: r6c6=4
Naked Single: r4c5=1
Full House: r5c5=9
Naked Single: r6c2=2
Naked Single: r9c6=7
Full House: r8c6=8
Naked Single: r4c8=4
Full House: r4c3=8
Naked Single: r8c5=4
Naked Single: r5c8=1
Full House: r6c8=9
Naked Single: r8c2=7
Full House: r8c1=1
Naked Single: r6c1=5
Full House: r6c3=1
Hidden Single: r1c5=8
Hidden Single: r2c2=8
Hidden Single: r3c3=5
Hidden Single: r3c1=7
Naked Single: r5c1=3
Full House: r2c1=2
Naked Single: r5c2=4
Full House: r5c3=7
Full House: r9c2=3
Naked Single: r1c3=9
Full House: r1c7=2
Full House: r2c7=9
Full House: r2c3=3
Naked Single: r7c3=2
Full House: r7c5=3
Full House: r9c4=2
Full House: r9c3=4
Full House: r3c5=2
Full House: r3c4=3
|
normal_sudoku_3844
|
......9....9.5..87...8.94......2.7..2.31..85...75.8..2.1.6....3..531..7...2.8..1.
|
486271935329456187571839426854923761293167854167548392718695243945312678632784519
|
Basic 9x9 Sudoku 3844
|
puzzles5_forum_hardest_1905_11+
|
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 . .
. . 9 . 5 . . 8 7
. . . 8 . 9 4 . .
. . . . 2 . 7 . .
2 . 3 1 . . 8 5 .
. . 7 5 . 8 . . 2
. 1 . 6 . . . . 3
. . 5 3 1 . . 7 .
. . 2 . 8 . . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
486271935329456187571839426854923761293167854167548392718695243945312678632784519 #1 Extreme (4002)
Locked Candidates Type 1 (Pointing): 5 in b3 => r9c9<>5
Locked Candidates Type 1 (Pointing): 2 in b8 => r12c6<>2
Hidden Pair: 1,3 in r26c7 => r2c7<>2, r26c7<>6
Locked Candidates Type 1 (Pointing): 2 in b3 => r7c8<>2
Hidden Pair: 2,5 in r7c67 => r7c6<>4, r7c6<>7, r7c7<>8
Locked Candidates Type 1 (Pointing): 8 in b9 => r8c12<>8
2-String Kite: 3 in r2c7,r4c6 (connected by r4c8,r6c7) => r2c6<>3
2-String Kite: 7 in r1c4,r7c1 (connected by r7c5,r9c4) => r1c1<>7
W-Wing: 4/9 in r4c4,r7c8 connected by 9 in r7c5,r9c4 => r4c8<>4
Grouped AIC: 1 1- r1c6 =1= r2c6 =6= r2c12 -6- r3c3 -1 => r1c13<>1
Grouped Discontinuous Nice Loop: 6 r4c6 -6- r4c3 =6= r13c3 -6- r2c12 =6= r2c6 -6- r4c6 => r4c6<>6
Almost Locked Set XY-Wing: A=r4c468 {3469}, B=r568c2 {4689}, C=r5c7 {68}, X,Y=6,8, Z=4,9 => r4c2<>4, r4c2<>9
Almost Locked Set XY-Wing: A=r4c468 {3469}, B=r13589c9 {145689}, C=r13c8,r2c7 {1236}, X,Y=1,6, Z=4,9 => r4c9<>4, r4c9<>9
Sue de Coq: r46c8 - {3469} (r7c8 - {49}, r4c9,r56c7 - {1368}) => r5c9<>6, r5c9<>8
AIC: 4 4- r4c4 -9- r9c4 =9= r7c5 -9- r7c8 -4- r6c8 =4= r5c9 -4 => r5c56<>4
Finned Swordfish: 4 c358 r167 fr4c3 => r6c12<>4
W-Wing: 9/4 in r4c4,r5c9 connected by 4 in r6c58 => r4c8,r5c5<>9
Locked Pair: 6,7 in r5c56 => r5c27,r6c5<>6
Naked Single: r5c7=8
Hidden Single: r8c9=8
Locked Candidates Type 2 (Claiming): 9 in r8 => r79c1,r9c2<>9
Locked Candidates Type 2 (Claiming): 6 in c7 => r9c9<>6
Naked Triple: 1,3,6 in r4c89,r6c7 => r6c8<>3, r6c8<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c123<>6
Locked Candidates Type 2 (Claiming): 6 in c3 => r1c12,r2c12,r3c12<>6
Hidden Single: r2c6=6
Naked Single: r5c6=7
Naked Single: r5c5=6
Hidden Single: r1c6=1
Hidden Single: r4c6=3
Naked Single: r4c8=6
Naked Single: r4c9=1
Naked Single: r6c7=3
Naked Single: r2c7=1
Hidden Single: r3c3=1
Hidden Single: r6c1=1
Hidden Single: r3c9=6
Naked Single: r1c9=5
Hidden Single: r1c3=6
Hidden Single: r6c2=6
Locked Candidates Type 2 (Claiming): 3 in r2 => r1c12,r3c12<>3
Locked Candidates Type 2 (Claiming): 4 in c6 => r7c5,r9c4<>4
Naked Pair: 4,9 in r58c2 => r129c2<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r4789c1<>4
XY-Chain: 4 4- r1c1 -8- r7c1 -7- r9c2 -3- r2c2 -2- r2c4 -4 => r1c45,r2c1<>4
Naked Single: r2c1=3
Naked Single: r2c2=2
Full House: r2c4=4
Naked Single: r4c4=9
Full House: r6c5=4
Full House: r6c8=9
Full House: r5c9=4
Full House: r5c2=9
Full House: r9c9=9
Naked Single: r9c4=7
Full House: r1c4=2
Naked Single: r7c8=4
Naked Single: r8c2=4
Naked Single: r7c5=9
Naked Single: r9c1=6
Naked Single: r9c2=3
Naked Single: r1c8=3
Full House: r3c8=2
Naked Single: r7c3=8
Full House: r4c3=4
Naked Single: r8c6=2
Naked Single: r8c1=9
Full House: r7c1=7
Full House: r8c7=6
Naked Single: r9c7=5
Full House: r7c7=2
Full House: r7c6=5
Full House: r9c6=4
Naked Single: r1c5=7
Full House: r3c5=3
Naked Single: r3c1=5
Full House: r3c2=7
Naked Single: r1c2=8
Full House: r1c1=4
Full House: r4c1=8
Full House: r4c2=5
|
normal_sudoku_1150
|
..1...6....9....235..8....181..45....97.18..4...7........4.29.77..58....928.7..3.
|
481327659679154823532896741816945372397218564254763198165432987743589216928671435
|
Basic 9x9 Sudoku 1150
|
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 . . . 6 . .
. . 9 . . . . 2 3
5 . . 8 . . . . 1
8 1 . . 4 5 . . .
. 9 7 . 1 8 . . 4
. . . 7 . . . . .
. . . 4 . 2 9 . 7
7 . . 5 8 . . . .
9 2 8 . 7 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
481327659679154823532896741816945372397218564254763198165432987743589216928671435 #1 Extreme (2318)
Hidden Single: r9c1=9
Hidden Single: r8c6=9
Hidden Single: r7c8=8
Hidden Single: r7c1=1
Hidden Single: r9c7=4
Naked Single: r3c7=7
Hidden Single: r7c5=3
Hidden Single: r9c9=5
Hidden Single: r4c8=7
Locked Candidates Type 1 (Pointing): 5 in b4 => r6c78<>5
Locked Candidates Type 1 (Pointing): 6 in b9 => r8c23<>6
Naked Pair: 1,6 in r29c4 => r45c4<>6
Locked Candidates Type 1 (Pointing): 6 in b5 => r6c12389<>6
Hidden Pair: 7,8 in r12c2 => r1c2<>3, r12c2<>4, r2c2<>6
Uniqueness Test 1: 1/6 in r2c46,r9c46 => r2c6<>1, r2c6<>6
Hidden Single: r2c4=1
Naked Single: r9c4=6
Full House: r9c6=1
Sue de Coq: r46c9 - {2689} (r1c9 - {89}, r45c7,r5c8 - {2356}) => r6c7<>2, r6c7<>3
Finned Swordfish: 3 r368 c236 fr6c1 => r4c3<>3
Hidden Rectangle: 2/3 in r4c47,r5c47 => r4c7<>2
Naked Single: r4c7=3
XY-Chain: 4 4- r2c1 -6- r2c5 -5- r2c7 -8- r1c9 -9- r3c8 -4 => r3c23<>4
Locked Candidates Type 1 (Pointing): 4 in b1 => r6c1<>4
Naked Triple: 2,3,6 in r4c3,r56c1 => r6c23<>3, r6c3<>2
Locked Candidates Type 1 (Pointing): 3 in b4 => r1c1<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r3c6<>3
Sue de Coq: r2c56 - {4567} (r2c27 - {578}, r3c6 - {46}) => r1c6<>4, r3c5<>6
W-Wing: 9/2 in r3c5,r4c4 connected by 2 in r34c3 => r1c4,r6c5<>9
Hidden Single: r4c4=9
Naked Pair: 2,6 in r48c9 => r6c9<>2
Skyscraper: 2 in r3c3,r6c1 (connected by r36c5) => r1c1,r4c3<>2
Naked Single: r1c1=4
Naked Single: r4c3=6
Full House: r4c9=2
Naked Single: r2c1=6
Naked Single: r7c3=5
Full House: r7c2=6
Naked Single: r5c7=5
Naked Single: r8c9=6
Naked Single: r2c5=5
Naked Single: r3c2=3
Naked Single: r6c3=4
Naked Single: r2c7=8
Naked Single: r5c8=6
Naked Single: r8c8=1
Full House: r8c7=2
Full House: r6c7=1
Naked Single: r3c3=2
Full House: r8c3=3
Full House: r8c2=4
Naked Single: r6c2=5
Naked Single: r1c9=9
Full House: r6c9=8
Full House: r6c8=9
Naked Single: r2c2=7
Full House: r1c2=8
Full House: r2c6=4
Naked Single: r3c5=9
Naked Single: r1c5=2
Full House: r6c5=6
Naked Single: r1c8=5
Full House: r3c8=4
Full House: r3c6=6
Naked Single: r1c4=3
Full House: r1c6=7
Full House: r6c6=3
Full House: r5c4=2
Full House: r6c1=2
Full House: r5c1=3
|
normal_sudoku_192
|
......1.4.1.2.....4...5..78..9.......64..9..27...8..6.5....7..6.4..3......38.5.4.
|
375698124918274653426351978259463817864719532731582469582147396147936285693825741
|
Basic 9x9 Sudoku 192
|
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
. 1 . 2 . . . . .
4 . . . 5 . . 7 8
. . 9 . . . . . .
. 6 4 . . 9 . . 2
7 . . . 8 . . 6 .
5 . . . . 7 . . 6
. 4 . . 3 . . . .
. . 3 8 . 5 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
375698124918274653426351978259463817864719532731582469582147396147936285693825741 #1 Extreme (27052) bf
Brute Force: r5c3=4
Brute Force: r5c4=7
Naked Single: r5c5=1
Locked Candidates Type 2 (Claiming): 5 in r5 => r4c789,r6c79<>5
Skyscraper: 1 in r6c3,r9c1 (connected by r69c9) => r4c1,r78c3<>1
Hidden Single: r6c3=1
Locked Candidates Type 1 (Pointing): 5 in b4 => r1c2<>5
Discontinuous Nice Loop: 6 r1c3 -6- r3c3 -2- r3c7 =2= r1c8 =5= r1c3 => r1c3<>6
Finned X-Wing: 6 r19 c15 fr1c4 fr1c6 => r2c5<>6
Discontinuous Nice Loop: 8 r1c3 -8- r1c6 =8= r2c6 =4= r2c5 =7= r2c3 =5= r1c3 => r1c3<>8
Discontinuous Nice Loop: 4 r6c6 -4- r6c7 =4= r4c7 =7= r4c9 =1= r4c8 -1- r7c8 =1= r7c4 =4= r7c5 -4- r2c5 =4= r2c6 -4- r6c6 => r6c6<>4
Grouped Discontinuous Nice Loop: 3 r2c1 -3- r2c9 =3= r46c9 -3- r5c78 =3= r5c1 -3- r2c1 => r2c1<>3
Grouped Discontinuous Nice Loop: 3 r3c7 -3- r7c7 =3= r7c8 =1= r7c4 =4= r7c5 -4- r2c5 =4= r2c6 =3= r2c789 -3- r3c7 => r3c7<>3
Almost Locked Set XZ-Rule: A=r1245c1 {23689}, B=r37c3 {268}, X=6, Z=8 => r8c1<>8
Forcing Chain Contradiction in r9c9 => r1c6=8
r1c6<>8 r2c6=8 r2c6<>4 r2c5=4 r7c5<>4 r7c4=4 r7c4<>1 r7c8=1 r9c9<>1
r1c6<>8 r2c6=8 r2c6<>4 r2c5=4 r2c5<>7 r2c3=7 r8c3<>7 r9c2=7 r9c9<>7
r1c6<>8 r2c6=8 r2c6<>4 r4c6=4 r4c7<>4 r6c7=4 r6c7<>9 r6c9=9 r9c9<>9
Discontinuous Nice Loop: 6 r2c1 -6- r3c3 -2- r7c3 -8- r2c3 =8= r2c1 => r2c1<>6
Almost Locked Set XY-Wing: A=r7c3 {28}, B=r245c1 {2389}, C=r2c356789 {3456789}, X,Y=8,9, Z=2 => r89c1<>2
Almost Locked Set XZ-Rule: A=r6c69 {239}, B=r8c146 {1269}, X=2, Z=9 => r8c9<>9
Forcing Chain Contradiction in r9c9 => r2c6=4
r2c6<>4 r2c5=4 r7c5<>4 r7c4=4 r7c4<>1 r7c8=1 r9c9<>1
r2c6<>4 r2c5=4 r2c5<>7 r2c3=7 r8c3<>7 r9c2=7 r9c9<>7
r2c6<>4 r4c6=4 r4c7<>4 r6c7=4 r6c7<>9 r6c9=9 r9c9<>9
Locked Candidates Type 2 (Claiming): 3 in r2 => r1c8<>3
Almost Locked Set XY-Wing: A=r3c3467 {12369}, B=r1245c1 {23689}, C=r1c45,r2c5 {3679}, X,Y=3,6, Z=9 => r3c2<>9
Almost Locked Set XY-Wing: A=r7c2378 {12389}, B=r12c5 {679}, C=r9c2579 {12679}, X,Y=1,6, Z=9 => r7c5<>9
Empty Rectangle: 9 in b8 (r3c47) => r9c7<>9
Discontinuous Nice Loop: 2 r1c2 -2- r1c8 =2= r3c7 -2- r9c7 -7- r9c2 =7= r1c2 => r1c2<>2
Discontinuous Nice Loop: 7 r1c3 -7- r1c2 =7= r9c2 -7- r9c7 -2- r3c7 =2= r1c8 =5= r1c3 => r1c3<>7
Grouped Discontinuous Nice Loop: 9 r9c9 -9- r9c5 =9= r78c4 -9- r3c4 =9= r3c7 -9- r6c7 =9= r6c9 -9- r9c9 => r9c9<>9
Grouped Discontinuous Nice Loop: 6 r3c6 =1= r3c4 -1- r7c4 =1= r7c8 -1- r9c9 -7- r9c2 =7= r8c3 =6= r89c1 -6- r1c1 =6= r1c45 -6- r3c6 => r3c6<>6
Almost Locked Set XZ-Rule: A=r9c1279 {12679}, B=r1245c1 {23689}, X=6, Z=9 => r8c1<>9
Finned X-Wing: 9 r38 c47 fr8c8 => r7c7<>9
Grouped AIC: 2 2- r4c1 =2= r1c1 -2- r1c8 =2= r3c7 =9= r3c4 -9- r78c4 =9= r9c5 -9- r9c12 =9= r7c2 =8= r4c2 =5= r6c2 =2= r6c6 -2 => r4c56,r6c2<>2
Hidden Single: r6c6=2
Naked Pair: 1,6 in r8c16 => r8c34<>6, r8c489<>1
Naked Single: r8c4=9
Hidden Single: r3c7=9
Hidden Single: r7c8=9
Hidden Single: r6c9=9
Hidden Single: r1c8=2
Naked Single: r1c3=5
Hidden Single: r2c7=6
Hidden Single: r7c4=1
Naked Single: r8c6=6
Naked Single: r4c6=3
Full House: r3c6=1
Naked Single: r8c1=1
Naked Single: r9c5=2
Full House: r7c5=4
Naked Single: r9c7=7
Naked Single: r4c5=6
Naked Single: r8c9=5
Naked Single: r9c2=9
Naked Single: r9c9=1
Full House: r9c1=6
Naked Single: r2c9=3
Full House: r4c9=7
Full House: r2c8=5
Naked Single: r8c8=8
Naked Single: r4c8=1
Full House: r5c8=3
Naked Single: r8c7=2
Full House: r7c7=3
Full House: r8c3=7
Naked Single: r5c1=8
Full House: r5c7=5
Naked Single: r6c7=4
Full House: r4c7=8
Naked Single: r2c3=8
Naked Single: r2c1=9
Full House: r2c5=7
Full House: r1c5=9
Naked Single: r4c1=2
Full House: r1c1=3
Naked Single: r6c4=5
Full House: r4c4=4
Full House: r4c2=5
Full House: r6c2=3
Naked Single: r7c3=2
Full House: r3c3=6
Full House: r7c2=8
Naked Single: r1c2=7
Full House: r1c4=6
Full House: r3c2=2
Full House: r3c4=3
|
normal_sudoku_814
|
.4.98....2.7..4......21.4...9...28...7...89.3..539.....2.4.97....4861.9......5.1.
|
341987526287654139569213478493572861672148953815396247126439785754861392938725614
|
Basic 9x9 Sudoku 814
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . 9 8 . . . .
2 . 7 . . 4 . . .
. . . 2 1 . 4 . .
. 9 . . . 2 8 . .
. 7 . . . 8 9 . 3
. . 5 3 9 . . . .
. 2 . 4 . 9 7 . .
. . 4 8 6 1 . 9 .
. . . . . 5 . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
341987526287654139569213478493572861672148953815396247126439785754861392938725614 #1 Medium (348)
Naked Single: r7c4=4
Naked Single: r7c5=3
Naked Single: r9c4=7
Full House: r9c5=2
Naked Single: r2c5=5
Naked Single: r2c4=6
Naked Single: r5c5=4
Full House: r4c5=7
Naked Single: r6c6=6
Hidden Single: r5c3=2
Hidden Single: r8c1=7
Hidden Single: r2c9=9
Hidden Single: r9c9=4
Locked Candidates Type 1 (Pointing): 3 in b9 => r12c7<>3
Naked Single: r2c7=1
Naked Single: r6c7=2
Hidden Single: r6c2=1
Naked Single: r5c1=6
Naked Single: r6c9=7
Naked Single: r4c3=3
Naked Single: r5c8=5
Full House: r5c4=1
Full House: r4c4=5
Naked Single: r6c8=4
Full House: r6c1=8
Full House: r4c1=4
Naked Single: r4c8=6
Full House: r4c9=1
Naked Single: r7c8=8
Naked Single: r2c8=3
Full House: r2c2=8
Naked Single: r3c8=7
Full House: r1c8=2
Naked Single: r3c6=3
Full House: r1c6=7
Hidden Single: r8c9=2
Hidden Single: r3c9=8
Hidden Single: r9c3=8
Hidden Single: r1c1=3
Naked Single: r9c1=9
Naked Single: r3c1=5
Full House: r7c1=1
Naked Single: r3c2=6
Full House: r3c3=9
Full House: r1c3=1
Full House: r7c3=6
Full House: r7c9=5
Full House: r1c9=6
Full House: r1c7=5
Naked Single: r9c2=3
Full House: r8c2=5
Full House: r8c7=3
Full House: r9c7=6
|
normal_sudoku_354
|
...1.2...5.6...24...1....7......6.391....4......72..5.7.......548295.36......38..
|
347192586596387241821645973254816739179534628638729154713268495482951367965473812
|
Basic 9x9 Sudoku 354
|
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 . . .
5 . 6 . . . 2 4 .
. . 1 . . . . 7 .
. . . . . 6 . 3 9
1 . . . . 4 . . .
. . . 7 2 . . 5 .
7 . . . . . . . 5
4 8 2 9 5 . 3 6 .
. . . . . 3 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
347192586596387241821645973254816739179534628638729154713268495482951367965473812 #1 Extreme (2200)
Naked Single: r8c3=2
Hidden Single: r2c9=1
Naked Single: r8c9=7
Full House: r8c6=1
Naked Single: r7c6=8
Naked Single: r6c6=9
Naked Single: r2c6=7
Full House: r3c6=5
Hidden Single: r1c7=5
Hidden Single: r9c5=7
Hidden Single: r6c7=1
Hidden Single: r4c5=1
Locked Candidates Type 1 (Pointing): 3 in b5 => r5c23<>3
Locked Candidates Type 1 (Pointing): 2 in b6 => r5c2<>2
Locked Candidates Type 2 (Claiming): 8 in r2 => r13c5,r3c4<>8
Naked Triple: 3,5,8 in r245c4 => r3c4<>3
W-Wing: 3/9 in r2c2,r7c3 connected by 9 in r5c23 => r1c3,r7c2<>3
Hidden Single: r7c3=3
XY-Wing: 6/9/4 in r3c47,r7c7 => r7c4<>4
XY-Wing: 4/9/6 in r37c7,r7c5 => r3c5<>6
XYZ-Wing: 3/8/9 in r1c18,r2c2 => r1c23<>9
Finned X-Wing: 8 r36 c19 fr6c3 => r4c1<>8
Naked Single: r4c1=2
Hidden Single: r3c2=2
Locked Candidates Type 1 (Pointing): 4 in b1 => r1c5<>4
Naked Triple: 3,8,9 in r13c1,r2c2 => r1c2<>3, r1c3<>8
Locked Candidates Type 1 (Pointing): 8 in b1 => r6c1<>8
AIC: 3 3- r2c4 -8- r4c4 =8= r4c3 -8- r6c3 -4- r6c9 =4= r9c9 =2= r5c9 -2- r5c8 -8- r5c5 -3 => r123c5,r5c4<>3
Hidden Single: r5c5=3
Hidden Single: r2c4=3
Naked Single: r2c2=9
Full House: r2c5=8
Hidden Single: r6c2=3
Naked Single: r6c1=6
Naked Single: r9c1=9
Naked Single: r9c3=5
Hidden Single: r5c3=9
Naked Triple: 4,6,9 in r3c457 => r3c9<>6
W-Wing: 4/7 in r1c2,r4c7 connected by 7 in r5c27 => r4c2<>4
Hidden Single: r1c2=4
Naked Single: r1c3=7
XY-Wing: 4/8/2 in r5c8,r69c9 => r5c9,r79c8<>2
Naked Single: r9c8=1
Naked Single: r7c8=9
Naked Single: r9c2=6
Full House: r7c2=1
Naked Single: r1c8=8
Full House: r5c8=2
Naked Single: r7c7=4
Full House: r9c9=2
Full House: r9c4=4
Naked Single: r1c1=3
Full House: r3c1=8
Naked Single: r3c9=3
Naked Single: r4c7=7
Naked Single: r7c5=6
Full House: r7c4=2
Naked Single: r3c4=6
Naked Single: r1c9=6
Full House: r1c5=9
Full House: r3c7=9
Full House: r5c7=6
Full House: r3c5=4
Naked Single: r4c2=5
Full House: r5c2=7
Naked Single: r5c9=8
Full House: r5c4=5
Full House: r4c4=8
Full House: r6c9=4
Full House: r4c3=4
Full House: r6c3=8
|
normal_sudoku_3621
|
98.5..34.3.....7.9.4..3..5..58.12.....9.4..8..3.........4.58.37..3...59..7......4
|
987526341365481729241937658458712963729643185136895472694158237813274596572369814
|
Basic 9x9 Sudoku 3621
|
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 . 5 . . 3 4 .
3 . . . . . 7 . 9
. 4 . . 3 . . 5 .
. 5 8 . 1 2 . . .
. . 9 . 4 . . 8 .
. 3 . . . . . . .
. . 4 . 5 8 . 3 7
. . 3 . . . 5 9 .
. 7 . . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
987526341365481729241937658458712963729643185136895472694158237813274596572369814 #1 Extreme (15664) bf
Hidden Single: r2c1=3
Hidden Single: r7c2=9
Hidden Single: r2c3=5
Hidden Single: r9c1=5
Hidden Single: r9c7=8
Hidden Single: r8c1=8
Hidden Single: r3c9=8
Naked Triple: 1,2,6 in r357c7 => r46c7<>6, r6c7<>1, r6c7<>2
Brute Force: r5c7=1
Skyscraper: 1 in r8c2,r9c8 (connected by r2c28) => r8c9,r9c3<>1
Hidden Single: r1c9=1
Hidden Single: r9c8=1
2-String Kite: 1 in r2c2,r7c4 (connected by r7c1,r8c2) => r2c4<>1
Finned X-Wing: 2 r19 c35 fr9c4 => r8c5<>2
Almost Locked Set XY-Wing: A=r8c259 {1267}, B=r123569c6 {1345679}, C=r2c2458 {12468}, X,Y=1,4, Z=6,7 => r8c6<>6, r8c6<>7
Forcing Chain Contradiction in b2 => r1c5<>7
r1c5=7 r1c5<>2
r1c5=7 r8c5<>7 r8c4=7 r8c4<>4 r2c4=4 r2c4<>2
r1c5=7 r8c5<>7 r8c4=7 r8c4<>4 r2c4=4 r2c4<>8 r2c5=8 r2c5<>2
r1c5=7 r8c5<>7 r8c5=6 r8c9<>6 r8c9=2 r7c7<>2 r3c7=2 r3c4<>2
Forcing Chain Contradiction in c3 => r8c5=7
r8c5<>7 r8c5=6 r1c5<>6 r1c5=2 r1c3<>2
r8c5<>7 r8c5=6 r8c9<>6 r8c9=2 r7c7<>2 r3c7=2 r3c3<>2
r8c5<>7 r8c5=6 r8c9<>6 r8c9=2 r5c9<>2 r5c12=2 r6c3<>2
r8c5<>7 r8c5=6 r9c456<>6 r9c3=6 r9c3<>2
Forcing Chain Contradiction in r7c4 => r2c4<>2
r2c4=2 r2c4<>4 r2c6=4 r8c6<>4 r8c6=1 r7c4<>1
r2c4=2 r7c4<>2
r2c4=2 r2c8<>2 r2c8=6 r3c7<>6 r7c7=6 r7c4<>6
Forcing Chain Contradiction in r7c4 => r2c4<>6
r2c4=6 r2c4<>4 r2c6=4 r8c6<>4 r8c6=1 r7c4<>1
r2c4=6 r2c8<>6 r2c8=2 r3c7<>2 r7c7=2 r7c4<>2
r2c4=6 r7c4<>6
Forcing Chain Verity => r2c5<>2
r8c2=6 r9c3<>6 r9c3=2 r1c3<>2 r1c5=2 r2c5<>2
r8c4=6 r8c4<>4 r2c4=4 r2c4<>8 r2c5=8 r2c5<>2
r8c9=6 r8c9<>2 r7c7=2 r3c7<>2 r2c8=2 r2c5<>2
Hidden Rectangle: 6/8 in r2c45,r6c45 => r6c4<>6
AIC: 6 6- r5c2 -2- r2c2 =2= r2c8 =6= r3c7 -6- r7c7 =6= r8c9 -6 => r5c9,r8c2<>6
2-String Kite: 6 in r3c7,r8c4 (connected by r7c7,r8c9) => r3c4<>6
Turbot Fish: 6 r3c7 =6= r7c7 -6- r7c1 =6= r9c3 => r3c3<>6
Discontinuous Nice Loop: 2 r7c4 -2- r7c7 =2= r8c9 -2- r8c2 -1- r7c1 =1= r7c4 => r7c4<>2
Grouped AIC: 1/4 4- r8c6 =4= r8c4 -4- r2c4 -8- r2c5 -6- r1c56 =6= r1c3 -6- r9c3 -2- r8c2 -1- r2c2 =1= r2c6 -1 => r8c6<>1, r2c6<>4
Naked Single: r8c6=4
Hidden Single: r2c4=4
Hidden Single: r2c5=8
Hidden Single: r6c4=8
Locked Candidates Type 1 (Pointing): 1 in b8 => r3c4<>1
Grouped AIC: 1/6 6- r7c1 =6= r9c3 -6- r1c3 =6= r1c56 -6- r2c6 -1- r2c2 =1= r8c2 -1- r8c4 =1= r7c4 -1 => r7c1<>1, r7c4<>6
Naked Single: r7c4=1
Hidden Single: r8c2=1
Hidden Single: r2c6=1
Remote Pair: 2/6 r5c2 -6- r2c2 -2- r2c8 -6- r3c7 -2- r7c7 -6- r7c1 => r56c1<>2, r456c1<>6
Naked Single: r5c1=7
Naked Single: r4c1=4
Naked Single: r4c7=9
Naked Single: r6c1=1
Naked Single: r6c7=4
Hidden Single: r3c3=1
Hidden Single: r1c3=7
Naked Single: r1c6=6
Full House: r1c5=2
X-Wing: 6 c35 r69 => r6c89,r9c4<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c4<>6
Remote Pair: 2/6 r5c2 -6- r6c3 -2- r9c3 -6- r7c1 -2- r3c1 -6- r2c2 -2- r2c8 -6- r3c7 -2- r7c7 -6- r8c9 => r5c9,r6c8<>2
Naked Single: r6c8=7
Naked Single: r4c8=6
Full House: r2c8=2
Full House: r2c2=6
Full House: r3c7=6
Full House: r3c1=2
Full House: r5c2=2
Full House: r7c7=2
Full House: r7c1=6
Full House: r6c3=6
Full House: r8c9=6
Full House: r9c3=2
Full House: r8c4=2
Naked Single: r4c9=3
Full House: r4c4=7
Naked Single: r6c5=9
Full House: r9c5=6
Naked Single: r5c9=5
Full House: r6c9=2
Full House: r6c6=5
Naked Single: r3c4=9
Full House: r3c6=7
Naked Single: r5c6=3
Full House: r5c4=6
Full House: r9c4=3
Full House: r9c6=9
|
normal_sudoku_1938
|
.952....3.......2.1...4.5.8.....6..4.63..8...7...1.8......9..8..7.1.49..9....5..1
|
895271643634589127127643598281936754463758219759412836516397482378124965942865371
|
Basic 9x9 Sudoku 1938
|
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 5 2 . . . . 3
. . . . . . . 2 .
1 . . . 4 . 5 . 8
. . . . . 6 . . 4
. 6 3 . . 8 . . .
7 . . . 1 . 8 . .
. . . . 9 . . 8 .
. 7 . 1 . 4 9 . .
9 . . . . 5 . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
895271643634589127127643598281936754463758219759412836516397482378124965942865371 #1 Extreme (32908) bf
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c78<>1
Forcing Net Contradiction in c1 => r4c2<>2
r4c2=2 (r4c2<>5) r4c2<>1 r4c3=1 (r4c3<>9 r6c3=9 r6c3<>4) r7c3<>1 r7c2=1 r7c2<>5 r6c2=5 (r4c1<>5 r4c1=8 r1c1<>8) r6c2<>4 r6c4=4 r5c4<>4 r5c1=4 r1c1<>4 r1c1=6
r4c2=2 (r3c2<>2 r3c2=3 r2c1<>3) (r4c2<>5) r4c2<>1 r4c3=1 (r4c3<>9 r6c3=9 r6c3<>4) r7c3<>1 r7c2=1 r7c2<>5 r6c2=5 (r4c1<>5 r4c1=8 r2c1<>8) r6c2<>4 r6c4=4 r5c4<>4 r5c1=4 r2c1<>4 r2c1=6
Brute Force: r5c6=8
Forcing Net Contradiction in r9c4 => r2c4<>7
r2c4=7 (r2c4<>5 r2c5=5 r5c5<>5) (r2c9<>7) (r1c6<>7) (r2c6<>7) r3c6<>7 r7c6=7 r7c9<>7 r5c9=7 r5c5<>7 r5c5=2 r6c6<>2 r7c6=2 r7c6<>7 r123c6=7 r2c4<>7
Forcing Net Contradiction in r4 => r2c5<>7
r2c5=7 (r4c5<>7) (r5c5<>7) (r1c6<>7) (r2c6<>7) r3c6<>7 r7c6=7 r7c6<>2 r6c6=2 (r4c5<>2) r5c5<>2 r5c5=5 r4c5<>5 r4c5=3
r2c5=7 (r1c6<>7 r1c6=1 r1c8<>1 r5c8=1 r5c7<>1) (r2c9<>7) (r1c6<>7) (r2c6<>7) r3c6<>7 r7c6=7 r7c9<>7 r5c9=7 (r4c7<>7) r5c7<>7 r5c7=2 r4c7<>2 r4c7=3
Forcing Net Contradiction in r4 => r3c4<>7
r3c4=7 (r4c4<>7) (r1c6<>7 r1c6=1 r1c8<>1 r5c8=1 r5c8<>9) (r3c3<>7 r2c3=7 r2c9<>7) (r1c6<>7) (r2c6<>7) r3c6<>7 r7c6=7 (r7c6<>2 r6c6=2 r5c5<>2 r5c5=5 r4c4<>5) r7c9<>7 r5c9=7 r5c9<>9 r5c4=9 r4c4<>9 r4c4=3
r3c4=7 (r1c6<>7 r1c6=1 r1c8<>1 r5c8=1 r5c7<>1) (r3c3<>7 r2c3=7 r2c9<>7) (r1c6<>7) (r2c6<>7) r3c6<>7 r7c6=7 r7c9<>7 r5c9=7 (r4c7<>7) r5c7<>7 r5c7=2 r4c7<>2 r4c7=3
Forcing Net Contradiction in r3c3 => r6c9<>9
r6c9=9 (r6c3<>9) (r5c8<>9) r5c9<>9 r5c4=9 r5c4<>4 r5c1=4 r6c3<>4 r6c3=2 r3c3<>2
r6c9=9 (r4c8<>9) (r5c8<>9) r5c9<>9 r5c4=9 (r5c4<>4 r5c1=4 r1c1<>4) r4c4<>9 r4c3=9 (r4c3<>8) r4c3<>1 r4c2=1 r4c2<>8 r4c1=8 r1c1<>8 r1c1=6 r3c3<>6
r6c9=9 (r6c8<>9 r3c8=9 r3c6<>9) (r6c9<>6 r6c8=6 r6c8<>3) (r5c8<>9) r5c9<>9 r5c4=9 r5c4<>4 r5c1=4 (r6c2<>4) r6c3<>4 r6c4=4 r6c4<>3 r6c6=3 r3c6<>3 r3c6=7 r3c3<>7
Brute Force: r5c5=5
Hidden Single: r2c4=5
Hidden Single: r9c4=8
Forcing Net Verity => r1c8<>6
r1c1=4 (r5c1<>4 r5c1=2 r5c7<>2) (r5c1<>4 r5c1=2 r5c9<>2) (r2c1<>4) (r2c2<>4) r2c3<>4 r2c7=4 r2c7<>1 r2c6=1 (r1c6<>1) r2c6<>9 r2c9=9 r5c9<>9 r5c9=7 r5c7<>7 r5c7=1 r1c7<>1 r1c8=1 r1c8<>6
r1c1=6 r1c8<>6
r1c1=8 (r4c1<>8) r2c2<>8 r4c2=8 (r4c2<>5) r4c2<>1 r4c3=1 r7c3<>1 r7c2=1 r7c2<>5 r6c2=5 (r6c2<>4) r4c1<>5 (r4c8=5 r8c8<>5) r4c1=2 (r4c5<>2 r6c6=2 r6c6<>3) r5c1<>2 r5c1=4 r6c3<>4 r6c4=4 r6c4<>3 r6c8=3 r8c8<>3 r8c8=6 r1c8<>6
Forcing Net Contradiction in r7c6 => r4c3<>2
r4c3=2 r4c5<>2 r6c6=2 r7c6<>2
r4c3=2 (r5c1<>2 r5c1=4 r6c3<>4 r6c4=4 r6c4<>3 r6c8=3 r8c8<>3) (r3c3<>2 r3c2=2 r3c2<>3) r4c3<>1 r4c2=1 r4c2<>8 r2c2=8 r2c2<>3 r2c1=3 r8c1<>3 r8c5=3 r7c6<>3
r4c3=2 (r4c3<>8) r4c3<>1 r4c2=1 r4c2<>8 r4c1=8 r1c1<>8 r1c5=8 r1c5<>7 r123c6=7 r7c6<>7
Empty Rectangle: 2 in b4 (r67c6) => r7c1<>2
Forcing Net Verity => r4c8<>7
r6c2=2 (r3c2<>2 r3c2=3 r3c4<>3) (r3c2<>2 r3c2=3 r2c1<>3) (r4c1<>2) r5c1<>2 (r5c1=4 r6c3<>4 r6c3=9 r4c3<>9) (r5c1=4 r6c3<>4 r6c4=4 r6c4<>3) r8c1=2 r8c1<>3 r7c1=3 r7c4<>3 r4c4=3 r4c4<>9 r4c8=9 r4c8<>7
r6c2=4 (r6c3<>4) r5c1<>4 (r5c4=4 r5c4<>7) (r5c4=4 r5c4<>9) r5c1=2 r6c3<>2 r6c3=9 (r6c4<>9) r6c6<>9 r4c4=9 r4c4<>7 r4c5=7 r4c8<>7
r6c2=5 (r4c1<>5) r4c2<>5 r4c8=5 r4c8<>7
Forcing Net Contradiction in r3c8 => r1c7<>7
r1c7=7 (r1c5<>7) (r1c8<>7) (r3c8<>7) r1c6<>7 r1c6=1 r1c8<>1 r5c8=1 r5c8<>7 r9c8=7 r9c5<>7 r4c5=7 (r4c4<>7) r5c4<>7 r7c4=7 r7c4<>6 r3c4=6 r3c8<>6
r1c7=7 r3c8<>7
r1c7=7 (r2c9<>7) (r1c8<>7) (r3c8<>7) r1c6<>7 r1c6=1 r1c8<>1 r5c8=1 r5c8<>7 r9c8=7 r7c9<>7 r5c9=7 r5c9<>9 r2c9=9 r3c8<>9
Forcing Net Verity => r4c8<>9
r6c2=2 (r3c2<>2 r3c2=3 r3c4<>3) (r3c2<>2 r3c2=3 r2c1<>3) (r4c1<>2) r5c1<>2 (r5c1=4 r6c3<>4 r6c4=4 r6c4<>3) (r5c1=4 r6c3<>4 r6c4=4 r6c4<>3) r8c1=2 (r8c1<>8 r8c3=8 r4c3<>8 r4c3=1 r4c2<>1 r4c2=5 r4c1<>5) r8c1<>3 r7c1=3 r7c4<>3 r4c4=3 (r4c4<>9) r6c6<>3 r6c8=3 (r6c8<>5) r6c8<>6 r6c9=6 r6c9<>5 r6c2=5 r4c2<>5 r4c8=5 r4c8<>9 r4c3=9 r4c8<>9
r6c2=4 (r6c3<>4) r5c1<>4 (r5c4=4 r5c4<>9) r5c1=2 r6c3<>2 r6c3=9 (r6c4<>9) r6c6<>9 r4c4=9 r4c8<>9
r6c2=5 (r4c1<>5) r4c2<>5 r4c8=5 r4c8<>9
Forcing Net Contradiction in r3c3 => r2c3<>8
r2c3=8 r2c2<>8 r4c2=8 (r4c1<>8) (r4c2<>5) r4c2<>1 r4c3=1 (r4c3<>9 r4c4=9 r4c4<>3) r7c3<>1 r7c2=1 r7c2<>5 r6c2=5 (r6c2<>4) r4c1<>5 (r4c8=5 r4c8<>3) r4c1=2 (r4c5<>2 r6c6=2 r6c6<>3) r5c1<>2 r5c1=4 r6c3<>4 r6c4=4 (r6c4<>3) r6c4<>3 r6c8=3 r4c7<>3 r4c5=3 (r8c5<>3) r6c6<>3 r6c8=3 r8c8<>3 r8c1=3 r8c1<>8 r8c3=8 r2c3<>8
Forcing Net Contradiction in r3c2 => r2c6<>3
r2c6=3 (r2c6<>9 r2c9=9 r5c9<>9) r2c6<>1 r2c7=1 r5c7<>1 r5c8=1 r5c8<>9 (r6c8=9 r6c3<>9) r5c4=9 r5c4<>4 r5c1=4 r6c3<>4 r6c3=2 r3c3<>2 r3c2=2
r2c6=3 (r3c4<>3) r3c6<>3 r3c2=3
Forcing Chain Contradiction in r8 => r6c2<>2
r6c2=2 r45c1<>2 r8c1=2 r8c1<>3
r6c2=2 r3c2<>2 r3c2=3 r2c12<>3 r2c5=3 r8c5<>3
r6c2=2 r6c2<>5 r4c12=5 r4c8<>5 r4c8=3 r8c8<>3
Forcing Net Verity => r8c3=8
r4c1=2 (r4c5<>2 r6c6=2 r6c6<>3) r5c1<>2 r5c1=4 (r6c2<>4 r6c2=5 r4c2<>5 r4c8=5 r4c8<>3) (r6c2<>4) r6c3<>4 (r6c3=9 r4c3<>9 r4c4=9 r4c4<>3) r6c4=4 (r6c4<>3) r6c4<>3 r6c8=3 r4c7<>3 r4c5=3 (r8c5<>3) r6c6<>3 r6c8=3 r8c8<>3 r8c1=3 r8c1<>8 r8c3=8
r4c1=5 (r4c8<>5 r4c8=3 r4c5<>3) r6c2<>5 r6c2=4 (r6c3<>4) r5c1<>4 (r5c4=4 r5c4<>7) r5c1=2 r6c3<>2 r6c3=9 r4c3<>9 r4c4=9 r4c4<>7 (r7c4=7 r7c6<>7) r4c5=7 r4c5<>2 r6c6=2 r7c6<>2 r7c6=3 (r7c1<>3) r9c5<>3 r2c5=3 (r8c5<>3) r2c1<>3 r8c1=3 r8c1<>8 r8c3=8
r4c1=8 r8c1<>8 r8c3=8
Finned Swordfish: 2 r458 c159 fr4c7 fr5c7 => r6c9<>2
Grouped Discontinuous Nice Loop: 5 r4c1 -5- r78c1 =5= r7c2 =1= r4c2 =8= r4c1 => r4c1<>5
Locked Candidates Type 1 (Pointing): 5 in b4 => r7c2<>5
Forcing Net Contradiction in r6c6 => r6c6=2
r6c6<>2 r6c3=2 (r5c1<>2 r8c1=2 r8c1<>5 r7c1=5 r7c1<>3 r2c1=3 r2c5<>3 r2c5=6 r8c5<>6 r8c5=3 r8c5<>6) (r5c1<>2 r5c1=4 r1c1<>4 r1c1=6 r3c3<>6 r3c3=7 r3c8<>7) (r5c1<>2 r8c1=2 r8c9<>2) r6c6<>2 r7c6=2 r7c9<>2 r5c9=2 r5c9<>9 r2c9=9 r3c8<>9 r3c8=6 (r8c8<>6) r6c8<>6 r6c9=6 r8c9<>6 r8c1=6 r8c1<>2 r45c1=2 r6c3<>2 r6c6=2
Locked Candidates Type 1 (Pointing): 2 in b4 => r8c1<>2
Locked Candidates Type 1 (Pointing): 9 in b5 => r3c4<>9
Discontinuous Nice Loop: 3 r4c7 -3- r6c8 =3= r6c4 =4= r5c4 -4- r5c1 -2- r4c1 =2= r4c7 => r4c7<>3
Locked Candidates Type 1 (Pointing): 3 in b6 => r89c8<>3
Hidden Triple: 3,5,6 in r46c8,r6c9 => r6c8<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r5c4<>9
Naked Triple: 3,5,6 in r468c8 => r39c8<>6
Continuous Nice Loop: 1/7 9= r2c6 =1= r2c7 -1- r5c7 =1= r5c8 =9= r5c9 -9- r2c9 =9= r2c6 =1 => r1c7<>1, r2c6,r5c8<>7
Discontinuous Nice Loop: 7 r2c7 -7- r3c8 -9- r3c6 =9= r2c6 =1= r2c7 => r2c7<>7
Grouped AIC: 3 3- r7c6 -7- r7c4 =7= r45c4 -7- r4c5 -3- r8c5 =3= r8c1 -3 => r7c12,r8c5<>3
Hidden Single: r8c1=3
Hidden Single: r7c1=5
Locked Candidates Type 1 (Pointing): 6 in b7 => r23c3<>6
Hidden Single: r3c4=6
Locked Pair: 3,7 in r7c46 => r7c7,r9c5<>3, r7c79,r9c5<>7
Hidden Single: r9c7=3
Hidden Single: r9c8=7
Naked Single: r3c8=9
Naked Single: r5c8=1
Naked Single: r1c8=4
Naked Single: r1c7=6
Naked Single: r1c1=8
Naked Single: r2c7=1
Full House: r2c9=7
Naked Single: r1c5=7
Full House: r1c6=1
Naked Single: r4c1=2
Naked Single: r2c6=9
Naked Single: r2c3=4
Naked Single: r3c6=3
Full House: r2c5=8
Full House: r7c6=7
Naked Single: r4c5=3
Naked Single: r4c7=7
Naked Single: r5c1=4
Full House: r2c1=6
Full House: r2c2=3
Naked Single: r6c3=9
Naked Single: r3c2=2
Full House: r3c3=7
Naked Single: r7c4=3
Naked Single: r4c8=5
Naked Single: r4c4=9
Naked Single: r5c7=2
Full House: r7c7=4
Naked Single: r5c4=7
Full House: r6c4=4
Full House: r5c9=9
Naked Single: r6c2=5
Naked Single: r4c3=1
Full House: r4c2=8
Naked Single: r9c2=4
Full House: r7c2=1
Naked Single: r6c9=6
Full House: r6c8=3
Full House: r8c8=6
Naked Single: r7c9=2
Full House: r7c3=6
Full House: r8c9=5
Full House: r8c5=2
Full House: r9c3=2
Full House: r9c5=6
|
normal_sudoku_2980
|
.....7.1237.21.........5.6.1.3...97.9..3..1.5...1....45....8.9168.59.....4.......
|
895637412376214859412985763153842976924376185768159324537428691681593247249761538
|
Basic 9x9 Sudoku 2980
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 7 . 1 2
3 7 . 2 1 . . . .
. . . . . 5 . 6 .
1 . 3 . . . 9 7 .
9 . . 3 . . 1 . 5
. . . 1 . . . . 4
5 . . . . 8 . 9 1
6 8 . 5 9 . . . .
. 4 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
895637412376214859412985763153842976924376185768159324537428691681593247249761538 #1 Hard (976)
Hidden Single: r1c8=1
Hidden Single: r6c6=9
Hidden Single: r5c3=4
Hidden Single: r7c2=3
Hidden Single: r9c3=9
Hidden Single: r3c2=1
Hidden Single: r5c5=7
Hidden Single: r2c9=9
Hidden Single: r9c6=1
Hidden Single: r8c3=1
Hidden Single: r1c2=9
Hidden Single: r5c8=8
Naked Single: r4c9=6
Hidden Single: r3c4=9
Hidden Single: r8c6=3
Naked Single: r8c9=7
Hidden Single: r3c7=7
Locked Candidates Type 1 (Pointing): 5 in b1 => r6c3<>5
Locked Candidates Type 1 (Pointing): 6 in b1 => r6c3<>6
Locked Candidates Type 1 (Pointing): 8 in b4 => r6c5<>8
Locked Candidates Type 1 (Pointing): 2 in b6 => r6c1235<>2
Locked Candidates Type 1 (Pointing): 2 in b8 => r4c5<>2
Locked Candidates Type 1 (Pointing): 4 in b8 => r7c7<>4
Locked Candidates Type 2 (Claiming): 2 in r8 => r79c7,r9c8<>2
Naked Single: r7c7=6
Naked Triple: 2,4,8 in r13c1,r3c3 => r12c3<>8
Hidden Single: r2c7=8
Naked Single: r3c9=3
Full House: r9c9=8
Hidden Single: r1c5=3
W-Wing: 8/4 in r3c5,r4c4 connected by 4 in r7c45 => r1c4,r4c5<>8
Hidden Single: r1c1=8
Naked Single: r3c3=2
Naked Single: r6c1=7
Naked Single: r3c1=4
Full House: r9c1=2
Full House: r7c3=7
Full House: r3c5=8
Naked Single: r6c3=8
Naked Single: r9c5=6
Naked Single: r7c4=4
Full House: r7c5=2
Full House: r9c4=7
Naked Single: r6c5=5
Full House: r4c5=4
Naked Single: r1c4=6
Full House: r4c4=8
Full House: r2c6=4
Naked Single: r6c2=6
Naked Single: r4c6=2
Full House: r4c2=5
Full House: r5c2=2
Full House: r5c6=6
Naked Single: r1c3=5
Full House: r1c7=4
Full House: r2c8=5
Full House: r2c3=6
Naked Single: r8c7=2
Full House: r8c8=4
Naked Single: r9c8=3
Full House: r6c8=2
Full House: r6c7=3
Full House: r9c7=5
|
normal_sudoku_183
|
97..3.6..2....41....1.........5.8..1.1..7.386.9..6.5...2..5..67......9...6.9...53
|
974135628286794135351826749637548291415279386892361574129453867543687912768912453
|
Basic 9x9 Sudoku 183
|
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 . . 3 . 6 . .
2 . . . . 4 1 . .
. . 1 . . . . . .
. . . 5 . 8 . . 1
. 1 . . 7 . 3 8 6
. 9 . . 6 . 5 . .
. 2 . . 5 . . 6 7
. . . . . . 9 . .
. 6 . 9 . . . 5 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
974135628286794135351826749637548291415279386892361574129453867543687912768912453 #1 Unfair (1536)
Hidden Single: r5c9=6
Hidden Single: r7c3=9
Hidden Single: r8c8=1
Hidden Single: r5c6=9
Hidden Single: r4c8=9
Hidden Single: r9c5=1
Naked Single: r7c6=3
Hidden Single: r7c1=1
Hidden Single: r6c4=3
Hidden Single: r6c6=1
Hidden Single: r1c4=1
2-String Kite: 4 in r4c5,r7c7 (connected by r7c4,r8c5) => r4c7<>4
Locked Candidates Type 1 (Pointing): 4 in b6 => r6c13<>4
Empty Rectangle: 2 in b2 (r9c67) => r3c7<>2
Hidden Rectangle: 8/9 in r2c59,r3c59 => r3c9<>8
Finned Swordfish: 8 r169 c139 fr9c7 => r8c9<>8
Locked Candidates Type 1 (Pointing): 8 in b9 => r3c7<>8
Naked Pair: 2,4 in r68c9 => r13c9<>2, r13c9<>4
Locked Candidates Type 1 (Pointing): 2 in b3 => r6c8<>2
W-Wing: 4/2 in r4c5,r8c9 connected by 2 in r49c7 => r8c5<>4
Hidden Single: r4c5=4
Full House: r5c4=2
Naked Single: r4c2=3
Naked Triple: 4,5,8 in r1c3,r23c2 => r2c3,r3c1<>5, r2c3,r3c1<>8, r3c1<>4
Naked Triple: 5,8,9 in r2c259 => r2c4<>8
Empty Rectangle: 4 in b9 (r38c2) => r3c7<>4
Naked Single: r3c7=7
Naked Single: r2c8=3
Naked Single: r4c7=2
Naked Single: r2c3=6
Naked Single: r6c9=4
Full House: r6c8=7
Naked Single: r2c4=7
Naked Single: r3c1=3
Naked Single: r4c3=7
Full House: r4c1=6
Naked Single: r8c9=2
Naked Single: r6c1=8
Full House: r6c3=2
Naked Single: r8c5=8
Naked Single: r2c5=9
Full House: r3c5=2
Naked Single: r7c4=4
Full House: r7c7=8
Full House: r9c7=4
Naked Single: r1c6=5
Naked Single: r3c8=4
Full House: r1c8=2
Naked Single: r8c4=6
Full House: r3c4=8
Full House: r3c6=6
Naked Single: r9c1=7
Naked Single: r9c3=8
Full House: r9c6=2
Full House: r8c6=7
Naked Single: r1c9=8
Full House: r1c3=4
Naked Single: r3c2=5
Full House: r2c2=8
Full House: r2c9=5
Full House: r3c9=9
Full House: r8c2=4
Naked Single: r5c3=5
Full House: r5c1=4
Full House: r8c1=5
Full House: r8c3=3
|
normal_sudoku_702
|
4973.58...5.......8.6.94...5.2........4...735...65...97.5...1........9.2.2.4.8..7
|
497365821253187496816294573532749618964821735178653249785932164341576982629418357
|
Basic 9x9 Sudoku 702
|
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 9 7 3 . 5 8 . .
. 5 . . . . . . .
8 . 6 . 9 4 . . .
5 . 2 . . . . . .
. . 4 . . . 7 3 5
. . . 6 5 . . . 9
7 . 5 . . . 1 . .
. . . . . . 9 . 2
. 2 . 4 . 8 . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
497365821253187496816294573532749618964821735178653249785932164341576982629418357 #1 Easy (392)
Hidden Single: r6c5=5
Hidden Single: r5c1=9
Hidden Single: r2c8=9
Hidden Single: r9c3=9
Hidden Single: r2c1=2
Hidden Single: r8c4=5
Hidden Single: r4c5=4
Naked Single: r4c7=6
Hidden Single: r5c2=6
Hidden Single: r3c8=7
Hidden Single: r3c7=5
Naked Single: r9c7=3
Naked Single: r2c7=4
Full House: r6c7=2
Hidden Single: r9c8=5
Hidden Single: r3c4=2
Naked Single: r7c4=9
Hidden Single: r1c8=2
Hidden Single: r7c9=4
Hidden Single: r6c8=4
Hidden Single: r4c6=9
Hidden Single: r8c2=4
Hidden Single: r4c9=8
Full House: r4c8=1
Naked Single: r4c4=7
Full House: r4c2=3
Naked Single: r3c2=1
Full House: r2c3=3
Full House: r3c9=3
Naked Single: r6c1=1
Naked Single: r7c2=8
Full House: r6c2=7
Full House: r6c3=8
Full House: r6c6=3
Full House: r8c3=1
Naked Single: r9c1=6
Full House: r8c1=3
Full House: r9c5=1
Naked Single: r7c8=6
Full House: r8c8=8
Naked Single: r1c5=6
Full House: r1c9=1
Full House: r2c9=6
Naked Single: r7c6=2
Full House: r7c5=3
Naked Single: r8c5=7
Full House: r8c6=6
Naked Single: r5c6=1
Full House: r2c6=7
Naked Single: r2c5=8
Full House: r2c4=1
Full House: r5c4=8
Full House: r5c5=2
|
normal_sudoku_5747
|
.4.......7....1..3..38...9......6..1...15.23.1..4.3..6.37.....5.....5...5.....61.
|
941532768768941523253867194382796451476158239195423876637214985819675342524389617
|
Basic 9x9 Sudoku 5747
|
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 . . . . 1 . . 3
. . 3 8 . . . 9 .
. . . . . 6 . . 1
. . . 1 5 . 2 3 .
1 . . 4 . 3 . . 6
. 3 7 . . . . . 5
. . . . . 5 . . .
5 . . . . . 6 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
941532768768941523253867194382796451476158239195423876637214985819675342524389617 #1 Extreme (36146) bf
Hidden Single: r5c4=1
Hidden Single: r4c1=3
Hidden Single: r8c7=3
Hidden Single: r7c5=1
Hidden Pair: 1,5 in r3c27 => r3c2<>2, r3c2<>6, r3c7<>4, r3c7<>7
Skyscraper: 6 in r3c5,r7c4 (connected by r37c1) => r12c4,r8c5<>6
Brute Force: r5c2=7
Discontinuous Nice Loop: 5 r1c8 -5- r3c7 -1- r3c2 =1= r8c2 =6= r2c2 -6- r2c8 =6= r1c8 => r1c8<>5
Brute Force: r5c1=4
Hidden Single: r5c3=6
Empty Rectangle: 9 in b9 (r5c69) => r7c6<>9
Finned Swordfish: 4 r247 c578 fr7c6 => r89c5<>4
Locked Candidates Type 1 (Pointing): 4 in b8 => r3c6<>4
Discontinuous Nice Loop: 4 r9c9 -4- r9c3 =4= r8c3 =1= r8c2 =6= r2c2 -6- r3c1 =6= r3c5 =4= r3c9 -4- r9c9 => r9c9<>4
Forcing Net Contradiction in c6 => r1c1<>6
r1c1=6 (r1c8<>6 r2c8=6 r2c8<>2) (r1c8<>6 r2c8=6 r2c8<>4) r3c1<>6 (r3c1=2 r2c2<>2) (r3c1=2 r2c3<>2) r3c5=6 r3c5<>4 r3c9=4 r2c7<>4 r2c5=4 r2c5<>2 r2c4=2 r1c6<>2
r1c1=6 r3c1<>6 r3c1=2 r3c6<>2
r1c1=6 (r2c2<>6 r8c2=6 r8c2<>1 r8c3=1 r8c3<>4) r3c1<>6 r3c5=6 r3c5<>4 r3c9=4 r8c9<>4 r8c8=4 (r7c7<>4) r7c8<>4 r7c6=4 r7c6<>2
r1c1=6 (r3c1<>6 r3c1=2 r7c1<>2) (r3c1<>6 r3c1=2 r8c1<>2) r2c2<>6 r8c2=6 (r8c2<>2) r8c2<>1 r8c3=1 (r8c3<>2) r8c3<>4 r9c3=4 r9c3<>2 r9c2=2 r9c6<>2
Forcing Net Contradiction in c8 => r8c2<>2
r8c2=2 r8c2<>6 r2c2=6 r2c8<>6 r1c8=6 r1c8<>7
r8c2=2 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r4c8<>7
r8c2=2 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r6c8<>7
r8c2=2 (r8c2<>1 r8c3=1 r8c3<>4) r8c2<>6 r2c2=6 r3c1<>6 r3c5=6 r3c5<>4 r3c9=4 r8c9<>4 r8c8=4 r8c8<>7
Forcing Net Contradiction in c8 => r8c2<>8
r8c2=8 r8c2<>6 r2c2=6 r2c8<>6 r1c8=6 r1c8<>7
r8c2=8 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r4c8<>7
r8c2=8 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r6c8<>7
r8c2=8 (r8c2<>1 r8c3=1 r8c3<>4) r8c2<>6 r2c2=6 r3c1<>6 r3c5=6 r3c5<>4 r3c9=4 r8c9<>4 r8c8=4 r8c8<>7
Forcing Net Contradiction in c8 => r8c2<>9
r8c2=9 r8c2<>6 r2c2=6 r2c8<>6 r1c8=6 r1c8<>7
r8c2=9 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r4c8<>7
r8c2=9 r8c2<>1 r8c3=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r6c8<>7
r8c2=9 (r8c2<>1 r8c3=1 r8c3<>4) r8c2<>6 r2c2=6 r3c1<>6 r3c5=6 r3c5<>4 r3c9=4 r8c9<>4 r8c8=4 r8c8<>7
Forcing Net Contradiction in r7c7 => r9c2<>9
r9c2=9 (r2c2<>9) (r7c1<>9) (r9c9<>9) (r9c6<>9) (r7c1<>9) r8c1<>9 r1c1=9 r1c6<>9 r5c6=9 r5c9<>9 r8c9=9 r7c7<>9 r7c4=9 (r2c4<>9) r7c4<>6 r7c1=6 r3c1<>6 r3c5=6 r3c5<>4 r3c9=4 (r2c7<>4) r2c8<>4 r2c5=4 r2c5<>9 r2c3=9 r1c1<>9 r78c1=9 r9c2<>9
Forcing Net Verity => r1c8<>2
r7c1=2 (r9c2<>2 r9c2=8 r8c1<>8 r1c1=8 r1c9<>8) (r9c2<>2 r9c2=8 r9c9<>8) (r9c2<>2 r9c2=8 r8c1<>8 r8c1=9 r8c9<>9) (r7c1<>9) r7c1<>6 r7c4=6 r7c4<>9 r7c7=9 r9c9<>9 r5c9=9 r5c9<>8 r8c9=8 (r8c9<>2) (r8c9<>4 r3c9=4 r3c9<>2) (r8c5<>8) r5c9<>8 r5c6=8 (r4c5<>8) r6c5<>8 r9c5=8 r9c2<>8 r9c2=2 r9c9<>2 r1c9=2 r1c8<>2
r7c4=2 (r7c6<>2) (r9c6<>2) r7c4<>6 r7c1=6 r3c1<>6 r3c1=2 r3c6<>2 r1c6=2 r1c8<>2
r7c6=2 r7c6<>4 r9c6=4 r9c3<>4 r8c3=4 r8c3<>1 r8c2=1 r8c2<>6 r2c2=6 r2c8<>6 r1c8=6 r1c8<>2
r7c8=2 r1c8<>2
Forcing Net Verity => r1c8<>8
r2c2=2 r9c2<>2 r9c2=8 (r7c1<>8) r8c1<>8 r1c1=8 r1c8<>8
r2c3=2 r13c1<>2 r78c1=2 r9c2<>2 r9c2=8 (r7c1<>8) r8c1<>8 r1c1=8 r1c8<>8
r2c4=2 r2c4<>5 r1c4=5 r1c4<>3 r1c5=3 r1c5<>6 r1c8=6 r1c8<>8
r2c5=2 (r3c6<>2 r3c6=7 r9c6<>7) (r3c6<>2 r3c6=7 r1c6<>7 r1c6=9 r5c6<>9 r5c6=8 r9c6<>8) (r3c6<>2 r3c6=7 r1c6<>7 r1c6=9 r9c6<>9) r2c5<>4 r3c5=4 r3c9<>4 r8c9=4 (r7c7<>4) r7c8<>4 r7c6=4 r9c6<>4 r9c6=2 r9c2<>2 r9c2=8 (r7c1<>8) r8c1<>8 r1c1=8 r1c8<>8
r2c8=2 r2c8<>6 r1c8=6 r1c8<>8
Forcing Net Contradiction in c6 => r2c5<>2
r2c5=2 r1c6<>2
r2c5=2 r3c6<>2
r2c5=2 r2c5<>4 r3c5=4 r3c9<>4 r8c9=4 (r7c7<>4) r7c8<>4 r7c6=4 r7c6<>2
r2c5=2 (r2c5<>6) r2c5<>4 r3c5=4 (r3c9<>4 r3c9=2 r1c9<>2) r3c5<>6 r1c5=6 r1c8<>6 r1c8=7 r1c9<>7 r1c9=8 r1c1<>8 r78c1=8 r9c2<>8 r9c2=2 r9c6<>2
Forcing Net Contradiction in c3 => r2c5<>9
r2c5=9 (r2c5<>6) r2c5<>4 r3c5=4 r3c5<>6 r1c5=6 (r1c5<>3 r1c4=3 r1c4<>5) r1c8<>6 r2c8=6 r2c2<>6 r8c2=6 r8c2<>1 r3c2=1 r3c7<>1 r3c7=5 r1c7<>5 r1c3=5 r1c3<>9
r2c5=9 r2c3<>9
r2c5=9 r2c2<>9 r46c2=9 r4c3<>9
r2c5=9 r2c2<>9 r46c2=9 r6c3<>9
r2c5=9 r2c5<>4 r3c5=4 r3c5<>6 r3c1=6 r2c2<>6 r8c2=6 r8c2<>1 r8c3=1 r8c3<>9
r2c5=9 r2c5<>4 r3c5=4 r3c9<>4 r8c9=4 (r7c7<>4) r7c8<>4 r7c6=4 r9c6<>4 r9c3=4 r9c3<>9
Forcing Net Contradiction in c1 => r1c8=6
r1c8<>6 (r2c8=6 r2c8<>2) r1c5=6 r2c5<>6 r2c5=4 r3c5<>4 r3c9=4 r3c9<>2 r1c9=2 r1c1<>2
r1c8<>6 r1c5=6 r3c5<>6 r3c1=6 r3c1<>2
r1c8<>6 (r1c5=6 r2c5<>6 r2c5=4 r3c5<>4 r3c9=4 r8c9<>4) r2c8=6 (r2c8<>2) r2c2<>6 r8c2=6 r8c2<>1 r8c3=1 r8c3<>4 r8c8=4 r8c8<>2 r7c8=2 r7c1<>2
r1c8<>6 r1c5=6 (r1c5<>9) r1c5<>3 r1c4=3 (r1c4<>9) r1c4<>5 r2c4=5 r2c4<>9 r1c6=9 (r1c1<>9) r5c6<>9 r5c9=9 (r4c7<>9) r6c7<>9 r7c7=9 r7c1<>9 r8c1=9 r8c1<>2
Hidden Pair: 4,6 in r23c5 => r3c5<>2, r3c5<>7
Forcing Net Contradiction in c6 => r2c2<>2
r2c2=2 (r9c2<>2 r9c2=8 r8c1<>8 r1c1=8 r1c9<>8) (r9c2<>2 r9c2=8 r9c9<>8) r3c1<>2 r3c1=6 r3c5<>6 r3c5=4 r3c9<>4 r8c9=4 r8c9<>8 r5c9=8 r5c6<>8
r2c2=2 r3c1<>2 r3c1=6 r3c5<>6 r3c5=4 r3c9<>4 r8c9=4 (r7c7<>4) r7c8<>4 r7c6=4 r7c6<>8
r2c2=2 r9c2<>2 r9c2=8 r9c6<>8
Forcing Net Contradiction in r2c8 => r2c2<>8
r2c2=8 (r9c2<>8 r9c2=2 r9c9<>2) r2c2<>6 r2c5=6 r3c5<>6 (r3c1=6 r3c1<>2 r1c1=2 r1c9<>2) r3c5=4 r3c9<>4 r8c9=4 r8c9<>2 r3c9=2 r2c8<>2
r2c2=8 (r2c7<>8) r2c2<>6 r8c2=6 r8c2<>1 r3c2=1 r3c7<>1 r3c7=5 r2c7<>5 r2c7=4 r2c8<>4
r2c2=8 r2c2<>6 r8c2=6 r8c2<>1 r3c2=1 r3c7<>1 r3c7=5 r2c8<>5
r2c2=8 r2c8<>8
Forcing Net Contradiction in r8c4 => r2c3<>5
r2c3=5 (r2c4<>5) (r2c2<>5) r3c2<>5 r3c2=1 r8c2<>1 r8c2=6 r2c2<>6 r2c2=9 r2c4<>9 r2c4=2 r8c4<>2
r2c3=5 r3c2<>5 r3c2=1 r8c2<>1 r8c2=6 r8c4<>6
r2c3=5 r3c2<>5 r3c2=1 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r46c8<>7 r8c8=7 r8c4<>7
r2c3=5 (r2c4<>5 r1c4=5 r1c4<>9) (r2c4<>5 r1c4=5 r1c4<>3 r1c5=3 r1c5<>9) (r2c2<>5) r3c2<>5 r3c2=1 r8c2<>1 r8c2=6 r2c2<>6 r2c2=9 (r1c1<>9) (r1c1<>9) r1c3<>9 r1c6=9 r5c6<>9 r5c9=9 (r4c7<>9) r6c7<>9 r7c7=9 r7c1<>9 r8c1=9 r8c4<>9
Forcing Net Contradiction in c9 => r7c1<>2
r7c1=2 (r7c1<>8) r9c2<>2 r9c2=8 r8c1<>8 r1c1=8 r1c9<>8
r7c1=2 (r9c2<>2 r9c2=8 r8c1<>8 r8c1=9 r8c9<>9) (r7c1<>9) r7c1<>6 r7c4=6 r7c4<>9 r7c7=9 r9c9<>9 r5c9=9 r5c9<>8
r7c1=2 r3c1<>2 r3c1=6 r3c5<>6 r3c5=4 r3c9<>4 r8c9=4 r8c9<>8
r7c1=2 r9c2<>2 r9c2=8 r9c9<>8
Forcing Chain Verity => r8c4<>2
r2c3=2 r13c1<>2 r8c1=2 r8c4<>2
r2c4=2 r8c4<>2
r2c8=2 r7c8<>2 r7c46=2 r8c4<>2
Forcing Chain Contradiction in r8c4 => r1c3<>9
r1c3=9 r1c3<>1 r8c3=1 r8c2<>1 r8c2=6 r8c4<>6
r1c3=9 r1c3<>1 r1c7=1 r1c7<>7 r46c7=7 r46c8<>7 r8c8=7 r8c4<>7
r1c3=9 r1c456<>9 r2c4=9 r8c4<>9
Forcing Chain Verity => r8c5<>2
r2c3=2 r13c1<>2 r8c1=2 r8c5<>2
r2c4=2 r4c4<>2 r46c5=2 r8c5<>2
r2c8=2 r7c8<>2 r7c46=2 r8c5<>2
Forcing Chain Verity => r1c1<>2
r7c4=2 r7c4<>6 r7c1=6 r3c1<>6 r3c1=2 r1c1<>2
r7c6=2 r7c6<>4 r7c78=4 r8c9<>4 r3c9=4 r3c5<>4 r3c5=6 r3c1<>6 r3c1=2 r1c1<>2
r7c8=2 r7c46<>2 r9c456=2 r9c2<>2 r9c2=8 r78c1<>8 r1c1=8 r1c1<>2
Grouped Discontinuous Nice Loop: 8 r1c3 =1= r8c3 -1- r8c2 -6- r2c2 =6= r3c1 =2= r8c1 -2- r9c2 -8- r78c1 =8= r1c1 -8- r1c3 => r1c3<>8
Forcing Net Contradiction in r7 => r1c3=1
r1c3<>1 r8c3=1 r8c2<>1 r8c2=6 (r7c1<>6) r2c2<>6 r2c5=6 r3c5<>6 r3c1=6 r3c1<>2 r8c1=2 r9c2<>2 r9c2=8 r7c1<>8 r7c1=9
r1c3<>1 r8c3=1 r8c2<>1 r8c2=6 r2c2<>6 r2c5=6 r3c5<>6 r3c1=6 r5c6=8 r5c9<>8 r5c9=9 (r4c7<>9) r6c7<>9 r7c7=9
Naked Single: r3c2=5
Naked Single: r3c7=1
Hidden Single: r8c2=1
Hidden Single: r2c2=6
Naked Single: r2c5=4
Naked Single: r3c1=2
Naked Single: r3c5=6
Naked Single: r3c6=7
Full House: r3c9=4
Locked Candidates Type 2 (Claiming): 9 in c2 => r46c3<>9
Finned X-Wing: 2 r27 c48 fr7c6 => r9c4<>2
Grouped Discontinuous Nice Loop: 5 r4c7 -5- r12c7 =5= r2c8 =2= r2c4 -2- r1c6 -9- r5c6 =9= r5c9 -9- r46c7 =9= r7c7 =4= r4c7 => r4c7<>5
Grouped Discontinuous Nice Loop: 8 r4c7 -8- r5c9 -9- r46c7 =9= r7c7 =4= r4c7 => r4c7<>8
Grouped Discontinuous Nice Loop: 2 r9c5 -2- r7c46 =2= r7c8 -2- r2c8 =2= r2c4 -2- r4c4 =2= r46c5 -2- r9c5 => r9c5<>2
Grouped Discontinuous Nice Loop: 8 r7c1 -8- r1c1 -9- r1c6 -2- r79c6 =2= r7c4 =6= r7c1 => r7c1<>8
Hidden Rectangle: 6/9 in r7c14,r8c14 => r8c4<>9
Sashimi X-Wing: 8 r57 c69 fr7c7 fr7c8 => r89c9<>8
W-Wing: 9/8 in r1c1,r5c6 connected by 8 in r15c9 => r1c6<>9
Naked Single: r1c6=2
Hidden Single: r2c8=2
Hidden Single: r7c4=2
Hidden Single: r7c1=6
Hidden Single: r8c4=6
Hidden Single: r7c7=9
Hidden Single: r5c9=9
Full House: r5c6=8
Naked Single: r7c6=4
Full House: r7c8=8
Full House: r9c6=9
Hidden Single: r4c7=4
Hidden Single: r1c9=8
Naked Single: r1c1=9
Full House: r2c3=8
Full House: r8c1=8
Naked Single: r2c7=5
Full House: r1c7=7
Full House: r2c4=9
Full House: r6c7=8
Naked Single: r1c5=3
Full House: r1c4=5
Naked Single: r8c5=7
Naked Single: r9c2=2
Naked Single: r4c4=7
Full House: r9c4=3
Full House: r9c5=8
Naked Single: r8c8=4
Naked Single: r8c9=2
Full House: r9c9=7
Full House: r9c3=4
Full House: r8c3=9
Naked Single: r6c2=9
Full House: r4c2=8
Naked Single: r4c8=5
Full House: r6c8=7
Naked Single: r6c5=2
Full House: r4c5=9
Full House: r4c3=2
Full House: r6c3=5
|
normal_sudoku_5069
|
4...68.....3.....8.8.2..4..6...5.3..32.7.49....8..3.5.......1...7...1.49...4...27
|
459368271213947568786215493647159382325784916198623754964872135872531649531496827
|
Basic 9x9 Sudoku 5069
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . . 6 8 . . .
. . 3 . . . . . 8
. 8 . 2 . . 4 . .
6 . . . 5 . 3 . .
3 2 . 7 . 4 9 . .
. . 8 . . 3 . 5 .
. . . . . . 1 . .
. 7 . . . 1 . 4 9
. . . 4 . . . 2 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
459368271213947568786215493647159382325784916198623754964872135872531649531496827 #1 Hard (790)
Hidden Single: r5c1=3
Hidden Single: r6c4=6
Hidden Single: r2c5=4
Hidden Single: r5c3=5
Locked Candidates Type 1 (Pointing): 8 in b6 => r7c8<>8
Locked Candidates Type 1 (Pointing): 3 in b9 => r7c245<>3
Hidden Single: r9c2=3
2-String Kite: 6 in r2c2,r8c7 (connected by r7c2,r8c3) => r2c7<>6
Locked Candidates Type 2 (Claiming): 6 in c7 => r7c89<>6
Naked Single: r7c8=3
Naked Single: r7c9=5
Locked Candidates Type 1 (Pointing): 5 in b7 => r23c1<>5
Hidden Single: r3c6=5
Hidden Single: r8c4=5
Hidden Single: r9c1=5
Hidden Single: r8c5=3
Hidden Single: r1c4=3
Hidden Single: r9c3=1
Hidden Single: r3c9=3
Hidden Single: r5c9=6
Locked Candidates Type 1 (Pointing): 9 in b7 => r7c456<>9
Naked Single: r7c4=8
Naked Single: r9c5=9
Naked Single: r9c6=6
Full House: r9c7=8
Full House: r8c7=6
Naked Single: r8c3=2
Full House: r8c1=8
Naked Single: r7c1=9
Hidden Single: r4c8=8
Naked Single: r5c8=1
Full House: r5c5=8
Hidden Single: r2c1=2
Hidden Single: r6c2=9
Hidden Single: r4c3=7
Naked Single: r1c3=9
Naked Single: r6c1=1
Full House: r3c1=7
Full House: r4c2=4
Naked Single: r1c8=7
Naked Single: r3c3=6
Full House: r7c3=4
Full House: r7c2=6
Naked Single: r6c5=2
Naked Single: r3c5=1
Full House: r3c8=9
Full House: r7c5=7
Full House: r2c8=6
Full House: r7c6=2
Naked Single: r4c9=2
Naked Single: r2c7=5
Naked Single: r4c6=9
Full House: r2c6=7
Full House: r2c4=9
Full House: r2c2=1
Full House: r4c4=1
Full House: r1c2=5
Naked Single: r6c7=7
Full House: r6c9=4
Full House: r1c9=1
Full House: r1c7=2
|
normal_sudoku_3062
|
.2.9.3..131..76..2....1..7.5..1..8...6..39..42........6..3....9.3..9.24......4...
|
427983651318576492956412378594127863761839524283645917642351789135798246879264135
|
Basic 9x9 Sudoku 3062
|
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 . 3 . . 1
3 1 . . 7 6 . . 2
. . . . 1 . . 7 .
5 . . 1 . . 8 . .
. 6 . . 3 9 . . 4
2 . . . . . . . .
6 . . 3 . . . . 9
. 3 . . 9 . 2 4 .
. . . . . 4 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
427983651318576492956412378594127863761839524283645917642351789135798246879264135 #1 Extreme (24392) bf
Brute Force: r6c1=2
Locked Candidates Type 2 (Claiming): 4 in c1 => r123c3,r3c2<>4
Brute Force: r6c2=8
Hidden Single: r5c4=8
Hidden Single: r5c8=2
Hidden Single: r5c7=5
Locked Candidates Type 1 (Pointing): 1 in b6 => r6c3<>1
Locked Candidates Type 2 (Claiming): 7 in r5 => r4c23,r6c3<>7
Locked Candidates Type 2 (Claiming): 7 in c2 => r789c3,r89c1<>7
Finned X-Wing: 7 r48 c69 fr8c4 => r7c6<>7
Discontinuous Nice Loop: 5 r3c4 -5- r3c2 -9- r4c2 -4- r7c2 =4= r7c3 =2= r9c3 -2- r9c4 =2= r3c4 => r3c4<>5
Forcing Chain Contradiction in r7c8 => r6c7<>3
r6c7=3 r6c7<>1 r6c8=1 r7c8<>1
r6c7=3 r3c7<>3 r3c9=3 r3c9<>5 r12c8=5 r7c8<>5
r6c7=3 r3c7<>3 r3c9=3 r3c9<>8 r12c8=8 r7c8<>8
Forcing Chain Contradiction in r7c8 => r7c3<>8
r7c3=8 r8c1<>8 r8c1=1 r8c6<>1 r7c6=1 r7c8<>1
r7c3=8 r7c3<>4 r7c2=4 r4c2<>4 r4c2=9 r3c2<>9 r3c2=5 r3c9<>5 r12c8=5 r7c8<>5
r7c3=8 r7c8<>8
Grouped Discontinuous Nice Loop: 8 r9c5 -8- r1c5 =8= r3c6 -8- r3c9 =8= r12c8 -8- r7c8 =8= r7c56 -8- r9c5 => r9c5<>8
Forcing Chain Contradiction in c6 => r3c1<>8
r3c1=8 r3c6<>8
r3c1=8 r8c1<>8 r8c1=1 r8c6<>1 r7c6=1 r7c6<>8
r3c1=8 r3c9<>8 r12c8=8 r7c8<>8 r7c56=8 r8c6<>8
Forcing Chain Contradiction in r7c8 => r7c3<>1
r7c3=1 r7c8<>1
r7c3=1 r7c3<>4 r7c2=4 r4c2<>4 r4c2=9 r3c2<>9 r3c2=5 r3c9<>5 r12c8=5 r7c8<>5
r7c3=1 r7c6<>1 r8c6=1 r8c6<>8 r7c56=8 r7c8<>8
Forcing Chain Contradiction in r8c3 => r9c2<>5
r9c2=5 r9c2<>7 r7c2=7 r7c7<>7 r7c7=1 r7c6<>1 r8c6=1 r8c3<>1
r9c2=5 r8c3<>5
r9c2=5 r9c2<>7 r7c2=7 r7c7<>7 r7c7=1 r7c6<>1 r8c6=1 r8c1<>1 r8c1=8 r8c3<>8
Empty Rectangle: 5 in b3 (r37c2) => r7c8<>5
W-Wing: 8/1 in r7c8,r8c1 connected by 1 in r78c6 => r8c9<>8
2-String Kite: 8 in r2c3,r9c9 (connected by r2c8,r3c9) => r9c3<>8
Sue de Coq: r7c56 - {1258} (r7c78 - {178}, r89c4,r9c5 - {2567}) => r8c6<>5, r7c2,r8c6<>7
Hidden Single: r7c7=7
Hidden Single: r9c2=7
Hidden Single: r8c4=7
Hidden Single: r8c9=6
Hidden Single: r8c3=5
Naked Single: r7c2=4
Naked Single: r4c2=9
Full House: r3c2=5
Naked Single: r7c3=2
Hidden Single: r9c9=5
Hidden Single: r3c9=8
Naked Single: r3c6=2
Naked Single: r3c4=4
Naked Single: r4c6=7
Naked Single: r2c4=5
Full House: r1c5=8
Naked Single: r3c1=9
Naked Single: r4c9=3
Full House: r6c9=7
Naked Single: r6c6=5
Naked Single: r2c8=9
Naked Single: r6c4=6
Full House: r9c4=2
Naked Single: r7c5=5
Naked Single: r2c3=8
Full House: r2c7=4
Naked Single: r3c3=6
Full House: r3c7=3
Naked Single: r4c3=4
Naked Single: r4c8=6
Full House: r4c5=2
Full House: r6c5=4
Full House: r9c5=6
Naked Single: r6c8=1
Full House: r6c7=9
Full House: r6c3=3
Naked Single: r1c7=6
Full House: r9c7=1
Full House: r1c8=5
Naked Single: r1c3=7
Full House: r1c1=4
Naked Single: r7c8=8
Full House: r7c6=1
Full House: r9c8=3
Full House: r8c6=8
Full House: r8c1=1
Naked Single: r9c1=8
Full House: r9c3=9
Full House: r5c3=1
Full House: r5c1=7
|
normal_sudoku_1507
|
...6.35.2..2.5.....5.4....3..........4..6.3.11.8.........7.92...2..4.7.64.7..6.1.
|
974613582382957164651482973293174658745268391168395427816739245529841736437526819
|
Basic 9x9 Sudoku 1507
|
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 . 3 5 . 2
. . 2 . 5 . . . .
. 5 . 4 . . . . 3
. . . . . . . . .
. 4 . . 6 . 3 . 1
1 . 8 . . . . . .
. . . 7 . 9 2 . .
. 2 . . 4 . 7 . 6
4 . 7 . . 6 . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
974613582382957164651482973293174658745268391168395427816739245529841736437526819 #1 Extreme (27906) bf
Hidden Single: r9c6=6
Hidden Single: r1c3=4
Brute Force: r5c3=5
Almost Locked Set XZ-Rule: A=r7c23589 {134568}, B=r9c279 {3589}, X=5, Z=3 => r7c1<>3
Brute Force: r5c1=7
Hidden Single: r4c1=2
Forcing Chain Contradiction in r9 => r2c2<>6
r2c2=6 r46c2<>6 r4c3=6 r4c3<>3 r46c2=3 r9c2<>3
r2c2=6 r23c1<>6 r7c1=6 r7c1<>5 r8c1=5 r8c46<>5 r9c4=5 r9c4<>3
r2c2=6 r23c1<>6 r7c1=6 r7c1<>5 r8c1=5 r8c46<>5 r9c4=5 r9c4<>2 r9c5=2 r9c5<>3
Forcing Chain Contradiction in r2c6 => r3c5<>1
r3c5=1 r2c6<>1
r3c5=1 r1c5<>1 r1c2=1 r1c2<>7 r2c2=7 r2c6<>7
r3c5=1 r3c5<>2 r3c6=2 r5c6<>2 r5c6=8 r2c6<>8
Forcing Chain Contradiction in r2c6 => r6c8<>7
r6c8=7 r123c8<>7 r2c9=7 r2c2<>7 r1c2=7 r1c2<>1 r1c5=1 r2c6<>1
r6c8=7 r3c8<>7 r3c56=7 r2c6<>7
r6c8=7 r6c8<>2 r5c8=2 r5c6<>2 r5c6=8 r2c6<>8
Forcing Net Contradiction in r9c4 => r1c2<>8
r1c2=8 (r1c2<>1 r1c5=1 r2c6<>1) r1c2<>7 r2c2=7 r2c6<>7 r2c6=8 r5c6<>8 r5c6=2 r3c6<>2 r3c5=2 r9c5<>2 r9c4=2
r1c2=8 (r1c2<>1 r1c5=1 r2c4<>1) (r1c2<>1 r1c5=1 r2c6<>1) r1c2<>7 r2c2=7 r2c6<>7 r2c6=8 r2c4<>8 r2c4=9 (r2c9<>9) r5c4<>9 r5c8=9 (r4c9<>9) r6c9<>9 r9c9=9 r9c9<>5 r9c4=5
Forcing Net Contradiction in r7c8 => r1c2<>9
r1c2=9 (r3c1<>9 r8c1=9 r8c3<>9) (r1c2<>1) r1c2<>7 r2c2=7 r2c2<>1 r7c2=1 r8c3<>1 r8c3=3 r8c8<>3 r7c8=3
r1c2=9 (r1c2<>1 r1c5=1 r2c4<>1) (r1c2<>1 r1c5=1 r2c6<>1) r1c2<>7 r2c2=7 (r2c9<>7) r2c6<>7 r2c6=8 (r2c9<>8) r2c4<>8 r2c4=9 r2c9<>9 r2c9=4 r7c9<>4 r7c8=4
Forcing Net Contradiction in r8c8 => r1c5<>8
r1c5=8 (r1c1<>8 r1c1=9 r1c8<>9 r1c8=7 r3c8<>7) (r1c1<>8 r1c1=9 r3c1<>9) (r1c1<>8 r1c1=9 r3c3<>9) r1c5<>1 r1c2=1 r3c3<>1 r3c3=6 (r3c8<>6) r3c1<>6 r3c1=8 r3c8<>8 r3c8=9 (r3c5<>9) r5c8<>9 r5c4=9 (r4c5<>9) r6c5<>9 r1c5=9 r1c5<>8
Forcing Net Contradiction in r8c8 => r2c1<>8
r2c1=8 (r8c1<>8) r2c1<>3 (r8c1=3 r8c8<>3 r7c8=3 r7c5<>3) r2c2=3 r2c2<>7 r1c2=7 r1c2<>1 r1c5=1 r7c5<>1 r7c5=8 (r8c4<>8) r8c6<>8 r8c8=8 r1c8<>8 r1c1=8 r2c1<>8
Forcing Net Contradiction in b3 => r2c1<>9
r2c1=9 r2c1<>3 r2c2=3 (r2c2<>1) r2c2<>7 r1c2=7 r1c2<>1 r1c5=1 (r2c4<>1) r2c6<>1 r2c7=1 r2c7<>6
r2c1=9 r2c1<>3 (r8c1=3 r8c8<>3 r7c8=3 r7c8<>4 r7c9=4 r2c9<>4) r2c2=3 (r2c2<>1) r2c2<>7 r1c2=7 r1c2<>1 r1c5=1 (r2c4<>1) r2c6<>1 r2c7=1 r2c7<>4 r2c8=4 r2c8<>6
r2c1=9 (r3c1<>9) r1c1<>9 r1c1=8 r3c1<>8 r3c1=6 r3c7<>6
r2c1=9 (r3c1<>9) r1c1<>9 r1c1=8 r3c1<>8 r3c1=6 r3c8<>6
Forcing Net Contradiction in r2c9 => r1c8<>9
r1c8=9 (r2c7<>9) (r2c8<>9) (r2c9<>9) r5c8<>9 r5c4=9 r2c4<>9 r2c2=9 (r3c1<>9 r8c1=9 r8c3<>9) (r2c2<>1) r2c2<>7 r1c2=7 r1c2<>1 r7c2=1 r8c3<>1 r8c3=3 r8c8<>3 r7c8=3 r7c8<>4 r7c9=4 r2c9<>4
r1c8=9 (r3c7<>9) (r3c8<>9) (r2c7<>9) (r2c8<>9) (r2c9<>9) r5c8<>9 r5c4=9 r2c4<>9 r2c2=9 (r3c1<>9) r3c3<>9 r3c5=9 (r3c5<>7) r3c5<>2 r3c6=2 r3c6<>7 r3c8=7 r2c9<>7
r1c8=9 (r2c7<>9) (r2c8<>9) (r2c9<>9) r5c8<>9 r5c4=9 (r2c4<>9) r2c4<>9 r2c2=9 r2c2<>7 r1c2=7 r1c2<>1 r1c5=1 r2c4<>1 r2c4=8 r2c9<>8
r1c8=9 r2c9<>9
Discontinuous Nice Loop: 9 r2c2 -9- r1c1 -8- r1c8 -7- r1c2 =7= r2c2 => r2c2<>9
Finned X-Wing: 9 r25 c48 fr2c7 fr2c9 => r3c8<>9
Almost Locked Set XY-Wing: A=r13c8 {678}, B=r1c5,r2c46 {1789}, C=r3c13567 {126789}, X,Y=6,7, Z=8 => r2c789<>8
Finned Jellyfish: 8 r1258 c1468 fr2c2 => r3c1<>8
Sue de Coq: r1c12 - {1789} (r1c8 - {78}, r23c1,r3c3 - {1369}) => r2c2<>1, r2c2<>3, r1c5<>7
Hidden Single: r2c1=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r3c78<>6
Locked Pair: 7,8 in r13c8 => r2c89,r4c8<>7, r3c7,r4578c8<>8
Locked Candidates Type 1 (Pointing): 8 in b6 => r4c456<>8
Naked Triple: 1,6,9 in r3c137 => r3c5<>9, r3c6<>1
Finned Swordfish: 8 r258 c146 fr2c2 => r1c1<>8
Naked Single: r1c1=9
Naked Single: r1c5=1
Naked Single: r3c1=6
Naked Single: r1c2=7
Full House: r1c8=8
Naked Single: r3c3=1
Full House: r2c2=8
Naked Single: r3c8=7
Naked Single: r3c7=9
Naked Single: r2c4=9
Naked Single: r2c6=7
Naked Single: r2c9=4
Naked Single: r9c7=8
Naked Single: r2c8=6
Full House: r2c7=1
Naked Single: r7c9=5
Naked Single: r7c1=8
Full House: r8c1=5
Naked Single: r9c9=9
Naked Single: r7c5=3
Naked Single: r6c9=7
Full House: r4c9=8
Naked Single: r8c8=3
Full House: r7c8=4
Naked Single: r9c2=3
Naked Single: r7c3=6
Full House: r7c2=1
Full House: r8c3=9
Full House: r4c3=3
Naked Single: r9c5=2
Full House: r9c4=5
Naked Single: r3c5=8
Full House: r3c6=2
Naked Single: r6c5=9
Full House: r4c5=7
Naked Single: r4c4=1
Naked Single: r5c6=8
Naked Single: r6c2=6
Full House: r4c2=9
Naked Single: r8c4=8
Full House: r8c6=1
Naked Single: r5c4=2
Full House: r5c8=9
Full House: r6c4=3
Naked Single: r6c7=4
Full House: r4c7=6
Naked Single: r4c8=5
Full House: r4c6=4
Full House: r6c6=5
Full House: r6c8=2
|
normal_sudoku_5025
|
...2......8...3...9.2.6...3...63.12..2.49..6...3...7.487.........43....6.6..2..5.
|
537249681186753249942168573459637128728491365613582794875916432294375816361824957
|
Basic 9x9 Sudoku 5025
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 2 . . . . .
. 8 . . . 3 . . .
9 . 2 . 6 . . . 3
. . . 6 3 . 1 2 .
. 2 . 4 9 . . 6 .
. . 3 . . . 7 . 4
8 7 . . . . . . .
. . 4 3 . . . . 6
. 6 . . 2 . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
537249681186753249942168573459637128728491365613582794875916432294375816361824957 #1 Hard (1024)
Hidden Single: r4c5=3
Hidden Single: r5c7=3
Hidden Single: r6c1=6
Hidden Single: r7c6=6
Hidden Single: r1c2=3
Hidden Single: r9c1=3
Hidden Single: r6c6=2
Hidden Single: r8c1=2
Hidden Single: r7c8=3
Locked Candidates Type 1 (Pointing): 7 in b5 => r1389c6<>7
Locked Candidates Type 1 (Pointing): 5 in b6 => r12c9<>5
Locked Candidates Type 1 (Pointing): 4 in b9 => r123c7<>4
Skyscraper: 7 in r3c4,r8c5 (connected by r38c8) => r12c5,r9c4<>7
Hidden Single: r8c5=7
Hidden Single: r9c9=7
Empty Rectangle: 5 in b5 (r8c26) => r6c2<>5
Locked Candidates Type 2 (Claiming): 5 in r6 => r45c6<>5
Empty Rectangle: 8 in b6 (r16c5) => r1c9<>8
Locked Candidates Type 2 (Claiming): 8 in c9 => r6c8<>8
Naked Single: r6c8=9
Naked Single: r6c2=1
Hidden Single: r5c6=1
Hidden Single: r8c8=1
Hidden Single: r4c6=7
Hidden Single: r3c4=1
Hidden Single: r7c5=1
Hidden Single: r9c3=1
Hidden Single: r3c8=7
Naked Single: r2c8=4
Full House: r1c8=8
Naked Single: r2c5=5
Naked Single: r3c7=5
Naked Single: r1c5=4
Full House: r6c5=8
Full House: r6c4=5
Naked Single: r3c2=4
Full House: r3c6=8
Naked Single: r1c6=9
Full House: r2c4=7
Naked Single: r7c4=9
Full House: r9c4=8
Naked Single: r1c7=6
Naked Single: r1c9=1
Naked Single: r8c6=5
Full House: r9c6=4
Full House: r9c7=9
Naked Single: r2c1=1
Naked Single: r2c3=6
Naked Single: r7c3=5
Full House: r8c2=9
Full House: r8c7=8
Full House: r4c2=5
Naked Single: r7c9=2
Full House: r7c7=4
Full House: r2c7=2
Full House: r2c9=9
Naked Single: r1c3=7
Full House: r1c1=5
Naked Single: r4c1=4
Full House: r5c1=7
Naked Single: r4c9=8
Full House: r4c3=9
Full House: r5c3=8
Full House: r5c9=5
|
normal_sudoku_2275
|
.......5.7...9.....4.8....6.....561..6.3....4..16.79..6.4.....2.8.......2.34..8..
|
896134257732596148145872396478925613569318724321647985614789532987253461253461879
|
Basic 9x9 Sudoku 2275
|
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 . . . 9 . . . .
. 4 . 8 . . . . 6
. . . . . 5 6 1 .
. 6 . 3 . . . . 4
. . 1 6 . 7 9 . .
6 . 4 . . . . . 2
. 8 . . . . . . .
2 . 3 4 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
896134257732596148145872396478925613569318724321647985614789532987253461253461879 #1 Extreme (27296) bf
Hidden Single: r4c7=6
Locked Candidates Type 1 (Pointing): 4 in b5 => r1c5<>4
Brute Force: r5c3=9
Hidden Single: r4c4=9
Locked Candidates Type 1 (Pointing): 7 in b4 => r4c9<>7
Forcing Chain Contradiction in r7c8 => r1c9<>3
r1c9=3 r123c7<>3 r78c7=3 r7c8<>3
r1c9=3 r1c9<>7 r89c9=7 r7c8<>7
r1c9=3 r1c9<>9 r3c8=9 r7c8<>9
Forcing Chain Contradiction in r3 => r8c8<>7
r8c8=7 r5c8<>7 r5c7=7 r5c7<>5 r5c1=5 r3c1<>5
r8c8=7 r8c3<>7 r8c3=5 r3c3<>5
r8c8=7 r89c9<>7 r1c9=7 r1c45<>7 r3c5=7 r3c5<>5
Forcing Net Verity => r2c9<>3
r4c1=3 (r4c9<>3 r4c9=8 r6c9<>8) (r4c9<>3 r4c9=8 r5c8<>8) (r4c9<>3 r4c9=8 r6c8<>8) (r4c9<>3 r4c9=8 r6c9<>8) r4c1<>4 r4c5=4 r6c5<>4 r6c1=4 r6c1<>8 r6c5=8 (r5c5<>8) r5c6<>8 r5c1=8 r5c1<>5 r5c7=5 r6c9<>5 r6c9=3 r2c9<>3
r4c2=3 (r4c9<>3 r4c9=8 r4c1<>8 r4c1=4 r6c1<>4 r6c5=4 r6c5<>8) (r4c2<>2) r4c2<>7 r4c3=7 (r8c3<>7 r8c3=5 r9c2<>5) (r8c3<>7 r8c3=5 r7c2<>5) (r8c3<>7 r8c3=5 r9c2<>5) r4c3<>2 r6c2=2 (r6c2<>5) r6c2<>5 r2c2=5 (r3c1<>5) r3c3<>5 r3c5=5 r9c5<>5 r9c9=5 r6c9<>5 r6c1=5 r5c1<>5 r5c1=8 (r5c5<>8) r5c6<>8 r7c6=8 r7c5<>8 r4c5=8 r4c9<>8 r4c9=3 r2c9<>3
r4c9=3 r2c9<>3
Forcing Net Contradiction in r7c8 => r3c8<>2
r3c8=2 (r3c3<>2 r3c3=5 r8c3<>5 r8c3=7 r8c9<>7) (r3c8<>9 r3c1=9 r1c2<>9 r1c9=9 r8c9<>9) (r3c8<>9 r3c1=9 r8c1<>9) (r1c7<>2) (r2c7<>2) r3c7<>2 r5c7=2 r5c7<>5 r5c1=5 r8c1<>5 r8c1=1 r8c9<>1 r8c9=3 (r6c9<>3 r6c8=3 r6c2<>3) r4c9<>3 r4c9=8 (r4c3<>8) r6c9<>8 r6c9=5 (r6c9<>3) (r8c9<>5) r6c2<>5 r6c2=2 r4c3<>2 r4c3=7 r8c3<>7 r8c3=5 r3c3<>5 r3c3=2 r3c8<>2
Forcing Net Contradiction in c2 => r4c2<>3
r4c2=3 r4c2=3
r4c2=3 (r4c9<>3 r4c9=8 r2c9<>8 r2c9=1 r2c2<>1) (r2c2<>3) (r4c2<>2) r4c2<>7 r4c3=7 (r8c3<>7 r8c3=5 r9c2<>5) r4c3<>2 r6c2=2 (r6c2<>5) (r6c8<>2 r5c8=2 r5c7<>2) (r6c2<>5) r2c2<>2 r2c2=5 (r3c1<>5) r3c3<>5 r3c5=5 r9c5<>5 r9c9=5 r6c9<>5 r6c1=5 r5c1<>5 r5c7=5 r5c7<>7 r5c8=7 r5c8<>2 r6c8=2 r6c2<>2 r6c2=3
Forcing Net Contradiction in r4c5 => r6c8<>3
r6c8=3 (r6c2<>3) (r6c9<>3) r4c9<>3 r4c9=8 r6c9<>8 r6c9=5 r6c2<>5 r6c2=2 (r4c2<>2) r4c3<>2 r4c5=2
r6c8=3 r4c9<>3 r4c1=3 r4c1<>4 r4c5=4
Locked Candidates Type 1 (Pointing): 3 in b6 => r8c9<>3
Forcing Net Contradiction in r9c5 => r7c7<>7
r7c7=7 (r7c4<>7) (r3c7<>7) r5c7<>7 r5c8=7 r3c8<>7 r3c5=7 r3c5<>5 r2c4=5 r7c4<>5 r7c4=1 r9c5<>1
r7c7=7 (r5c7<>7 r5c8=7 r3c8<>7 r3c5=7 r3c5<>5) (r7c4<>7) (r8c9<>7) r9c9<>7 r1c9=7 r1c4<>7 r8c4=7 r8c3<>7 r8c3=5 (r8c9<>5) r3c3<>5 r3c1=5 r5c1<>5 r5c7=5 r6c9<>5 r9c9=5 r9c5<>5
r7c7=7 (r9c8<>7) (r8c9<>7) r9c9<>7 r1c9=7 r1c9<>9 r3c8=9 r9c8<>9 r9c8=6 r9c5<>6
r7c7=7 (r3c7<>7) r5c7<>7 r5c8=7 r3c8<>7 r3c5=7 r9c5<>7
Forcing Net Contradiction in r8 => r7c8<>7
r7c8=7 r5c8<>7 r5c7=7 (r3c7<>7 r3c5=7 r3c5<>5) r5c7<>5 r5c1=5 r3c1<>5 r3c3=5 r8c3<>5 r8c3=7
r7c8=7 (r7c4<>7) (r8c9<>7) r9c9<>7 r1c9=7 r1c4<>7 r8c4=7
Forcing Net Contradiction in c9 => r2c8<>3
r2c8=3 r7c8<>3 r7c8=9 r3c8<>9 r3c1=9 (r1c1<>9) r1c2<>9 r1c9=9 r1c9<>1
r2c8=3 (r2c8<>8) r7c8<>3 r7c8=9 r3c8<>9 r3c1=9 (r1c1<>9) r1c2<>9 r1c9=9 r1c9<>8 r2c9=8 r2c9<>1
r2c8=3 (r3c8<>3) r7c8<>3 r7c8=9 r3c8<>9 (r3c1=9 r8c1<>9) r3c8=7 r5c8<>7 r5c7=7 r5c7<>5 r5c1=5 r8c1<>5 r8c1=1 r8c9<>1
r2c8=3 (r2c8<>4 r8c8=4 r8c8<>6 r9c8=6 r9c6<>6) r7c8<>3 r7c8=9 (r7c2<>9) r3c8<>9 r3c1=9 r1c2<>9 r9c2=9 r9c6<>9 r9c6=1 r9c9<>1
Forcing Net Contradiction in r3 => r7c6<>3
r7c6=3 r7c6<>8 r5c6=8 r5c1<>8 r5c1=5 r3c1<>5
r7c6=3 (r7c8<>3 r7c8=9 r3c8<>9 r3c1=9 r8c1<>9 r8c1=1 r8c9<>1) (r7c8<>3 r7c8=9 r8c9<>9) r7c6<>8 r5c6=8 r5c1<>8 r5c1=5 (r6c1<>5) r6c2<>5 r6c9=5 r8c9<>5 r8c9=7 r8c3<>7 r8c3=5 r3c3<>5
r7c6=3 (r7c6<>8 r5c6=8 r5c1<>8 r5c1=5 r6c2<>5 r6c9=5 r9c9<>5) r7c8<>3 r7c8=9 (r7c2<>9) r3c8<>9 r3c1=9 r1c2<>9 r9c2=9 r9c2<>5 r9c5=5 r3c5<>5
Forcing Net Contradiction in r7c8 => r8c1<>5
r8c1=5 (r8c3<>5 r8c3=7 r9c2<>7) r5c1<>5 r5c7=5 (r6c9<>5 r9c9=5 r9c9<>7) r5c7<>7 r5c8=7 r9c8<>7 r9c5=7 (r7c4<>7) r7c5<>7 r7c2=7 r8c3<>7 r8c3=5 r8c1<>5
Forcing Chain Contradiction in r7 => r8c5<>1
r8c5=1 r8c1<>1 r8c1=9 r7c2<>9
r8c5=1 r5c5<>1 r5c6=1 r5c6<>8 r7c6=8 r7c6<>9
r8c5=1 r8c1<>1 r8c1=9 r3c1<>9 r3c8=9 r7c8<>9
Forcing Net Contradiction in c7 => r8c4<>1
r8c4=1 r8c1<>1 r8c1=9 (r7c2<>9) r3c1<>9 r3c8=9 r7c8<>9 r7c6=9 r7c6<>8 r5c6=8 r5c1<>8 r5c1=5 r5c7<>5
r8c4=1 (r7c4<>1) (r7c5<>1) (r7c6<>1) (r9c5<>1) (r9c6<>1) r8c1<>1 r8c1=9 (r8c9<>9) r3c1<>9 r3c8=9 r1c9<>9 r9c9=9 r9c9<>1 r9c2=1 r7c2<>1 r7c7=1 r7c7<>5
r8c4=1 (r9c6<>1) r8c1<>1 r8c1=9 (r8c9<>9) r3c1<>9 r3c8=9 r1c9<>9 r9c9=9 r9c6<>9 r9c6=6 (r8c5<>6) r8c6<>6 r8c8=6 r8c8<>4 r8c7=4 r8c7<>5
Forcing Net Contradiction in r3 => r4c9=3
r4c9<>3 (r4c9=8 r6c8<>8 r6c8=2 r6c2<>2) r4c1=3 r6c2<>3 r6c2=5 (r5c1<>5) r6c1<>5 r3c1=5 r3c1<>1
r4c9<>3 (r4c9=8 r2c9<>8 r2c9=1 r2c4<>1) (r4c9=8 r6c8<>8 r6c8=2 r6c2<>2) r4c1=3 r6c2<>3 r6c2=5 (r5c1<>5 r5c7=5 r7c7<>5) (r5c1<>5) r6c1<>5 r3c1=5 r3c1<>9 r3c8=9 r7c8<>9 r7c8=3 r7c7<>3 r7c7=1 r7c4<>1 r1c4=1 r3c5<>1
r4c9<>3 (r4c9=8 r2c9<>8 r2c9=1 r2c4<>1) (r4c9=8 r6c8<>8 r6c8=2 r6c2<>2) r4c1=3 r6c2<>3 r6c2=5 (r5c1<>5 r5c7=5 r7c7<>5) (r5c1<>5) r6c1<>5 r3c1=5 r3c1<>9 r3c8=9 r7c8<>9 r7c8=3 r7c7<>3 r7c7=1 r7c4<>1 r1c4=1 r3c6<>1
r4c9<>3 r4c9=8 r2c9<>8 r2c9=1 r3c7<>1
Hidden Rectangle: 4/8 in r4c15,r6c15 => r6c5<>8
Forcing Net Contradiction in r3 => r3c1<>5
r3c1=5 r3c1<>1
r3c1=5 (r2c3<>5 r2c4=5 r2c4<>1) (r5c1<>5 r5c7=5 r7c7<>5) r3c1<>9 r3c8=9 r7c8<>9 r7c8=3 r7c7<>3 r7c7=1 r7c4<>1 r1c4=1 r3c5<>1
r3c1=5 (r2c3<>5 r2c4=5 r2c4<>1) (r5c1<>5 r5c7=5 r7c7<>5) r3c1<>9 r3c8=9 r7c8<>9 r7c8=3 r7c7<>3 r7c7=1 r7c4<>1 r1c4=1 r3c6<>1
r3c1=5 r5c1<>5 r5c7=5 r6c9<>5 r6c9=8 r2c9<>8 r2c9=1 r3c7<>1
Locked Candidates Type 2 (Claiming): 5 in c1 => r6c2<>5
Grouped Discontinuous Nice Loop: 7 r8c7 -7- r8c3 -5- r3c3 =5= r3c5 =7= r1c45 -7- r1c9 =7= r89c9 -7- r8c7 => r8c7<>7
Forcing Net Contradiction in r2 => r4c2=7
r4c2<>7 r4c3=7 r8c3<>7 r8c3=5 (r8c4<>5 r8c4=2 r2c4<>2) (r9c2<>5) r3c3<>5 r3c5=5 r9c5<>5 r9c9=5 (r9c9<>7) r6c9<>5 r6c1=5 r5c1<>5 r5c7=5 r5c7<>7 r5c8=7 r9c8<>7 r8c9=7 r8c3<>7 r8c3=5 (r8c4<>5 r8c4=2 r2c4<>2) (r9c2<>5) r3c3<>5 r3c5=5 r2c4<>5 r2c4=1
r4c2<>7 r4c3=7 r8c3<>7 r8c3=5 (r9c2<>5) r3c3<>5 r3c5=5 r9c5<>5 r9c9=5 r6c9<>5 r6c9=8 r2c9<>8 r2c9=1
Hidden Single: r8c3=7
Locked Candidates Type 1 (Pointing): 5 in b7 => r2c2<>5
Locked Candidates Type 1 (Pointing): 7 in b9 => r9c5<>7
Discontinuous Nice Loop: 2 r8c5 -2- r8c4 -5- r2c4 =5= r2c3 -5- r3c3 -2- r4c3 =2= r4c5 -2- r8c5 => r8c5<>2
Discontinuous Nice Loop: 5 r9c9 -5- r6c9 =5= r5c7 =7= r5c8 -7- r9c8 =7= r9c9 => r9c9<>5
Almost Locked Set XY-Wing: A=r8c19 {159}, B=r3567c8 {23789}, C=r6c9 {58}, X,Y=5,8, Z=9 => r8c8<>9
Forcing Chain Contradiction in r8c9 => r3c8<>7
r3c8=7 r3c8<>9 r3c1=9 r8c1<>9 r8c1=1 r8c9<>1
r3c8=7 r5c8<>7 r5c7=7 r5c7<>5 r6c9=5 r8c9<>5
r3c8=7 r3c8<>9 r1c9=9 r8c9<>9
Naked Pair: 3,9 in r37c8 => r8c8<>3, r9c8<>9
Forcing Chain Contradiction in r5c7 => r2c4<>2
r2c4=2 r2c8<>2 r123c7=2 r5c7<>2
r2c4=2 r8c4<>2 r8c4=5 r8c9<>5 r6c9=5 r5c7<>5
r2c4=2 r2c4<>5 r3c5=5 r3c5<>7 r3c7=7 r5c7<>7
Forcing Chain Contradiction in r5 => r2c6<>1
r2c6=1 r2c9<>1 r2c9=8 r6c9<>8 r6c9=5 r6c1<>5 r5c1=5 r5c1<>8
r2c6=1 r5c6<>1 r5c5=1 r5c5<>8
r2c6=1 r12c4<>1 r7c4=1 r7c4<>7 r7c5=7 r7c5<>8 r7c6=8 r5c6<>8
r2c6=1 r12c4<>1 r7c4=1 r7c4<>7 r7c5=7 r3c5<>7 r3c7=7 r5c7<>7 r5c8=7 r5c8<>8
Forcing Chain Contradiction in c6 => r7c4<>5
r7c4=5 r2c4<>5 r2c3=5 r2c3<>6 r2c6=6 r2c6<>4 r1c6=4 r1c6<>2
r7c4=5 r2c4<>5 r2c3=5 r2c3<>6 r2c6=6 r2c6<>2
r7c4=5 r2c4<>5 r2c3=5 r3c3<>5 r3c3=2 r3c6<>2
r7c4=5 r2c4<>5 r2c3=5 r3c3<>5 r3c3=2 r4c3<>2 r4c5=2 r5c6<>2
r7c4=5 r8c4<>5 r8c4=2 r8c6<>2
Forcing Chain Contradiction in b9 => r7c7<>3
r7c7=3 r7c7<>1
r7c7=3 r7c8<>3 r7c8=9 r3c8<>9 r3c1=9 r8c1<>9 r8c1=1 r8c7<>1
r7c7=3 r7c8<>3 r7c8=9 r3c8<>9 r3c1=9 r8c1<>9 r8c1=1 r8c9<>1
r7c7=3 r7c8<>3 r7c8=9 r3c8<>9 r1c9=9 r1c9<>7 r9c9=7 r9c9<>1
XYZ-Wing: 1/5/9 in r7c7,r8c19 => r8c7<>1
Forcing Chain Contradiction in r9c5 => r7c4=7
r7c4<>7 r7c4=1 r9c5<>1
r7c4<>7 r7c4=1 r7c7<>1 r7c7=5 r7c2<>5 r9c2=5 r9c5<>5
r7c4<>7 r1c4=7 r1c9<>7 r9c9=7 r9c8<>7 r9c8=6 r9c5<>6
Locked Candidates Type 2 (Claiming): 1 in c4 => r1c56,r3c56<>1
AIC: 1 1- r1c4 =1= r2c4 =5= r3c5 =7= r3c7 =1= r3c1 -1 => r1c12<>1
Discontinuous Nice Loop: 9 r9c2 -9- r8c1 -1- r3c1 =1= r3c7 -1- r7c7 -5- r7c2 =5= r9c2 => r9c2<>9
Skyscraper: 9 in r1c2,r3c8 (connected by r7c28) => r1c9,r3c1<>9
Hidden Single: r3c8=9
Naked Single: r7c8=3
XYZ-Wing: 1/2/3 in r26c2,r3c1 => r1c2<>3
Discontinuous Nice Loop: 2/3/5 r3c5 =7= r3c7 =1= r3c1 -1- r8c1 -9- r8c9 =9= r9c9 =7= r1c9 -7- r1c5 =7= r3c5 => r3c5<>2, r3c5<>3, r3c5<>5
Naked Single: r3c5=7
Hidden Single: r3c3=5
Hidden Single: r2c4=5
Naked Single: r8c4=2
Full House: r1c4=1
AIC: 4 4- r2c8 =4= r8c8 =6= r9c8 =7= r9c9 =9= r8c9 -9- r8c1 -1- r3c1 =1= r3c7 -1- r7c7 -5- r8c7 -4 => r12c7,r8c8<>4
Naked Single: r8c8=6
Naked Single: r9c8=7
Hidden Single: r1c6=4
Hidden Single: r8c7=4
Hidden Single: r2c8=4
Hidden Single: r5c7=7
Hidden Single: r1c9=7
Hidden Single: r5c1=5
Hidden Single: r7c7=5
Hidden Single: r6c9=5
Hidden Single: r2c9=8
Hidden Single: r9c2=5
Hidden Single: r8c5=5
Hidden Single: r8c6=3
Naked Single: r3c6=2
Naked Single: r2c6=6
Full House: r1c5=3
Naked Single: r2c3=2
Naked Single: r1c7=2
Naked Single: r1c2=9
Naked Single: r4c3=8
Full House: r1c3=6
Full House: r1c1=8
Naked Single: r7c2=1
Full House: r8c1=9
Full House: r8c9=1
Full House: r9c9=9
Naked Single: r4c1=4
Full House: r4c5=2
Naked Single: r2c2=3
Full House: r2c7=1
Full House: r3c1=1
Full House: r6c1=3
Full House: r6c2=2
Full House: r3c7=3
Naked Single: r7c5=8
Full House: r7c6=9
Naked Single: r9c6=1
Full House: r5c6=8
Full House: r9c5=6
Naked Single: r6c5=4
Full House: r6c8=8
Full House: r5c5=1
Full House: r5c8=2
|
normal_sudoku_594
|
.1.....3.67.4...8.5.8.....7251..73..9..2.37....4..9.....5...81.....8..298...9....
|
419578632673412985528936147251867394986243751734159268395724816167385429842691573
|
Basic 9x9 Sudoku 594
|
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 . . . . . 3 .
6 7 . 4 . . . 8 .
5 . 8 . . . . . 7
2 5 1 . . 7 3 . .
9 . . 2 . 3 7 . .
. . 4 . . 9 . . .
. . 5 . . . 8 1 .
. . . . 8 . . 2 9
8 . . . 9 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
419578632673412985528936147251867394986243751734159268395724816167385429842691573 #1 Unfair (1066)
Naked Single: r5c1=9
Naked Single: r1c1=4
Naked Single: r5c3=6
Naked Single: r5c2=8
Naked Single: r6c2=3
Full House: r6c1=7
Naked Single: r7c1=3
Full House: r8c1=1
Naked Single: r8c3=7
Naked Single: r9c3=2
Naked Single: r1c3=9
Full House: r2c3=3
Full House: r3c2=2
Hidden Single: r1c6=8
Hidden Single: r9c8=7
Hidden Single: r4c8=9
Hidden Single: r7c2=9
Hidden Single: r9c9=3
Hidden Single: r8c4=3
Hidden Single: r3c4=9
Hidden Single: r2c7=9
Hidden Single: r3c5=3
Locked Candidates Type 1 (Pointing): 4 in b5 => r7c5<>4
Locked Candidates Type 1 (Pointing): 5 in b9 => r16c7<>5
Locked Candidates Type 1 (Pointing): 5 in b3 => r56c9<>5
Hidden Rectangle: 6/8 in r4c49,r6c49 => r6c9<>6
Hidden Rectangle: 6/7 in r1c45,r7c45 => r1c5<>6
Turbot Fish: 6 r1c4 =6= r3c6 -6- r3c8 =6= r6c8 => r6c4<>6
AIC: 6 6- r1c7 -2- r6c7 =2= r6c9 =8= r6c4 -8- r4c4 -6- r1c4 =6= r3c6 -6 => r1c4,r3c78<>6
Naked Single: r3c8=4
Naked Single: r3c7=1
Full House: r3c6=6
Naked Single: r5c8=5
Full House: r6c8=6
Naked Single: r6c7=2
Naked Single: r1c7=6
Hidden Single: r7c9=6
Naked Single: r7c4=7
Naked Single: r1c4=5
Naked Single: r7c5=2
Full House: r7c6=4
Naked Single: r1c9=2
Full House: r1c5=7
Full House: r2c9=5
Naked Single: r2c5=1
Full House: r2c6=2
Naked Single: r8c6=5
Full House: r9c6=1
Full House: r9c4=6
Naked Single: r5c5=4
Full House: r5c9=1
Naked Single: r6c5=5
Full House: r4c5=6
Naked Single: r8c7=4
Full House: r8c2=6
Full House: r9c2=4
Full House: r9c7=5
Naked Single: r4c4=8
Full House: r4c9=4
Full House: r6c9=8
Full House: r6c4=1
|
normal_sudoku_1750
|
.8....1.7...7....8.1.28.5....3...8..8.21..6..9..8.3.4...4.7...667..5....3.14.....
|
489635127235714968716289534163542879842197653957863241524978316678351492391426785
|
Basic 9x9 Sudoku 1750
|
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 . 7
. . . 7 . . . . 8
. 1 . 2 8 . 5 . .
. . 3 . . . 8 . .
8 . 2 1 . . 6 . .
9 . . 8 . 3 . 4 .
. . 4 . 7 . . . 6
6 7 . . 5 . . . .
3 . 1 4 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
489635127235714968716289534163542879842197653957863241524978316678351492391426785 #1 Easy (306)
Hidden Single: r5c1=8
Hidden Single: r2c2=3
Hidden Single: r6c9=1
Hidden Single: r4c1=1
Hidden Single: r2c5=1
Hidden Single: r8c3=8
Hidden Single: r1c5=3
Hidden Single: r3c1=7
Hidden Single: r6c3=7
Naked Single: r6c7=2
Naked Single: r6c5=6
Full House: r6c2=5
Naked Single: r5c2=4
Full House: r4c2=6
Naked Single: r5c5=9
Naked Single: r4c4=5
Naked Single: r9c5=2
Full House: r4c5=4
Naked Single: r4c9=9
Naked Single: r5c6=7
Full House: r4c6=2
Full House: r4c8=7
Naked Single: r9c2=9
Full House: r7c2=2
Full House: r7c1=5
Naked Single: r9c9=5
Naked Single: r9c7=7
Naked Single: r5c9=3
Full House: r5c8=5
Naked Single: r9c8=8
Full House: r9c6=6
Naked Single: r3c9=4
Full House: r8c9=2
Naked Single: r2c7=9
Naked Single: r3c6=9
Naked Single: r7c7=3
Full House: r8c7=4
Naked Single: r1c4=6
Naked Single: r3c3=6
Full House: r3c8=3
Naked Single: r8c6=1
Naked Single: r7c4=9
Full House: r8c4=3
Full House: r7c6=8
Full House: r8c8=9
Full House: r7c8=1
Naked Single: r1c8=2
Full House: r2c8=6
Naked Single: r2c3=5
Full House: r1c3=9
Naked Single: r1c1=4
Full House: r1c6=5
Full House: r2c6=4
Full House: r2c1=2
|
normal_sudoku_3658
|
9...2.31.4.1.37.2...3..9......38.26.3...6...1...7..43.6...431..7.9........5..8.4.
|
957826314461537829823419756594381267378264591216795438682943175749152683135678942
|
Basic 9x9 Sudoku 3658
|
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 . 3 1 .
4 . 1 . 3 7 . 2 .
. . 3 . . 9 . . .
. . . 3 8 . 2 6 .
3 . . . 6 . . . 1
. . . 7 . . 4 3 .
6 . . . 4 3 1 . .
7 . 9 . . . . . .
. . 5 . . 8 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
957826314461537829823419756594381267378264591216795438682943175749152683135678942 #1 Hard (908)
Hidden Single: r4c4=3
Hidden Single: r9c5=7
Hidden Single: r8c2=4
Hidden Single: r6c5=9
Hidden Single: r8c9=3
Hidden Single: r9c2=3
Hidden Single: r9c1=1
Naked Single: r4c1=5
Locked Candidates Type 1 (Pointing): 1 in b5 => r8c6<>1
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c49<>2
Hidden Single: r9c9=2
Locked Candidates Type 1 (Pointing): 8 in b7 => r7c89<>8
Locked Candidates Type 1 (Pointing): 6 in b9 => r23c7<>6
W-Wing: 8/2 in r6c1,r7c2 connected by 2 in r3c12 => r56c2<>8
Uniqueness Test 4: 1/5 in r3c45,r8c45 => r38c4<>5
Finned X-Wing: 8 c19 r36 fr1c9 fr2c9 => r3c78<>8
Locked Pair: 5,7 in r3c78 => r123c9,r2c7,r3c25<>5, r13c9,r3c2<>7
Naked Single: r3c5=1
Full House: r8c5=5
Naked Single: r7c4=9
Naked Single: r8c8=8
Naked Single: r9c4=6
Full House: r9c7=9
Naked Single: r8c7=6
Naked Single: r8c6=2
Full House: r8c4=1
Naked Single: r2c7=8
Naked Single: r2c4=5
Naked Single: r2c2=6
Full House: r2c9=9
Naked Single: r4c9=7
Naked Single: r4c3=4
Naked Single: r5c7=5
Full House: r3c7=7
Naked Single: r7c9=5
Full House: r7c8=7
Naked Single: r4c6=1
Full House: r4c2=9
Naked Single: r5c6=4
Naked Single: r5c8=9
Full House: r6c9=8
Full House: r3c8=5
Naked Single: r6c6=5
Full House: r1c6=6
Full House: r5c4=2
Naked Single: r6c1=2
Full House: r3c1=8
Naked Single: r1c9=4
Full House: r3c9=6
Naked Single: r5c2=7
Full House: r5c3=8
Naked Single: r6c2=1
Full House: r6c3=6
Naked Single: r1c3=7
Full House: r7c3=2
Full House: r7c2=8
Naked Single: r3c2=2
Full House: r3c4=4
Full House: r1c4=8
Full House: r1c2=5
|
normal_sudoku_1473
|
4.9..6....5.....64.3..4.....7......2...76.49...49.2..11..4397.........29..762.1..
|
429856317851397264736241985978514632215763498364982571182439756643175829597628143
|
Basic 9x9 Sudoku 1473
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . 9 . . 6 . . .
. 5 . . . . . 6 4
. 3 . . 4 . . . .
. 7 . . . . . . 2
. . . 7 6 . 4 9 .
. . 4 9 . 2 . . 1
1 . . 4 3 9 7 . .
. . . . . . . 2 9
. . 7 6 2 . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
429856317851397264736241985978514632215763498364982571182439756643175829597628143 #1 Extreme (3898)
Hidden Single: r2c9=4
Hidden Single: r4c1=9
Hidden Single: r4c6=4
Hidden Single: r2c5=9
Hidden Single: r6c8=7
Hidden Single: r9c8=4
Hidden Single: r3c7=9
Hidden Single: r9c2=9
Hidden Single: r8c2=4
Hidden Single: r7c9=6
Hidden Single: r6c2=6
Hidden Single: r4c7=6
Skyscraper: 3 in r6c7,r9c9 (connected by r69c1) => r5c9,r8c7<>3
Hidden Single: r9c9=3
Naked Triple: 2,5,8 in r7c23,r9c1 => r8c13<>5, r8c13<>8
Discontinuous Nice Loop: 1 r3c3 -1- r3c8 =1= r1c8 =3= r4c8 -3- r6c7 =3= r6c1 -3- r8c1 -6- r8c3 =6= r3c3 => r3c3<>1
Finned Franken Swordfish: 8 c29b9 r157 fr3c9 fr8c7 => r1c7<>8
Forcing Chain Verity => r1c8<>5
r5c1=5 r5c9<>5 r13c9=5 r1c8<>5
r6c1=5 r6c1<>3 r6c7=3 r4c8<>3 r1c8=3 r1c8<>5
r9c1=5 r7c3<>5 r7c8=5 r1c8<>5
Forcing Chain Verity => r3c8<>5
r5c1=5 r5c9<>5 r13c9=5 r3c8<>5
r6c1=5 r6c1<>3 r6c7=3 r4c8<>3 r1c8=3 r1c8<>1 r3c8=1 r3c8<>5
r9c1=5 r7c3<>5 r7c8=5 r3c8<>5
W-Wing: 8/5 in r5c9,r8c7 connected by 5 in r47c8 => r6c7<>8
Skyscraper: 8 in r6c5,r9c6 (connected by r69c1) => r5c6,r8c5<>8
Empty Rectangle: 8 in b8 (r28c7) => r2c6<>8
Almost Locked Set XZ-Rule: A=r69c1 {358}, B=r5c9,r6c7 {358}, X=3, Z=8 => r5c1<>8
Forcing Chain Contradiction in r6c1 => r5c9=8
r5c9<>8 r5c9=5 r6c7<>5 r6c7=3 r6c1<>3
r5c9<>8 r5c9=5 r4c8<>5 r7c8=5 r7c3<>5 r9c1=5 r6c1<>5
r5c9<>8 r5c23=8 r6c1<>8
Locked Candidates Type 2 (Claiming): 5 in c9 => r1c7<>5
Finned X-Wing: 5 r59 c16 fr5c3 => r6c1<>5
XY-Chain: 8 8- r8c7 -5- r6c7 -3- r6c1 -8- r9c1 -5- r9c6 -8 => r8c46<>8
Hidden Single: r8c7=8
Full House: r7c8=5
Naked Single: r4c8=3
Full House: r6c7=5
Naked Single: r6c5=8
Full House: r6c1=3
Naked Single: r8c1=6
Naked Single: r8c3=3
Hidden Single: r9c6=8
Full House: r9c1=5
Naked Single: r5c1=2
Naked Single: r5c2=1
Naked Single: r5c3=5
Full House: r4c3=8
Full House: r5c6=3
Naked Single: r7c3=2
Full House: r7c2=8
Full House: r1c2=2
Naked Single: r2c3=1
Full House: r3c3=6
Naked Single: r1c7=3
Full House: r2c7=2
Naked Single: r2c6=7
Naked Single: r2c1=8
Full House: r2c4=3
Full House: r3c1=7
Naked Single: r3c9=5
Full House: r1c9=7
Naked Single: r3c6=1
Full House: r8c6=5
Naked Single: r1c5=5
Naked Single: r3c8=8
Full House: r1c8=1
Full House: r1c4=8
Full House: r3c4=2
Naked Single: r8c4=1
Full House: r4c4=5
Full House: r4c5=1
Full House: r8c5=7
|
normal_sudoku_3585
|
....9...2..7..2..9.2.1..5.375.6..1.48....4..5..4....8.6..27..5.....316...3.....2.
|
361495872587362419429187563753628194896714235214953786648279351972531648135846927
|
Basic 9x9 Sudoku 3585
|
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
. . 7 . . 2 . . 9
. 2 . 1 . . 5 . 3
7 5 . 6 . . 1 . 4
8 . . . . 4 . . 5
. . 4 . . . . 8 .
6 . . 2 7 . . 5 .
. . . . 3 1 6 . .
. 3 . . . . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
361495872587362419429187563753628194896714235214953786648279351972531648135846927 #1 Medium (456)
Naked Single: r4c9=4
Hidden Single: r6c9=6
Hidden Single: r7c7=3
Hidden Single: r8c2=7
Naked Single: r8c9=8
Naked Single: r7c9=1
Full House: r9c9=7
Hidden Single: r7c2=4
Locked Candidates Type 1 (Pointing): 8 in b7 => r13c3<>8
Locked Candidates Type 2 (Claiming): 8 in r3 => r1c46,r2c45<>8
Hidden Single: r9c4=8
Naked Single: r7c6=9
Full House: r7c3=8
Locked Candidates Type 2 (Claiming): 9 in c2 => r45c3,r6c1<>9
Hidden Single: r4c8=9
Naked Single: r8c8=4
Full House: r9c7=9
Naked Single: r8c4=5
Naked Single: r9c6=6
Full House: r9c5=4
Hidden Single: r5c8=3
Hidden Single: r3c1=4
Hidden Single: r3c3=9
Naked Single: r8c3=2
Full House: r8c1=9
Naked Single: r4c3=3
Naked Single: r4c6=8
Full House: r4c5=2
Naked Single: r3c6=7
Naked Single: r5c5=1
Naked Single: r3c8=6
Full House: r3c5=8
Naked Single: r5c3=6
Naked Single: r6c5=5
Full House: r2c5=6
Naked Single: r2c8=1
Full House: r1c8=7
Naked Single: r5c2=9
Naked Single: r6c6=3
Full House: r1c6=5
Naked Single: r2c2=8
Naked Single: r5c4=7
Full House: r5c7=2
Full House: r6c4=9
Full House: r6c7=7
Naked Single: r6c2=1
Full House: r1c2=6
Full House: r6c1=2
Naked Single: r1c3=1
Full House: r9c3=5
Full House: r9c1=1
Naked Single: r2c7=4
Full House: r1c7=8
Naked Single: r1c1=3
Full House: r1c4=4
Full House: r2c4=3
Full House: r2c1=5
|
normal_sudoku_3195
|
....83.92..9..58.38......1.6.7..9.8....8....55....2......5.13..1..92...89.....12.
|
461783592279165843853294716617359284324816975598472631782541369136927458945638127
|
Basic 9x9 Sudoku 3195
|
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 2
. . 9 . . 5 8 . 3
8 . . . . . . 1 .
6 . 7 . . 9 . 8 .
. . . 8 . . . . 5
5 . . . . 2 . . .
. . . 5 . 1 3 . .
1 . . 9 2 . . . 8
9 . . . . . 1 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
461783592279165843853294716617359284324816975598472631782541369136927458945638127 #1 Extreme (18220) bf
Hidden Single: r2c7=8
Hidden Single: r4c5=5
Hidden Single: r3c5=9
Hidden Single: r9c6=8
Hidden Single: r7c9=9
Hidden Single: r5c1=3
Hidden Single: r8c8=5
Hidden Single: r4c4=3
Hidden Single: r6c8=3
Hidden Single: r9c5=3
Forcing Chain Contradiction in c8 => r2c2<>4
r2c2=4 r2c8<>4
r2c2=4 r4c2<>4 r4c79=4 r5c8<>4
r2c2=4 r12c1<>4 r7c1=4 r7c8<>4
Brute Force: r5c6=6
X-Wing: 6 c58 r27 => r2c24,r7c23<>6
Forcing Chain Contradiction in b3 => r3c2<>4
r3c2=4 r1c1<>4 r1c1=7 r1c7<>7
r3c2=4 r4c2<>4 r4c79=4 r5c8<>4 r5c8=7 r2c8<>7
r3c2=4 r3c6<>4 r3c6=7 r3c7<>7
r3c2=4 r3c6<>4 r3c6=7 r3c9<>7
Forcing Net Verity => r4c7=2
r3c9=4 (r9c9<>4) r3c6<>4 r8c6=4 (r9c4<>4) r8c7<>4 r7c8=4 r7c8<>6 r7c5=6 r9c4<>6 r9c4=7 (r9c9<>7) r8c6<>7 r3c6=7 r3c9<>7 r6c9=7 r5c8<>7 r5c8=4 r4c7<>4 r4c7=2
r3c9=6 r6c9<>6 r6c7=6 r6c7<>9 r6c2=9 r5c2<>9 r5c7=9 r5c7<>2 r4c7=2
r3c9=7 (r9c9<>7) r3c6<>7 r8c6=7 r8c7<>7 r7c8=7 r5c8<>7 r5c8=4 r4c7<>4 r4c7=2
Discontinuous Nice Loop: 4 r6c2 -4- r4c2 -1- r4c9 =1= r6c9 =6= r6c7 =9= r6c2 => r6c2<>4
Discontinuous Nice Loop: 4 r6c3 -4- r4c2 -1- r4c9 =1= r6c9 =6= r6c7 =9= r6c2 =8= r6c3 => r6c3<>4
Discontinuous Nice Loop: 4 r7c2 -4- r4c2 -1- r6c3 -8- r6c2 =8= r7c2 => r7c2<>4
Almost Locked Set XZ-Rule: A=r4c2 {14}, B=r12c1,r2c2 {1247}, X=1, Z=4 => r1c2<>4
Almost Locked Set XY-Wing: A=r4c2 {14}, B=r8c67 {467}, C=r4c9,r5c78,r6c7 {14679}, X,Y=1,6, Z=4 => r8c2<>4
Forcing Net Verity => r5c7=9
r3c9=4 (r9c9<>4) r3c6<>4 r8c6=4 (r9c4<>4) r8c7<>4 r7c8=4 (r5c8<>4 r5c8=7 r5c7<>7) r7c8<>6 r7c5=6 r9c4<>6 r9c4=7 (r9c9<>7) r8c6<>7 r3c6=7 r3c9<>7 r6c9=7 r5c8<>7 r5c8=4 r5c7<>4 r5c7=9
r3c9=6 r6c9<>6 r6c7=6 r6c7<>9 r6c2=9 r5c2<>9 r5c7=9
r3c9=7 (r3c9<>4) (r9c9<>7) r3c6<>7 r8c6=7 (r9c4<>7) r8c7<>7 r7c8=7 r7c8<>6 r7c5=6 r9c4<>6 r9c4=4 (r9c9<>4) r9c4<>6 r7c5=6 r2c5<>6 r2c8=6 r3c9<>6 r3c9=7 (r3c9<>4) (r9c9<>7) r9c9<>7 r9c9=6 r6c9<>6 r6c7=6 r6c7<>9 r6c2=9 r5c2<>9 r5c7=9
Hidden Single: r6c2=9
Hidden Single: r6c3=8
Hidden Single: r7c2=8
Almost Locked Set XZ-Rule: A=r12c1 {247}, B=r245c2 {1247}, X=7, Z=2 => r3c2<>2
Forcing Net Verity => r1c1=4
r1c7=7 r1c1<>7 r1c1=4
r2c8=7 (r7c8<>7) r5c8<>7 r5c5=7 r7c5<>7 r7c1=7 r1c1<>7 r1c1=4
r3c7=7 (r3c6<>7 r8c6=7 r7c5<>7) (r3c7<>4) (r3c6<>7 r3c6=4 r3c9<>4) r3c7<>5 r1c7=5 r1c7<>4 r2c8=4 r5c8<>4 r5c8=7 r7c8<>7 r7c1=7 r1c1<>7 r1c1=4
r3c9=7 (r2c8<>7) (r1c7<>7) (r3c7<>7) r3c6<>7 (r3c6=4 r8c6<>4) (r3c6=4 r1c4<>4) (r3c6=4 r2c4<>4) (r3c6=4 r2c5<>4) r8c6=7 (r9c4<>7) r8c7<>7 r6c7=7 r5c8<>7 r7c8=7 r7c8<>6 r7c5=6 r9c4<>6 r9c4=4 r9c4<>6 r7c5=6 r2c5<>6 r2c8=6 r2c8<>4 r2c1=4 (r7c1<>4) (r1c1<>4) r1c3<>4 r1c7=4 r8c7<>4 r8c3=4 r7c3<>4 r7c3=2 r7c1<>2 r7c1=7 r1c1<>7 r1c1=4
Grouped Discontinuous Nice Loop: 4 r9c4 =6= r7c5 -6- r7c8 =6= r2c8 =4= r2c45 -4- r3c6 =4= r8c6 -4- r9c4 => r9c4<>4
Discontinuous Nice Loop: 7 r2c5 -7- r3c6 -4- r8c6 =4= r7c5 =6= r2c5 => r2c5<>7
Discontinuous Nice Loop: 7 r3c4 -7- r3c6 -4- r8c6 =4= r7c5 -4- r7c3 -2- r3c3 =2= r3c4 => r3c4<>7
Grouped Discontinuous Nice Loop: 4 r5c2 -4- r4c2 =4= r4c9 -4- r9c9 =4= r9c23 -4- r7c3 -2- r5c3 =2= r5c2 => r5c2<>4
Almost Locked Set XZ-Rule: A=r7c13,r9c23 {24567}, B=r8c6,r9c4 {467}, X=6, Z=4 => r8c3<>4
Hidden Rectangle: 3/6 in r3c23,r8c23 => r3c2<>6
Forcing Chain Contradiction in r7c5 => r2c8<>7
r2c8=7 r2c8<>4 r2c45=4 r3c6<>4 r8c6=4 r7c5<>4
r2c8=7 r2c8<>6 r2c5=6 r7c5<>6
r2c8=7 r2c1<>7 r7c1=7 r7c5<>7
Empty Rectangle: 7 in b3 (r38c6) => r8c7<>7
XY-Wing: 4/7/6 in r8c67,r9c4 => r9c9<>6
W-Wing: 7/4 in r3c6,r9c9 connected by 4 in r8c67 => r3c9<>7
Locked Candidates Type 1 (Pointing): 7 in b3 => r6c7<>7
Naked Pair: 4,6 in r2c8,r3c9 => r13c7<>6, r3c7<>4
Turbot Fish: 4 r6c7 =4= r8c7 -4- r8c6 =4= r7c5 => r6c5<>4
W-Wing: 4/6 in r2c8,r6c7 connected by 6 in r36c9 => r5c8<>4
Naked Single: r5c8=7
Hidden Single: r9c9=7
Naked Single: r9c4=6
Hidden Single: r2c5=6
Naked Single: r2c8=4
Full House: r7c8=6
Full House: r8c7=4
Naked Single: r3c9=6
Naked Single: r6c7=6
Naked Single: r8c6=7
Full House: r3c6=4
Full House: r7c5=4
Naked Single: r3c4=2
Naked Single: r5c5=1
Full House: r6c5=7
Full House: r6c4=4
Full House: r6c9=1
Full House: r4c9=4
Full House: r4c2=1
Naked Single: r7c3=2
Full House: r7c1=7
Full House: r2c1=2
Naked Single: r5c2=2
Full House: r5c3=4
Naked Single: r2c2=7
Full House: r2c4=1
Full House: r1c4=7
Naked Single: r9c3=5
Full House: r9c2=4
Naked Single: r1c7=5
Full House: r3c7=7
Naked Single: r3c3=3
Full House: r3c2=5
Naked Single: r1c2=6
Full House: r1c3=1
Full House: r8c3=6
Full House: r8c2=3
|
normal_sudoku_2689
|
...1.....9..7...52..8..9....298....73.625.4.8....1........9..25..567..8..91.....6
|
672145839934768152158329674429836517316257498587914263863491725245673981791582346
|
Basic 9x9 Sudoku 2689
|
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 . . . . .
9 . . 7 . . . 5 2
. . 8 . . 9 . . .
. 2 9 8 . . . . 7
3 . 6 2 5 . 4 . 8
. . . . 1 . . . .
. . . . 9 . . 2 5
. . 5 6 7 . . 8 .
. 9 1 . . . . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
672145839934768152158329674429836517316257498587914263863491725245673981791582346 #1 Easy (236)
Naked Single: r5c5=5
Naked Single: r5c6=7
Naked Single: r5c2=1
Full House: r5c8=9
Naked Single: r6c9=3
Naked Single: r6c8=6
Naked Single: r4c8=1
Naked Single: r6c6=4
Naked Single: r4c7=5
Full House: r6c7=2
Naked Single: r6c3=7
Naked Single: r6c4=9
Naked Single: r4c1=4
Naked Single: r8c1=2
Hidden Single: r1c3=2
Hidden Single: r2c7=1
Naked Single: r3c9=4
Naked Single: r1c9=9
Full House: r8c9=1
Naked Single: r8c6=3
Naked Single: r4c6=6
Full House: r4c5=3
Naked Single: r7c4=4
Naked Single: r8c2=4
Full House: r8c7=9
Naked Single: r2c6=8
Naked Single: r7c3=3
Full House: r2c3=4
Naked Single: r9c4=5
Full House: r3c4=3
Naked Single: r1c6=5
Naked Single: r7c6=1
Full House: r9c6=2
Full House: r9c5=8
Naked Single: r7c7=7
Naked Single: r2c5=6
Full House: r2c2=3
Naked Single: r3c8=7
Naked Single: r9c1=7
Naked Single: r3c7=6
Naked Single: r9c7=3
Full House: r1c7=8
Full House: r1c8=3
Full House: r9c8=4
Naked Single: r1c5=4
Full House: r3c5=2
Naked Single: r1c1=6
Full House: r1c2=7
Naked Single: r3c2=5
Full House: r3c1=1
Naked Single: r7c1=8
Full House: r6c1=5
Full House: r6c2=8
Full House: r7c2=6
|
normal_sudoku_6249
|
.21.3....9..4..2...4...5.8..84.9...6.....67..6..5.4.2.4....9.5..7.8..4....3.4...1
|
821937645957468213346125987784291536215386794639574128468719352172853469593642871
|
Basic 9x9 Sudoku 6249
|
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 . 3 . . . .
9 . . 4 . . 2 . .
. 4 . . . 5 . 8 .
. 8 4 . 9 . . . 6
. . . . . 6 7 . .
6 . . 5 . 4 . 2 .
4 . . . . 9 . 5 .
. 7 . 8 . . 4 . .
. . 3 . 4 . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
821937645957468213346125987784291536215386794639574128468719352172853469593642871 #1 Extreme (3086)
Hidden Single: r9c5=4
Hidden Single: r8c5=5
Locked Candidates Type 1 (Pointing): 8 in b5 => r2c5<>8
Empty Rectangle: 6 in b1 (r8c38) => r2c8<>6
Discontinuous Nice Loop: 1 r4c1 -1- r4c8 -3- r4c6 =3= r8c6 =1= r8c1 -1- r4c1 => r4c1<>1
Discontinuous Nice Loop: 6 r7c3 -6- r3c3 -7- r6c3 -9- r8c3 =9= r9c2 =5= r9c1 =8= r7c3 => r7c3<>6
AIC: 2 2- r7c3 -8- r2c3 =8= r2c6 -8- r1c6 -7- r9c6 -2 => r7c45,r9c1<>2
Locked Candidates Type 2 (Claiming): 2 in r9 => r8c6<>2
Discontinuous Nice Loop: 1/3 r4c7 =5= r4c1 -5- r9c1 -8- r1c1 =8= r2c3 =5= r5c3 -5- r5c9 =5= r4c7 => r4c7<>1, r4c7<>3
Naked Single: r4c7=5
Discontinuous Nice Loop: 6 r1c8 -6- r8c8 =6= r8c3 =9= r9c2 =5= r9c1 -5- r1c1 =5= r1c9 =4= r1c8 => r1c8<>6
Locked Candidates Type 1 (Pointing): 6 in b3 => r79c7<>6
XY-Chain: 3 3- r7c7 -8- r7c3 -2- r8c1 -1- r8c6 -3 => r7c4,r8c89<>3
Hidden Single: r8c6=3
Hidden Single: r8c1=1
Naked Single: r7c2=6
Hidden Single: r9c4=6
Hidden Single: r8c8=6
Hidden Single: r1c7=6
Hidden Single: r9c6=2
Hidden Single: r9c8=7
Locked Candidates Type 1 (Pointing): 2 in b7 => r5c3<>2
Naked Pair: 1,3 in r24c8 => r5c8<>1, r5c8<>3
X-Wing: 1 c68 r24 => r2c5,r4c4<>1
Turbot Fish: 3 r3c1 =3= r2c2 -3- r2c8 =3= r4c8 => r4c1<>3
W-Wing: 6/7 in r2c5,r3c3 connected by 7 in r6c35 => r2c3,r3c5<>6
Hidden Single: r2c5=6
Hidden Single: r3c3=6
Uniqueness Test 4: 4/9 in r1c89,r5c89 => r15c9<>9
Finned Swordfish: 3 r267 c279 fr2c8 => r3c79<>3
Hidden Single: r3c1=3
Naked Single: r2c2=5
Naked Single: r9c2=9
Naked Single: r8c3=2
Full House: r8c9=9
Naked Single: r9c7=8
Full House: r9c1=5
Full House: r7c3=8
Naked Single: r3c9=7
Naked Single: r7c7=3
Full House: r7c9=2
Naked Single: r5c1=2
Naked Single: r2c3=7
Full House: r1c1=8
Full House: r4c1=7
Naked Single: r2c9=3
Naked Single: r6c3=9
Full House: r5c3=5
Naked Single: r1c6=7
Naked Single: r4c6=1
Full House: r2c6=8
Full House: r2c8=1
Naked Single: r6c9=8
Naked Single: r6c7=1
Full House: r3c7=9
Naked Single: r1c4=9
Naked Single: r4c8=3
Full House: r4c4=2
Naked Single: r5c4=3
Naked Single: r5c5=8
Full House: r6c5=7
Full House: r6c2=3
Full House: r5c2=1
Naked Single: r5c9=4
Full House: r1c9=5
Full House: r1c8=4
Full House: r5c8=9
Naked Single: r3c4=1
Full House: r3c5=2
Full House: r7c5=1
Full House: r7c4=7
|
normal_sudoku_6878
|
......1..3....2.5875.9..2.38.....9..1.267.3....5.....292....8.1.1....5.....8.1..9
|
286354197349712658751968243874123965192675384635489712923546871418297536567831429
|
Basic 9x9 Sudoku 6878
|
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 . . . . 2 . 5 8
7 5 . 9 . . 2 . 3
8 . . . . . 9 . .
1 . 2 6 7 . 3 . .
. . 5 . . . . . 2
9 2 . . . . 8 . 1
. 1 . . . . 5 . .
. . . 8 . 1 . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
286354197349712658751968243874123965192675384635489712923546871418297536567831429 #1 Extreme (3262)
Hidden Single: r5c3=2
Hidden Single: r1c1=2
Hidden Single: r9c1=5
Hidden Single: r8c3=8
Hidden Single: r1c2=8
Hidden Single: r1c8=9
Hidden Single: r2c3=9
Hidden Single: r3c3=1
Finned Franken Swordfish: 4 c17b1 r269 fr1c3 fr8c1 => r9c3<>4
Finned Franken Swordfish: 6 c17b1 r269 fr1c3 fr8c1 => r9c3<>6
Finned Franken Swordfish: 6 c19b1 r148 fr2c2 fr6c1 => r4c2<>6
Forcing Net Verity => r1c9=7
r6c7=4 (r6c7<>6) (r4c9<>4) (r5c9<>4) r6c1<>4 r8c1=4 (r7c3<>4) r8c9<>4 r1c9=4 (r3c8<>4 r3c8=6 r2c7<>6 r2c5=6 r7c5<>6 r7c6=6 r7c6<>7 r1c6=7 r1c4<>7) r1c3<>4 (r1c3=6 r2c2<>6) r4c3=4 r6c1<>4 r6c1=6 r6c2<>6 r9c2=6 r9c7<>6 r2c7=6 r2c7<>7 r2c4=7 r1c6<>7 r1c9=7
r6c7=6 (r6c7<>4) (r4c8<>6) r4c9<>6 r4c3=6 (r1c3<>6 r1c3=4 r2c2<>4) r6c1<>6 r6c1=4 (r4c2<>4) (r5c2<>4) r6c2<>4 r9c2=4 r9c7<>4 r2c7=4 r2c7<>7 r2c4=7 (r1c4<>7) r1c6<>7 r1c9=7
r6c7=7 r2c7<>7 r2c4=7 (r1c4<>7) r1c6<>7 r1c9=7
Hidden Single: r2c4=7
Hidden Single: r2c5=1
Naked Pair: 4,6 in r8c19 => r8c4568<>4, r8c568<>6
Skyscraper: 6 in r4c9,r6c1 (connected by r8c19) => r4c3,r6c78<>6
Empty Rectangle: 6 in b8 (r17c3) => r1c5<>6
W-Wing: 4/6 in r2c2,r8c1 connected by 6 in r6c12 => r9c2<>4
W-Wing: 4/6 in r3c8,r8c9 connected by 6 in r4c89 => r79c8<>4
Turbot Fish: 4 r3c8 =4= r2c7 -4- r9c7 =4= r9c5 => r3c5<>4
Turbot Fish: 4 r6c1 =4= r8c1 -4- r8c9 =4= r9c7 => r6c7<>4
Naked Single: r6c7=7
Naked Pair: 4,6 in r8c9,r9c7 => r79c8<>6
Remote Pair: 4/6 r2c2 -6- r2c7 -4- r9c7 -6- r8c9 -4- r8c1 -6- r6c1 => r456c2<>4, r6c2<>6
Naked Single: r5c2=9
Naked Single: r6c2=3
Naked Single: r4c2=7
Naked Single: r4c3=4
Full House: r6c1=6
Full House: r8c1=4
Naked Single: r9c2=6
Full House: r2c2=4
Full House: r1c3=6
Full House: r2c7=6
Full House: r9c7=4
Full House: r3c8=4
Naked Single: r8c9=6
Naked Single: r5c8=8
Naked Single: r4c9=5
Full House: r5c9=4
Full House: r5c6=5
Naked Single: r6c8=1
Full House: r4c8=6
Naked Single: r4c6=3
Naked Single: r6c4=4
Naked Single: r1c6=4
Naked Single: r4c5=2
Full House: r4c4=1
Naked Single: r9c5=3
Naked Single: r1c5=5
Full House: r1c4=3
Naked Single: r7c4=5
Full House: r8c4=2
Naked Single: r8c5=9
Naked Single: r9c3=7
Full House: r7c3=3
Full House: r9c8=2
Naked Single: r6c5=8
Full House: r6c6=9
Naked Single: r8c6=7
Full House: r8c8=3
Full House: r7c8=7
Naked Single: r3c5=6
Full House: r3c6=8
Full House: r7c6=6
Full House: r7c5=4
|
normal_sudoku_6693
|
......4..51.34...78.4..2.9....9581..9...3..2..5.2.7....45..........6.7.969.821.3.
|
739186452512349687864572391426958173971634825358217946145793268283465719697821534
|
Basic 9x9 Sudoku 6693
|
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 . .
5 1 . 3 4 . . . 7
8 . 4 . . 2 . 9 .
. . . 9 5 8 1 . .
9 . . . 3 . . 2 .
. 5 . 2 . 7 . . .
. 4 5 . . . . . .
. . . . 6 . 7 . 9
6 9 . 8 2 1 . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
739186452512349687864572391426958173971634825358217946145793268283465719697821534 #1 Easy (304)
Naked Single: r4c5=5
Naked Single: r6c5=1
Naked Single: r7c4=7
Naked Single: r9c3=7
Naked Single: r9c7=5
Full House: r9c9=4
Naked Single: r3c5=7
Naked Single: r7c5=9
Full House: r1c5=8
Naked Single: r7c6=3
Hidden Single: r4c8=7
Hidden Single: r6c7=9
Hidden Single: r5c3=1
Hidden Single: r5c2=7
Hidden Single: r5c9=5
Hidden Single: r1c8=5
Hidden Single: r1c1=7
Hidden Single: r4c1=4
Naked Single: r6c1=3
Hidden Single: r6c8=4
Hidden Single: r3c7=3
Naked Single: r3c2=6
Naked Single: r3c9=1
Full House: r3c4=5
Naked Single: r4c2=2
Naked Single: r8c4=4
Full House: r8c6=5
Naked Single: r1c2=3
Full House: r8c2=8
Naked Single: r4c3=6
Full House: r4c9=3
Full House: r6c3=8
Full House: r6c9=6
Full House: r5c7=8
Naked Single: r5c4=6
Full House: r1c4=1
Full House: r5c6=4
Naked Single: r8c8=1
Naked Single: r1c9=2
Full House: r7c9=8
Naked Single: r8c1=2
Full House: r7c1=1
Full House: r8c3=3
Naked Single: r1c3=9
Full House: r1c6=6
Full House: r2c3=2
Full House: r2c6=9
Naked Single: r2c7=6
Full House: r2c8=8
Full House: r7c8=6
Full House: r7c7=2
|
normal_sudoku_5168
|
1.28.654....3..2..........76.524..9.......6.......7.524.7..5..6...4..9..29.76....
|
132876549974351268856924137615248793728539614349617852487195326563482971291763485
|
Basic 9x9 Sudoku 5168
|
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 . 2 8 . 6 5 4 .
. . . 3 . . 2 . .
. . . . . . . . 7
6 . 5 2 4 . . 9 .
. . . . . . 6 . .
. . . . . 7 . 5 2
4 . 7 . . 5 . . 6
. . . 4 . . 9 . .
2 9 . 7 6 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
132876549974351268856924137615248793728539614349617852487195326563482971291763485 #1 Extreme (21598) bf
Hidden Single: r9c4=7
Hidden Single: r5c2=2
Hidden Single: r9c9=5
Hidden Single: r6c4=6
Hidden Single: r8c8=7
Hidden Single: r4c7=7
Hidden Single: r9c7=4
Hidden Single: r5c9=4
Hidden Single: r5c1=7
Hidden Single: r7c8=2
Brute Force: r5c4=5
Discontinuous Nice Loop: 4 r2c2 -4- r2c6 =4= r3c6 =2= r3c5 =5= r2c5 =7= r2c2 => r2c2<>4
Forcing Net Contradiction in r3 => r2c2<>8
r2c2=8 (r2c2<>6) (r2c2<>5) r2c2<>7 r2c5=7 r2c5<>5 r2c1=5 r8c1<>5 r8c2=5 r8c2<>6 r3c2=6
r2c2=8 r2c2<>7 r2c5=7 (r2c5<>1) r1c5<>7 r1c5=9 (r3c4<>9 r3c4=1 r2c6<>1) r1c9<>9 r2c9=9 r2c9<>1 r2c8=1 r2c8<>6 r3c8=6
Forcing Net Contradiction in b5 => r2c5<>1
r2c5=1 (r3c4<>1 r7c4=1 r7c2<>1) r2c5<>7 r2c2=7 r1c2<>7 r1c2=3 (r4c2<>3) r7c2<>3 r7c2=8 r4c2<>8 r4c2=1 r4c6<>1
r2c5=1 r5c5<>1
r2c5=1 r3c4<>1 r3c4=9 (r2c6<>9) r3c6<>9 r5c6=9 r5c6<>1
r2c5=1 r6c5<>1
Forcing Net Contradiction in c3 => r3c3<>3
r3c3=3 r1c2<>3 r1c2=7 r1c5<>7 r1c5=9 (r2c6<>9) r3c4<>9 r3c4=1 r2c6<>1 r2c6=4 r2c3<>4
r3c3=3 r3c3<>4
r3c3=3 (r3c3<>9) r1c2<>3 r1c2=7 r1c5<>7 r1c5=9 (r6c5<>9) (r3c4<>9) (r3c5<>9) r3c6<>9 r3c1=9 r6c1<>9 r6c3=9 r6c3<>4
Forcing Net Contradiction in b5 => r3c5<>1
r3c5=1 r3c4<>1 (r7c4=1 r7c2<>1) r3c4=9 r1c5<>9 r1c5=7 r1c2<>7 r1c2=3 (r4c2<>3) r7c2<>3 r7c2=8 r4c2<>8 r4c2=1 r4c6<>1
r3c5=1 r5c5<>1
r3c5=1 r3c4<>1 r3c4=9 (r2c6<>9) r3c6<>9 r5c6=9 r5c6<>1
r3c5=1 r6c5<>1
Forcing Net Contradiction in r3c7 => r3c8<>1
r3c8=1 r3c4<>1 r3c4=9 (r7c4<>9 r7c5=9 r7c5<>3) r1c5<>9 r1c5=7 r1c2<>7 r1c2=3 (r3c1<>3) (r3c2<>3) r7c2<>3 r7c7=3 r3c7<>3 r3c8=3 r3c8<>1
Forcing Net Contradiction in r6c3 => r6c2<>3
r6c2=3 (r6c5<>3) (r4c2<>3) r1c2<>3 r1c9=3 (r3c7<>3 r7c7=3 r7c5<>3) r4c9<>3 r4c6=3 r5c5<>3 r8c5=3 r8c5<>2 r8c6=2 r3c6<>2 r3c5=2 r3c5<>5 r2c5=5 r2c5<>7 r2c2=7 r1c2<>7 r1c2=3 r6c2<>3
Forcing Net Contradiction in c5 => r7c2<>3
r7c2=3 r1c2<>3 r1c2=7 r2c2<>7 r2c5=7 r2c5<>5 r3c5=5 r3c5<>2
r7c2=3 (r8c1<>3) (r8c2<>3) (r8c3<>3) (r4c2<>3) r1c2<>3 r1c9=3 (r8c9<>3) r4c9<>3 r4c6=3 r8c6<>3 r8c5=3 r8c5<>2
Forcing Net Contradiction in c2 => r3c2<>8
r3c2=8 (r3c7<>8) r7c2<>8 r7c2=1 r7c4<>1 r3c4=1 r3c7<>1 r3c7=3 r1c9<>3 r1c2=3
r3c2=8 (r4c2<>8) r7c2<>8 r7c2=1 r4c2<>1 r4c2=3
Forcing Net Contradiction in b9 => r3c6<>1
r3c6=1 r3c4<>1 r7c4=1 r7c7<>1
r3c6=1 (r3c7<>1) r3c4<>1 (r3c4=9 r1c5<>9 r1c9=9 r2c9<>9) r7c4=1 (r7c2<>1 r7c2=8 r7c7<>8) r7c7<>1 r6c7=1 r6c7<>8 r3c7=8 r2c9<>8 r2c9=1 r8c9<>1
r3c6=1 r3c4<>1 (r7c4=1 r7c2<>1 r7c2=8 r9c3<>8) (r7c4=1 r7c2<>1 r7c2=8 r4c2<>8) r3c4=9 (r1c5<>9 r1c9=9 r1c9<>3) r7c4<>9 r7c5=9 r7c5<>3 r7c7=3 r8c9<>3 r4c9=3 r4c9<>8 r4c6=8 r9c6<>8 r9c8=8 r9c8<>1
Forcing Net Contradiction in c6 => r6c2<>1
r6c2=1 (r4c2<>1) r7c2<>1 r7c2=8 r4c2<>8 r4c2=3 r4c6<>3
r6c2=1 (r6c2<>4 r6c3=4 r2c3<>4 r2c6=4 r2c6<>1 r3c4=1 r3c4<>9) (r4c2<>1) r7c2<>1 r7c2=8 r4c2<>8 r4c2=3 r1c2<>3 (r1c9=3 r3c8<>3 r3c1=3 r3c1<>9) r1c2=7 r1c5<>7 r1c5=9 (r5c5<>9) (r3c5<>9) r3c6<>9 r3c3=9 r5c3<>9 r5c6=9 r5c6<>3
r6c2=1 (r6c7<>1) r6c2<>4 r6c3=4 r2c3<>4 r2c6=4 r2c6<>1 r3c4=1 r3c7<>1 r7c7=1 r7c7<>3 r7c5=3 r8c6<>3
r6c2=1 (r6c7<>1) r6c2<>4 r6c3=4 r2c3<>4 r2c6=4 r2c6<>1 r3c4=1 r3c7<>1 r7c7=1 r7c7<>3 r7c5=3 r9c6<>3
Forcing Net Contradiction in r2c5 => r6c2=4
r6c2<>4 (r6c3=4 r6c3<>1 r5c3=1 r5c5<>1) r6c2=8 r7c2<>8 r7c2=1 (r7c5<>1) (r7c7<>1) r7c4<>1 r3c4=1 r3c7<>1 r6c7=1 r6c5<>1 r8c5=1 r8c5<>2 r8c6=2 r3c6<>2 r3c5=2 r3c5<>5 r2c5=5
r6c2<>4 r6c2=8 (r4c2<>8) r7c2<>8 r7c2=1 r4c2<>1 r4c2=3 r1c2<>3 r1c2=7 r2c2<>7 r2c5=7
Forcing Chain Contradiction in b1 => r3c1<>3
r3c1=3 r1c2<>3 r1c9=3 r1c9<>9 r2c9=9 r2c1<>9
r3c1=3 r1c2<>3 r1c9=3 r1c9<>9 r2c9=9 r2c3<>9
r3c1=3 r3c1<>9
r3c1=3 r1c2<>3 r1c2=7 r1c5<>7 r2c5=7 r2c5<>5 r3c5=5 r3c5<>2 r3c6=2 r3c6<>4 r3c3=4 r3c3<>9
Locked Candidates Type 1 (Pointing): 3 in b1 => r48c2<>3
Naked Pair: 1,8 in r47c2 => r8c2<>1, r8c2<>8
Finned Swordfish: 1 c247 r347 fr6c7 => r4c9<>1
Sashimi Swordfish: 1 c247 r367 fr4c2 => r6c3<>1
Finned Jellyfish: 1 c3689 r2589 fr4c6 => r5c5<>1
Forcing Chain Contradiction in r6 => r7c5<>8
r7c5=8 r7c2<>8 r4c2=8 r6c1<>8
r7c5=8 r7c2<>8 r4c2=8 r6c3<>8
r7c5=8 r6c5<>8
r7c5=8 r7c2<>8 r7c2=1 r4c2<>1 r4c6=1 r6c5<>1 r6c7=1 r6c7<>8
Finned Franken Swordfish: 8 r47b8 c269 fr7c7 fr8c5 => r8c9<>8
Multi Colors 1: 8 (r2c9) / (r4c9), (r4c2,r7c7) / (r7c2,r9c8) => r23c8<>8
Discontinuous Nice Loop: 1 r9c8 -1- r8c9 -3- r4c9 -8- r5c8 =8= r9c8 => r9c8<>1
Skyscraper: 1 in r4c2,r9c3 (connected by r49c6) => r5c3,r7c2<>1
Naked Single: r7c2=8
Naked Single: r4c2=1
Hidden Single: r9c8=8
Naked Triple: 1,3,9 in r7c45,r9c6 => r8c56<>1, r8c56<>3
Turbot Fish: 3 r6c1 =3= r8c1 -3- r8c9 =3= r7c7 => r6c7<>3
Empty Rectangle: 8 in b4 (r36c7) => r3c3<>8
W-Wing: 1/3 in r5c8,r9c6 connected by 3 in r4c69 => r5c6<>1
Hidden Single: r5c8=1
Naked Single: r2c8=6
Full House: r3c8=3
Naked Single: r6c7=8
Full House: r4c9=3
Full House: r4c6=8
Naked Single: r1c9=9
Naked Single: r3c7=1
Full House: r2c9=8
Full House: r8c9=1
Full House: r7c7=3
Naked Single: r8c6=2
Naked Single: r1c5=7
Full House: r1c2=3
Naked Single: r3c4=9
Full House: r7c4=1
Full House: r7c5=9
Naked Single: r8c5=8
Full House: r9c6=3
Full House: r9c3=1
Naked Single: r2c5=5
Naked Single: r3c6=4
Naked Single: r5c5=3
Naked Single: r5c6=9
Full House: r2c6=1
Full House: r3c5=2
Full House: r6c5=1
Full House: r5c3=8
Naked Single: r2c1=9
Naked Single: r2c2=7
Full House: r2c3=4
Naked Single: r3c3=6
Naked Single: r6c1=3
Full House: r6c3=9
Full House: r8c3=3
Naked Single: r3c2=5
Full House: r3c1=8
Full House: r8c1=5
Full House: r8c2=6
|
normal_sudoku_5980
|
....68.......453..4..7...5...1...5.252.4..89...8....7.8....4..5...8..9...9..57.8.
|
235968741179245368486713259741689532523471896968532174817394625354826917692157483
|
Basic 9x9 Sudoku 5980
|
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 . . .
. . . . 4 5 3 . .
4 . . 7 . . . 5 .
. . 1 . . . 5 . 2
5 2 . 4 . . 8 9 .
. . 8 . . . . 7 .
8 . . . . 4 . . 5
. . . 8 . . 9 . .
. 9 . . 5 7 . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
235968741179245368486713259741689532523471896968532174817394625354826917692157483 #1 Extreme (43964) bf
Hidden Single: r2c5=4
Hidden Single: r4c5=8
Hidden Single: r6c4=5
Hidden Single: r5c5=7
Locked Candidates Type 1 (Pointing): 4 in b4 => r8c2<>4
Locked Candidates Type 1 (Pointing): 9 in b4 => r12c1<>9
Brute Force: r5c6=1
Brute Force: r5c9=6
Full House: r5c3=3
Brute Force: r6c1=9
Forcing Net Contradiction in r8c8 => r3c2<>6
r3c2=6 (r3c7<>6) r6c2<>6 r6c2=4 (r4c2<>4 r4c8=4 r1c8<>4) r6c7<>4 r6c7=1 r3c7<>1 r3c7=2 r1c8<>2 r1c8=1 r8c8<>1
r3c2=6 (r3c7<>6) r6c2<>6 (r6c6=6 r6c6<>2) r6c2=4 r6c7<>4 r6c7=1 r3c7<>1 r3c7=2 r3c6<>2 r8c6=2 r8c8<>2
r3c2=6 (r3c2<>1) (r3c2<>8 r3c9=8 r3c9<>1) r6c2<>6 (r6c6=6 r6c6<>2 r6c5=2 r8c5<>2) r6c2=4 r6c7<>4 r6c7=1 r3c7<>1 r3c5=1 r8c5<>1 r8c5=3 r8c8<>3
r3c2=6 r6c2<>6 r6c2=4 r4c2<>4 r4c8=4 r8c8<>4
r3c2=6 (r2c1<>6) (r2c2<>6) r2c3<>6 r2c8=6 r8c8<>6
Brute Force: r4c8=3
Hidden Single: r4c2=4
Naked Single: r6c2=6
Full House: r4c1=7
Finned Swordfish: 3 r367 c256 fr7c4 => r8c56<>3
Almost Locked Set XZ-Rule: A=r8c1568 {12346}, B=r12368c9 {134789}, X=3, Z=4 => r9c9<>4
Almost Locked Set XY-Wing: A=r7c378 {1267}, B=r8c56,r9c4 {1236}, C=r9c9 {13}, X,Y=1,3, Z=2,6 => r7c45<>2, r7c4<>6
Finned X-Wing: 6 r37 c37 fr7c8 => r9c7<>6
Forcing Chain Contradiction in r3 => r9c7<>2
r9c7=2 r7c78<>2 r7c3=2 r3c3<>2
r9c7=2 r9c4<>2 r12c4=2 r3c5<>2
r9c7=2 r9c4<>2 r12c4=2 r3c6<>2
r9c7=2 r3c7<>2
Naked Pair: 1,4 in r69c7 => r137c7<>1, r1c7<>4
Uniqueness Test 1: 1/4 in r6c79,r9c79 => r9c9<>1
Naked Single: r9c9=3
Locked Candidates Type 1 (Pointing): 3 in b8 => r7c2<>3
Naked Triple: 1,2,6 in r8c56,r9c4 => r7c45<>1
Discontinuous Nice Loop: 1 r8c1 -1- r8c5 =1= r9c4 -1- r9c7 -4- r9c3 =4= r8c3 =5= r8c2 =3= r8c1 => r8c1<>1
Finned Swordfish: 1 c148 r129 fr7c8 fr8c8 => r9c7<>1
Naked Single: r9c7=4
Naked Single: r6c7=1
Full House: r6c9=4
Hidden Single: r1c8=4
Hidden Single: r8c3=4
Hidden Single: r8c2=5
Hidden Single: r1c3=5
Hidden Single: r8c1=3
Hidden Single: r8c9=7
Hidden Single: r1c7=7
Locked Candidates Type 1 (Pointing): 1 in b9 => r2c8<>1
W-Wing: 2/6 in r2c8,r9c3 connected by 6 in r3c37 => r2c3<>2
W-Wing: 2/6 in r7c7,r9c3 connected by 6 in r3c37 => r7c3<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r9c4<>2
Locked Candidates Type 1 (Pointing): 2 in b8 => r8c8<>2
Locked Candidates Type 2 (Claiming): 2 in c4 => r3c56<>2
Hidden Pair: 2,6 in r3c37 => r3c3<>9
Hidden Single: r2c3=9
Hidden Single: r2c2=7
Naked Single: r7c2=1
Naked Single: r1c2=3
Full House: r3c2=8
Hidden Single: r7c3=7
Hidden Single: r2c9=8
Hidden Single: r8c8=1
Naked Single: r8c5=2
Full House: r8c6=6
Naked Single: r6c5=3
Full House: r6c6=2
Naked Single: r4c6=9
Full House: r3c6=3
Full House: r4c4=6
Naked Single: r9c4=1
Naked Single: r7c5=9
Full House: r3c5=1
Full House: r7c4=3
Naked Single: r2c4=2
Full House: r1c4=9
Naked Single: r3c9=9
Full House: r1c9=1
Full House: r1c1=2
Naked Single: r2c8=6
Full House: r2c1=1
Full House: r3c3=6
Full House: r9c1=6
Full House: r3c7=2
Full House: r7c8=2
Full House: r9c3=2
Full House: r7c7=6
|
normal_sudoku_2059
|
..6.8.3....32..91....13..64.......7.8...1.....91.2.65.93..4..8.5....2.3.2..3.1...
|
156489327483267915729135864642958173875613492391724658937546281514892736268371549
|
Basic 9x9 Sudoku 2059
|
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 . 3 . .
. . 3 2 . . 9 1 .
. . . 1 3 . . 6 4
. . . . . . . 7 .
8 . . . 1 . . . .
. 9 1 . 2 . 6 5 .
9 3 . . 4 . . 8 .
5 . . . . 2 . 3 .
2 . . 3 . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
156489327483267915729135864642958173875613492391724658937546281514892736268371549 #1 Easy (212)
Naked Single: r2c8=1
Naked Single: r3c1=7
Naked Single: r7c3=7
Naked Single: r1c8=2
Naked Single: r2c1=4
Naked Single: r1c1=1
Naked Single: r6c1=3
Full House: r4c1=6
Naked Single: r1c2=5
Naked Single: r6c9=8
Naked Single: r1c9=7
Naked Single: r2c2=8
Naked Single: r2c9=5
Full House: r3c7=8
Naked Single: r3c2=2
Full House: r3c3=9
Full House: r3c6=5
Naked Single: r4c2=4
Naked Single: r7c6=6
Naked Single: r5c2=7
Naked Single: r9c2=6
Full House: r8c2=1
Naked Single: r2c6=7
Full House: r2c5=6
Naked Single: r7c4=5
Naked Single: r9c9=9
Naked Single: r6c6=4
Full House: r6c4=7
Naked Single: r8c9=6
Naked Single: r9c5=7
Naked Single: r9c8=4
Full House: r5c8=9
Naked Single: r1c6=9
Full House: r1c4=4
Naked Single: r8c5=9
Full House: r4c5=5
Full House: r8c4=8
Naked Single: r8c7=7
Full House: r8c3=4
Full House: r9c3=8
Full House: r9c7=5
Naked Single: r5c4=6
Full House: r4c4=9
Naked Single: r5c6=3
Full House: r4c6=8
Naked Single: r4c3=2
Full House: r5c3=5
Naked Single: r5c9=2
Full House: r5c7=4
Naked Single: r4c7=1
Full House: r4c9=3
Full House: r7c9=1
Full House: r7c7=2
|
normal_sudoku_2852
|
7815......968.7...3...61...2.34..1..8..1....461...5.28.6..9.4.......4.8..3..5.6..
|
781542396596837241342961875253489167879126534614375928168793452925614783437258619
|
Basic 9x9 Sudoku 2852
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 8 1 5 . . . . .
. 9 6 8 . 7 . . .
3 . . . 6 1 . . .
2 . 3 4 . . 1 . .
8 . . 1 . . . . 4
6 1 . . . 5 . 2 8
. 6 . . 9 . 4 . .
. . . . . 4 . 8 .
. 3 . . 5 . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
781542396596837241342961875253489167879126534614375928168793452925614783437258619 #1 Easy (344)
Hidden Single: r2c3=6
Hidden Single: r6c3=4
Hidden Single: r3c7=8
Hidden Single: r3c2=4
Naked Single: r2c1=5
Full House: r3c3=2
Naked Single: r7c1=1
Naked Single: r3c4=9
Naked Single: r8c1=9
Full House: r9c1=4
Hidden Single: r8c5=1
Hidden Single: r4c5=8
Hidden Single: r8c4=6
Hidden Single: r5c3=9
Hidden Single: r8c2=2
Hidden Single: r6c7=9
Hidden Single: r4c6=9
Hidden Single: r5c6=6
Hidden Single: r5c5=2
Hidden Single: r1c6=2
Naked Single: r1c7=3
Naked Single: r9c6=8
Full House: r7c6=3
Naked Single: r1c5=4
Full House: r2c5=3
Full House: r6c5=7
Full House: r6c4=3
Naked Single: r2c7=2
Naked Single: r9c3=7
Naked Single: r2c9=1
Full House: r2c8=4
Naked Single: r8c3=5
Full House: r7c3=8
Naked Single: r9c4=2
Full House: r7c4=7
Naked Single: r8c7=7
Full House: r5c7=5
Full House: r8c9=3
Naked Single: r9c9=9
Full House: r9c8=1
Naked Single: r7c8=5
Full House: r7c9=2
Naked Single: r5c2=7
Full House: r4c2=5
Full House: r5c8=3
Naked Single: r1c9=6
Full House: r1c8=9
Naked Single: r3c8=7
Full House: r3c9=5
Full House: r4c9=7
Full House: r4c8=6
|
normal_sudoku_1224
|
.7..........4...3.684.93.5....3.15.2.5.2.....9.......6.......8.1.3..........5.7.3
|
375612849219485637684793251768341592451269378932578416527936184143827965896154723
|
Basic 9x9 Sudoku 1224
|
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.
|
. 7 . . . . . . .
. . . 4 . . . 3 .
6 8 4 . 9 3 . 5 .
. . . 3 . 1 5 . 2
. 5 . 2 . . . . .
9 . . . . . . . 6
. . . . . . . 8 .
1 . 3 . . . . . .
. . . . 5 . 7 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
375612849219485637684793251768341592451269378932578416527936184143827965896154723 #1 Easy (506)
Hidden Single: r3c6=3
Hidden Single: r4c8=9
Hidden Single: r5c6=9
Hidden Single: r1c1=3
Hidden Single: r6c2=3
Hidden Single: r8c9=5
Hidden Single: r7c5=3
Hidden Single: r3c7=2
Hidden Single: r5c7=3
Hidden Single: r2c2=1
Hidden Single: r6c3=2
Hidden Single: r1c5=1
Naked Single: r3c4=7
Full House: r3c9=1
Hidden Single: r2c1=2
Hidden Single: r5c3=1
Hidden Single: r1c6=2
Hidden Single: r2c9=7
Hidden Single: r8c5=2
Hidden Single: r7c1=5
Hidden Single: r5c5=6
Naked Single: r2c5=8
Hidden Single: r7c2=2
Hidden Single: r9c8=2
Hidden Single: r8c6=7
Hidden Single: r7c3=7
Hidden Single: r9c4=1
Hidden Single: r6c8=1
Hidden Single: r7c7=1
Hidden Single: r8c4=8
Naked Single: r6c4=5
Naked Single: r1c4=6
Full House: r2c6=5
Full House: r7c4=9
Naked Single: r1c8=4
Naked Single: r2c3=9
Full House: r1c3=5
Full House: r2c7=6
Naked Single: r7c9=4
Full House: r7c6=6
Full House: r9c6=4
Full House: r6c6=8
Naked Single: r5c8=7
Full House: r8c8=6
Full House: r8c7=9
Full House: r8c2=4
Naked Single: r5c9=8
Full House: r6c7=4
Full House: r1c7=8
Full House: r1c9=9
Full House: r5c1=4
Full House: r6c5=7
Full House: r4c5=4
Naked Single: r9c1=8
Full House: r4c1=7
Naked Single: r4c2=6
Full House: r4c3=8
Full House: r9c3=6
Full House: r9c2=9
|
normal_sudoku_2165
|
8..2.....5....4....1..7..9...5..217....9..63..7..6...9.3..1.9..4......1..518....3
|
897235461526194387314678295965382174148957632273461859732516948489723516651849723
|
Basic 9x9 Sudoku 2165
|
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 . . . . .
5 . . . . 4 . . .
. 1 . . 7 . . 9 .
. . 5 . . 2 1 7 .
. . . 9 . . 6 3 .
. 7 . . 6 . . . 9
. 3 . . 1 . 9 . .
4 . . . . . . 1 .
. 5 1 8 . . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
897235461526194387314678295965382174148957632273461859732516948489723516651849723 #1 Extreme (18762) bf
Locked Candidates Type 1 (Pointing): 7 in b1 => r78c3<>7
Brute Force: r5c4=9
Hidden Single: r5c6=7
Hidden Single: r5c1=1
Naked Triple: 3,4,8 in r4c459 => r4c1<>3, r4c2<>4, r4c2<>8
Locked Candidates Type 1 (Pointing): 3 in b4 => r6c46<>3
2-String Kite: 8 in r3c6,r4c9 (connected by r4c5,r6c6) => r3c9<>8
Forcing Net Verity => r1c5<>5
r5c5=4 (r5c5<>5 r5c9=5 r3c9<>5) (r4c5<>4 r4c9=4 r3c9<>4) r5c2<>4 r1c2=4 r3c3<>4 r3c7=4 (r3c7<>5) r3c7<>8 r3c6=8 r3c6<>5 r3c4=5 r1c5<>5
r5c5=5 r1c5<>5
r5c5=8 (r5c5<>5 r5c9=5 r6c8<>5) (r4c5<>8 r4c9=8 r7c9<>8) r5c2<>8 r8c2=8 r7c3<>8 r7c8=8 r7c8<>5 r1c8=5 r1c5<>5
Almost Locked Set XZ-Rule: A=r12c5 {389}, B=r3789c6 {35689}, X=8, Z=3,9 => r1c6<>3, r1c6,r89c5<>9
Almost Locked Set Chain: 6- r3679c1 {23679} -9- r13679c6 {135689} -3- r12c2,r3c13 {23469} -9- r45c2,r56c3,r6c1 {234689} -6 => r4c1<>6
Naked Single: r4c1=9
Naked Single: r4c2=6
Hidden Single: r9c6=9
Forcing Net Contradiction in r4c4 => r4c4=3
r4c4<>3 r4c5=3 (r2c5<>3) r1c5<>3 r1c5=9 r2c5<>9 r2c5=8 (r2c8<>8 r7c8=8 r7c8<>4) (r3c6<>8 r3c7=8 r3c7<>4) r2c5<>9 r1c5=9 r1c2<>9 r1c2=4 r3c3<>4 r3c9=4 r7c9<>4 r7c4=4 r4c4<>4 r4c4=3
Naked Triple: 1,5,6 in r1c6,r23c4 => r3c6<>5, r3c6<>6
2-String Kite: 4 in r4c9,r7c4 (connected by r4c5,r6c4) => r7c9<>4
Forcing Chain Contradiction in r6 => r1c8<>4
r1c8=4 r1c2<>4 r5c2=4 r6c3<>4
r1c8=4 r7c8<>4 r7c4=4 r6c4<>4
r1c8=4 r79c8<>4 r9c7=4 r6c7<>4
r1c8=4 r6c8<>4
Discontinuous Nice Loop: 5 r8c4 -5- r3c4 =5= r1c6 -5- r1c8 -6- r9c8 =6= r9c1 =7= r7c1 -7- r7c4 =7= r8c4 => r8c4<>5
Almost Locked Set XY-Wing: A=r1c8 {56}, B=r34578c9 {245678}, C=r9c578 {2467}, X,Y=6,7, Z=5 => r1c9<>5
Forcing Chain Verity => r8c9<>7
r3c9=5 r3c4<>5 r3c4=6 r8c4<>6 r8c4=7 r8c9<>7
r5c9=5 r5c5<>5 r8c5=5 r7c6<>5 r7c6=6 r8c4<>6 r8c4=7 r8c9<>7
r7c9=5 r7c6<>5 r7c6=6 r8c4<>6 r8c4=7 r8c9<>7
r8c9=5 r8c9<>7
Forcing Net Contradiction in c3 => r3c6=8
r3c6<>8 (r6c6=8 r4c5<>8 r4c5=4 r5c5<>4) (r3c7=8 r3c7<>4) r3c6=3 r1c5<>3 r1c5=9 r1c2<>9 r1c2=4 (r5c2<>4) r3c3<>4 r3c9=4 r5c9<>4 r5c3=4 r5c3<>8
r3c6<>8 r6c6=8 r6c3<>8
r3c6<>8 (r3c7=8 r2c8<>8) r6c6=8 r6c8<>8 r7c8=8 r7c3<>8
r3c6<>8 (r3c7=8 r2c8<>8) r6c6=8 r6c6<>1 r6c4=1 r2c4<>1 r2c4=6 r2c8<>6 r2c8=2 r2c2<>2 r2c2=9 r8c2<>9 r8c3=9 r8c3<>8
Hidden Single: r8c6=3
Empty Rectangle: 5 in b8 (r5c59) => r7c9<>5
Sue de Coq: r7c46 - {4567} (r7c139 - {2678}, r89c5 - {245}) => r7c8<>2, r7c8<>6, r7c8<>8
2-String Kite: 8 in r5c2,r7c9 (connected by r7c3,r8c2) => r5c9<>8
Empty Rectangle: 8 in b6 (r7c39) => r6c3<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r5c5<>8
Hidden Single: r4c5=8
Full House: r4c9=4
Locked Candidates Type 1 (Pointing): 4 in b3 => r9c7<>4
Discontinuous Nice Loop: 6 r1c9 -6- r1c8 -5- r7c8 -4- r7c4 =4= r6c4 =1= r6c6 -1- r1c6 =1= r1c9 => r1c9<>6
Grouped Discontinuous Nice Loop: 3 r1c3 -3- r1c5 -9- r1c2 -4- r1c7 =4= r3c7 =3= r3c13 -3- r1c3 => r1c3<>3
Grouped Discontinuous Nice Loop: 6 r7c9 -6- r9c8 =6= r9c1 =7= r9c7 -7- r8c7 =7= r8c4 =6= r7c46 -6- r7c9 => r7c9<>6
Discontinuous Nice Loop: 2 r8c9 -2- r8c5 =2= r9c5 =4= r9c8 =6= r8c9 => r8c9<>2
Grouped Discontinuous Nice Loop: 2 r9c1 -2- r9c5 -4- r5c5 -5- r5c9 -2- r7c9 =2= r7c13 -2- r9c1 => r9c1<>2
Almost Locked Set XY-Wing: A=r3c49 {256}, B=r9c157 {2467}, C=r5c59 {245}, X,Y=2,4, Z=6 => r3c1<>6
Locked Candidates Type 1 (Pointing): 6 in b1 => r78c3<>6
Naked Pair: 2,3 in r36c1 => r7c1<>2
Hidden Pair: 2,8 in r7c39 => r7c9<>7
Locked Candidates Type 1 (Pointing): 7 in b9 => r12c7<>7
Hidden Pair: 1,7 in r12c9 => r2c9<>2, r2c9<>6, r2c9<>8
Locked Candidates Type 2 (Claiming): 8 in c9 => r8c7<>8
Empty Rectangle: 2 in b6 (r36c1) => r3c9<>2
Naked Pair: 5,6 in r1c8,r3c9 => r13c7<>5, r2c8<>6
Naked Pair: 5,6 in r3c49 => r3c3<>6
Naked Triple: 3,4,9 in r1c257 => r1c3<>4, r1c3<>9
Hidden Pair: 6,7 in r12c3 => r2c3<>2, r2c3<>3, r2c3<>9
Hidden Single: r8c3=9
Locked Candidates Type 1 (Pointing): 3 in b1 => r3c7<>3
X-Wing: 6 r38 c49 => r27c4<>6
Naked Single: r2c4=1
Naked Single: r2c9=7
Naked Single: r1c9=1
Naked Single: r2c3=6
Naked Single: r1c3=7
Hidden Single: r6c6=1
Skyscraper: 5 in r3c4,r5c5 (connected by r35c9) => r6c4<>5
Naked Single: r6c4=4
Full House: r5c5=5
Naked Single: r5c9=2
Naked Single: r8c5=2
Naked Single: r7c9=8
Naked Single: r8c2=8
Naked Single: r9c5=4
Naked Single: r7c3=2
Naked Single: r5c2=4
Full House: r5c3=8
Naked Single: r6c3=3
Full House: r3c3=4
Full House: r6c1=2
Naked Single: r1c2=9
Full House: r2c2=2
Full House: r3c1=3
Naked Single: r3c7=2
Naked Single: r1c5=3
Full House: r2c5=9
Naked Single: r2c8=8
Full House: r2c7=3
Naked Single: r9c7=7
Naked Single: r1c7=4
Naked Single: r6c8=5
Full House: r6c7=8
Full House: r8c7=5
Naked Single: r9c1=6
Full House: r7c1=7
Full House: r9c8=2
Naked Single: r1c8=6
Full House: r7c8=4
Full House: r8c9=6
Full House: r1c6=5
Full House: r3c9=5
Full House: r8c4=7
Full House: r3c4=6
Full House: r7c4=5
Full House: r7c6=6
|
normal_sudoku_894
|
..9...3.....4...5.8.....94.48..157.661.94..2..25.8.4...7.13..8......2....3..9..71
|
749851362362479158851326947483215796617943825925687413576134289198762534234598671
|
Basic 9x9 Sudoku 894
|
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 . . . 3 . .
. . . 4 . . . 5 .
8 . . . . . 9 4 .
4 8 . . 1 5 7 . 6
6 1 . 9 4 . . 2 .
. 2 5 . 8 . 4 . .
. 7 . 1 3 . . 8 .
. . . . . 2 . . .
. 3 . . 9 . . 7 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
749851362362479158851326947483215796617943825925687413576134289198762534234598671 #1 Easy (224)
Naked Single: r4c7=7
Naked Single: r2c2=6
Naked Single: r4c3=3
Naked Single: r3c2=5
Naked Single: r4c4=2
Full House: r4c8=9
Naked Single: r5c3=7
Full House: r6c1=9
Naked Single: r1c2=4
Full House: r8c2=9
Naked Single: r6c9=3
Naked Single: r5c6=3
Naked Single: r6c8=1
Naked Single: r1c8=6
Full House: r8c8=3
Hidden Single: r2c6=9
Hidden Single: r2c7=1
Naked Single: r2c3=2
Naked Single: r2c5=7
Naked Single: r3c3=1
Naked Single: r2c1=3
Full House: r2c9=8
Full House: r1c1=7
Naked Single: r3c6=6
Naked Single: r5c9=5
Full House: r5c7=8
Naked Single: r1c9=2
Full House: r3c9=7
Naked Single: r3c4=3
Full House: r3c5=2
Naked Single: r6c6=7
Full House: r6c4=6
Naked Single: r7c6=4
Naked Single: r8c9=4
Full House: r7c9=9
Naked Single: r1c5=5
Full House: r8c5=6
Naked Single: r7c3=6
Naked Single: r9c6=8
Full House: r1c6=1
Full House: r1c4=8
Naked Single: r8c3=8
Full House: r9c3=4
Naked Single: r8c7=5
Naked Single: r9c4=5
Full House: r8c4=7
Full House: r8c1=1
Naked Single: r7c7=2
Full House: r7c1=5
Full House: r9c1=2
Full House: r9c7=6
|
normal_sudoku_1879
|
8...5...9..9.4..676........9..7....4.....237....1.49..496...5.2..8.....6..2....9.
|
873651249259843167641279853925738614164592378387164925496317582718925436532486791
|
Basic 9x9 Sudoku 1879
|
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 . . . 9
. . 9 . 4 . . 6 7
6 . . . . . . . .
9 . . 7 . . . . 4
. . . . . 2 3 7 .
. . . 1 . 4 9 . .
4 9 6 . . . 5 . 2
. . 8 . . . . . 6
. . 2 . . . . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
873651249259843167641279853925738614164592378387164925496317582718925436532486791 #1 Medium (544)
Hidden Single: r6c7=9
Hidden Single: r4c7=6
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c23<>5
Locked Candidates Type 1 (Pointing): 2 in b6 => r13c8<>2
Locked Candidates Type 2 (Claiming): 7 in r7 => r8c56,r9c56<>7
Locked Candidates Type 2 (Claiming): 5 in c3 => r456c2,r56c1<>5
Naked Single: r5c1=1
Hidden Single: r4c8=1
Hidden Single: r4c2=2
Hidden Single: r6c8=2
Hidden Single: r2c1=2
Hidden Single: r3c8=5
Hidden Single: r2c2=5
Hidden Single: r7c8=8
Naked Single: r7c4=3
Naked Single: r2c4=8
Naked Single: r2c7=1
Full House: r2c6=3
Hidden Single: r3c7=8
Naked Single: r3c9=3
Naked Single: r1c8=4
Full House: r1c7=2
Full House: r8c8=3
Naked Single: r9c9=1
Naked Single: r1c4=6
Hidden Single: r8c2=1
Hidden Single: r9c6=6
Naked Single: r9c5=8
Naked Single: r4c5=3
Naked Single: r4c3=5
Full House: r4c6=8
Naked Single: r6c5=6
Naked Single: r5c3=4
Naked Single: r5c5=9
Full House: r5c4=5
Naked Single: r8c5=2
Naked Single: r5c9=8
Full House: r5c2=6
Full House: r6c9=5
Naked Single: r9c4=4
Naked Single: r8c4=9
Full House: r3c4=2
Naked Single: r9c7=7
Full House: r8c7=4
Naked Single: r8c6=5
Full House: r8c1=7
Naked Single: r9c2=3
Full House: r9c1=5
Full House: r6c1=3
Naked Single: r1c2=7
Naked Single: r6c3=7
Full House: r6c2=8
Full House: r3c2=4
Naked Single: r1c6=1
Full House: r1c3=3
Full House: r3c3=1
Naked Single: r3c5=7
Full House: r3c6=9
Full House: r7c6=7
Full House: r7c5=1
|
normal_sudoku_4866
|
..6.2....7..53.9...5...9.3...5.1.8...1.9..72.2....36..........8.4..9..5...7..42..
|
936421587721538964458679132375216849614985723289743615593162478142897356867354291
|
Basic 9x9 Sudoku 4866
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 . 2 . . . .
7 . . 5 3 . 9 . .
. 5 . . . 9 . 3 .
. . 5 . 1 . 8 . .
. 1 . 9 . . 7 2 .
2 . . . . 3 6 . .
. . . . . . . . 8
. 4 . . 9 . . 5 .
. . 7 . . 4 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
936421587721538964458679132375216849614985723289743615593162478142897356867354291 #1 Extreme (13690) bf
Hidden Pair: 3,9 in r1c12 => r1c1<>1, r1c1<>4, r1c12<>8
Forcing Chain Contradiction in r2c6 => r3c9<>1
r3c9=1 r1c789<>1 r1c46=1 r2c6<>1
r3c9=1 r3c9<>6 r2c89=6 r2c6<>6
r3c9=1 r3c9<>2 r3c3=2 r2c2<>2 r2c2=8 r2c6<>8
Brute Force: r5c7=7
Hidden Single: r1c7=5
Locked Candidates Type 1 (Pointing): 3 in b6 => r89c9<>3
Sue de Coq: r3c13 - {1248} (r3c7 - {14}, r1c12,r2c2 - {2389}) => r2c3<>2, r2c3<>8, r3c4<>1, r3c459<>4
Hidden Single: r1c4=4
Locked Candidates Type 1 (Pointing): 1 in b2 => r78c6<>1
Continuous Nice Loop: 1/6/7/9 7= r7c8 =4= r7c7 -4- r3c7 -1- r1c9 -7- r1c8 =7= r7c8 =4 => r2c89,r7c8<>1, r7c8<>6, r1c6,r3c9<>7, r7c8<>9
Locked Candidates Type 1 (Pointing): 9 in b9 => r9c12<>9
Discontinuous Nice Loop: 1 r1c8 -1- r3c7 -4- r7c7 =4= r7c8 =7= r1c8 => r1c8<>1
Forcing Chain Contradiction in c2 => r3c4<>8
r3c4=8 r6c4<>8 r6c4=7 r6c2<>7 r4c2=7 r4c2<>6
r3c4=8 r3c13<>8 r2c2=8 r2c2<>2 r7c2=2 r7c2<>6
r3c4=8 r3c13<>8 r2c2=8 r2c2<>2 r2c9=2 r3c9<>2 r3c9=6 r8c9<>6 r9c89=6 r9c2<>6
Grouped Discontinuous Nice Loop: 8 r5c6 -8- r6c4 -7- r3c4 =7= r3c5 =8= r12c6 -8- r5c6 => r5c6<>8
Finned Swordfish: 8 r358 c135 fr8c4 fr8c6 => r9c5<>8
Grouped Continuous Nice Loop: 6/7 8= r3c5 =7= r3c4 -7- r6c4 -8- r56c5 =8= r3c5 =7 => r3c5<>6, r478c4<>7
2-String Kite: 6 in r3c4,r9c8 (connected by r2c8,r3c9) => r9c4<>6
Discontinuous Nice Loop: 3/6/9 r4c2 =7= r4c6 -7- r8c6 =7= r8c9 -7- r1c9 -1- r1c6 -8- r3c5 -7- r3c4 =7= r6c4 -7- r6c2 =7= r4c2 => r4c2<>3, r4c2<>6, r4c2<>9
Naked Single: r4c2=7
Locked Pair: 2,6 in r4c46 => r4c1,r5c56<>6
Naked Single: r5c6=5
Hidden Single: r5c1=6
Hidden Single: r6c9=5
Hidden Single: r6c8=1
Locked Candidates Type 1 (Pointing): 9 in b6 => r4c1<>9
Locked Candidates Type 2 (Claiming): 6 in c5 => r7c46,r8c46<>6
Hidden Single: r8c9=6
Naked Single: r3c9=2
Naked Single: r9c8=9
Naked Single: r2c9=4
Naked Single: r4c8=4
Naked Single: r9c9=1
Naked Single: r2c3=1
Naked Single: r3c7=1
Naked Single: r5c9=3
Full House: r4c9=9
Full House: r1c9=7
Naked Single: r4c1=3
Naked Single: r7c8=7
Naked Single: r8c7=3
Full House: r7c7=4
Naked Single: r1c8=8
Full House: r2c8=6
Naked Single: r1c1=9
Naked Single: r7c6=2
Naked Single: r1c6=1
Full House: r1c2=3
Naked Single: r2c6=8
Full House: r2c2=2
Naked Single: r4c6=6
Full House: r8c6=7
Full House: r4c4=2
Naked Single: r3c5=7
Full House: r3c4=6
Hidden Single: r3c1=4
Full House: r3c3=8
Naked Single: r5c3=4
Full House: r5c5=8
Naked Single: r8c3=2
Naked Single: r6c3=9
Full House: r6c2=8
Full House: r7c3=3
Naked Single: r6c4=7
Full House: r6c5=4
Naked Single: r9c2=6
Full House: r7c2=9
Naked Single: r7c4=1
Naked Single: r9c5=5
Full House: r7c5=6
Full House: r7c1=5
Naked Single: r8c4=8
Full House: r8c1=1
Full House: r9c1=8
Full House: r9c4=3
|
normal_sudoku_2428
|
.8.93..4.......1.8.6.8.435..9....42.7.3....81......6.......6814.32......1....7...
|
281935746354762198967814352896153427723649581415278639579326814632481975148597263
|
Basic 9x9 Sudoku 2428
|
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 . 9 3 . . 4 .
. . . . . . 1 . 8
. 6 . 8 . 4 3 5 .
. 9 . . . . 4 2 .
7 . 3 . . . . 8 1
. . . . . . 6 . .
. . . . . 6 8 1 4
. 3 2 . . . . . .
1 . . . . 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
281935746354762198967814352896153427723649581415278639579326814632481975148597263 #1 Hard (1010)
Hidden Single: r2c9=8
Hidden Single: r1c9=6
Hidden Single: r2c1=3
Hidden Single: r7c4=3
Hidden Single: r6c2=1
Hidden Single: r7c5=2
Locked Candidates Type 1 (Pointing): 6 in b4 => r4c45<>6
Locked Candidates Type 2 (Claiming): 5 in r7 => r8c1,r9c23<>5
Naked Single: r9c2=4
Naked Single: r9c4=5
Hidden Single: r2c3=4
Hidden Single: r6c1=4
Hidden Single: r2c8=9
Hidden Single: r5c2=2
Locked Candidates Type 2 (Claiming): 2 in r2 => r1c6<>2
Locked Candidates Type 2 (Claiming): 9 in r7 => r8c1,r9c3<>9
Naked Pair: 5,9 in r5c67 => r5c5<>5, r5c5<>9
Naked Triple: 2,5,9 in r137c1 => r4c1<>5
Locked Candidates Type 1 (Pointing): 5 in b4 => r17c3<>5
2-String Kite: 8 in r4c1,r9c5 (connected by r8c1,r9c3) => r4c5<>8
W-Wing: 1/7 in r1c3,r3c5 connected by 7 in r1c7,r3c9 => r1c6,r3c3<>1
Naked Single: r1c6=5
Naked Single: r1c1=2
Naked Single: r2c6=2
Naked Single: r5c6=9
Naked Single: r1c7=7
Full House: r1c3=1
Full House: r3c9=2
Naked Single: r3c1=9
Naked Single: r5c7=5
Naked Single: r3c3=7
Full House: r2c2=5
Full House: r3c5=1
Full House: r7c2=7
Naked Single: r7c1=5
Full House: r7c3=9
Naked Single: r8c7=9
Full House: r9c7=2
Naked Single: r9c9=3
Naked Single: r4c9=7
Naked Single: r9c8=6
Naked Single: r4c4=1
Naked Single: r4c5=5
Naked Single: r6c8=3
Full House: r6c9=9
Full House: r8c9=5
Full House: r8c8=7
Naked Single: r9c3=8
Full House: r8c1=6
Full House: r9c5=9
Full House: r4c1=8
Naked Single: r8c4=4
Naked Single: r6c6=8
Naked Single: r4c3=6
Full House: r6c3=5
Full House: r4c6=3
Full House: r8c6=1
Full House: r8c5=8
Naked Single: r5c4=6
Full House: r5c5=4
Naked Single: r6c5=7
Full House: r2c5=6
Full House: r2c4=7
Full House: r6c4=2
|
normal_sudoku_1591
|
8.92475...........5..1...9...73.4....9......72..76...39..5..67...861..3..6...3..9
|
839247516471956328526138794617394285394825167285761943943582671758619432162473859
|
Basic 9x9 Sudoku 1591
|
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 . 9 2 4 7 5 . .
. . . . . . . . .
5 . . 1 . . . 9 .
. . 7 3 . 4 . . .
. 9 . . . . . . 7
2 . . 7 6 . . . 3
9 . . 5 . . 6 7 .
. . 8 6 1 . . 3 .
. 6 . . . 3 . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
839247516471956328526138794617394285394825167285761943943582671758619432162473859 #1 Medium (452)
Naked Single: r1c4=2
Naked Single: r5c4=8
Naked Single: r2c4=9
Full House: r9c4=4
Hidden Single: r9c5=7
Naked Single: r9c1=1
Naked Single: r4c1=6
Hidden Single: r1c2=3
Hidden Single: r8c6=9
Hidden Single: r4c5=9
Hidden Single: r7c9=1
Naked Single: r1c9=6
Full House: r1c8=1
Hidden Single: r5c8=6
Hidden Single: r5c1=3
Hidden Single: r7c3=3
Hidden Single: r6c7=9
Hidden Single: r7c2=4
Naked Single: r8c1=7
Full House: r2c1=4
Hidden Single: r6c8=4
Hidden Single: r5c3=4
Hidden Single: r6c2=8
Locked Pair: 2,8 in r2c89 => r2c237,r3c79<>2, r2c567,r3c79<>8
Naked Single: r3c9=4
Hidden Single: r8c7=4
Locked Candidates Type 1 (Pointing): 2 in b5 => r5c7<>2
Naked Single: r5c7=1
Hidden Single: r4c2=1
Full House: r6c3=5
Full House: r6c6=1
Naked Single: r2c2=7
Naked Single: r9c3=2
Full House: r8c2=5
Full House: r3c2=2
Full House: r8c9=2
Naked Single: r2c7=3
Naked Single: r3c3=6
Full House: r2c3=1
Naked Single: r9c7=8
Full House: r9c8=5
Naked Single: r2c9=8
Full House: r4c9=5
Naked Single: r2c5=5
Naked Single: r3c7=7
Full House: r4c7=2
Full House: r2c8=2
Full House: r2c6=6
Full House: r4c8=8
Naked Single: r3c6=8
Full House: r3c5=3
Naked Single: r5c5=2
Full House: r5c6=5
Full House: r7c6=2
Full House: r7c5=8
|
normal_sudoku_5349
|
1..6...3...9.2.....5...4..12..8..9.....432....1...7..4.8.5..74...7..815.........8
|
172689435439125687856374291245816973798432516613957824981563742367248159524791368
|
Basic 9x9 Sudoku 5349
|
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 . . 6 . . . 3 .
. . 9 . 2 . . . .
. 5 . . . 4 . . 1
2 . . 8 . . 9 . .
. . . 4 3 2 . . .
. 1 . . . 7 . . 4
. 8 . 5 . . 7 4 .
. . 7 . . 8 1 5 .
. . . . . . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
172689435439125687856374291245816973798432516613957824981563742367248159524791368 #1 Extreme (19448) bf
Brute Force: r5c6=2
Naked Single: r6c4=9
Hidden Single: r5c8=1
Empty Rectangle: 2 in b1 (r7c39) => r1c9<>2
Locked Candidates Type 2 (Claiming): 2 in c9 => r9c78<>2
Grouped Discontinuous Nice Loop: 8 r1c7 -8- r1c5 =8= r3c5 =9= r3c8 =2= r6c8 =8= r56c7 -8- r1c7 => r1c7<>8
Forcing Chain Contradiction in r1 => r4c2<>7
r4c2=7 r1c2<>7
r4c2=7 r4c8<>7 r4c8=6 r9c8<>6 r9c8=9 r3c8<>9 r3c5=9 r3c5<>8 r1c5=8 r1c5<>7
r4c2=7 r4c8<>7 r23c8=7 r1c9<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r5c9<>7
Naked Triple: 5,6,8 in r5c379 => r5c1<>5, r5c12<>6, r5c1<>8
Forcing Chain Contradiction in r9c6 => r7c9<>3
r7c9=3 r7c9<>2 r7c3=2 r7c3<>1 r9c3=1 r9c6<>1
r7c9=3 r7c9<>2 r8c9=2 r8c4<>2 r8c4=3 r9c6<>3
r7c9=3 r9c7<>3 r9c7=6 r9c6<>6
r7c9=3 r9c7<>3 r9c7=6 r9c8<>6 r9c8=9 r9c6<>9
Forcing Chain Contradiction in c2 => r7c9=2
r7c9<>2 r8c9=2 r8c4<>2 r8c4=3 r3c4<>3 r2c46=3 r2c2<>3
r7c9<>2 r8c9=2 r8c9<>3 r4c9=3 r4c2<>3
r7c9<>2 r8c9=2 r8c4<>2 r8c4=3 r8c2<>3
r7c9<>2 r8c9=2 r8c9<>3 r9c7=3 r9c2<>3
2-String Kite: 9 in r3c5,r8c9 (connected by r1c9,r3c8) => r8c5<>9
Forcing Chain Contradiction in c2 => r8c4=2
r8c4<>2 r8c4=3 r3c4<>3 r2c46=3 r2c2<>3
r8c4<>2 r8c4=3 r8c9<>3 r4c9=3 r4c2<>3
r8c4<>2 r8c4=3 r8c2<>3
r8c4<>2 r8c4=3 r8c9<>3 r9c7=3 r9c2<>3
Almost Locked Set XZ-Rule: A=r9c45678 {134679}, B=r468c5 {1456}, X=4, Z=1 => r7c5<>1
W-Wing: 6/9 in r7c5,r9c8 connected by 9 in r3c58 => r9c56<>6
Discontinuous Nice Loop: 7 r3c8 -7- r4c8 -6- r4c6 =6= r7c6 -6- r7c5 -9- r3c5 =9= r3c8 => r3c8<>7
Discontinuous Nice Loop: 6 r4c8 -6- r4c6 =6= r7c6 -6- r7c5 -9- r3c5 =9= r3c8 -9- r9c8 -6- r4c8 => r4c8<>6
Naked Single: r4c8=7
Discontinuous Nice Loop: 6 r4c9 -6- r4c6 =6= r7c6 -6- r7c5 -9- r3c5 =9= r3c8 -9- r9c8 =9= r8c9 =3= r4c9 => r4c9<>6
Discontinuous Nice Loop: 3 r9c1 -3- r9c7 -6- r9c8 -9- r3c8 =9= r3c5 -9- r7c5 -6- r6c5 -5- r6c1 =5= r9c1 => r9c1<>3
Discontinuous Nice Loop: 6 r9c1 -6- r9c8 -9- r3c8 =9= r3c5 -9- r7c5 -6- r6c5 -5- r6c1 =5= r9c1 => r9c1<>6
Grouped AIC: 5 5- r4c9 -3- r8c9 =3= r9c7 -3- r9c46 =3= r7c6 =6= r4c6 -6- r6c5 -5 => r4c56,r6c7<>5
Hidden Single: r6c5=5
Hidden Single: r9c1=5
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c23<>6
AIC: 4 4- r2c1 =4= r8c1 -4- r8c5 -6- r7c5 -9- r3c5 =9= r3c8 -9- r9c8 =9= r8c9 =3= r4c9 -3- r4c2 -4 => r12c2<>4
Discontinuous Nice Loop: 8 r2c1 -8- r2c8 -6- r9c8 -9- r3c8 =9= r3c5 -9- r7c5 -6- r8c5 -4- r8c1 =4= r2c1 => r2c1<>8
Locked Candidates Type 2 (Claiming): 8 in r2 => r3c78<>8
XYZ-Wing: 2/6/9 in r3c78,r9c8 => r2c8<>6
Naked Single: r2c8=8
Hidden Rectangle: 2/6 in r3c78,r6c78 => r6c8<>6
Naked Single: r6c8=2
Discontinuous Nice Loop: 4 r8c2 -4- r8c5 -6- r7c5 -9- r3c5 =9= r3c8 -9- r9c8 =9= r8c9 =3= r4c9 -3- r4c2 -4- r8c2 => r8c2<>4
Grouped AIC: 1/6 1- r4c5 -6- r7c5 -9- r3c5 =9= r3c8 =6= r9c8 -6- r9c7 -3- r9c46 =3= r7c6 =6= r4c6 -6 => r4c6<>1, r4c5<>6
Naked Single: r4c6=6
Full House: r4c5=1
Grouped Discontinuous Nice Loop: 6 r2c1 -6- r2c2 =6= r89c2 -6- r7c13 =6= r7c5 -6- r8c5 -4- r8c1 =4= r2c1 => r2c1<>6
Empty Rectangle: 6 in b1 (r39c8) => r9c2<>6
Grouped Discontinuous Nice Loop: 6 r7c3 -6- r7c5 -9- r3c5 =9= r3c8 =6= r9c8 -6- r9c7 -3- r9c46 =3= r7c6 =1= r7c3 => r7c3<>6
Almost Locked Set XZ-Rule: A=r8c5 {46}, B=r9c45678 {134679}, X=4, Z=6 => r8c9<>6
Locked Candidates Type 1 (Pointing): 6 in b9 => r9c3<>6
Forcing Chain Contradiction in r9c3 => r3c7=2
r3c7<>2 r3c7=6 r9c7<>6 r9c7=3 r8c9<>3 r8c12=3 r7c3<>3 r7c3=1 r9c3<>1
r3c7<>2 r3c3=2 r9c3<>2
r3c7<>2 r3c7=6 r9c7<>6 r9c7=3 r9c3<>3
r3c7<>2 r1c7=2 r1c7<>4 r1c3=4 r9c3<>4
Grouped AIC: 4 4- r1c7 -5- r1c6 -9- r1c9 =9= r3c8 =6= r2c79 -6- r2c2 =6= r8c2 -6- r8c5 -4- r8c1 =4= r2c1 -4 => r1c3,r2c7<>4
Hidden Single: r1c7=4
Hidden Single: r2c1=4
Hidden Single: r8c5=4
Hidden Single: r7c5=6
Naked Triple: 3,6,9 in r78c1,r8c2 => r79c3,r9c2<>3, r9c2<>9
Naked Single: r7c3=1
Discontinuous Nice Loop: 7/9 r1c5 =8= r1c3 =2= r1c2 -2- r9c2 -4- r4c2 -3- r4c9 =3= r8c9 =9= r1c9 -9- r3c8 =9= r3c5 =8= r1c5 => r1c5<>7, r1c5<>9
Naked Single: r1c5=8
Naked Single: r1c3=2
Naked Single: r1c2=7
Naked Single: r9c3=4
Naked Single: r5c2=9
Naked Single: r9c2=2
Naked Single: r5c1=7
Hidden Single: r2c9=7
Hidden Single: r4c2=4
Hidden Single: r5c9=6
X-Wing: 9 c58 r39 => r9c6<>9
2-String Kite: 3 in r2c2,r7c6 (connected by r7c1,r8c2) => r2c6<>3
Locked Candidates Type 1 (Pointing): 3 in b2 => r9c4<>3
W-Wing: 3/6 in r8c2,r9c7 connected by 6 in r2c27 => r8c9<>3
Naked Single: r8c9=9
Naked Single: r1c9=5
Full House: r1c6=9
Full House: r4c9=3
Full House: r4c3=5
Naked Single: r9c8=6
Full House: r3c8=9
Full House: r2c7=6
Full House: r9c7=3
Naked Single: r3c5=7
Full House: r9c5=9
Naked Single: r7c6=3
Full House: r7c1=9
Naked Single: r6c7=8
Full House: r5c7=5
Full House: r5c3=8
Naked Single: r2c2=3
Full House: r8c2=6
Full House: r8c1=3
Naked Single: r9c6=1
Full House: r2c6=5
Full House: r2c4=1
Full House: r3c4=3
Full House: r9c4=7
Naked Single: r3c3=6
Full House: r3c1=8
Full House: r6c1=6
Full House: r6c3=3
|
normal_sudoku_27
|
..6.7..21...4.2.......1.74..1...7.6.83.6.4.........9.......9.72....6.19.92...14..
|
346975821197482653258316749419537268832694517675128934561849372784263195923751486
|
Basic 9x9 Sudoku 27
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 . 7 . . 2 1
. . . 4 . 2 . . .
. . . . 1 . 7 4 .
. 1 . . . 7 . 6 .
8 3 . 6 . 4 . . .
. . . . . . 9 . .
. . . . . 9 . 7 2
. . . . 6 . 1 9 .
9 2 . . . 1 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
346975821197482653258316749419537268832694517675128934561849372784263195923751486 #1 Extreme (22432) bf
Hidden Single: r5c4=6
Hidden Single: r8c4=2
Hidden Single: r7c5=4
Hidden Single: r9c9=6
Hidden Single: r3c6=6
Hidden Single: r5c8=1
Hidden Single: r6c4=1
Hidden Single: r9c4=7
Hidden Single: r2c7=6
Locked Candidates Type 1 (Pointing): 9 in b4 => r23c3<>9
Brute Force: r5c5=9
Hidden Single: r4c3=9
Brute Force: r5c7=5
Naked Single: r5c9=7
Full House: r5c3=2
Hidden Single: r4c7=2
Hidden Single: r3c1=2
Hidden Single: r6c5=2
Almost Locked Set XY-Wing: A=r6c689 {3458}, B=r14c1 {345}, C=r1c67 {358}, X,Y=3,5, Z=4 => r6c1<>4
Finned Franken Swordfish: 3 c67b6 r168 fr4c9 fr7c7 => r8c9<>3
W-Wing: 8/3 in r1c7,r6c8 connected by 3 in r7c7,r9c8 => r2c8<>8
Sashimi Swordfish: 8 c678 r168 fr7c7 fr9c8 => r8c9<>8
Naked Single: r8c9=5
Hidden Single: r2c8=5
Empty Rectangle: 5 in b4 (r16c6) => r1c1<>5
Discontinuous Nice Loop: 3 r4c9 -3- r6c8 =3= r9c8 -3- r7c7 =3= r1c7 -3- r1c1 -4- r4c1 =4= r4c9 => r4c9<>3
Locked Candidates Type 1 (Pointing): 3 in b6 => r6c6<>3
Skyscraper: 3 in r7c7,r8c6 (connected by r1c67) => r7c4<>3
W-Wing: 8/5 in r6c6,r7c4 connected by 5 in r49c5 => r4c4,r8c6<>8
Naked Single: r8c6=3
Locked Candidates Type 2 (Claiming): 8 in r8 => r7c23,r9c3<>8
Skyscraper: 8 in r4c9,r9c8 (connected by r49c5) => r6c8<>8
Naked Single: r6c8=3
Full House: r9c8=8
Full House: r7c7=3
Full House: r1c7=8
Naked Single: r9c5=5
Full House: r7c4=8
Full House: r9c3=3
Naked Single: r1c6=5
Full House: r6c6=8
Naked Single: r4c5=3
Full House: r2c5=8
Full House: r4c4=5
Naked Single: r6c9=4
Full House: r4c9=8
Full House: r4c1=4
Naked Single: r1c1=3
Naked Single: r8c1=7
Naked Single: r1c4=9
Full House: r1c2=4
Full House: r3c4=3
Naked Single: r2c1=1
Naked Single: r8c2=8
Full House: r8c3=4
Naked Single: r3c9=9
Full House: r2c9=3
Naked Single: r2c3=7
Full House: r2c2=9
Naked Single: r3c2=5
Full House: r3c3=8
Naked Single: r6c3=5
Full House: r7c3=1
Naked Single: r7c2=6
Full House: r6c2=7
Full House: r6c1=6
Full House: r7c1=5
|
normal_sudoku_4015
|
7..1...65.6..4.7..2....6..3...2..8.49..3..65..5..6.3.74....1....31.8..7...94.....
|
784123965163549728295876143316257894947318652852964317428791536531682479679435281
|
Basic 9x9 Sudoku 4015
|
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 . . 1 . . . 6 5
. 6 . . 4 . 7 . .
2 . . . . 6 . . 3
. . . 2 . . 8 . 4
9 . . 3 . . 6 5 .
. 5 . . 6 . 3 . 7
4 . . . . 1 . . .
. 3 1 . 8 . . 7 .
. . 9 4 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
784123965163549728295876143316257894947318652852964317428791536531682479679435281 #1 Unfair (1342)
Hidden Single: r1c8=6
Hidden Single: r8c7=4
Hidden Single: r3c8=4
Locked Candidates Type 1 (Pointing): 8 in b3 => r2c1346<>8
Locked Candidates Type 1 (Pointing): 9 in b6 => r27c8<>9
Hidden Pair: 3,6 in r4c13 => r4c1<>1, r4c3<>7
Simple Colors Trap: 1 (r2c1,r3c7,r6c8) / (r3c2,r6c1,r9c7) => r9c8<>1
Continuous Nice Loop: 1/5/7/8/9 8= r3c4 =7= r7c4 -7- r7c3 =7= r5c3 -7- r4c2 -1- r6c1 -8- r6c4 =8= r3c4 =7 => r5c2<>1, r3c4<>5, r57c2,r7c5<>7, r6c36<>8, r3c4<>9
Finned X-Wing: 7 c26 r49 fr5c6 => r4c5<>7
AIC: 2 2- r5c9 -1- r5c5 =1= r4c5 -1- r4c2 =1= r3c2 =9= r1c2 =4= r1c3 -4- r6c3 -2 => r5c23,r6c8<>2
Hidden Single: r5c9=2
Hidden Single: r6c3=2
Hidden Single: r8c6=2
Hidden Single: r5c5=1
Hidden Single: r6c6=4
Hidden Single: r2c8=2
Naked Single: r1c7=9
Naked Single: r3c7=1
Full House: r2c9=8
Hidden Single: r1c5=2
Hidden Single: r3c2=9
Hidden Single: r2c1=1
Naked Single: r6c1=8
Naked Single: r5c2=4
Naked Single: r6c4=9
Full House: r6c8=1
Full House: r4c8=9
Naked Single: r1c2=8
Naked Single: r5c3=7
Full House: r5c6=8
Naked Single: r2c4=5
Naked Single: r4c5=5
Full House: r4c6=7
Naked Single: r1c6=3
Full House: r1c3=4
Naked Single: r3c3=5
Full House: r2c3=3
Full House: r2c6=9
Full House: r9c6=5
Naked Single: r7c2=2
Naked Single: r4c2=1
Full House: r9c2=7
Naked Single: r3c5=7
Full House: r3c4=8
Naked Single: r8c4=6
Full House: r7c4=7
Naked Single: r4c3=6
Full House: r4c1=3
Full House: r7c3=8
Naked Single: r9c1=6
Full House: r8c1=5
Full House: r8c9=9
Naked Single: r9c7=2
Full House: r7c7=5
Naked Single: r9c5=3
Full House: r7c5=9
Naked Single: r7c8=3
Full House: r7c9=6
Full House: r9c9=1
Full House: r9c8=8
|
normal_sudoku_375
|
.8...1..99714.65.2.367..8.....6..2.....1......63..27.8...8..9.57.52........3.5.4.
|
482531679971486532536729814847653291259178463163942758314867925795214386628395147
|
Basic 9x9 Sudoku 375
|
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
9 7 1 4 . 6 5 . 2
. 3 6 7 . . 8 . .
. . . 6 . . 2 . .
. . . 1 . . . . .
. 6 3 . . 2 7 . 8
. . . 8 . . 9 . 5
7 . 5 2 . . . . .
. . . 3 . 5 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
482531679971486532536729814847653291259178463163942758314867925795214386628395147 #1 Easy (204)
Naked Single: r2c4=4
Naked Single: r2c8=3
Full House: r2c5=8
Naked Single: r3c8=1
Naked Single: r1c4=5
Full House: r6c4=9
Naked Single: r3c6=9
Naked Single: r3c9=4
Naked Single: r6c8=5
Naked Single: r3c5=2
Full House: r1c5=3
Full House: r3c1=5
Naked Single: r8c6=4
Naked Single: r1c7=6
Full House: r1c8=7
Naked Single: r4c8=9
Naked Single: r6c5=4
Full House: r6c1=1
Naked Single: r7c6=7
Naked Single: r9c7=1
Naked Single: r5c8=6
Naked Single: r8c7=3
Full House: r5c7=4
Naked Single: r5c9=3
Full House: r4c9=1
Naked Single: r7c8=2
Full House: r8c8=8
Naked Single: r8c9=6
Full House: r9c9=7
Naked Single: r5c6=8
Full House: r4c6=3
Naked Single: r7c3=4
Naked Single: r5c1=2
Naked Single: r1c3=2
Full House: r1c1=4
Naked Single: r7c2=1
Naked Single: r4c1=8
Naked Single: r7c5=6
Full House: r7c1=3
Full House: r9c1=6
Naked Single: r8c2=9
Full House: r8c5=1
Full House: r9c5=9
Naked Single: r4c3=7
Naked Single: r5c2=5
Naked Single: r9c2=2
Full House: r9c3=8
Full House: r5c3=9
Full House: r4c2=4
Full House: r4c5=5
Full House: r5c5=7
|
normal_sudoku_2583
|
1286593.7...4...8.9...3...5....9.....7.3....4...78...9.83...7.....5..4.85....8.9.
|
128659347356417982947832615435291876879365124612784539283946751791523468564178293
|
Basic 9x9 Sudoku 2583
|
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 2 8 6 5 9 3 . 7
. . . 4 . . . 8 .
9 . . . 3 . . . 5
. . . . 9 . . . .
. 7 . 3 . . . . 4
. . . 7 8 . . . 9
. 8 3 . . . 7 . .
. . . 5 . . 4 . 8
5 . . . . 8 . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
128659347356417982947832615435291876879365124612784539283946751791523468564178293 #1 Extreme (2272)
Naked Single: r1c4=6
Full House: r1c8=4
Hidden Single: r2c7=9
Hidden Single: r5c3=9
Hidden Single: r4c8=7
Hidden Single: r7c8=5
Hidden Single: r3c4=8
Hidden Single: r8c6=3
Hidden Single: r7c4=9
Hidden Single: r8c2=9
Hidden Single: r9c9=3
Hidden Single: r6c8=3
Locked Candidates Type 1 (Pointing): 4 in b5 => r7c6<>4
Locked Candidates Type 1 (Pointing): 7 in b8 => r2c5<>7
Empty Rectangle: 1 in b7 (r49c4) => r4c3<>1
Finned Swordfish: 1 r257 c569 fr5c7 fr5c8 => r4c9<>1
Empty Rectangle: 1 in b2 (r27c9) => r7c6<>1
W-Wing: 6/2 in r4c9,r7c6 connected by 2 in r49c4 => r4c6,r7c9<>6
Grouped AIC: 6 6- r4c9 -2- r4c4 =2= r9c4 -2- r7c6 -6- r789c5 =6= r5c5 -6 => r5c78<>6
Grouped Discontinuous Nice Loop: 1 r2c9 -1- r7c9 =1= r7c5 =4= r9c5 =7= r9c3 -7- r3c3 =7= r3c6 =1= r2c56 -1- r2c9 => r2c9<>1
Hidden Single: r7c9=1
Locked Candidates Type 1 (Pointing): 1 in b3 => r3c6<>1
Empty Rectangle: 2 in b2 (r24c9) => r4c6<>2
W-Wing: 1/2 in r2c5,r4c4 connected by 2 in r24c9 => r5c5<>1
W-Wing: 2/6 in r2c9,r9c7 connected by 6 in r38c8 => r3c7<>2
W-Wing: 6/2 in r4c9,r9c7 connected by 2 in r49c4 => r46c7<>6
Hidden Single: r4c9=6
Full House: r2c9=2
Naked Single: r2c5=1
Naked Single: r2c6=7
Full House: r3c6=2
Naked Single: r7c6=6
Hidden Single: r8c3=1
Hidden Single: r9c4=1
Full House: r4c4=2
Naked Single: r5c5=6
Hidden Single: r8c1=7
Naked Single: r8c5=2
Full House: r8c8=6
Full House: r9c7=2
Naked Single: r7c5=4
Full House: r7c1=2
Full House: r9c5=7
Naked Single: r3c8=1
Full House: r3c7=6
Full House: r5c8=2
Naked Single: r5c1=8
Naked Single: r3c2=4
Full House: r3c3=7
Naked Single: r9c2=6
Full House: r9c3=4
Naked Single: r4c3=5
Naked Single: r2c3=6
Full House: r6c3=2
Naked Single: r6c2=1
Naked Single: r2c1=3
Full House: r2c2=5
Full House: r4c2=3
Naked Single: r6c7=5
Naked Single: r4c1=4
Full House: r6c1=6
Full House: r6c6=4
Naked Single: r5c7=1
Full House: r4c7=8
Full House: r4c6=1
Full House: r5c6=5
|
normal_sudoku_2666
|
...6.....5.1..3.8...37..95..7....8.4..8..2.....6....2..39.45...72.3..59..8.2.74.1
|
297658143541923687863714952972536814458172369316489725139845276724361598685297431
|
Basic 9x9 Sudoku 2666
|
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 . . . . .
5 . 1 . . 3 . 8 .
. . 3 7 . . 9 5 .
. 7 . . . . 8 . 4
. . 8 . . 2 . . .
. . 6 . . . . 2 .
. 3 9 . 4 5 . . .
7 2 . 3 . . 5 9 .
. 8 . 2 . 7 4 . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
297658143541923687863714952972536814458172369316489725139845276724361598685297431 #1 Easy (258)
Naked Single: r7c3=9
Naked Single: r8c3=4
Naked Single: r9c1=6
Naked Single: r9c3=5
Full House: r7c1=1
Naked Single: r9c5=9
Full House: r9c8=3
Naked Single: r4c3=2
Full House: r1c3=7
Naked Single: r7c4=8
Naked Single: r2c5=2
Hidden Single: r1c5=5
Hidden Single: r1c8=4
Naked Single: r1c2=9
Hidden Single: r8c9=8
Hidden Single: r4c4=5
Hidden Single: r1c7=1
Naked Single: r1c6=8
Naked Single: r1c1=2
Full House: r1c9=3
Naked Single: r3c5=1
Naked Single: r3c6=4
Full House: r2c4=9
Naked Single: r8c5=6
Full House: r8c6=1
Naked Single: r3c1=8
Naked Single: r3c2=6
Full House: r2c2=4
Full House: r3c9=2
Naked Single: r4c5=3
Naked Single: r6c6=9
Full House: r4c6=6
Naked Single: r4c1=9
Full House: r4c8=1
Naked Single: r5c5=7
Full House: r6c5=8
Naked Single: r5c8=6
Full House: r7c8=7
Naked Single: r5c7=3
Naked Single: r7c9=6
Full House: r7c7=2
Naked Single: r5c1=4
Full House: r6c1=3
Naked Single: r6c7=7
Full House: r2c7=6
Full House: r2c9=7
Naked Single: r5c4=1
Full House: r6c4=4
Naked Single: r6c9=5
Full House: r5c9=9
Full House: r5c2=5
Full House: r6c2=1
|
normal_sudoku_2052
|
.7.38...23....5.......9......6..3..7.3...9..8.2.47.5.....9.78.5.....12.4.5..4..7.
|
679384152342165789815792346596813427734259618128476593461927835987531264253648971
|
Basic 9x9 Sudoku 2052
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . 3 8 . . . 2
3 . . . . 5 . . .
. . . . 9 . . . .
. . 6 . . 3 . . 7
. 3 . . . 9 . . 8
. 2 . 4 7 . 5 . .
. . . 9 . 7 8 . 5
. . . . . 1 2 . 4
. 5 . . 4 . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
679384152342165789815792346596813427734259618128476593461927835987531264253648971 #1 Extreme (34960) bf
Empty Rectangle: 2 in b1 (r39c6) => r9c3<>2
Brute Force: r5c2=3
Brute Force: r5c3=4
Hidden Single: r5c1=7
Hidden Single: r8c3=7
Hidden Single: r4c1=5
Grouped Discontinuous Nice Loop: 8 r9c3 -8- r8c12 =8= r8c4 =5= r8c5 =3= r8c8 -3- r9c79 =3= r9c3 => r9c3<>8
Forcing Chain Verity => r3c3<>2
r2c3=8 r2c8<>8 r3c8=8 r3c8<>5 r3c3=5 r3c3<>2
r3c3=8 r3c3<>2
r6c3=8 r6c6<>8 r9c6=8 r9c6<>2 r3c6=2 r3c3<>2
Grouped Discontinuous Nice Loop: 1 r2c3 -1- r2c45 =1= r3c4 =7= r3c7 =3= r9c7 -3- r9c3 =3= r7c3 =2= r2c3 => r2c3<>1
Forcing Net Contradiction in b3 => r2c7<>1
r2c7=1 (r1c7<>1) r5c7<>1 r5c7=6 (r1c7<>6) (r6c8<>6) r6c9<>6 r6c6=6 r1c6<>6 r1c6=4 r1c7<>4 r1c7=9
r2c7=1 (r2c9<>1) (r2c7<>7 r2c4=7 r2c4<>6) (r2c5<>1 r3c4=1 r3c4<>6) r5c7<>1 r5c7=6 (r6c8<>6) r6c9<>6 r6c6=6 (r1c6<>6) r3c6<>6 r2c5=6 r2c9<>6 r2c9=9
Forcing Net Contradiction in c9 => r3c4<>2
r3c4=2 (r3c4<>1) r3c4<>7 r3c7=7 r2c7<>7 r2c4=7 r2c4<>1 r2c5=1 r2c9<>1
r3c4=2 (r3c4<>7 r3c7=7 r2c7<>7 r2c4=7 r2c4<>1 r2c5=1 r2c2<>1) (r2c5<>2 r2c3=2 r7c3<>2) r3c6<>2 r9c6=2 (r9c6<>8 r6c6=8 r4c4<>8 r4c4=1 r4c2<>1) r7c5<>2 r7c1=2 r7c1<>4 r7c2=4 r7c2<>1 r3c2=1 r3c9<>1
r3c4=2 (r3c4<>7 r3c7=7 r2c7<>7 r2c4=7 r2c4<>1 r2c5=1 r5c5<>1) (r5c4<>2) (r4c4<>2) r3c6<>2 r9c6=2 r9c6<>8 r6c6=8 r4c4<>8 r4c4=1 (r5c4<>1) r4c5<>1 r4c5=2 r5c5<>2 r5c8=2 r5c8<>1 r5c7=1 r6c9<>1
r3c4=2 (r3c6<>2 r9c6=2 r7c5<>2 r7c1=2 r7c1<>1) (r3c6<>2 r9c6=2 r7c5<>2 r7c1=2 r7c1<>4 r7c2=4 r7c2<>1) r3c4<>7 r3c7=7 r3c7<>3 r9c7=3 (r7c8<>3) r8c8<>3 r8c5=3 r7c5<>3 r7c3=3 r7c3<>1 r7c8=1 r9c9<>1
Forcing Net Contradiction in c8 => r1c8<>4
r1c8=4 r1c8<>1
r1c8=4 r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>8 r2c8=8 r2c8<>1
r1c8=4 r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>1
r1c8=4 (r4c8<>4 r4c7=4 r4c7<>9) r1c6<>4 r1c6=6 r6c6<>6 r6c6=8 r4c4<>8 r4c2=8 r4c2<>9 r4c8=9 r4c8<>1
r1c8=4 r1c6<>4 r1c6=6 r6c6<>6 r5c45=6 r5c7<>6 r5c7=1 r5c8<>1
r1c8=4 (r1c6<>4 r1c6=6 r6c6<>6 r6c6=8 r6c3<>8) (r1c6<>4 r3c6=4 r3c6<>2 r3c1=2 r2c3<>2) r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>8 r2c8=8 r2c3<>8 r2c3=9 r6c3<>9 r6c3=1 r6c8<>1
r1c8=4 (r2c8<>4 r2c2=4 r7c2<>4) (r2c8<>4 r2c2=4 r2c2<>6) r1c6<>4 (r1c6=6 r1c1<>6) r3c6=4 r3c6<>2 r3c1=2 r3c1<>6 r3c2=6 r7c2<>6 r7c2=1 r7c8<>1
Forcing Net Contradiction in b1 => r4c7<>1
r4c7=1 (r1c7<>1) r5c7<>1 r5c7=6 (r1c7<>6) (r6c8<>6) r6c9<>6 r6c6=6 r1c6<>6 r1c6=4 r1c7<>4 r1c7=9 r1c1<>9
r4c7=1 (r1c7<>1) r5c7<>1 r5c7=6 (r1c7<>6) (r6c8<>6) r6c9<>6 r6c6=6 r1c6<>6 r1c6=4 r1c7<>4 r1c7=9 r1c3<>9
r4c7=1 (r4c7<>9) r4c7<>4 r4c8=4 r4c8<>9 r4c2=9 r2c2<>9
r4c7=1 (r4c4<>1) r4c5<>1 r4c5=2 r4c4<>2 r4c4=8 r6c6<>8 r9c6=8 r9c6<>2 r3c6=2 (r2c4<>2) r2c5<>2 r2c3=2 r2c3<>9
Forcing Net Contradiction in b9 => r1c7<>4
r1c7=4 (r2c8<>4 r2c2=4 r7c2<>4) (r2c8<>4 r2c2=4 r2c2<>6) r1c6<>4 (r1c6=6 r1c1<>6) r3c6=4 r3c6<>2 r3c1=2 r3c1<>6 r3c2=6 r7c2<>6 r7c2=1 r7c8<>1
r1c7=4 r1c6<>4 r1c6=6 r6c6<>6 r5c45=6 r5c7<>6 r5c7=1 r9c7<>1
r1c7=4 (r4c7<>4 r4c7=9 r9c7<>9) (r4c7<>4 r4c7=9 r4c2<>9) (r2c7<>4) r2c8<>4 r2c2=4 r2c2<>9 r8c2=9 (r9c1<>9) r9c3<>9 r9c9=9 r9c9<>1
Forcing Net Contradiction in r4 => r2c3<>9
r2c3=9 r2c3<>2 r7c3=2 r7c3<>3 r9c3=3 r9c7<>3 r3c7=3 (r3c7<>4) r3c7<>7 r3c4=7 r2c4<>7 r2c7=7 r2c7<>4 r4c7=4
r2c3=9 (r2c3<>8) r2c3<>2 r7c3=2 (r7c1<>2) r9c1<>2 r3c1=2 r3c6<>2 r9c6=2 r9c6<>8 r6c6=8 r6c3<>8 r3c3=8 (r2c3<>8 r2c8=8 r2c8<>4) r3c3<>5 r3c8=5 r3c8<>4 r4c8=4
Forcing Net Contradiction in r2 => r2c7<>6
r2c7=6 r2c7<>7 r2c4=7 r2c4<>2 r2c3=2
r2c7=6 (r2c5<>6) (r2c9<>6) (r1c7<>6) r5c7<>6 r5c7=1 r1c7<>1 r1c7=9 r2c9<>9 r2c9=1 r2c5<>1 r2c5=2
Forcing Net Contradiction in c2 => r2c8<>1
r2c8=1 (r2c8<>9) (r2c8<>4) r2c8<>8 r3c8=8 (r3c3<>8 r3c3=5 r1c3<>5 r1c8=5 r1c8<>9) r3c8<>4 r4c8=4 r4c7<>4 r4c7=9 (r1c7<>9) r2c7<>9 r2c9=9 r2c2<>9
r2c8=1 (r2c8<>4) r2c8<>8 r3c8=8 r3c8<>4 r4c8=4 r4c7<>4 r4c7=9 r4c2<>9
r2c8=1 (r2c8<>9) (r2c8<>4) r2c8<>8 r3c8=8 (r3c3<>8 r3c3=5 r1c3<>5 r1c8=5 r1c8<>9) r3c8<>4 r4c8=4 (r4c8<>9) r4c7<>4 r4c7=9 r6c8<>9 r8c8=9 r8c2<>9
Forcing Net Contradiction in c2 => r2c8<>6
r2c8=6 (r2c8<>9) (r2c8<>4) r2c8<>8 r3c8=8 (r3c8<>5 r3c3=5 r1c3<>5 r1c8=5 r1c8<>9) r3c8<>4 r4c8=4 r4c7<>4 r4c7=9 (r1c7<>9) r2c7<>9 r2c9=9 r2c2<>9
r2c8=6 (r2c8<>4) r2c8<>8 r3c8=8 r3c8<>4 r4c8=4 r4c7<>4 r4c7=9 r4c2<>9
r2c8=6 (r2c8<>9) (r2c8<>4) r2c8<>8 r3c8=8 (r3c8<>5 r3c3=5 r1c3<>5 r1c8=5 r1c8<>9) r3c8<>4 r4c8=4 (r4c8<>9) r4c7<>4 r4c7=9 r6c8<>9 r8c8=9 r8c2<>9
Forcing Net Contradiction in c2 => r2c9<>1
r2c9=1 r2c2<>1
r2c9=1 (r2c4<>1) r2c5<>1 r3c4=1 r3c2<>1
r2c9=1 (r1c7<>1) (r3c7<>1) (r2c4<>1) r2c5<>1 r3c4=1 r3c4<>7 r3c7=7 r3c7<>3 r9c7=3 r9c7<>1 r5c7=1 r5c45<>1 r4c45=1 r4c2<>1
r2c9=1 (r1c8<>1) (r3c8<>1) (r1c7<>1) (r3c7<>1) (r2c4<>1) r2c5<>1 r3c4=1 r3c4<>7 r3c7=7 r3c7<>3 r9c7=3 r9c7<>1 r5c7=1 (r4c8<>1) (r5c8<>1) r6c8<>1 r7c8=1 r7c2<>1
XYZ-Wing: 1/6/9 in r15c7,r2c9 => r3c7<>6
Forcing Net Contradiction in r3 => r1c8<>9
r1c8=9 (r1c7<>9) r2c9<>9 (r2c2=9 r4c2<>9 r4c7=9 r6c9<>9) r2c9=6 (r6c9<>6) (r3c9<>6) r1c7<>6 r1c7=1 (r5c7<>1 r5c7=6 r6c9<>6 r6c6=6 r6c6<>8 r9c6=8 r9c4<>8) r3c9<>1 r3c9=3 r6c9<>3 r6c9=1 (r6c3<>1 r4c2=1 r4c5<>1 r4c5=2 r7c5<>2) r6c9<>3 r6c8=3 r8c8<>3 r8c5=3 r7c5<>3 r7c5=6 (r7c2<>6 r7c2=4 r7c1<>4) r9c4<>6 r9c4=2 r9c6<>2 r3c6=2 r3c6<>4 r1c6=4 r1c1<>4 r3c1=4 r3c1<>1
r1c8=9 (r1c7<>9) r2c9<>9 (r2c2=9 r4c2<>9 r4c7=9 r6c9<>9) r2c9=6 (r6c9<>6) (r3c9<>6) r1c7<>6 r1c7=1 r3c9<>1 r3c9=3 r6c9<>3 r6c9=1 (r6c1<>1) r6c3<>1 r4c2=1 r3c2<>1
r1c8=9 (r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>8 r2c8=8 r2c3<>8) (r6c8<>9) (r8c8<>9) (r2c7<>9) (r2c8<>9) r2c9<>9 r2c2=9 (r4c2<>9 r4c7=9 r6c9<>9) r8c2<>9 r8c1=9 r6c1<>9 r6c3=9 r6c3<>8 r3c3=8 r3c3<>1
r1c8=9 (r2c9<>9 r2c9=6 r2c5<>6) r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>8 r2c8=8 r2c3<>8 r2c3=2 r2c5<>2 r2c5=1 r3c4<>1
r1c8=9 (r1c7<>9) r2c9<>9 r2c9=6 r1c7<>6 r1c7=1 r3c7<>1
r1c8=9 r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 r3c8<>1
r1c8=9 (r1c7<>9) r2c9<>9 r2c9=6 r1c7<>6 r1c7=1 r3c9<>1
Forcing Net Contradiction in c2 => r1c8=5
r1c8<>5 r1c3=5 (r1c3<>9) r3c3<>5 r3c8=5 (r3c8<>4) r3c8<>8 r2c8=8 r2c8<>4 r4c8=4 r4c7<>4 r4c7=9 r1c7<>9 r1c1=9 r2c2<>9
r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 (r3c8<>4) r3c8<>8 r2c8=8 r2c8<>4 r4c8=4 r4c7<>4 r4c7=9 r4c2<>9
r1c8<>5 r1c3=5 r3c3<>5 r3c8=5 (r3c8<>4) r3c8<>8 r2c8=8 (r2c8<>9) r2c8<>4 r4c8=4 (r4c8<>9) r4c7<>4 r4c7=9 r6c8<>9 r8c8=9 r8c2<>9
Hidden Single: r3c3=5
Continuous Nice Loop: 6/8 8= r9c6 =2= r3c6 -2- r3c1 =2= r2c3 =8= r6c3 -8- r6c6 =8= r9c6 =2 => r9c6<>6, r6c1<>8
Grouped Discontinuous Nice Loop: 6 r6c9 -6- r6c6 -8- r6c3 =8= r2c3 =2= r7c3 =3= r9c3 -3- r9c79 =3= r78c8 -3- r6c8 =3= r6c9 => r6c9<>6
Forcing Chain Contradiction in c2 => r1c6=4
r1c6<>4 r1c6=6 r6c6<>6 r6c8=6 r5c7<>6 r5c7=1 r1c7<>1 r1c13=1 r2c2<>1
r1c6<>4 r1c6=6 r6c6<>6 r6c8=6 r5c7<>6 r5c7=1 r1c7<>1 r1c13=1 r3c2<>1
r1c6<>4 r1c6=6 r6c6<>6 r6c6=8 r6c3<>8 r4c2=8 r4c2<>1
r1c6<>4 r1c1=4 r7c1<>4 r7c2=4 r7c2<>1
Grouped Discontinuous Nice Loop: 6 r9c1 -6- r9c9 =6= r23c9 -6- r1c7 =6= r1c1 -6- r9c1 => r9c1<>6
Forcing Chain Contradiction in r9 => r1c1<>9
r1c1=9 r6c1<>9 r6c1=1 r9c1<>1
r1c1=9 r1c3<>9 r1c3=1 r9c3<>1
r1c1=9 r1c1<>6 r1c7=6 r5c7<>6 r5c7=1 r9c7<>1
r1c1=9 r1c1<>6 r1c7=6 r23c9<>6 r9c9=6 r9c9<>1
Finned Franken Swordfish: 9 c19b1 r269 fr1c3 fr8c1 => r9c3<>9
Almost Locked Set XZ-Rule: A=r1689c1 {12689}, B=r79c3 {123}, X=2, Z=1 => r7c1<>1
Almost Locked Set Chain: 1- r5c7 {16} -6- r6c1389 {13689} -8- r1279c3 {12389} -9- r15c7 {169} -1 => r39c7<>1
Forcing Chain Contradiction in c2 => r1c1=6
r1c1<>6 r1c1=1 r2c2<>1
r1c1<>6 r1c1=1 r3c2<>1
r1c1<>6 r1c1=1 r1c7<>1 r5c7=1 r5c45<>1 r4c45=1 r4c2<>1
r1c1<>6 r1c7=6 r23c9<>6 r9c9=6 r9c9<>1 r7c8=1 r7c2<>1
Continuous Nice Loop: 1/6 9= r6c3 =8= r6c6 =6= r6c8 -6- r5c7 -1- r1c7 -9- r1c3 =9= r6c3 =8 => r6c3<>1, r5c8<>6
Discontinuous Nice Loop: 1 r3c8 -1- r1c7 -9- r1c3 =9= r6c3 =8= r2c3 -8- r2c8 =8= r3c8 => r3c8<>1
Grouped Discontinuous Nice Loop: 1 r7c2 -1- r7c8 =1= r9c9 -1- r3c9 =1= r1c7 -1- r1c3 =1= r79c3 -1- r7c2 => r7c2<>1
Sashimi Jellyfish: 1 r1679 c1389 fr1c7 => r3c9<>1
Hidden Single: r1c7=1
Full House: r1c3=9
Naked Single: r5c7=6
Naked Single: r6c3=8
Naked Single: r2c3=2
Naked Single: r6c6=6
Naked Single: r3c6=2
Full House: r9c6=8
Hidden Single: r4c4=8
Locked Candidates Type 2 (Claiming): 1 in c3 => r9c1<>1
Empty Rectangle: 6 in b2 (r9c49) => r2c9<>6
Naked Single: r2c9=9
Locked Candidates Type 1 (Pointing): 6 in b3 => r3c4<>6
Skyscraper: 9 in r6c8,r9c7 (connected by r69c1) => r4c7,r8c8<>9
Naked Single: r4c7=4
Naked Single: r2c7=7
Naked Single: r3c7=3
Full House: r9c7=9
Naked Single: r3c9=6
Naked Single: r9c1=2
Naked Single: r7c1=4
Naked Single: r9c4=6
Naked Single: r7c2=6
Naked Single: r2c4=1
Naked Single: r8c4=5
Naked Single: r2c5=6
Full House: r3c4=7
Full House: r5c4=2
Naked Single: r8c5=3
Full House: r7c5=2
Naked Single: r4c5=1
Full House: r5c5=5
Full House: r5c8=1
Naked Single: r8c8=6
Naked Single: r4c2=9
Full House: r4c8=2
Full House: r6c1=1
Naked Single: r6c9=3
Full House: r6c8=9
Full House: r9c9=1
Full House: r7c8=3
Full House: r9c3=3
Full House: r7c3=1
Naked Single: r8c2=8
Full House: r8c1=9
Full House: r3c1=8
Naked Single: r2c2=4
Full House: r2c8=8
Full House: r3c8=4
Full House: r3c2=1
|
normal_sudoku_415
|
....8..15..4.56.....82.7.3.....9.65.63.....98...........192..63..3....7.8.5...24.
|
326489715174356982958217436482193657637542198519678324741925863293864571865731249
|
Basic 9x9 Sudoku 415
|
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 5
. . 4 . 5 6 . . .
. . 8 2 . 7 . 3 .
. . . . 9 . 6 5 .
6 3 . . . . . 9 8
. . . . . . . . .
. . 1 9 2 . . 6 3
. . 3 . . . . 7 .
8 . 5 . . . 2 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
326489715174356982958217436482193657637542198519678324741925863293864571865731249 #1 Easy (326)
Naked Single: r9c8=4
Naked Single: r6c8=2
Full House: r2c8=8
Hidden Single: r3c9=6
Hidden Single: r1c6=9
Hidden Single: r6c7=3
Hidden Single: r1c3=6
Hidden Single: r2c9=2
Hidden Single: r6c3=9
Hidden Single: r9c5=3
Naked Single: r9c6=1
Naked Single: r9c9=9
Naked Single: r8c9=1
Hidden Single: r4c6=3
Hidden Single: r9c4=7
Full House: r9c2=6
Hidden Single: r5c7=1
Hidden Single: r5c6=2
Naked Single: r5c3=7
Full House: r4c3=2
Naked Single: r5c5=4
Full House: r5c4=5
Naked Single: r3c5=1
Naked Single: r8c5=6
Full House: r6c5=7
Naked Single: r6c6=8
Naked Single: r2c4=3
Full House: r1c4=4
Naked Single: r6c9=4
Full House: r4c9=7
Naked Single: r4c4=1
Full House: r6c4=6
Full House: r8c4=8
Naked Single: r1c7=7
Naked Single: r4c1=4
Full House: r4c2=8
Naked Single: r8c7=5
Full House: r7c7=8
Naked Single: r1c2=2
Full House: r1c1=3
Naked Single: r2c7=9
Full House: r3c7=4
Naked Single: r7c1=7
Naked Single: r8c6=4
Full House: r7c6=5
Full House: r7c2=4
Naked Single: r2c1=1
Full House: r2c2=7
Naked Single: r8c2=9
Full House: r8c1=2
Naked Single: r6c1=5
Full House: r3c1=9
Full House: r3c2=5
Full House: r6c2=1
|
normal_sudoku_450
|
6...457.....7...6...2.3..84.2....6....8.2..7.7..5.8..3.192..83.3..46..25.....1.9.
|
693845712845712369172936584924173658538624971761598243419257836387469125256381497
|
Basic 9x9 Sudoku 450
|
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 . . . 4 5 7 . .
. . . 7 . . . 6 .
. . 2 . 3 . . 8 4
. 2 . . . . 6 . .
. . 8 . 2 . . 7 .
7 . . 5 . 8 . . 3
. 1 9 2 . . 8 3 .
3 . . 4 6 . . 2 5
. . . . . 1 . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
693845712845712369172936584924173658538624971761598243419257836387469125256381497 #1 Easy (204)
Naked Single: r7c4=2
Naked Single: r8c3=7
Naked Single: r1c8=1
Naked Single: r8c7=1
Naked Single: r9c7=4
Naked Single: r7c6=7
Naked Single: r8c2=8
Full House: r8c6=9
Naked Single: r1c3=3
Naked Single: r6c8=4
Full House: r4c8=5
Naked Single: r7c5=5
Naked Single: r7c9=6
Full House: r7c1=4
Full House: r9c9=7
Naked Single: r2c6=2
Naked Single: r3c6=6
Naked Single: r1c2=9
Naked Single: r5c7=9
Naked Single: r9c5=8
Full House: r9c4=3
Naked Single: r2c9=9
Naked Single: r1c4=8
Full House: r1c9=2
Naked Single: r6c2=6
Naked Single: r3c7=5
Full House: r2c7=3
Full House: r6c7=2
Naked Single: r5c9=1
Full House: r4c9=8
Naked Single: r2c5=1
Full House: r3c4=9
Naked Single: r6c3=1
Full House: r6c5=9
Full House: r4c5=7
Naked Single: r9c2=5
Naked Single: r3c1=1
Full House: r3c2=7
Naked Single: r5c1=5
Naked Single: r5c4=6
Full House: r4c4=1
Naked Single: r4c1=9
Naked Single: r4c3=4
Full House: r4c6=3
Full House: r5c2=3
Full House: r2c2=4
Full House: r5c6=4
Naked Single: r9c1=2
Full House: r9c3=6
Full House: r2c1=8
Full House: r2c3=5
|
normal_sudoku_5112
|
.4..9.....61..89....36.......6.79.2.48...1397.7.83.6...9.38.1..5.......9..4....3.
|
842193576761528943953647281316479825485261397279835614697384152538712469124956738
|
Basic 9x9 Sudoku 5112
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . . 9 . . . .
. 6 1 . . 8 9 . .
. . 3 6 . . . . .
. . 6 . 7 9 . 2 .
4 8 . . . 1 3 9 7
. 7 . 8 3 . 6 . .
. 9 . 3 8 . 1 . .
5 . . . . . . . 9
. . 4 . . . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
842193576761528943953647281316479825485261397279835614697384152538712469124956738 #1 Extreme (1828)
Hidden Single: r5c7=3
Hidden Single: r5c5=6
Hidden Single: r3c1=9
Hidden Single: r6c3=9
Hidden Single: r1c6=3
Hidden Single: r9c4=9
Hidden Single: r2c9=3
Hidden Single: r8c2=3
Hidden Single: r4c1=3
Locked Candidates Type 1 (Pointing): 8 in b1 => r1c789<>8
Locked Candidates Type 1 (Pointing): 1 in b7 => r9c5<>1
W-Wing: 7/2 in r2c1,r7c3 connected by 2 in r39c2 => r1c3,r79c1<>7
XY-Wing: 1/5/2 in r34c2,r6c1 => r12c1<>2
Naked Single: r2c1=7
Naked Single: r1c1=8
Hidden Single: r8c3=8
Hidden Single: r3c8=8
Hidden Single: r7c3=7
Locked Candidates Type 2 (Claiming): 2 in r2 => r1c4,r3c56<>2
Naked Triple: 2,4,5 in r245c4 => r1c4<>5, r8c4<>2, r8c4<>4
X-Wing: 7 r39 c67 => r18c7,r8c6<>7
Naked Pair: 2,5 in r1c37 => r1c89<>5, r1c9<>2
2-String Kite: 2 in r1c7,r9c2 (connected by r1c3,r3c2) => r9c7<>2
2-String Kite: 5 in r1c7,r4c2 (connected by r1c3,r3c2) => r4c7<>5
Empty Rectangle: 2 in b7 (r6c16) => r9c6<>2
XY-Wing: 2/5/4 in r18c7,r2c8 => r3c7,r78c8<>4
Skyscraper: 4 in r4c4,r6c8 (connected by r2c48) => r4c79,r6c6<>4
Naked Single: r4c7=8
Hidden Single: r8c7=4
Hidden Single: r4c4=4
Hidden Single: r9c9=8
Hidden Single: r7c6=4
Hidden Single: r7c9=2
Naked Single: r7c1=6
Full House: r7c8=5
Naked Single: r2c8=4
Naked Single: r9c7=7
Full House: r8c8=6
Naked Single: r6c8=1
Full House: r1c8=7
Naked Single: r8c6=2
Naked Single: r4c9=5
Full House: r4c2=1
Full House: r6c9=4
Naked Single: r6c1=2
Full House: r6c6=5
Full House: r5c3=5
Full House: r9c1=1
Full House: r9c2=2
Full House: r5c4=2
Full House: r1c3=2
Full House: r3c2=5
Naked Single: r1c4=1
Naked Single: r8c5=1
Full House: r8c4=7
Full House: r2c4=5
Full House: r2c5=2
Naked Single: r9c5=5
Full House: r9c6=6
Full House: r3c6=7
Full House: r3c5=4
Naked Single: r3c9=1
Full House: r3c7=2
Full House: r1c7=5
Full House: r1c9=6
|
normal_sudoku_1922
|
.58..6..........98.1.9....7.7........2.5817648....3.2......52...41.9..86..3.4...1
|
958736412732154698416928357174269835329581764865473129697815243241397586583642971
|
Basic 9x9 Sudoku 1922
|
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 8 . . 6 . . .
. . . . . . . 9 8
. 1 . 9 . . . . 7
. 7 . . . . . . .
. 2 . 5 8 1 7 6 4
8 . . . . 3 . 2 .
. . . . . 5 2 . .
. 4 1 . 9 . . 8 6
. . 3 . 4 . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
958736412732154698416928357174269835329581764865473129697815243241397586583642971 #1 Easy (212)
Naked Single: r5c4=5
Naked Single: r5c3=9
Full House: r5c1=3
Naked Single: r6c2=6
Naked Single: r2c2=3
Naked Single: r6c5=7
Naked Single: r6c4=4
Naked Single: r6c3=5
Naked Single: r4c3=4
Full House: r4c1=1
Naked Single: r6c9=9
Full House: r6c7=1
Naked Single: r7c9=3
Naked Single: r1c9=2
Full House: r4c9=5
Naked Single: r8c7=5
Naked Single: r4c8=3
Full House: r4c7=8
Naked Single: r9c7=9
Naked Single: r9c8=7
Full House: r7c8=4
Naked Single: r9c2=8
Full House: r7c2=9
Naked Single: r1c8=1
Full House: r3c8=5
Naked Single: r9c6=2
Naked Single: r1c5=3
Naked Single: r4c6=9
Naked Single: r8c6=7
Naked Single: r9c4=6
Full House: r9c1=5
Naked Single: r1c4=7
Naked Single: r1c7=4
Full House: r1c1=9
Naked Single: r3c5=2
Naked Single: r2c6=4
Full House: r3c6=8
Naked Single: r8c1=2
Full House: r8c4=3
Naked Single: r4c4=2
Full House: r4c5=6
Naked Single: r7c5=1
Full House: r2c5=5
Full House: r2c4=1
Full House: r7c4=8
Naked Single: r2c7=6
Full House: r3c7=3
Naked Single: r3c3=6
Full House: r3c1=4
Naked Single: r2c1=7
Full House: r2c3=2
Full House: r7c3=7
Full House: r7c1=6
|
normal_sudoku_2626
|
1....5.2..7......8..6.3.9.....6..5....4.9...3.9...7....2.....198..75..34..94.16..
|
148975326973246158256138947387614592614592873592387461425863719861759234739421685
|
Basic 9x9 Sudoku 2626
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . . . . 5 . 2 .
. 7 . . . . . . 8
. . 6 . 3 . 9 . .
. . . 6 . . 5 . .
. . 4 . 9 . . . 3
. 9 . . . 7 . . .
. 2 . . . . . 1 9
8 . . 7 5 . . 3 4
. . 9 4 . 1 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
148975326973246158256138947387614592614592873592387461425863719861759234739421685 #1 Easy (320)
Naked Single: r8c8=3
Naked Single: r8c3=1
Naked Single: r8c7=2
Naked Single: r8c2=6
Full House: r8c6=9
Hidden Single: r4c8=9
Hidden Single: r1c5=7
Naked Single: r1c9=6
Hidden Single: r1c4=9
Hidden Single: r2c1=9
Hidden Single: r7c1=4
Hidden Single: r9c5=2
Hidden Single: r7c3=5
Naked Single: r9c2=3
Full House: r9c1=7
Naked Single: r9c9=5
Full House: r9c8=8
Full House: r7c7=7
Hidden Single: r2c8=5
Hidden Single: r4c3=7
Hidden Single: r5c8=7
Naked Single: r3c8=4
Full House: r6c8=6
Naked Single: r1c7=3
Naked Single: r1c3=8
Full House: r1c2=4
Naked Single: r2c7=1
Full House: r3c9=7
Naked Single: r3c2=5
Naked Single: r2c4=2
Naked Single: r5c7=8
Full House: r6c7=4
Naked Single: r3c1=2
Full House: r2c3=3
Full House: r6c3=2
Naked Single: r3c6=8
Full House: r3c4=1
Naked Single: r5c2=1
Full House: r4c2=8
Naked Single: r5c6=2
Naked Single: r4c1=3
Naked Single: r6c9=1
Full House: r4c9=2
Naked Single: r5c4=5
Full House: r5c1=6
Full House: r6c1=5
Naked Single: r4c6=4
Full House: r4c5=1
Naked Single: r6c5=8
Full House: r6c4=3
Full House: r7c4=8
Naked Single: r2c6=6
Full House: r2c5=4
Full House: r7c5=6
Full House: r7c6=3
|
normal_sudoku_2302
|
.1..3.54...65....1..41..23...2.5...48...267...7........6.8.9........5.9...3.1.4.5
|
718632549326594871594178236632751984859426713471983652165849327247365198983217465
|
Basic 9x9 Sudoku 2302
|
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 4 .
. . 6 5 . . . . 1
. . 4 1 . . 2 3 .
. . 2 . 5 . . . 4
8 . . . 2 6 7 . .
. 7 . . . . . . .
. 6 . 8 . 9 . . .
. . . . . 5 . 9 .
. . 3 . 1 . 4 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
718632549326594871594178236632751984859426713471983652165849327247365198983217465 #1 Medium (506)
Hidden Single: r2c4=5
Hidden Single: r8c4=3
Locked Pair: 4,9 in r56c4 => r14c4,r6c5<>9, r6c56<>4
Naked Single: r4c4=7
Naked Single: r6c5=8
Hidden Single: r2c6=4
Locked Candidates Type 1 (Pointing): 2 in b2 => r1c1<>2
Locked Candidates Type 1 (Pointing): 6 in b3 => r68c9<>6
Locked Candidates Type 1 (Pointing): 2 in b8 => r9c128<>2
Naked Pair: 7,9 in r19c1 => r2378c1<>7, r2346c1<>9
Naked Single: r3c1=5
Hidden Single: r5c2=5
Naked Single: r5c8=1
Naked Single: r5c3=9
Naked Single: r4c2=3
Naked Single: r5c4=4
Full House: r5c9=3
Naked Single: r6c3=1
Naked Single: r4c6=1
Naked Single: r6c4=9
Full House: r6c6=3
Naked Single: r4c1=6
Full House: r6c1=4
Naked Single: r6c7=6
Naked Single: r6c9=2
Full House: r6c8=5
Naked Single: r4c8=8
Full House: r4c7=9
Naked Single: r7c9=7
Naked Single: r2c8=7
Naked Single: r2c7=8
Naked Single: r7c3=5
Naked Single: r7c5=4
Naked Single: r7c8=2
Full House: r9c8=6
Naked Single: r8c9=8
Naked Single: r2c5=9
Naked Single: r8c7=1
Full House: r7c7=3
Full House: r7c1=1
Naked Single: r9c4=2
Full House: r1c4=6
Naked Single: r8c3=7
Full House: r1c3=8
Naked Single: r2c2=2
Full House: r2c1=3
Naked Single: r8c1=2
Naked Single: r9c6=7
Full House: r8c5=6
Full House: r3c5=7
Full House: r8c2=4
Naked Single: r1c9=9
Full House: r3c9=6
Naked Single: r9c1=9
Full House: r1c1=7
Full House: r3c2=9
Full House: r1c6=2
Full House: r3c6=8
Full House: r9c2=8
|
normal_sudoku_1720
|
.7...41..1.37..9.4....3.27..4..1...7.1.87...38.....51...4....9..3..4...27.6......
|
572984136163725984498136275349512867615879423827463519284357691931648752756291348
|
Basic 9x9 Sudoku 1720
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . . 4 1 . .
1 . 3 7 . . 9 . 4
. . . . 3 . 2 7 .
. 4 . . 1 . . . 7
. 1 . 8 7 . . . 3
8 . . . . . 5 1 .
. . 4 . . . . 9 .
. 3 . . 4 . . . 2
7 . 6 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
572984136163725984498136275349512867615879423827463519284357691931648752756291348 #1 Extreme (3426)
Hidden Single: r3c8=7
Hidden Single: r1c8=3
Hidden Single: r6c3=7
Hidden Single: r3c1=4
Hidden Single: r6c9=9
Hidden Single: r4c1=3
Hidden Single: r6c4=4
Hidden Single: r8c3=1
Hidden Single: r6c6=3
Locked Candidates Type 1 (Pointing): 8 in b7 => r23c2<>8
Skyscraper: 9 in r1c5,r3c2 (connected by r9c25) => r1c13,r3c46<>9
2-String Kite: 6 in r1c1,r6c5 (connected by r5c1,r6c2) => r1c5<>6
Empty Rectangle: 2 in b1 (r6c25) => r1c5<>2
Empty Rectangle: 2 in b7 (r6c25) => r7c5<>2
Finned Swordfish: 2 r269 c256 fr9c4 => r7c6<>2
Finned Swordfish: 8 r248 c678 fr2c5 => r3c6<>8
Discontinuous Nice Loop: 6 r3c2 -6- r6c2 =6= r5c1 =9= r8c1 -9- r9c2 =9= r3c2 => r3c2<>6
Sashimi Swordfish: 6 c259 r267 fr1c9 fr3c9 => r2c8<>6
Locked Candidates Type 1 (Pointing): 6 in b3 => r7c9<>6
Discontinuous Nice Loop: 5 r3c2 =9= r3c3 =8= r3c9 =6= r1c9 -6- r1c1 =6= r5c1 =9= r8c1 -9- r9c2 =9= r3c2 => r3c2<>5
Naked Single: r3c2=9
Hidden Single: r8c1=9
Grouped Discontinuous Nice Loop: 2 r1c1 -2- r1c3 =2= r45c3 -2- r6c2 -6- r2c2 =6= r1c1 => r1c1<>2
Discontinuous Nice Loop: 8 r1c3 -8- r3c3 =8= r3c9 =6= r1c9 -6- r1c1 =6= r2c2 =2= r1c3 => r1c3<>8
Hidden Single: r3c3=8
Grouped AIC: 5 5- r3c9 =5= r3c46 -5- r12c5 =5= r79c5 -5- r8c46 =5= r8c8 -5 => r2c8,r79c9<>5
Naked Single: r2c8=8
Hidden Single: r1c5=8
Hidden Single: r4c7=8
Hidden Single: r1c4=9
Hidden Single: r9c5=9
Hidden Single: r8c6=8
Hidden Single: r1c3=2
Hidden Single: r8c7=7
Hidden Single: r7c6=7
Locked Candidates Type 2 (Claiming): 5 in c3 => r5c1<>5
Naked Pair: 5,6 in r7c5,r8c4 => r79c4,r9c6<>5, r7c4<>6
Naked Triple: 2,4,6 in r5c178 => r5c6<>2, r5c6<>6
Skyscraper: 5 in r1c1,r2c5 (connected by r7c15) => r2c2<>5
Naked Single: r2c2=6
Full House: r1c1=5
Full House: r1c9=6
Full House: r3c9=5
Naked Single: r6c2=2
Full House: r6c5=6
Naked Single: r7c1=2
Full House: r5c1=6
Naked Single: r7c5=5
Full House: r2c5=2
Full House: r2c6=5
Naked Single: r5c7=4
Naked Single: r7c2=8
Full House: r9c2=5
Naked Single: r8c4=6
Full House: r8c8=5
Naked Single: r5c6=9
Naked Single: r5c8=2
Full House: r5c3=5
Full House: r4c8=6
Full House: r9c8=4
Full House: r4c3=9
Naked Single: r9c7=3
Full House: r7c7=6
Naked Single: r7c9=1
Full House: r7c4=3
Full House: r9c9=8
Naked Single: r3c4=1
Full House: r3c6=6
Naked Single: r4c6=2
Full House: r4c4=5
Full House: r9c4=2
Full House: r9c6=1
|
normal_sudoku_516
|
....3.....5.2..1.8..48...6.7....1.242....938..8...3........8.1.54.....97....9..43
|
178936452659274138324815769793581624216749385485623971937458216541362897862197543
|
Basic 9x9 Sudoku 516
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 3 . . . .
. 5 . 2 . . 1 . 8
. . 4 8 . . . 6 .
7 . . . . 1 . 2 4
2 . . . . 9 3 8 .
. 8 . . . 3 . . .
. . . . . 8 . 1 .
5 4 . . . . . 9 7
. . . . 9 . . 4 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
178936452659274138324815769793581624216749385485623971937458216541362897862197543 #1 Easy (410)
Naked Single: r8c8=9
Hidden Single: r4c5=8
Hidden Single: r6c5=2
Hidden Single: r6c1=4
Hidden Single: r1c4=9
Hidden Single: r1c7=4
Hidden Single: r2c8=3
Hidden Single: r3c5=1
Naked Single: r8c5=6
Naked Single: r8c6=2
Naked Single: r8c7=8
Hidden Single: r2c6=4
Naked Single: r2c5=7
Naked Single: r3c6=5
Full House: r1c6=6
Full House: r9c6=7
Hidden Single: r5c4=7
Hidden Single: r5c5=4
Full House: r7c5=5
Naked Single: r9c4=1
Naked Single: r8c4=3
Full House: r7c4=4
Full House: r8c3=1
Hidden Single: r9c7=5
Hidden Single: r1c1=1
Hidden Single: r6c9=1
Hidden Single: r5c2=1
Hidden Single: r1c3=8
Hidden Single: r9c1=8
Hidden Single: r3c9=9
Naked Single: r3c1=3
Hidden Single: r7c3=7
Hidden Single: r9c3=2
Full House: r9c2=6
Naked Single: r7c1=9
Full House: r2c1=6
Full House: r7c2=3
Full House: r2c3=9
Naked Single: r4c2=9
Naked Single: r4c7=6
Naked Single: r4c4=5
Full House: r4c3=3
Full House: r6c4=6
Naked Single: r5c9=5
Full House: r5c3=6
Full House: r6c3=5
Naked Single: r7c7=2
Full House: r7c9=6
Full House: r1c9=2
Naked Single: r6c8=7
Full House: r1c8=5
Full House: r3c7=7
Full House: r1c2=7
Full House: r6c7=9
Full House: r3c2=2
|
normal_sudoku_465
|
397.261.....9.3..6..4..8.5....2..6...816.5..9..9.....1.........9...14....48...5..
|
397526148815943726624178953473291685281635479569487231136752894952814367748369512
|
Basic 9x9 Sudoku 465
|
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 7 . 2 6 1 . .
. . . 9 . 3 . . 6
. . 4 . . 8 . 5 .
. . . 2 . . 6 . .
. 8 1 6 . 5 . . 9
. . 9 . . . . . 1
. . . . . . . . .
9 . . . 1 4 . . .
. 4 8 . . . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
397526148815943726624178953473291685281635479569487231136752894952814367748369512 #1 Easy (260)
Naked Single: r1c6=6
Naked Single: r6c6=7
Naked Single: r3c5=7
Naked Single: r3c4=1
Hidden Single: r1c4=5
Full House: r2c5=4
Naked Single: r5c5=3
Naked Single: r6c5=8
Naked Single: r4c5=9
Naked Single: r6c4=4
Full House: r4c6=1
Naked Single: r9c5=6
Full House: r7c5=5
Hidden Single: r3c7=9
Hidden Single: r2c1=8
Hidden Single: r4c9=5
Naked Single: r4c3=3
Naked Single: r4c2=7
Naked Single: r4c1=4
Full House: r4c8=8
Naked Single: r5c1=2
Naked Single: r1c8=4
Full House: r1c9=8
Naked Single: r3c1=6
Naked Single: r5c8=7
Full House: r5c7=4
Naked Single: r3c2=2
Full House: r3c9=3
Naked Single: r6c1=5
Full House: r6c2=6
Naked Single: r2c8=2
Full House: r2c7=7
Naked Single: r2c3=5
Full House: r2c2=1
Naked Single: r6c8=3
Full House: r6c7=2
Naked Single: r7c2=3
Full House: r8c2=5
Naked Single: r8c8=6
Naked Single: r7c7=8
Full House: r8c7=3
Naked Single: r8c3=2
Full House: r7c3=6
Naked Single: r7c4=7
Naked Single: r8c9=7
Full House: r8c4=8
Full House: r9c4=3
Naked Single: r7c1=1
Full House: r9c1=7
Naked Single: r9c9=2
Full House: r7c9=4
Naked Single: r7c8=9
Full House: r7c6=2
Full House: r9c6=9
Full House: r9c8=1
|
normal_sudoku_2512
|
........3..89...2...9372..6..6.1....51...9..2...2...816...9......7..13..8..6.7.45
|
725168493368954127149372856286513974514789632973246581632495718457821369891637245
|
Basic 9x9 Sudoku 2512
|
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 9 . . . 2 .
. . 9 3 7 2 . . 6
. . 6 . 1 . . . .
5 1 . . . 9 . . 2
. . . 2 . . . 8 1
6 . . . 9 . . . .
. . 7 . . 1 3 . .
8 . . 6 . 7 . 4 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
725168493368954127149372856286513974514789632973246581632495718457821369891637245 #1 Medium (346)
Naked Single: r9c4=6
Hidden Single: r3c7=8
Hidden Single: r1c4=1
Hidden Single: r4c2=8
Hidden Single: r8c8=6
Hidden Single: r4c1=2
Locked Pair: 3,4 in r56c3 => r17c3,r6c12<>4, r6c12,r79c3<>3
Hidden Single: r2c1=3
Hidden Single: r2c7=1
Naked Single: r3c8=5
Naked Single: r3c2=4
Full House: r3c1=1
Naked Single: r1c1=7
Naked Single: r1c8=9
Naked Single: r6c1=9
Full House: r8c1=4
Naked Single: r1c7=4
Full House: r2c9=7
Naked Single: r6c2=7
Naked Single: r7c9=8
Naked Single: r8c9=9
Full House: r4c9=4
Naked Single: r9c7=2
Naked Single: r7c7=7
Full House: r7c8=1
Naked Single: r9c3=1
Naked Single: r9c5=3
Full House: r9c2=9
Naked Single: r5c7=6
Naked Single: r6c7=5
Full House: r4c7=9
Hidden Single: r1c6=8
Hidden Single: r8c5=2
Naked Single: r8c2=5
Full House: r8c4=8
Naked Single: r2c2=6
Naked Single: r7c3=2
Full House: r7c2=3
Full House: r1c2=2
Full House: r1c3=5
Full House: r1c5=6
Naked Single: r6c5=4
Naked Single: r2c5=5
Full House: r5c5=8
Full House: r2c6=4
Naked Single: r5c4=7
Naked Single: r6c3=3
Full House: r5c3=4
Full House: r5c8=3
Full House: r6c6=6
Full House: r4c8=7
Naked Single: r7c6=5
Full House: r4c6=3
Full House: r4c4=5
Full House: r7c4=4
|
normal_sudoku_2212
|
.7.3..2...12.8.....5..7.9..6.....134..........31...6.91.3.27....4...67.....5.3.2.
|
879364251412985367356172948628759134794631582531248679163427895245896713987513426
|
Basic 9x9 Sudoku 2212
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . 3 . . 2 . .
. 1 2 . 8 . . . .
. 5 . . 7 . 9 . .
6 . . . . . 1 3 4
. . . . . . . . .
. 3 1 . . . 6 . 9
1 . 3 . 2 7 . . .
. 4 . . . 6 7 . .
. . . 5 . 3 . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
879364251412985367356172948628759134794631582531248679163427895245896713987513426 #1 Easy (410)
Hidden Single: r2c2=1
Hidden Single: r5c5=3
Hidden Single: r8c9=3
Hidden Single: r2c7=3
Hidden Single: r5c9=2
Hidden Single: r8c1=2
Hidden Single: r5c4=6
Hidden Single: r1c5=6
Hidden Single: r3c1=3
Hidden Single: r4c2=2
Hidden Single: r2c9=7
Hidden Single: r8c3=5
Hidden Single: r5c6=1
Hidden Single: r3c3=6
Hidden Single: r2c8=6
Hidden Single: r3c4=1
Naked Single: r3c9=8
Naked Single: r3c8=4
Full House: r3c6=2
Hidden Single: r2c6=5
Hidden Single: r6c4=2
Hidden Single: r4c5=5
Naked Single: r6c5=4
Naked Single: r6c6=8
Naked Single: r4c6=9
Full House: r1c6=4
Full House: r4c4=7
Full House: r2c4=9
Full House: r4c3=8
Full House: r2c1=4
Naked Single: r8c4=8
Full House: r7c4=4
Naked Single: r1c3=9
Full House: r1c1=8
Naked Single: r5c2=9
Naked Single: r9c3=7
Full House: r5c3=4
Naked Single: r9c1=9
Naked Single: r9c5=1
Full House: r8c5=9
Full House: r8c8=1
Naked Single: r9c9=6
Naked Single: r1c8=5
Full House: r1c9=1
Full House: r7c9=5
Naked Single: r9c2=8
Full House: r7c2=6
Full House: r9c7=4
Naked Single: r6c8=7
Full House: r6c1=5
Full House: r5c1=7
Naked Single: r7c7=8
Full House: r5c7=5
Full House: r5c8=8
Full House: r7c8=9
|
normal_sudoku_5237
|
.96...3.8.25.78...8..6....2...71.....5.8....9..893..4.....4....1.25....6.....718.
|
496152378325478961871693452964715823753824619218936547687341295142589736539267184
|
Basic 9x9 Sudoku 5237
|
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 6 . . . 3 . 8
. 2 5 . 7 8 . . .
8 . . 6 . . . . 2
. . . 7 1 . . . .
. 5 . 8 . . . . 9
. . 8 9 3 . . 4 .
. . . . 4 . . . .
1 . 2 5 . . . . 6
. . . . . 7 1 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
496152378325478961871693452964715823753824619218936547687341295142589736539267184 #1 Extreme (2116)
Hidden Single: r2c6=8
Hidden Single: r4c7=8
Hidden Single: r8c5=8
Hidden Single: r7c2=8
Locked Candidates Type 1 (Pointing): 1 in b1 => r3c68<>1
Locked Candidates Type 1 (Pointing): 9 in b2 => r3c78<>9
Locked Candidates Type 1 (Pointing): 4 in b5 => r13c6<>4
Locked Candidates Type 1 (Pointing): 5 in b5 => r13c6<>5
Locked Candidates Type 1 (Pointing): 2 in b9 => r7c46<>2
Naked Pair: 3,9 in r38c6 => r7c6<>3, r7c6<>9
Naked Triple: 1,3,4 in r2c149 => r2c7<>4, r2c8<>1
2-String Kite: 6 in r5c5,r7c1 (connected by r7c6,r9c5) => r5c1<>6
Empty Rectangle: 7 in b7 (r67c9) => r6c2<>7
2-String Kite: 7 in r1c8,r8c2 (connected by r1c1,r3c2) => r8c8<>7
Naked Pair: 3,9 in r8c68 => r8c2<>3, r8c7<>9
Empty Rectangle: 7 in b4 (r1c18) => r5c8<>7
Sue de Coq: r79c9 - {3457} (r4c9 - {35}, r8c7 - {47}) => r7c78<>7, r6c9<>5
Locked Candidates Type 2 (Claiming): 7 in c8 => r3c7<>7
Discontinuous Nice Loop: 3/4/6/9 r9c1 =5= r9c9 =4= r2c9 =1= r2c4 -1- r7c4 =1= r7c6 =6= r7c1 =5= r9c1 => r9c1<>3, r9c1<>4, r9c1<>6, r9c1<>9
Naked Single: r9c1=5
XY-Chain: 7 7- r6c9 -1- r2c9 -4- r9c9 -3- r8c8 -9- r8c6 -3- r3c6 -9- r3c5 -5- r3c7 -4- r8c7 -7 => r56c7,r7c9<>7
Hidden Single: r8c7=7
Naked Single: r8c2=4
Hidden Single: r6c9=7
Hidden Single: r3c2=7
Naked Single: r1c1=4
Naked Single: r3c8=5
Naked Single: r2c1=3
Full House: r3c3=1
Naked Single: r3c5=9
Naked Single: r3c7=4
Full House: r3c6=3
Naked Single: r2c9=1
Naked Single: r8c6=9
Full House: r8c8=3
Naked Single: r1c8=7
Naked Single: r2c4=4
Naked Single: r7c9=5
Naked Single: r9c9=4
Full House: r4c9=3
Naked Single: r4c2=6
Naked Single: r4c8=2
Naked Single: r6c1=2
Naked Single: r6c2=1
Full House: r9c2=3
Naked Single: r4c1=9
Naked Single: r5c7=6
Naked Single: r7c8=9
Full House: r7c7=2
Naked Single: r5c1=7
Full House: r7c1=6
Naked Single: r9c3=9
Full House: r7c3=7
Naked Single: r9c4=2
Full House: r9c5=6
Naked Single: r4c3=4
Full House: r4c6=5
Full House: r5c3=3
Naked Single: r2c7=9
Full House: r6c7=5
Full House: r5c8=1
Full House: r2c8=6
Full House: r6c6=6
Naked Single: r5c5=2
Full House: r1c5=5
Full House: r5c6=4
Naked Single: r7c6=1
Full House: r1c6=2
Full House: r1c4=1
Full House: r7c4=3
|
normal_sudoku_2810
|
.....38..8.....3.5....46..16.59.41.7.2......3.87...69...3..........3.419...461...
|
796153824814792365352846971635924187921678543487315692143289756268537419579461238
|
Basic 9x9 Sudoku 2810
|
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 . .
8 . . . . . 3 . 5
. . . . 4 6 . . 1
6 . 5 9 . 4 1 . 7
. 2 . . . . . . 3
. 8 7 . . . 6 9 .
. . 3 . . . . . .
. . . . 3 . 4 1 9
. . . 4 6 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
796153824814792365352846971635924187921678543487315692143289756268537419579461238 #1 Unfair (1066)
Naked Single: r4c3=5
Naked Single: r5c7=5
Naked Single: r4c2=3
Hidden Single: r3c4=8
Hidden Single: r6c4=3
Hidden Single: r9c8=3
Hidden Single: r3c7=9
Naked Single: r3c3=2
Naked Single: r3c8=7
Naked Single: r3c2=5
Full House: r3c1=3
Hidden Single: r5c4=6
Hidden Single: r7c8=5
Hidden Single: r9c1=5
Hidden Single: r7c9=6
Hidden Single: r9c9=8
Naked Single: r9c3=9
Naked Single: r9c2=7
Full House: r9c7=2
Full House: r7c7=7
Naked Single: r8c1=2
Naked Single: r8c2=6
Naked Single: r7c4=2
Naked Single: r8c3=8
Hidden Single: r5c1=9
Hidden Single: r1c1=7
Locked Candidates Type 1 (Pointing): 1 in b5 => r12c5<>1
Skyscraper: 2 in r1c9,r2c6 (connected by r6c69) => r1c5,r2c8<>2
2-String Kite: 4 in r1c9,r5c3 (connected by r5c8,r6c9) => r1c3<>4
Sue de Coq: r12c5 - {2579} (r47c5 - {289}, r12c4 - {157}) => r2c6<>7, r5c5<>8, r6c5<>2
XY-Wing: 2/9/5 in r1c5,r26c6 => r6c5<>5
Naked Single: r6c5=1
Naked Single: r5c5=7
Naked Single: r6c1=4
Full House: r5c3=1
Full House: r7c1=1
Full House: r7c2=4
Naked Single: r5c6=8
Full House: r5c8=4
Naked Single: r6c9=2
Full House: r1c9=4
Full House: r4c8=8
Full House: r4c5=2
Full House: r6c6=5
Naked Single: r1c3=6
Full House: r2c3=4
Naked Single: r7c6=9
Full House: r7c5=8
Naked Single: r2c8=6
Full House: r1c8=2
Naked Single: r2c5=9
Full House: r1c5=5
Naked Single: r8c6=7
Full House: r2c6=2
Full House: r8c4=5
Naked Single: r2c2=1
Full House: r1c2=9
Full House: r1c4=1
Full House: r2c4=7
|
normal_sudoku_2491
|
.1.642..3.............9.1....6..4..1.2.....3.14..8.25..71.......6.72.3..2..4.1..7
|
715642983392178645684395172856234791927516438143987256471863529568729314239451867
|
Basic 9x9 Sudoku 2491
|
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 . 6 4 2 . . 3
. . . . . . . . .
. . . . 9 . 1 . .
. . 6 . . 4 . . 1
. 2 . . . . . 3 .
1 4 . . 8 . 2 5 .
. 7 1 . . . . . .
. 6 . 7 2 . 3 . .
2 . . 4 . 1 . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
715642983392178645684395172856234791927516438143987256471863529568729314239451867 #1 Extreme (17562) bf
Hidden Single: r1c2=1
Hidden Single: r4c4=2
Hidden Single: r8c8=1
Empty Rectangle: 7 in b2 (r6c36) => r2c3<>7
Brute Force: r5c3=7
Hidden Single: r6c6=7
Hidden Single: r2c5=7
Hidden Single: r6c9=6
Hidden Single: r2c4=1
Hidden Single: r5c5=1
Hidden Single: r5c6=6
Locked Candidates Type 1 (Pointing): 9 in b5 => r7c4<>9
Naked Triple: 3,5,8 in r3c246 => r3c13<>3, r3c139<>5, r3c1389<>8
Naked Pair: 2,4 in r3c39 => r3c18<>4, r3c8<>2
Hidden Pair: 2,4 in r27c8 => r27c8<>6, r27c8<>8, r27c8<>9
Naked Pair: 2,4 in r2c8,r3c9 => r2c79<>4, r2c9<>2
Forcing Chain Verity => r1c1<>5
r2c1=3 r2c1<>6 r3c1=6 r3c1<>7 r1c1=7 r1c1<>5
r4c1=3 r4c5<>3 r4c5=5 r4c2<>5 r45c1=5 r1c1<>5
r7c1=3 r7c456<>3 r9c5=3 r4c5<>3 r4c5=5 r4c2<>5 r45c1=5 r1c1<>5
Forcing Chain Verity => r2c1<>5
r2c1=3 r2c1<>5
r4c1=3 r4c5<>3 r4c5=5 r4c2<>5 r45c1=5 r2c1<>5
r7c1=3 r7c456<>3 r9c5=3 r4c5<>3 r4c5=5 r4c2<>5 r45c1=5 r2c1<>5
Forcing Chain Verity => r4c7<>8
r2c1=3 r2c1<>6 r2c7=6 r3c8<>6 r3c8=7 r4c8<>7 r4c7=7 r4c7<>8
r4c1=3 r4c5<>3 r4c5=5 r5c4<>5 r5c1=5 r5c1<>8 r4c12=8 r4c7<>8
r7c1=3 r7c456<>3 r9c5=3 r4c5<>3 r4c5=5 r5c4<>5 r5c1=5 r5c1<>8 r4c12=8 r4c7<>8
Forcing Chain Verity => r7c5<>5
r2c1=3 r2c1<>6 r2c7=6 r7c7<>6 r7c5=6 r7c5<>5
r4c1=3 r4c5<>3 r4c5=5 r7c5<>5
r7c1=3 r7c456<>3 r9c5=3 r9c5<>6 r7c5=6 r7c5<>5
Forcing Chain Contradiction in c2 => r9c7<>5
r9c7=5 r1c7<>5 r1c3=5 r2c2<>5
r9c7=5 r1c7<>5 r1c3=5 r3c2<>5
r9c7=5 r9c5<>5 r4c5=5 r4c2<>5
r9c7=5 r9c2<>5
Forcing Net Verity => r1c1<>9
r2c3=3 (r2c3<>4) r2c3<>2 r2c8=2 r2c8<>4 r2c1=4 r2c1<>6 r2c7=6 r3c8<>6 r3c8=7 (r1c7<>7) r1c8<>7 r1c1=7 r1c1<>9
r6c3=3 (r4c1<>3) (r9c3<>3) (r4c1<>3) r4c2<>3 r4c5=3 r9c5<>3 r9c2=3 r7c1<>3 r2c1=3 r2c1<>6 r2c7=6 r3c8<>6 r3c8=7 (r1c7<>7) r1c8<>7 r1c1=7 r1c1<>9
r9c3=3 (r9c3<>5) r6c3<>3 (r6c3=9 r4c2<>9) r6c4=3 r4c5<>3 r4c5=5 r9c5<>5 r9c2=5 r9c2<>9 r2c2=9 r1c1<>9
Forcing Chain Verity => r2c7<>9
r2c1=3 r2c1<>6 r2c7=6 r2c7<>9
r4c1=3 r6c3<>3 r6c3=9 r1c3<>9 r1c78=9 r2c7<>9
r7c1=3 r7c456<>3 r9c5=3 r4c5<>3 r6c4=3 r6c4<>9 r6c3=9 r1c3<>9 r1c78=9 r2c7<>9
Forcing Chain Verity => r9c8<>9
r1c8=8 r1c1<>8 r1c1=7 r3c1<>7 r3c1=6 r3c8<>6 r9c8=6 r9c8<>9
r4c8=8 r4c2<>8 r45c1=8 r1c1<>8 r1c1=7 r3c1<>7 r3c1=6 r3c8<>6 r9c8=6 r9c8<>9
r9c8=8 r9c8<>9
Forcing Net Verity => r1c1=7
r9c5=3 (r7c6<>3 r7c1=3 r4c1<>3) r4c5<>3 (r4c5=5 r4c1<>5) r6c4=3 r6c3<>3 r6c3=9 r4c1<>9 r4c1=8 r1c1<>8 r1c1=7
r9c5=5 (r9c5<>3) r4c5<>5 r4c5=3 (r4c1<>3) r6c4<>3 r6c3=3 r9c3<>3 r9c2=3 r7c1<>3 r2c1=3 r2c1<>6 r2c7=6 r3c8<>6 r3c8=7 (r1c7<>7) r1c8<>7 r1c1=7
r9c5=6 (r9c8<>6 r3c8=6 r3c1<>6 r3c1=7 r1c1<>7 r1c1=8 r1c7<>8 r1c7=5 r1c3<>5) (r9c8<>6 r9c8=8 r9c7<>8 r9c7=9 r7c9<>9) (r9c8<>6 r9c8=8 r9c7<>8 r9c7=9 r8c9<>9) r9c5<>5 r4c5=5 r5c4<>5 r5c4=9 r5c9<>9 r2c9=9 (r2c2<>9) r1c8<>9 (r1c3=9 r6c3<>9 r6c3=3 r9c3<>3) r4c8=9 r4c2<>9 r9c2=9 (r9c2<>5) r9c2<>3 r9c5=3 r9c5<>5 r9c3=5 r9c5<>5 r4c5=5 r4c5<>3 r6c4=3 r6c3<>3 r6c3=9 r1c3<>9 r1c3=8 r1c1<>8 r1c1=7
Naked Single: r3c1=6
Naked Single: r3c8=7
Hidden Single: r4c7=7
Hidden Single: r2c7=6
Hidden Single: r9c8=6
Hidden Single: r7c5=6
2-String Kite: 3 in r6c3,r9c5 (connected by r4c5,r6c4) => r9c3<>3
Turbot Fish: 3 r4c5 =3= r9c5 -3- r9c2 =3= r7c1 => r4c1<>3
X-Wing: 3 r49 c25 => r23c2<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r2c6<>3
Naked Triple: 5,8,9 in r1c3,r23c2 => r2c13<>8, r2c13<>9, r2c3<>5
2-String Kite: 9 in r2c2,r4c8 (connected by r1c8,r2c9) => r4c2<>9
Empty Rectangle: 8 in b1 (r14c8) => r4c2<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r78c1<>8
Naked Pair: 3,5 in r4c25 => r4c1<>5
Sashimi X-Wing: 5 c37 r17 fr8c3 fr9c3 => r7c1<>5
XY-Chain: 8 8- r1c8 -9- r4c8 -8- r4c1 -9- r6c3 -3- r4c2 -5- r3c2 -8 => r1c3<>8
Locked Candidates Type 1 (Pointing): 8 in b1 => r9c2<>8
Locked Candidates Type 2 (Claiming): 8 in r1 => r2c9<>8
W-Wing: 9/8 in r4c8,r9c7 connected by 8 in r1c78 => r5c7<>9
XY-Wing: 3/9/5 in r16c3,r4c2 => r23c2<>5
Naked Single: r3c2=8
Naked Single: r2c2=9
Naked Single: r1c3=5
Naked Single: r2c9=5
Naked Single: r2c6=8
Hidden Single: r7c4=8
Hidden Single: r7c7=5
Hidden Single: r5c7=4
Remote Pair: 9/8 r4c1 -8- r4c8 -9- r1c8 -8- r1c7 -9- r9c7 -8- r9c3 => r6c3,r78c1<>9
Naked Single: r6c3=3
Full House: r6c4=9
Naked Single: r4c2=5
Full House: r9c2=3
Naked Single: r5c4=5
Full House: r4c5=3
Full House: r9c5=5
Full House: r3c4=3
Full House: r3c6=5
Naked Single: r7c1=4
Naked Single: r8c6=9
Full House: r7c6=3
Naked Single: r2c1=3
Naked Single: r7c8=2
Full House: r7c9=9
Naked Single: r8c1=5
Naked Single: r8c3=8
Full House: r8c9=4
Full House: r9c7=8
Full House: r9c3=9
Full House: r1c7=9
Full House: r1c8=8
Naked Single: r2c8=4
Full House: r3c9=2
Full House: r5c9=8
Full House: r4c8=9
Full House: r2c3=2
Full House: r3c3=4
Full House: r5c1=9
Full House: r4c1=8
|
normal_sudoku_3842
|
..81..4..2...5...961..4....12.73..9..7.8.6..3..5..47....1..25...6.....2..3...16.7
|
958173462243658179617249385126735894479816253385924716791462538564387921832591647
|
Basic 9x9 Sudoku 3842
|
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 . . 4 . .
2 . . . 5 . . . 9
6 1 . . 4 . . . .
1 2 . 7 3 . . 9 .
. 7 . 8 . 6 . . 3
. . 5 . . 4 7 . .
. . 1 . . 2 5 . .
. 6 . . . . . 2 .
. 3 . . . 1 6 . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
958173462243658179617249385126735894479816253385924716791462538564387921832591647 #1 Easy (278)
Naked Single: r4c5=3
Naked Single: r2c2=4
Naked Single: r4c7=8
Naked Single: r4c6=5
Hidden Single: r5c8=5
Hidden Single: r4c3=6
Full House: r4c9=4
Naked Single: r7c9=8
Naked Single: r7c2=9
Naked Single: r8c9=1
Naked Single: r9c8=4
Naked Single: r1c2=5
Full House: r6c2=8
Naked Single: r7c8=3
Full House: r8c7=9
Naked Single: r9c3=2
Hidden Single: r6c1=3
Hidden Single: r3c9=5
Hidden Single: r1c6=3
Naked Single: r2c4=6
Naked Single: r7c4=4
Naked Single: r7c1=7
Full House: r7c5=6
Naked Single: r1c1=9
Naked Single: r8c3=4
Naked Single: r5c1=4
Full House: r5c3=9
Hidden Single: r8c4=3
Hidden Single: r3c6=9
Naked Single: r3c4=2
Naked Single: r1c5=7
Full House: r2c6=8
Full House: r8c6=7
Naked Single: r3c7=3
Naked Single: r6c4=9
Full House: r9c4=5
Naked Single: r1c8=6
Full House: r1c9=2
Full House: r6c9=6
Naked Single: r8c5=8
Full House: r8c1=5
Full House: r9c1=8
Full House: r9c5=9
Naked Single: r2c7=1
Full House: r5c7=2
Full House: r6c8=1
Full House: r5c5=1
Full House: r6c5=2
Naked Single: r3c3=7
Full House: r2c3=3
Full House: r2c8=7
Full House: r3c8=8
|
normal_sudoku_3381
|
7.....98...4.7...2.8........5...682...21...3.4...2...7.....935...56..1.4.41.5..98
|
726534981314978562589261743157346829862197435493825617278419356935682174641753298
|
Basic 9x9 Sudoku 3381
|
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 8 .
. . 4 . 7 . . . 2
. 8 . . . . . . .
. 5 . . . 6 8 2 .
. . 2 1 . . . 3 .
4 . . . 2 . . . 7
. . . . . 9 3 5 .
. . 5 6 . . 1 . 4
. 4 1 . 5 . . 9 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
726534981314978562589261743157346829862197435493825617278419356935682174641753298 #1 Easy (332)
Naked Single: r8c9=4
Naked Single: r7c9=6
Naked Single: r8c8=7
Full House: r9c7=2
Hidden Single: r7c5=1
Hidden Single: r5c7=4
Hidden Single: r3c8=4
Hidden Single: r9c1=6
Hidden Single: r3c7=7
Hidden Single: r7c4=4
Hidden Single: r1c6=4
Hidden Single: r5c2=6
Hidden Single: r4c5=4
Hidden Single: r8c6=2
Hidden Single: r5c6=7
Naked Single: r9c6=3
Full House: r9c4=7
Full House: r8c5=8
Naked Single: r5c5=9
Naked Single: r4c4=3
Naked Single: r5c1=8
Full House: r5c9=5
Naked Single: r7c1=2
Naked Single: r6c7=6
Full House: r2c7=5
Naked Single: r7c2=7
Full House: r7c3=8
Naked Single: r6c8=1
Full House: r2c8=6
Full House: r4c9=9
Naked Single: r4c1=1
Full House: r4c3=7
Hidden Single: r1c4=5
Naked Single: r3c6=1
Naked Single: r6c4=8
Full House: r6c6=5
Full House: r2c6=8
Naked Single: r3c9=3
Full House: r1c9=1
Naked Single: r2c4=9
Full House: r3c4=2
Naked Single: r3c5=6
Full House: r1c5=3
Naked Single: r2c1=3
Full House: r2c2=1
Naked Single: r3c3=9
Full House: r3c1=5
Full House: r8c1=9
Full House: r8c2=3
Naked Single: r1c2=2
Full House: r1c3=6
Full House: r6c3=3
Full House: r6c2=9
|
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