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_917
|
...6....8.1.....9.3....5.16.47.......2...17..5..24..31.7.3.916....1....9....2...7
|
459613278716482593382795416147938625923561784568247931874359162235176849691824357
|
Basic 9x9 Sudoku 917
|
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
. 1 . . . . . 9 .
3 . . . . 5 . 1 6
. 4 7 . . . . . .
. 2 . . . 1 7 . .
5 . . 2 4 . . 3 1
. 7 . 3 . 9 1 6 .
. . . 1 . . . . 9
. . . . 2 . . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
459613278716482593382795416147938625923561784568247931874359162235176849691824357 #1 Easy (340)
Naked Single: r6c9=1
Hidden Single: r1c5=1
Hidden Single: r6c6=7
Hidden Single: r5c3=3
Hidden Single: r1c8=7
Hidden Single: r2c9=3
Hidden Single: r4c1=1
Hidden Single: r9c3=1
Hidden Single: r8c5=7
Naked Single: r2c5=8
Naked Single: r3c5=9
Naked Single: r7c5=5
Naked Single: r3c2=8
Naked Single: r5c5=6
Full House: r4c5=3
Naked Single: r4c6=8
Hidden Single: r2c1=7
Naked Single: r2c4=4
Naked Single: r2c6=2
Naked Single: r3c4=7
Full House: r1c6=3
Naked Single: r9c4=8
Naked Single: r2c7=5
Full House: r2c3=6
Hidden Single: r4c7=6
Hidden Single: r6c2=6
Hidden Single: r4c4=9
Full House: r5c4=5
Naked Single: r5c9=4
Naked Single: r5c8=8
Full House: r5c1=9
Full House: r6c3=8
Full House: r6c7=9
Naked Single: r7c9=2
Full House: r4c9=5
Full House: r4c8=2
Naked Single: r7c3=4
Full House: r7c1=8
Naked Single: r3c3=2
Full House: r3c7=4
Full House: r1c7=2
Naked Single: r9c1=6
Naked Single: r1c1=4
Full House: r8c1=2
Naked Single: r8c3=5
Full House: r1c3=9
Full House: r1c2=5
Naked Single: r9c7=3
Full House: r8c7=8
Naked Single: r9c6=4
Full House: r8c6=6
Naked Single: r8c2=3
Full House: r8c8=4
Full House: r9c2=9
Full House: r9c8=5
|
normal_sudoku_2417
|
.46..5.2.5.8....672.........8.2...5.....31.487....8...8.24...7.45....2...6.8..4..
|
346975821518324967279186534681247359925631748734598612892463175453719286167852493
|
Basic 9x9 Sudoku 2417
|
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 6 . . 5 . 2 .
5 . 8 . . . . 6 7
2 . . . . . . . .
. 8 . 2 . . . 5 .
. . . . 3 1 . 4 8
7 . . . . 8 . . .
8 . 2 4 . . . 7 .
4 5 . . . . 2 . .
. 6 . 8 . . 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
346975821518324967279186534681247359925631748734598612892463175453719286167852493 #1 Extreme (24014) bf
Hidden Single: r4c2=8
Hidden Single: r5c2=2
Hidden Single: r6c9=2
Hidden Single: r3c2=7
Hidden Single: r8c8=8
Hidden Single: r3c9=4
Hidden Single: r3c7=5
Hidden Single: r3c5=8
Hidden Single: r1c7=8
Locked Candidates Type 1 (Pointing): 5 in b8 => r6c5<>5
Naked Triple: 1,3,9 in r2c247 => r2c5<>1, r2c56<>9, r2c6<>3
Hidden Rectangle: 5/9 in r5c34,r6c34 => r6c4<>9
Brute Force: r5c7=7
Brute Force: r6c2=3
Skyscraper: 3 in r1c1,r3c8 (connected by r9c18) => r1c9,r3c3<>3
Hidden Single: r1c1=3
Naked Pair: 1,9 in r7c2,r9c1 => r89c3<>1, r89c3<>9
Finned Swordfish: 3 r247 c479 fr7c6 => r8c4<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r3c6<>3
Forcing Chain Verity => r2c4<>1
r9c1=1 r7c2<>1 r2c2=1 r2c4<>1
r9c5=1 r8c45<>1 r8c9=1 r1c9<>1 r1c45=1 r2c4<>1
r9c8=1 r9c8<>3 r3c8=3 r3c4<>3 r2c4=3 r2c4<>1
r9c9=1 r1c9<>1 r1c45=1 r2c4<>1
W-Wing: 9/1 in r1c9,r3c3 connected by 1 in r2c27 => r3c8<>9
Turbot Fish: 9 r1c9 =9= r2c7 -9- r2c2 =9= r7c2 => r7c9<>9
Sashimi X-Wing: 9 c18 r69 fr4c1 fr5c1 => r6c3<>9
Grouped Discontinuous Nice Loop: 9 r7c5 -9- r7c2 =9= r2c2 -9- r2c7 =9= r1c9 -9- r8c9 =9= r8c456 -9- r7c5 => r7c5<>9
Grouped Discontinuous Nice Loop: 9 r7c6 -9- r7c2 =9= r2c2 -9- r2c7 =9= r1c9 -9- r8c9 =9= r8c456 -9- r7c6 => r7c6<>9
Discontinuous Nice Loop: 3 r7c7 -3- r7c6 -6- r3c6 -9- r3c3 =9= r2c2 -9- r7c2 =9= r7c7 => r7c7<>3
Discontinuous Nice Loop: 9 r4c7 -9- r6c8 -1- r3c8 -3- r2c7 =3= r4c7 => r4c7<>9
Almost Locked Set XZ-Rule: A=r9c18 {139}, B=r1c9,r3c8 {139}, X=3, Z=9 => r9c9<>9
Forcing Chain Contradiction in r6 => r2c2=1
r2c2<>1 r3c3=1 r6c3<>1
r2c2<>1 r2c7=1 r6c7<>1
r2c2<>1 r2c2=9 r7c2<>9 r7c7=9 r9c8<>9 r6c8=9 r6c8<>1
Full House: r3c3=9
Full House: r7c2=9
Naked Single: r3c6=6
Naked Single: r5c3=5
Naked Single: r9c1=1
Naked Single: r7c6=3
Hidden Single: r6c4=5
W-Wing: 1/9 in r1c9,r6c8 connected by 9 in r26c7 => r3c8,r4c9<>1
Naked Single: r3c8=3
Full House: r3c4=1
Naked Single: r2c7=9
Full House: r1c9=1
Naked Single: r9c8=9
Full House: r6c8=1
Naked Single: r2c4=3
Naked Single: r6c3=4
Naked Single: r6c7=6
Full House: r6c5=9
Naked Single: r4c3=1
Naked Single: r4c7=3
Full House: r7c7=1
Full House: r4c9=9
Naked Single: r1c5=7
Full House: r1c4=9
Naked Single: r5c4=6
Full House: r5c1=9
Full House: r4c1=6
Full House: r8c4=7
Naked Single: r4c5=4
Full House: r4c6=7
Naked Single: r8c3=3
Full House: r9c3=7
Naked Single: r8c6=9
Naked Single: r9c6=2
Full House: r2c6=4
Full House: r2c5=2
Naked Single: r8c9=6
Full House: r8c5=1
Naked Single: r9c5=5
Full House: r7c5=6
Full House: r7c9=5
Full House: r9c9=3
|
normal_sudoku_966
|
.9.45178......9..3..5.3..14......3..64.5...9..57.......8...5.6.....6.12...69..5.7
|
293451786174689253865237914928146375641573892357892641782315469539764128416928537
|
Basic 9x9 Sudoku 966
|
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 . 4 5 1 7 8 .
. . . . . 9 . . 3
. . 5 . 3 . . 1 4
. . . . . . 3 . .
6 4 . 5 . . . 9 .
. 5 7 . . . . . .
. 8 . . . 5 . 6 .
. . . . 6 . 1 2 .
. . 6 9 . . 5 . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
293451786174689253865237914928146375641573892357892641782315469539764128416928537 #1 Hard (612)
Naked Single: r1c8=8
Naked Single: r7c9=9
Naked Single: r2c8=5
Naked Single: r6c8=4
Naked Single: r7c7=4
Naked Single: r8c9=8
Full House: r9c8=3
Full House: r4c8=7
Hidden Single: r3c7=9
Hidden Single: r1c9=6
Full House: r2c7=2
Naked Single: r5c7=8
Full House: r6c7=6
Hidden Single: r8c1=5
Hidden Single: r4c9=5
Hidden Single: r8c2=3
Naked Single: r8c4=7
Naked Single: r8c6=4
Full House: r8c3=9
Hidden Single: r7c4=3
Hidden Single: r7c1=7
Hidden Single: r4c5=4
Hidden Single: r2c3=4
Hidden Single: r9c1=4
Hidden Single: r4c1=9
Hidden Single: r6c5=9
Hidden Single: r4c3=8
Locked Candidates Type 1 (Pointing): 2 in b2 => r3c12<>2
Naked Single: r3c1=8
Naked Single: r2c1=1
Locked Candidates Type 1 (Pointing): 1 in b8 => r5c5<>1
W-Wing: 2/1 in r4c2,r6c9 connected by 1 in r5c39 => r6c1<>2
Naked Single: r6c1=3
Full House: r1c1=2
Full House: r1c3=3
Hidden Single: r5c6=3
Hidden Single: r5c5=7
Naked Single: r2c5=8
Naked Single: r2c4=6
Full House: r2c2=7
Full House: r3c2=6
Naked Single: r3c4=2
Full House: r3c6=7
Naked Single: r4c4=1
Full House: r6c4=8
Naked Single: r4c2=2
Full House: r4c6=6
Full House: r6c6=2
Full House: r5c3=1
Full House: r9c2=1
Full House: r6c9=1
Full House: r9c6=8
Full House: r5c9=2
Full House: r7c3=2
Full House: r9c5=2
Full House: r7c5=1
|
normal_sudoku_1123
|
75..6..232.3...5.....3....1........7...6.....97.....45.9..4.3..1.7..9........821.
|
758961423213784596469352781321495867845617932976823145592146378187239654634578219
|
Basic 9x9 Sudoku 1123
|
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 5 . . 6 . . 2 3
2 . 3 . . . 5 . .
. . . 3 . . . . 1
. . . . . . . . 7
. . . 6 . . . . .
9 7 . . . . . 4 5
. 9 . . 4 . 3 . .
1 . 7 . . 9 . . .
. . . . . 8 2 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
758961423213784596469352781321495867845617932976823145592146378187239654634578219 #1 Hard (838)
Hidden Single: r1c9=3
Hidden Single: r7c6=6
Naked Single: r7c9=8
Naked Single: r7c1=5
Naked Single: r7c3=2
Naked Single: r7c8=7
Full House: r7c4=1
Hidden Single: r5c9=2
Hidden Single: r3c7=7
Hidden Single: r9c9=9
Hidden Single: r8c2=8
Hidden Single: r8c8=5
Naked Single: r8c4=2
Naked Single: r6c4=8
Naked Single: r8c5=3
Hidden Single: r4c2=2
Hidden Single: r6c6=3
Hidden Single: r6c5=2
Hidden Single: r3c6=2
Hidden Single: r3c5=5
Naked Single: r9c5=7
Full House: r9c4=5
Hidden Single: r2c5=8
Hidden Single: r5c6=7
Hidden Single: r2c4=7
Hidden Single: r5c3=5
Hidden Single: r4c6=5
Hidden Single: r2c8=9
Hidden Single: r1c4=9
Full House: r4c4=4
Hidden Single: r3c3=9
Locked Candidates Type 2 (Claiming): 4 in r3 => r1c3,r2c2<>4
Hidden Single: r9c3=4
Locked Candidates Type 2 (Claiming): 6 in c3 => r4c1<>6
2-String Kite: 8 in r3c8,r4c3 (connected by r1c3,r3c1) => r4c8<>8
W-Wing: 3/8 in r4c1,r5c8 connected by 8 in r3c18 => r4c8,r5c12<>3
Naked Single: r4c8=6
Naked Single: r3c8=8
Full House: r5c8=3
Naked Single: r6c7=1
Full House: r6c3=6
Naked Single: r1c7=4
Full House: r2c9=6
Full House: r8c9=4
Full House: r8c7=6
Naked Single: r1c6=1
Full House: r1c3=8
Full House: r2c6=4
Full House: r2c2=1
Full House: r4c3=1
Naked Single: r5c2=4
Naked Single: r4c5=9
Full House: r5c5=1
Naked Single: r3c2=6
Full House: r3c1=4
Full House: r9c2=3
Full House: r9c1=6
Naked Single: r5c1=8
Full House: r4c1=3
Full House: r4c7=8
Full House: r5c7=9
|
normal_sudoku_993
|
....7...8..96.......41.5....37....54..8.5...9.9.4.73...758.94.38.3.42...9......7.
|
126374598359628147784195236237981654468253719591467382675819423813742965942536871
|
Basic 9x9 Sudoku 993
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 7 . . . 8
. . 9 6 . . . . .
. . 4 1 . 5 . . .
. 3 7 . . . . 5 4
. . 8 . 5 . . . 9
. 9 . 4 . 7 3 . .
. 7 5 8 . 9 4 . 3
8 . 3 . 4 2 . . .
9 . . . . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
126374598359628147784195236237981654468253719591467382675819423813742965942536871 #1 Extreme (7726)
Naked Single: r7c4=8
Hidden Single: r6c1=5
Hidden Single: r9c2=4
Hidden Single: r5c1=4
Hidden Single: r5c7=7
Hidden Single: r8c4=7
Hidden Single: r6c8=8
Hidden Single: r9c7=8
Hidden Single: r9c4=5
Hidden Rectangle: 3/4 in r1c68,r2c68 => r2c8<>3
Almost Locked Set XZ-Rule: A=r2679c5 {12368}, B=r12c6 {348}, X=8, Z=3 => r3c5<>3
Finned Franken Swordfish: 2 r69b2 c359 fr1c4 => r1c3<>2
Forcing Chain Contradiction in r3 => r1c8<>2
r1c8=2 r7c8<>2 r7c1=2 r3c1<>2
r1c8=2 r123c7<>2 r4c7=2 r4c4<>2 r4c4=9 r4c5<>9 r3c5=9 r3c5<>8 r3c2=8 r3c2<>2
r1c8=2 r123c7<>2 r4c7=2 r4c4<>2 r4c4=9 r4c5<>9 r3c5=9 r3c5<>2
r1c8=2 r3c7<>2
r1c8=2 r3c8<>2
r1c8=2 r3c9<>2
Forcing Chain Contradiction in r5 => r2c8<>2
r2c8=2 r7c8<>2 r7c1=2 r9c3<>2 r6c3=2 r5c2<>2
r2c8=2 r2c8<>4 r2c6=4 r1c6<>4 r1c6=3 r1c4<>3 r5c4=3 r5c4<>2
r2c8=2 r5c8<>2
Forcing Chain Contradiction in r5 => r3c8<>2
r3c8=2 r7c8<>2 r7c1=2 r9c3<>2 r6c3=2 r5c2<>2
r3c8=2 r3c8<>3 r1c8=3 r1c4<>3 r5c4=3 r5c4<>2
r3c8=2 r5c8<>2
Forcing Net Verity => r7c8=2
r9c3=1 (r8c2<>1 r8c2=6 r7c1<>6 r4c1=6 r4c7<>6) (r6c3<>1) (r9c5<>1) r9c6<>1 r7c5=1 r6c5<>1 r6c9=1 r4c7<>1 r4c7=2 r5c8<>2 r7c8=2
r9c3=2 r7c1<>2 r7c8=2
r9c3=6 (r8c2<>6 r8c2=1 r7c1<>1 r4c1=1 r4c7<>1) (r6c3<>6) (r9c5<>6) r9c6<>6 r7c5=6 r6c5<>6 r6c9=6 r4c7<>6 r4c7=2 r5c8<>2 r7c8=2
Hidden Single: r9c3=2
Discontinuous Nice Loop: 2 r3c2 -2- r5c2 =2= r5c4 =3= r1c4 =9= r3c5 =8= r3c2 => r3c2<>2
Almost Locked Set Chain: 2- r5c268 {1236} -3- r5c4 {23} -2- r14c4 {239} -3- r12c6,r2c5 {2348} -2 => r2c2<>2
Forcing Chain Contradiction in r6c5 => r3c2=8
r3c2<>8 r3c2=6 r8c2<>6 r8c2=1 r7c1<>1 r7c5=1 r6c5<>1
r3c2<>8 r3c5=8 r3c5<>9 r4c5=9 r4c4<>9 r4c4=2 r6c5<>2
r3c2<>8 r3c2=6 r1c3<>6 r6c3=6 r6c5<>6
Discontinuous Nice Loop: 6 r1c7 -6- r1c3 -1- r2c2 -5- r1c2 =5= r1c7 => r1c7<>6
Discontinuous Nice Loop: 6 r8c9 -6- r8c2 -1- r2c2 -5- r2c9 =5= r8c9 => r8c9<>6
Forcing Chain Contradiction in r6 => r1c7=5
r1c7<>5 r1c2=5 r2c2<>5 r2c2=1 r1c3<>1 r1c3=6 r6c3<>6
r1c7<>5 r1c2=5 r2c2<>5 r2c2=1 r8c2<>1 r8c2=6 r7c1<>6 r7c5=6 r6c5<>6
r1c7<>5 r1c2=5 r2c2<>5 r2c2=1 r8c2<>1 r8c2=6 r8c78<>6 r9c9=6 r6c9<>6
Hidden Single: r2c2=5
Hidden Single: r8c9=5
Almost Locked Set XY-Wing: A=r1c1234 {12369}, B=r47c1 {126}, C=r4c4 {29}, X,Y=2,9, Z=1,6 => r2c1<>1, r3c1<>6
Locked Candidates Type 1 (Pointing): 1 in b1 => r1c8<>1
Locked Candidates Type 1 (Pointing): 6 in b1 => r1c8<>6
Forcing Chain Contradiction in r6 => r1c2<>1
r1c2=1 r1c3<>1 r1c3=6 r6c3<>6
r1c2=1 r8c2<>1 r8c2=6 r7c1<>6 r7c5=6 r6c5<>6
r1c2=1 r8c2<>1 r8c2=6 r8c78<>6 r9c9=6 r6c9<>6
W-Wing: 6/1 in r6c3,r7c1 connected by 1 in r1c13 => r4c1<>6
Discontinuous Nice Loop: 6 r6c9 -6- r6c3 -1- r4c1 -2- r4c7 =2= r6c9 => r6c9<>6
Discontinuous Nice Loop: 1 r8c7 -1- r8c2 =1= r5c2 =2= r5c4 =3= r1c4 =9= r1c8 -9- r8c8 =9= r8c7 => r8c7<>1
AIC: 4 4- r1c6 -3- r1c4 =3= r5c4 =2= r5c2 -2- r4c1 -1- r4c7 =1= r2c7 -1- r2c8 -4 => r1c8,r2c6<>4
Hidden Single: r1c6=4
Hidden Single: r2c8=4
X-Wing: 1 c28 r58 => r5c6<>1
2-String Kite: 1 in r4c6,r7c1 (connected by r7c5,r9c6) => r4c1<>1
Naked Single: r4c1=2
Naked Single: r4c4=9
Hidden Single: r1c2=2
Naked Single: r1c4=3
Full House: r5c4=2
Naked Single: r1c8=9
Naked Single: r2c6=8
Naked Single: r2c5=2
Full House: r3c5=9
Naked Single: r2c7=1
Naked Single: r2c9=7
Full House: r2c1=3
Naked Single: r4c7=6
Naked Single: r3c1=7
Naked Single: r3c7=2
Full House: r8c7=9
Naked Single: r4c6=1
Full House: r4c5=8
Naked Single: r5c8=1
Full House: r6c9=2
Naked Single: r3c9=6
Full House: r3c8=3
Full House: r8c8=6
Full House: r9c9=1
Full House: r8c2=1
Full House: r5c2=6
Full House: r7c1=6
Full House: r5c6=3
Full House: r6c5=6
Full House: r6c3=1
Full House: r1c1=1
Full House: r7c5=1
Full House: r9c6=6
Full House: r9c5=3
Full House: r1c3=6
|
normal_sudoku_2779
|
..2..763...7.219.4.4.3....2..6..92......5..6.8......9...9......71...6..926....1..
|
582947631637821954941365782376489215194752863825613497459178326718236549263594178
|
Basic 9x9 Sudoku 2779
|
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 6 3 .
. . 7 . 2 1 9 . 4
. 4 . 3 . . . . 2
. . 6 . . 9 2 . .
. . . . 5 . . 6 .
8 . . . . . . 9 .
. . 9 . . . . . .
7 1 . . . 6 . . 9
2 6 . . . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
582947631637821954941365782376489215194752863825613497459178326718236549263594178 #1 Extreme (36744) bf
Hidden Pair: 6,9 in r3c15 => r3c1<>1, r3c1<>5, r3c5<>8
Brute Force: r5c8=6
Hidden Single: r7c9=6
2-String Kite: 1 in r1c1,r4c8 (connected by r1c9,r3c8) => r4c1<>1
Brute Force: r5c7=8
Discontinuous Nice Loop: 7 r6c7 -7- r3c7 =7= r3c8 =1= r4c8 =4= r6c7 => r6c7<>7
Forcing Chain Contradiction in r2c4 => r9c4<>8
r9c4=8 r9c9<>8 r1c9=8 r2c8<>8 r2c8=5 r2c4<>5
r9c4=8 r9c4<>9 r9c5=9 r3c5<>9 r3c5=6 r2c4<>6
r9c4=8 r2c4<>8
Forcing Net Contradiction in r2 => r1c4<>8
r1c4=8 (r1c2<>8) (r3c6<>8) r1c9<>8 r9c9=8 r9c6<>8 r7c6=8 r7c2<>8 r2c2=8
r1c4=8 (r1c9<>8 r9c9=8 r9c8<>8) (r3c6<>8 r3c6=5 r9c6<>5) (r1c9<>8 r9c9=8 r9c6<>8) (r4c4<>8 r4c5=8 r8c5<>8) r1c4<>4 r1c5=4 r8c5<>4 r8c5=3 (r9c5<>3 r9c5=7 r9c8<>7) r9c6<>3 r9c6=4 r9c8<>4 r9c8=5 r2c8<>5 r2c8=8
Brute Force: r5c9=3
Discontinuous Nice Loop: 7 r6c5 -7- r5c4 =7= r5c2 =9= r5c1 -9- r3c1 -6- r3c5 =6= r6c5 => r6c5<>7
Discontinuous Nice Loop: 7 r9c4 -7- r5c4 =7= r5c2 =9= r1c2 -9- r1c4 =9= r9c4 => r9c4<>7
Forcing Net Contradiction in b8 => r3c7=7
r3c7<>7 r3c7=5 (r6c7<>5 r6c7=4 r8c7<>4 r8c7=3 r8c5<>3) (r3c6<>5 r3c6=8 r3c3<>8) r2c8<>5 r2c8=8 r1c9<>8 r9c9=8 r9c3<>8 r8c3=8 r8c5<>8 r8c5=4
r3c7<>7 (r3c7=5 r6c7<>5 r6c7=4 r6c6<>4) r3c8=7 r3c8<>1 r3c3=1 r5c3<>1 r5c3=4 (r5c6<>4) (r4c1<>4) r5c1<>4 r7c1=4 r7c6<>4 r9c6=4
Forcing Net Contradiction in r9c8 => r1c1<>9
r1c1=9 r1c1<>1 (r5c1=1 r5c3<>1 r5c3=4 r5c6<>4) (r5c1=1 r5c3<>1 r5c3=4 r4c1<>4 r7c1=4 r7c6<>4) r1c9=1 r3c8<>1 r4c8=1 r4c8<>4 r6c7=4 r6c6<>4 r9c6=4 r9c8<>4
r1c1=9 r1c1<>1 r1c9=1 r1c9<>5 r23c8=5 r9c8<>5
r1c1=9 (r5c1<>9 r5c2=9 r5c2<>7 r5c4=7 r7c4<>7) (r1c1<>1 r5c1=1 r6c3<>1) (r1c1<>1 r1c9=1 r6c9<>1) r3c1<>9 r3c1=6 r2c1<>6 r2c4=6 r6c4<>6 r6c5=6 r6c5<>1 r6c4=1 r7c4<>1 r7c5=1 r7c5<>7 r7c8=7 r9c8<>7
r1c1=9 r1c1<>1 r1c9=1 r1c9<>8 r9c9=8 r9c8<>8
Forcing Net Contradiction in r4 => r1c2<>5
r1c2=5 (r3c3<>5) r1c1<>5 r1c1=1 (r1c9<>1 r1c9=8 r2c8<>8) r3c3<>1 r3c3=8 (r2c2<>8) r2c2<>8 r2c4=8 (r4c4<>8 r4c5=8 r4c5<>3) r2c8<>8 r2c8=5 r2c2<>5 r2c2=3 r4c2<>3 r4c1=3 r4c1<>5
r1c2=5 r4c2<>5
r1c2=5 (r1c9<>5) r1c1<>5 r1c1=1 r1c9<>1 r1c9=8 r2c8<>8 r2c8=5 r4c8<>5
r1c2=5 (r1c1<>5 r1c1=1 r1c9<>1 r1c9=8 r9c9<>8) r1c2<>9 r5c2=9 (r5c2<>2 r6c2=2 r6c2<>7) r5c2<>7 r5c4=7 r6c4<>7 r6c9=7 r9c9<>7 r9c9=5 r4c9<>5
Forcing Chain Verity => r9c6<>8
r1c1=5 r1c1<>1 r1c9=1 r1c9<>8 r9c9=8 r9c6<>8
r1c4=5 r3c6<>5 r3c6=8 r9c6<>8
r1c9=5 r1c9<>8 r9c9=8 r9c6<>8
Empty Rectangle: 8 in b1 (r37c6) => r7c2<>8
Locked Candidates Type 1 (Pointing): 8 in b7 => r3c3<>8
Naked Pair: 1,5 in r1c1,r3c3 => r2c12<>5
Naked Triple: 3,4,5 in r7c127 => r7c4568<>4, r7c468<>5, r7c56<>3
2-String Kite: 5 in r2c8,r9c6 (connected by r2c4,r3c6) => r9c8<>5
Turbot Fish: 4 r4c8 =4= r6c7 -4- r7c7 =4= r7c1 => r4c1<>4
W-Wing: 5/3 in r4c1,r7c2 connected by 3 in r2c12 => r46c2,r7c1<>5
Hidden Single: r7c2=5
Empty Rectangle: 5 in b3 (r14c1) => r4c8<>5
Finned Swordfish: 5 r149 c149 fr9c6 => r8c4<>5
Locked Candidates Type 1 (Pointing): 5 in b8 => r9c9<>5
XY-Chain: 4 4- r5c3 -1- r3c3 -5- r3c6 -8- r7c6 -2- r5c6 -4 => r5c14<>4
Hidden Single: r7c1=4
Naked Single: r7c7=3
Locked Candidates Type 1 (Pointing): 3 in b7 => r6c3<>3
Finned Swordfish: 4 r148 c458 fr8c7 => r9c8<>4
Locked Pair: 7,8 in r9c89 => r78c8,r9c35<>8, r7c8,r9c5<>7
Naked Single: r9c3=3
Full House: r8c3=8
Naked Single: r7c8=2
Naked Single: r7c6=8
Naked Single: r3c6=5
Naked Single: r3c3=1
Naked Single: r9c6=4
Naked Single: r1c1=5
Naked Single: r3c8=8
Naked Single: r5c3=4
Full House: r6c3=5
Naked Single: r5c6=2
Full House: r6c6=3
Naked Single: r8c4=2
Naked Single: r8c5=3
Naked Single: r9c5=9
Naked Single: r4c1=3
Naked Single: r1c9=1
Full House: r2c8=5
Naked Single: r9c8=7
Naked Single: r6c7=4
Full House: r8c7=5
Full House: r8c8=4
Full House: r9c9=8
Full House: r9c4=5
Full House: r4c8=1
Naked Single: r3c5=6
Full House: r3c1=9
Naked Single: r2c1=6
Full House: r5c1=1
Naked Single: r4c2=7
Naked Single: r6c9=7
Full House: r4c9=5
Naked Single: r2c4=8
Full House: r2c2=3
Full House: r1c2=8
Naked Single: r6c5=1
Naked Single: r5c4=7
Full House: r5c2=9
Full House: r6c2=2
Full House: r6c4=6
Naked Single: r1c5=4
Full House: r1c4=9
Naked Single: r4c4=4
Full House: r7c4=1
Full House: r7c5=7
Full House: r4c5=8
|
normal_sudoku_4505
|
...1.52.7..1.2...9......18...8.1.5....54.67..9........28...1...5.9....2..17...8.5
|
893145267461728359752369184348217596125496738976583412284651973539874621617932845
|
Basic 9x9 Sudoku 4505
|
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 . 5 2 . 7
. . 1 . 2 . . . 9
. . . . . . 1 8 .
. . 8 . 1 . 5 . .
. . 5 4 . 6 7 . .
9 . . . . . . . .
2 8 . . . 1 . . .
5 . 9 . . . . 2 .
. 1 7 . . . 8 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
893145267461728359752369184348217596125496738976583412284651973539874621617932845 #1 Extreme (13922) bf
Hidden Single: r1c4=1
Hidden Single: r5c1=1
Hidden Single: r8c9=1
Hidden Single: r7c8=7
Hidden Single: r7c7=9
Hidden Single: r3c2=5
Hidden Single: r2c8=5
Hidden Single: r6c8=1
Hidden Single: r3c3=2
Hidden Single: r1c2=9
Brute Force: r5c8=3
Naked Single: r5c2=2
Naked Single: r5c9=8
Full House: r5c5=9
Hidden Single: r4c8=9
Naked Triple: 3,4,6 in r9c158 => r9c46<>3, r9c4<>6, r9c6<>4
Finned X-Wing: 3 r19 c15 fr1c3 => r23c1<>3
Finned Franken Swordfish: 4 c38b6 r167 fr4c9 fr9c8 => r7c9<>4
W-Wing: 6/4 in r1c8,r6c7 connected by 4 in r8c7,r9c8 => r2c7<>6
Sashimi Swordfish: 6 c378 r167 fr8c7 fr9c8 => r7c9<>6
Naked Single: r7c9=3
Hidden Single: r2c7=3
Locked Candidates Type 1 (Pointing): 3 in b1 => r1c5<>3
Grouped Discontinuous Nice Loop: 4 r3c5 -4- r3c9 =4= r1c8 -4- r9c8 =4= r8c7 -4- r8c6 =4= r789c5 -4- r3c5 => r3c5<>4
Forcing Chain Contradiction in r9c1 => r1c3<>4
r1c3=4 r1c3<>3 r1c1=3 r9c1<>3
r1c3=4 r1c8<>4 r9c8=4 r9c1<>4
r1c3=4 r7c3<>4 r7c3=6 r9c1<>6
Skyscraper: 4 in r7c3,r8c7 (connected by r6c37) => r8c2<>4
Discontinuous Nice Loop: 6 r9c5 -6- r9c8 =6= r8c7 -6- r8c2 -3- r9c1 =3= r9c5 => r9c5<>6
Turbot Fish: 6 r3c9 =6= r1c8 -6- r9c8 =6= r9c1 => r3c1<>6
Almost Locked Set XY-Wing: A=r3c9 {46}, B=r6c37 {346}, C=r1c38 {346}, X,Y=3,4, Z=6 => r6c9<>6
Forcing Chain Contradiction in r9c1 => r1c3=3
r1c3<>3 r1c1=3 r9c1<>3
r1c3<>3 r1c3=6 r7c3<>6 r7c3=4 r9c1<>4
r1c3<>3 r1c3=6 r1c8<>6 r9c8=6 r9c1<>6
Naked Pair: 4,6 in r6c37 => r6c29<>4, r6c2<>6
Naked Single: r6c9=2
Remote Pair: 6/4 r7c3 -4- r6c3 -6- r6c7 -4- r8c7 => r8c2<>6
Naked Single: r8c2=3
Naked Single: r6c2=7
Hidden Single: r4c1=3
Hidden Single: r9c5=3
Naked Triple: 4,6,7 in r3c159 => r3c4<>6, r3c46<>7, r3c6<>4
Remote Pair: 4/6 r2c2 -6- r4c2 -4- r4c9 -6- r3c9 => r3c1<>4
Naked Single: r3c1=7
Naked Single: r3c5=6
Naked Single: r3c9=4
Full House: r1c8=6
Full House: r4c9=6
Full House: r9c8=4
Full House: r6c7=4
Full House: r8c7=6
Naked Single: r4c2=4
Full House: r6c3=6
Full House: r2c2=6
Full House: r7c3=4
Full House: r9c1=6
Naked Single: r7c5=5
Full House: r7c4=6
Naked Single: r6c5=8
Naked Single: r1c5=4
Full House: r1c1=8
Full House: r8c5=7
Full House: r2c1=4
Naked Single: r6c6=3
Full House: r6c4=5
Naked Single: r8c4=8
Full House: r8c6=4
Naked Single: r3c6=9
Full House: r3c4=3
Naked Single: r2c4=7
Full House: r2c6=8
Naked Single: r9c6=2
Full House: r4c6=7
Full House: r4c4=2
Full House: r9c4=9
|
normal_sudoku_2539
|
7.5..4..6.2.....7....8...............5.43....973..6.4..3..4..95.1.....644.9..57..
|
795214836628953471341867529284179653156432987973586142837641295512798364469325718
|
Basic 9x9 Sudoku 2539
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 . 5 . . 4 . . 6
. 2 . . . . . 7 .
. . . 8 . . . . .
. . . . . . . . .
. 5 . 4 3 . . . .
9 7 3 . . 6 . 4 .
. 3 . . 4 . . 9 5
. 1 . . . . . 6 4
4 . 9 . . 5 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
795214836628953471341867529284179653156432987973586142837641295512798364469325718 #1 Extreme (14226) bf
Hidden Single: r7c5=4
Hidden Single: r8c1=5
Brute Force: r4c8=5
Naked Triple: 1,2,8 in r5c8,r6c79 => r4c79,r5c79<>1, r4c79,r5c79<>2, r4c79,r5c79<>8
Hidden Pair: 4,5 in r23c7 => r23c7<>1, r23c7<>3, r2c7<>8, r23c7<>9, r3c7<>2
Grouped Discontinuous Nice Loop: 9 r1c4 -9- r1c2 -8- r1c78 =8= r2c9 =9= r2c456 -9- r1c4 => r1c4<>9
Grouped Discontinuous Nice Loop: 9 r1c5 -9- r1c2 -8- r1c78 =8= r2c9 =9= r2c456 -9- r1c5 => r1c5<>9
Forcing Chain Verity => r2c9<>3
r1c7=9 r1c2<>9 r1c2=8 r1c78<>8 r2c9=8 r2c9<>3
r4c7=9 r4c7<>3 r4c9=3 r2c9<>3
r5c7=9 r5c7<>6 r4c7=6 r4c7<>3 r4c9=3 r2c9<>3
Forcing Net Contradiction in r1c5 => r1c7<>1
r1c7=1 (r1c7<>3) (r1c4<>1) r1c5<>1 r1c5=2 r1c4<>2 r1c4=3 (r2c6<>3) r3c6<>3 r8c6=3 r8c7<>3 r4c7=3 (r4c7<>9) r4c7<>6 r5c7=6 r5c7<>9 r1c7=9 r1c7<>1
Forcing Chain Contradiction in c6 => r5c8<>1
r5c8=1 r1c8<>1 r1c45=1 r2c6<>1
r5c8=1 r1c8<>1 r1c45=1 r3c6<>1
r5c8=1 r5c13<>1 r4c13=1 r4c6<>1
r5c8=1 r5c6<>1
r5c8=1 r6c7<>1 r7c7=1 r7c6<>1
Locked Candidates Type 1 (Pointing): 1 in b6 => r6c45<>1
Forcing Net Contradiction in r1c5 => r1c7<>2
r1c7=2 (r1c7<>3) (r1c4<>2) r1c5<>2 r1c5=1 r1c4<>1 r1c4=3 (r2c6<>3) r3c6<>3 r8c6=3 r8c7<>3 r4c7=3 (r4c7<>9) r4c7<>6 r5c7=6 r5c7<>9 r1c7=9 r1c7<>2
Forcing Chain Contradiction in c6 => r5c8=8
r5c8<>8 r5c8=2 r1c8<>2 r1c45=2 r3c6<>2
r5c8<>8 r5c8=2 r5c13<>2 r4c13=2 r4c6<>2
r5c8<>8 r5c8=2 r5c6<>2
r5c8<>8 r5c8=2 r6c7<>2 r78c7=2 r9c89<>2 r9c45=2 r7c6<>2
r5c8<>8 r5c8=2 r6c7<>2 r78c7=2 r9c89<>2 r9c45=2 r8c6<>2
Hidden Single: r6c5=8
Hidden Single: r6c4=5
Naked Triple: 1,2,3 in r1c458 => r1c7<>3
Skyscraper: 8 in r1c7,r9c9 (connected by r19c2) => r2c9,r78c7<>8
Hidden Single: r9c9=8
Naked Single: r9c2=6
Hidden Single: r1c7=8
Naked Single: r1c2=9
Naked Single: r3c2=4
Full House: r4c2=8
Naked Single: r3c7=5
Naked Single: r2c7=4
Hidden Single: r7c4=6
Hidden Single: r4c3=4
Hidden Single: r2c5=5
Hidden Single: r3c5=6
Naked Single: r3c3=1
Naked Single: r3c1=3
Naked Single: r3c8=2
Naked Single: r3c9=9
Full House: r3c6=7
Naked Single: r2c9=1
Full House: r1c8=3
Full House: r9c8=1
Naked Single: r5c9=7
Naked Single: r6c9=2
Full House: r4c9=3
Full House: r6c7=1
Naked Single: r7c7=2
Full House: r8c7=3
Naked Single: r9c5=2
Full House: r9c4=3
Naked Single: r7c1=8
Naked Single: r1c5=1
Full House: r1c4=2
Naked Single: r2c4=9
Full House: r2c6=3
Naked Single: r2c1=6
Full House: r2c3=8
Naked Single: r7c3=7
Full House: r7c6=1
Full House: r8c3=2
Full House: r5c3=6
Naked Single: r8c4=7
Full House: r4c4=1
Naked Single: r5c7=9
Full House: r4c7=6
Naked Single: r8c5=9
Full House: r4c5=7
Full House: r8c6=8
Naked Single: r4c1=2
Full House: r4c6=9
Full House: r5c6=2
Full House: r5c1=1
|
normal_sudoku_2332
|
..7.3946...9.4...7.487..52.2.....1.............5.87..2.8..5.......1....676.4..8..
|
157239468629845317348716529273964185896521734415387692984653271532178946761492853
|
Basic 9x9 Sudoku 2332
|
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 9 4 6 .
. . 9 . 4 . . . 7
. 4 8 7 . . 5 2 .
2 . . . . . 1 . .
. . . . . . . . .
. . 5 . 8 7 . . 2
. 8 . . 5 . . . .
. . . 1 . . . . 6
7 6 . 4 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
157239468629845317348716529273964185896521734415387692984653271532178946761492853 #1 Hard (720)
Naked Single: r1c7=4
Naked Single: r2c7=3
Hidden Single: r3c9=9
Hidden Single: r5c1=8
Hidden Single: r8c5=7
Hidden Single: r8c6=8
Hidden Single: r3c1=3
Hidden Single: r2c1=6
Locked Candidates Type 1 (Pointing): 2 in b1 => r8c2<>2
Locked Candidates Type 1 (Pointing): 1 in b5 => r5c23<>1
Locked Candidates Type 1 (Pointing): 5 in b7 => r8c8<>5
Locked Candidates Type 2 (Claiming): 1 in r3 => r2c6<>1
Locked Candidates Type 2 (Claiming): 1 in c3 => r7c1<>1
Empty Rectangle: 4 in b9 (r6c18) => r7c1<>4
Naked Single: r7c1=9
Hidden Single: r9c5=9
Naked Single: r4c5=6
Naked Single: r3c5=1
Full House: r3c6=6
Full House: r5c5=2
Hidden Single: r5c3=6
Hidden Single: r6c7=6
Hidden Single: r7c4=6
Hidden Single: r5c6=1
Hidden Single: r4c6=4
Naked Single: r4c3=3
Hidden Single: r6c1=4
Naked Single: r8c1=5
Full House: r1c1=1
Naked Single: r8c2=3
Naked Single: r1c9=8
Full House: r2c8=1
Naked Single: r4c9=5
Naked Single: r4c4=9
Naked Single: r4c2=7
Full House: r4c8=8
Naked Single: r6c4=3
Full House: r5c4=5
Naked Single: r5c2=9
Full House: r6c2=1
Full House: r6c8=9
Naked Single: r1c4=2
Full House: r1c2=5
Full House: r2c4=8
Full House: r2c6=5
Full House: r2c2=2
Naked Single: r5c7=7
Naked Single: r8c8=4
Naked Single: r7c7=2
Full House: r8c7=9
Full House: r8c3=2
Naked Single: r5c8=3
Full House: r5c9=4
Naked Single: r7c6=3
Full House: r9c6=2
Naked Single: r9c3=1
Full House: r7c3=4
Naked Single: r7c8=7
Full House: r9c8=5
Full House: r7c9=1
Full House: r9c9=3
|
normal_sudoku_4247
|
.........326....9..793.........8...4..84.153.7..6.....9..2...6......41.9....5...8
|
581927643326845791479316285163582974298471536754693812915238467832764159647159328
|
Basic 9x9 Sudoku 4247
|
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 2 6 . . . . 9 .
. 7 9 3 . . . . .
. . . . 8 . . . 4
. . 8 4 . 1 5 3 .
7 . . 6 . . . . .
9 . . 2 . . . 6 .
. . . . . 4 1 . 9
. . . . 5 . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
581927643326845791479316285163582974298471536754693812915238467832764159647159328 #1 Extreme (46764) bf
Brute Force: r5c4=4
Discontinuous Nice Loop: 9 r6c2 -9- r6c7 =9= r4c7 =6= r5c9 -6- r5c2 -9- r6c2 => r6c2<>9
Brute Force: r5c2=9
Discontinuous Nice Loop: 7 r1c5 -7- r5c5 =7= r5c9 =6= r4c7 =9= r6c7 -9- r6c5 =9= r1c5 => r1c5<>7
Forcing Net Contradiction in r1c8 => r1c5<>1
r1c5=1 r1c8<>1
r1c5=1 (r1c5<>9 r6c5=9 r6c5<>3) (r1c4<>1) r2c4<>1 r9c4=1 r9c4<>9 r9c6=9 r9c6<>6 r8c5=6 r8c5<>3 r7c5=3 (r7c7<>3) r7c9<>3 r1c9=3 r1c7<>3 r9c7=3 r9c7<>2 r89c8=2 r1c8<>2
r1c5=1 (r1c1<>1) (r1c2<>1) r1c3<>1 r3c1=1 r3c1<>4 r1c123=4 r1c8<>4
r1c5=1 (r1c3<>1 r3c1=1 r3c9<>1) (r2c5<>1 r2c9=1 r6c9<>1 r6c9=2 r3c9<>2) r1c5<>9 r6c5=9 (r4c4<>9) r4c6<>9 r4c7=9 r4c7<>6 r5c9=6 r3c9<>6 r3c9=5 r1c8<>5
r1c5=1 r1c5<>9 r6c5=9 (r4c4<>9) r4c6<>9 r4c7=9 (r4c7<>7) r4c7<>6 r5c9=6 r5c9<>7 r5c5=7 (r4c4<>7) r4c6<>7 r4c8=7 r1c8<>7
r1c5=1 (r1c1<>1) (r1c2<>1) r1c3<>1 r3c1=1 r3c1<>8 r1c12=8 r1c8<>8
Forcing Net Contradiction in r9c4 => r8c5<>7
r8c5=7 (r5c5<>7 r5c9=7 r5c9<>6) (r7c6<>7) r8c4<>7 r8c4=8 r7c6<>8 r7c6=3 r7c9<>3 r1c9=3 r1c9<>6 r3c9=6 (r3c5<>6) r3c7<>6 r4c7=6 (r1c7<>6) r4c7<>9 r6c7=9 r6c5<>9 r1c5=9 r1c5<>6 r8c5=6 r8c5<>7
Brute Force: r5c5=7
Forcing Chain Contradiction in r1c8 => r1c5<>4
r1c5=4 r1c123<>4 r3c1=4 r3c1<>1 r1c123=1 r1c8<>1
r1c5=4 r2c5<>4 r2c5=1 r7c5<>1 r7c5=3 r7c79<>3 r9c7=3 r9c7<>2 r89c8=2 r1c8<>2
r1c5=4 r1c8<>4
r1c5=4 r1c123<>4 r3c1=4 r3c1<>5 r1c123=5 r1c8<>5
r1c5=4 r1c5<>9 r6c5=9 r6c7<>9 r4c7=9 r4c7<>7 r4c8=7 r1c8<>7
r1c5=4 r1c123<>4 r3c1=4 r3c1<>8 r1c12=8 r1c8<>8
Forcing Net Contradiction in r4 => r2c5=4
r2c5<>4 (r2c7=4 r7c7<>4 r7c7=7 r7c6<>7 r7c6=8 r2c6<>8) (r2c7=4 r7c7<>4 r7c7=7 r7c9<>7) r2c5=1 r7c5<>1 r7c5=3 r7c9<>3 r1c9=3 r1c9<>7 r2c9=7 r2c6<>7 r2c6=5 (r1c4<>5) r2c4<>5 r4c4=5 r4c4<>9
r2c5<>4 r2c5=1 (r1c4<>1) r2c4<>1 r9c4=1 r9c4<>9 r9c6=9 r4c6<>9
r2c5<>4 (r2c5=1 r2c4<>1 r9c4=1 r9c1<>1) (r2c5=1 r2c4<>1 r9c4=1 r9c2<>1) (r2c5=1 r7c5<>1 r7c5=3 r7c9<>3 r1c9=3 r1c7<>3 r9c7=3 r9c2<>3) r2c7=4 (r1c8<>4) r3c8<>4 r9c8=4 (r9c1<>4) r9c2<>4 r9c2=6 r9c1<>6 r9c1=2 r5c1<>2 r5c1=6 (r4c1<>6) r4c2<>6 r4c7=6 r4c7<>9
Forcing Net Contradiction in r1c8 => r1c4<>5
r1c4=5 (r1c1<>5) (r1c2<>5) r1c3<>5 r3c1=5 r3c1<>1 r1c123=1 r1c8<>1
r1c4=5 (r4c4<>5 r4c4=9 r9c4<>9) (r2c4<>5) r2c6<>5 r2c9=5 r2c9<>1 r2c4=1 r9c4<>1 r9c4=7 (r7c6<>7) r8c4<>7 r8c4=8 r7c6<>8 r7c6=3 (r7c7<>3) r7c9<>3 r1c9=3 r1c7<>3 r9c7=3 r9c7<>2 r89c8=2 r1c8<>2
r1c4=5 (r1c1<>5) (r1c2<>5) r1c3<>5 r3c1=5 r3c1<>4 r1c123=4 r1c8<>4
r1c4=5 r1c8<>5
r1c4=5 (r1c3<>5 r3c1=5 r8c1<>5) (r4c4<>5 r4c4=9 r9c4<>9 r9c6=9 r9c6<>6 r8c5=6 r8c1<>6) (r1c4<>8) (r2c4<>5) r2c6<>5 r2c9=5 r2c9<>1 r2c4=1 r2c4<>8 r8c4=8 r8c1<>8 r8c1=2 r5c1<>2 r5c9=2 (r4c8<>2) r6c9<>2 r6c9=1 r4c8<>1 r4c8=7 r1c8<>7
r1c4=5 r4c4<>5 r4c4=9 (r6c5<>9) r6c6<>9 r6c7=9 r6c7<>8 r6c8=8 r1c8<>8
Grouped Discontinuous Nice Loop: 5 r4c6 -5- r4c4 =5= r2c4 =1= r2c9 -1- r6c9 -2- r6c56 =2= r4c6 => r4c6<>5
Forcing Chain Contradiction in r6 => r6c2<>3
r6c2=3 r6c2<>5
r6c2=3 r6c2<>4 r6c3=4 r6c3<>5
r6c2=3 r4c23<>3 r4c6=3 r4c6<>2 r6c56=2 r6c9<>2 r6c9=1 r2c9<>1 r2c4=1 r2c4<>5 r4c4=5 r6c6<>5
Forcing Chain Contradiction in r6 => r4c6<>3
r4c6=3 r4c23<>3 r6c3=3 r6c3<>4 r6c2=4 r6c2<>5
r4c6=3 r4c23<>3 r6c3=3 r6c3<>5
r4c6=3 r4c6<>2 r6c56=2 r6c9<>2 r6c9=1 r2c9<>1 r2c4=1 r2c4<>5 r4c4=5 r6c6<>5
Locked Candidates Type 1 (Pointing): 3 in b5 => r6c3<>3
Forcing Chain Contradiction in r6 => r6c3<>2
r6c3=2 r6c3<>4 r6c2=4 r6c2<>5
r6c3=2 r6c3<>5
r6c3=2 r6c9<>2 r6c9=1 r2c9<>1 r2c4=1 r2c4<>5 r4c4=5 r6c6<>5
Forcing Net Contradiction in r4c4 => r4c4=5
r4c4<>5 (r2c4=5 r3c6<>5 r6c6=5 r6c6<>3) r4c4=9 (r4c6<>9 r4c6=2 r4c3<>2 r5c1=2 r8c1<>2) (r6c5<>9 r1c5=9 r1c5<>2 r3c5=2 r3c5<>6 r8c5=6 r8c1<>6) r9c4<>9 r9c6=9 r9c6<>3 r7c6=3 r7c6<>8 r7c2=8 (r7c2<>5) r8c1<>8 r8c1=5 r7c3<>5 r7c9=5 (r7c9<>7) r7c9<>3 r1c9=3 r1c9<>7 r2c9=7 r2c9<>1 r2c4=1 r2c4<>5 r4c4=5
Hidden Pair: 4,5 in r6c23 => r6c23<>1
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c8<>1
Discontinuous Nice Loop: 7 r2c4 -7- r2c7 -8- r6c7 =8= r6c8 =1= r6c9 -1- r2c9 =1= r2c4 => r2c4<>7
Grouped Discontinuous Nice Loop: 1 r1c9 -1- r6c9 =1= r6c8 =8= r6c7 -8- r2c7 -7- r12c9 =7= r7c9 =3= r1c9 => r1c9<>1
Almost Locked Set XY-Wing: A=r9c123678 {1234679}, B=r7c6,r8c4 {378}, C=r46c6 {239}, X,Y=3,9, Z=7 => r9c4<>7
Forcing Net Contradiction in r3 => r1c7<>8
r1c7=8 (r1c1<>8) r1c2<>8 r3c1=8 r3c1<>4
r1c7=8 (r2c7<>8 r2c7=7 r2c6<>7) (r2c7<>8 r2c7=7 r2c9<>7) r6c7<>8 r6c8=8 r6c8<>1 r6c9=1 r2c9<>1 (r2c4=1 r2c4<>8 r8c4=8 r7c6<>8 r7c2=8 r7c2<>4) (r2c4=1 r2c4<>8 r8c4=8 r7c6<>8 r7c2=8 r7c2<>5) r2c9=5 r2c6<>5 r2c6=8 r2c6<>5 r2c9=5 r7c9<>5 r7c3=5 r7c3<>4 r7c7=4 r3c7<>4
r1c7=8 (r1c2<>8 r3c1=8 r3c1<>1) r6c7<>8 r6c8=8 r6c8<>1 r6c9=1 (r3c9<>1) r2c9<>1 r2c4=1 r3c5<>1 r3c8=1 r3c8<>4
Forcing Net Contradiction in r9 => r1c8<>7
r1c8=7 (r4c8<>7 r4c8=2 r8c8<>2 r8c8=5 r8c1<>5) (r2c7<>7 r2c7=8 r3c7<>8) (r2c7<>7 r2c7=8 r3c8<>8) (r2c7<>7 r2c7=8 r2c4<>8) r1c4<>7 r8c4=7 r8c4<>8 r1c4=8 r3c6<>8 r3c1=8 r8c1<>8 r8c1=6 (r9c1<>6) (r4c1<>6) r5c1<>6 r5c1=2 (r9c1<>2) (r8c1<>2) r4c1<>2 r4c1=1 r9c1<>1 r9c1=4
r1c8=7 (r9c8<>7) r4c8<>7 r4c8=2 r9c8<>2 r9c8=4
Forcing Net Contradiction in c6 => r1c9<>2
r1c9=2 (r6c9<>2 r6c9=1 r3c9<>1 r3c9=5 r3c6<>5) (r5c9<>2 r5c9=6 r4c7<>6) r1c9<>3 (r7c9=3 r7c5<>3 r7c5=1 r3c5<>1) r1c7=3 r1c7<>6 r3c7=6 (r3c6<>6) r3c5<>6 r3c5=2 r3c6<>2 r3c6=8
r1c9=2 (r5c9<>2 r5c1=2 r8c1<>2) (r3c9<>2) (r5c9<>2 r5c9=6 r3c9<>6) r6c9<>2 r6c9=1 r3c9<>1 r3c9=5 (r1c8<>5) r3c8<>5 r8c8=5 (r8c8<>7) r8c8<>2 r8c3=2 r8c3<>7 r8c4=7 r8c4<>8 r7c6=8
Forcing Net Contradiction in c6 => r1c5<>6
r1c5=6 (r1c5<>9) (r1c6<>6) r3c6<>6 r9c6=6 r9c6<>9 r9c4=9 r1c4<>9 r1c6=9 r1c6<>7
r1c5=6 r1c5<>9 r6c5=9 (r6c5<>2 r3c5=2 r3c9<>2) r4c6<>9 r4c6=2 (r4c1<>2) r4c3<>2 r5c1=2 r5c9<>2 r6c9=2 r6c9<>1 r6c8=1 r6c8<>8 r6c7=8 r2c7<>8 r2c7=7 r2c6<>7
r1c5=6 r1c5<>9 r6c5=9 (r6c5<>2 r3c5=2 r3c9<>2) r4c6<>9 r4c6=2 (r4c1<>2) r4c3<>2 r5c1=2 r5c9<>2 r6c9=2 r6c9<>1 r6c8=1 r6c8<>8 r6c7=8 r2c7<>8 r2c7=7 (r1c9<>7) r2c9<>7 r7c9=7 r7c6<>7
r1c5=6 (r1c6<>6) r3c6<>6 r9c6=6 r9c6<>7
Forcing Net Contradiction in r9 => r1c7<>7
r1c7=7 (r2c9<>7 r2c6=7 r2c6<>5 r2c9=5 r3c8<>5 r8c8=5 r8c1<>5) (r1c4<>7 r8c4=7 r8c4<>8 r1c4=8 r3c6<>8 r3c1=8 r8c1<>8) (r1c7<>6) r1c7<>3 r1c9=3 r1c9<>6 r1c6=6 r3c5<>6 r8c5=6 r8c1<>6 r8c1=2 (r9c1<>2) (r4c1<>2) r5c1<>2 r5c1=6 (r9c1<>6) r4c1<>6 r4c1=1 r9c1<>1 r9c1=4
r1c7=7 (r1c7<>2) (r2c7<>7 r2c7=8 r2c4<>8 r2c4=1 r3c5<>1) (r1c7<>6) r1c7<>3 r1c9=3 r1c9<>6 r1c6=6 (r1c6<>2) r3c5<>6 r3c5=2 r1c5<>2 r1c8=2 (r9c8<>2) r4c8<>2 r4c8=7 r9c8<>7 r9c8=4
Forcing Net Contradiction in c1 => r1c9<>5
r1c9=5 (r1c3<>5 r3c1=5 r3c6<>5) (r1c9<>6) r1c9<>3 (r7c9=3 r7c9<>7 r2c9=7 r2c7<>7 r2c7=8 r1c8<>8) (r7c9=3 r7c5<>3 r7c5=1 r3c5<>1) r1c7=3 r1c7<>6 r1c6=6 (r1c6<>7 r1c4=7 r1c4<>8) (r1c6<>8) (r3c6<>6) r3c5<>6 r3c5=2 r3c6<>2 r3c6=8 r7c6<>8 r7c2=8 r1c2<>8 r1c1=8 r1c1<>4
r1c9=5 (r1c1<>5) (r1c2<>5) r1c3<>5 r3c1=5 r3c1<>4
r1c9=5 (r1c9<>6) r1c9<>3 (r7c9=3 r7c5<>3 r7c5=1 r3c5<>1) r1c7=3 (r1c7<>2) r1c7<>6 r1c6=6 (r1c6<>2) r3c5<>6 r3c5=2 r1c5<>2 r1c8=2 (r9c8<>2) r4c8<>2 r4c8=7 r9c8<>7 r9c8=4 r9c1<>4
Forcing Net Contradiction in r9 => r1c9<>7
r1c9=7 (r2c9<>7 r2c6=7 r2c6<>5 r2c9=5 r3c8<>5 r8c8=5 r8c1<>5) (r1c9<>6) r1c9<>3 (r7c9=3 r7c6<>3 r7c6=8 r3c6<>8 r3c1=8 r8c1<>8) r1c7=3 r1c7<>6 r1c6=6 r3c5<>6 r8c5=6 r8c1<>6 r8c1=2 (r9c1<>2) (r4c1<>2) r5c1<>2 r5c1=6 (r9c1<>6) r4c1<>6 r4c1=1 r9c1<>1 r9c1=4
r1c9=7 (r2c7<>7 r2c7=8 r2c4<>8 r2c4=1 r3c5<>1) (r1c9<>6) r1c9<>3 r1c7=3 (r1c7<>2) r1c7<>6 r1c6=6 (r1c6<>2) r3c5<>6 r3c5=2 r1c5<>2 r1c8=2 (r9c8<>2) r4c8<>2 r4c8=7 r9c8<>7 r9c8=4
Locked Candidates Type 1 (Pointing): 7 in b3 => r2c6<>7
Forcing Net Contradiction in c2 => r2c6=5
r2c6<>5 (r2c9=5 r3c8<>5 r8c8=5 r8c8<>2) r2c6=8 (r2c4<>8 r8c4=8 r8c4<>7) r2c7<>8 r2c7=7 r2c9<>7 r7c9=7 r8c8<>7 r8c3=7 (r8c3<>2) r8c3<>2 r8c1=2 r9c3<>2 r4c3=2 r4c3<>3 r4c2=3
r2c6<>5 r2c6=8 (r2c4<>8 r8c4=8 r8c4<>7) r2c7<>8 r2c7=7 r2c9<>7 r7c9=7 (r7c6<>7 r7c6=3 r8c5<>3) r8c8<>7 r8c3=7 r8c3<>3 r8c2=3
Sue de Coq: r13c8 - {12458} (r489c8 - {2457}, r2c79 - {178}) => r3c7<>8, r3c9<>1, r6c8<>2
Forcing Chain Contradiction in r8c8 => r9c8<>7
r9c8=7 r4c8<>7 r4c8=2 r8c8<>2
r9c8=7 r4c8<>7 r4c8=2 r56c9<>2 r3c9=2 r3c9<>5 r7c9=5 r8c8<>5
r9c8=7 r8c8<>7
Forcing Net Contradiction in c1 => r4c8=7
r4c8<>7 r4c8=2 r6c9<>2 (r3c9=2 r3c7<>2) (r3c9=2 r3c5<>2) r6c9=1 r2c9<>1 r2c4=1 r3c5<>1 r3c5=6 r3c7<>6 r3c7=4 (r3c1<>4) r3c8<>4 r9c8=4 (r1c8<>4) r9c1<>4 r1c1=4 r1c1<>8
r4c8<>7 r4c8=2 r6c9<>2 (r3c9=2 r3c6<>2) (r3c9=2 r3c5<>2) r6c9=1 r2c9<>1 r2c4=1 r3c5<>1 r3c5=6 r3c6<>6 r3c6=8 r3c1<>8
r4c8<>7 r8c8=7 r8c4<>7 r8c4=8 r8c1<>8
Forcing Net Verity => r1c1<>1
r9c1=1 r1c1<>1
r9c1=2 (r4c1<>2) r5c1<>2 r5c1=6 r4c1<>6 r4c1=1 r1c1<>1
r9c1=4 r9c8<>4 r9c8=2 r8c8<>2 r8c8=5 (r8c1<>5) r7c9<>5 r3c9=5 r3c1<>5 r1c1=5 r1c1<>1
r9c1=6 (r4c1<>6) r5c1<>6 r5c1=2 r4c1<>2 r4c1=1 r1c1<>1
Forcing Net Verity => r1c1<>4
r1c8=5 (r1c8<>8) r3c9<>5 (r3c1=5 r3c1<>8) r7c9=5 r7c9<>7 r2c9=7 r2c7<>7 r2c7=8 r3c8<>8 r3c6=8 (r1c4<>8) (r1c6<>8) r7c6<>8 r7c2=8 r1c2<>8 r1c1=8 r1c1<>4
r3c8=5 (r3c8<>8) (r3c8<>1) r3c9<>5 r7c9=5 r7c9<>7 r2c9=7 (r2c7<>7 r2c7=8 r1c8<>8) r2c9<>1 r6c9=1 r6c8<>1 r1c8=1 (r1c2<>1) r1c3<>1 r3c1=1 r3c1<>8 r3c6=8 (r1c4<>8 r1c4=7 r1c4<>8) (r1c6<>8) r7c6<>8 r7c2=8 r1c2<>8 r1c1=8 r1c1<>4
r8c8=5 (r8c1<>5) r7c9<>5 r3c9=5 r3c1<>5 r1c1=5 r1c1<>4
Empty Rectangle: 4 in b9 (r39c1) => r3c7<>4
Sue de Coq: r1c78 - {1234568} (r1c123 - {1458}, r1c9,r3c7 - {236}) => r3c89<>2, r3c9<>6, r1c4<>1, r1c46<>8
Naked Single: r3c9=5
Hidden Single: r8c8=5
Hidden Single: r1c1=5
Locked Candidates Type 1 (Pointing): 2 in b9 => r9c13<>2
Locked Candidates Type 2 (Claiming): 2 in c9 => r46c7<>2
Skyscraper: 8 in r2c4,r3c1 (connected by r8c14) => r3c6<>8
Hidden Single: r7c6=8
Naked Single: r8c4=7
Naked Single: r1c4=9
Naked Single: r1c5=2
Naked Single: r9c4=1
Full House: r2c4=8
Naked Single: r3c6=6
Naked Single: r7c5=3
Naked Single: r2c7=7
Full House: r2c9=1
Naked Single: r1c6=7
Full House: r3c5=1
Naked Single: r3c7=2
Naked Single: r6c5=9
Full House: r8c5=6
Full House: r9c6=9
Naked Single: r7c9=7
Naked Single: r7c7=4
Naked Single: r6c9=2
Naked Single: r4c6=2
Full House: r6c6=3
Naked Single: r6c7=8
Naked Single: r9c7=3
Full House: r9c8=2
Naked Single: r5c9=6
Full House: r1c9=3
Full House: r5c1=2
Naked Single: r6c8=1
Full House: r4c7=9
Full House: r1c7=6
Naked Single: r8c1=8
Naked Single: r3c1=4
Full House: r3c8=8
Full House: r1c8=4
Naked Single: r8c2=3
Full House: r8c3=2
Naked Single: r1c3=1
Full House: r1c2=8
Naked Single: r9c1=6
Full House: r4c1=1
Naked Single: r4c3=3
Full House: r4c2=6
Naked Single: r7c3=5
Full House: r7c2=1
Naked Single: r9c2=4
Full House: r6c2=5
Full House: r6c3=4
Full House: r9c3=7
|
normal_sudoku_1208
|
.3...2..5..24..1..7...9.62......846...65...81.....65.2.5...7...9...3......16..8..
|
139862745862475193745391628513928467276543981498716532654287319987134256321659874
|
Basic 9x9 Sudoku 1208
|
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 . . . 2 . . 5
. . 2 4 . . 1 . .
7 . . . 9 . 6 2 .
. . . . . 8 4 6 .
. . 6 5 . . . 8 1
. . . . . 6 5 . 2
. 5 . . . 7 . . .
9 . . . 3 . . . .
. . 1 6 . . 8 . .
| 9
| 9
|
None
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Complete the sudoku board based on the rules and visual elements.
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sudoku
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sudoku_annotation
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hard
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139862745862475193745391628513928467276543981498716532654287319987134256321659874 #1 Extreme (7738)
Hidden Single: r3c8=2
Empty Rectangle: 3 in b7 (r57c7) => r5c1<>3
Discontinuous Nice Loop: 2 r8c2 -2- r8c7 -7- r1c7 -9- r1c3 =9= r2c2 =6= r8c2 => r8c2<>2
Grouped Discontinuous Nice Loop: 4 r7c8 -4- r1c8 =4= r3c9 =3= r2c89 -3- r2c6 -5- r8c6 =5= r8c8 =1= r7c8 => r7c8<>4
Grouped Discontinuous Nice Loop: 4 r8c8 -4- r1c8 =4= r3c9 =3= r2c89 -3- r2c6 -5- r8c6 =5= r8c8 => r8c8<>4
Almost Locked Set XZ-Rule: A=r1c3478 {14789}, B=r23c6,r3c4 {1358}, X=1, Z=8 => r1c5<>8
Discontinuous Nice Loop: 1 r7c5 -1- r7c8 =1= r8c8 =5= r8c6 -5- r9c5 =5= r2c5 =8= r7c5 => r7c5<>1
Forcing Chain Contradiction in r5 => r7c8=1
r7c8<>1 r8c8=1 r8c8<>5 r8c6=5 r9c5<>5 r2c5=5 r2c5<>7 r1c45=7 r1c7<>7 r1c7=9 r1c3<>9 r2c2=9 r5c2<>9
r7c8<>1 r7c4=1 r7c4<>9 r9c6=9 r5c6<>9
r7c8<>1 r8c8=1 r8c8<>5 r8c6=5 r2c6<>5 r2c6=3 r5c6<>3 r5c7=3 r5c7<>9
Forcing Chain Contradiction in c8 => r8c8=5
r8c8<>5 r8c6=5 r2c6<>5 r2c6=3 r2c8<>3
r8c8<>5 r8c6=5 r2c6<>5 r2c6=3 r5c6<>3 r5c7=3 r6c8<>3
r8c8<>5 r9c8=5 r9c8<>3
Grouped Discontinuous Nice Loop: 4 r9c5 -4- r56c5 =4= r5c6 =9= r9c6 =5= r9c5 => r9c5<>4
Forcing Chain Contradiction in r7c7 => r9c5=5
r9c5<>5 r9c5=2 r8c4<>2 r8c7=2 r7c7<>2
r9c5<>5 r9c6=5 r9c6<>9 r5c6=9 r5c6<>3 r5c7=3 r7c7<>3
r9c5<>5 r9c6=5 r9c6<>9 r7c4=9 r7c7<>9
Locked Candidates Type 2 (Claiming): 2 in r9 => r7c1<>2
Forcing Chain Contradiction in b8 => r1c1<>4
r1c1=4 r1c8<>4 r3c9=4 r3c9<>8 r2c9=8 r2c5<>8 r7c5=8 r7c5<>4
r1c1=4 r1c1<>1 r3c2=1 r3c6<>1 r8c6=1 r8c6<>4
r1c1=4 r1c8<>4 r9c8=4 r9c6<>4
Forcing Chain Contradiction in r5 => r1c8<>7
r1c8=7 r1c8<>4 r1c3=4 r1c3<>9 r2c2=9 r5c2<>9
r1c8=7 r1c8<>4 r9c8=4 r9c6<>4 r9c6=9 r5c6<>9
r1c8=7 r1c7<>7 r1c7=9 r5c7<>9
Almost Locked Set XY-Wing: A=r1c378 {4789}, B=r5c125 {2479}, C=r34678c3 {345789}, X,Y=8,9, Z=7 => r5c7<>7
Grouped AIC: 7 7- r2c5 =7= r1c45 -7- r1c7 =7= r8c7 -7- r8c3 =7= r89c2 -7- r5c2 =7= r5c5 -7 => r146c5<>7
Simple Colors Trap: 7 (r1c4,r5c5,r8c7) / (r1c7,r2c5,r5c2) => r8c2<>7
Multi Colors 1: 7 (r1c4,r5c5,r8c7) / (r1c7,r2c5,r5c2), (r8c3) / (r9c2) => r46c2,r8c9<>7
AIC: 4/9 9- r1c3 =9= r2c2 =6= r8c2 -6- r8c9 -4- r3c9 =4= r1c8 -4 => r1c3<>4, r1c8<>9
Naked Single: r1c8=4
AIC: 2/8 8- r7c5 =8= r2c5 =7= r1c4 -7- r1c7 =7= r8c7 =2= r8c4 -2 => r7c5<>2, r8c4<>8
Locked Candidates Type 1 (Pointing): 2 in b8 => r4c4<>2
Locked Candidates Type 1 (Pointing): 8 in b8 => r7c13<>8
XYZ-Wing: 2/3/4 in r59c1,r7c3 => r7c1<>4
AIC: 1 1- r1c1 =1= r3c2 =4= r3c3 -4- r7c3 -3- r7c1 -6- r8c2 =6= r2c2 =9= r1c3 -9- r1c7 -7- r8c7 -2- r8c4 -1- r8c6 =1= r3c6 -1 => r1c45,r3c2<>1
Naked Single: r1c5=6
Hidden Single: r1c1=1
Locked Candidates Type 2 (Claiming): 1 in c5 => r46c4<>1
Naked Pair: 7,8 in r1c4,r2c5 => r3c4<>8
Sue de Coq: r5c56 - {23479} (r5c1 - {24}, r46c4 - {379}) => r5c2<>2, r5c2<>4
XY-Chain: 8 8- r1c3 -9- r1c7 -7- r8c7 -2- r8c4 -1- r3c4 -3- r3c9 -8 => r3c23<>8
Naked Single: r3c2=4
Naked Single: r3c3=5
Hidden Single: r3c9=8
Hidden Single: r2c6=5
Hidden Single: r4c1=5
Naked Triple: 3,7,9 in r4c349 => r4c2<>9
XY-Chain: 7 7- r1c7 -9- r1c3 -8- r2c1 -6- r7c1 -3- r7c3 -4- r7c5 -8- r2c5 -7 => r1c4,r2c89<>7
Naked Single: r1c4=8
Naked Single: r1c3=9
Full House: r1c7=7
Naked Single: r2c5=7
Naked Single: r8c7=2
Naked Single: r8c4=1
Naked Single: r3c4=3
Full House: r3c6=1
Naked Single: r8c6=4
Naked Single: r7c5=8
Naked Single: r8c9=6
Naked Single: r9c6=9
Full House: r5c6=3
Full House: r7c4=2
Naked Single: r8c2=8
Full House: r8c3=7
Naked Single: r5c7=9
Full House: r7c7=3
Naked Single: r2c2=6
Full House: r2c1=8
Naked Single: r4c3=3
Naked Single: r9c2=2
Naked Single: r5c2=7
Naked Single: r7c1=6
Naked Single: r7c3=4
Full House: r6c3=8
Full House: r7c9=9
Full House: r9c1=3
Naked Single: r9c8=7
Full House: r9c9=4
Naked Single: r4c9=7
Full House: r2c9=3
Full House: r6c8=3
Full House: r2c8=9
Naked Single: r6c1=4
Full House: r5c1=2
Full House: r5c5=4
Naked Single: r4c2=1
Full House: r6c2=9
Naked Single: r4c4=9
Full House: r4c5=2
Full House: r6c5=1
Full House: r6c4=7
|
normal_sudoku_2503
|
......9475.6...2.....2.....3.2.7....87......3.1.9.........2...6.3.6..592...85.1.4
|
283165947546793281791284365362578419879412653415936728954321876138647592627859134
|
Basic 9x9 Sudoku 2503
|
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 4 7
5 . 6 . . . 2 . .
. . . 2 . . . . .
3 . 2 . 7 . . . .
8 7 . . . . . . 3
. 1 . 9 . . . . .
. . . . 2 . . . 6
. 3 . 6 . . 5 9 2
. . . 8 5 . 1 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
283165947546793281791284365362578419879412653415936728954321876138647592627859134 #1 Hard (724)
Naked Single: r9c9=4
Hidden Single: r5c3=9
Naked Single: r9c3=7
Naked Single: r9c8=3
Naked Single: r9c6=9
Hidden Single: r4c9=9
Hidden Single: r8c3=8
Hidden Single: r3c1=7
Hidden Single: r8c6=7
Hidden Single: r3c7=3
Hidden Single: r7c1=9
Hidden Single: r2c4=7
Hidden Single: r1c3=3
Hidden Single: r3c8=6
Hidden Single: r7c4=3
Hidden Single: r3c9=5
Naked Single: r6c9=8
Full House: r2c9=1
Full House: r2c8=8
Naked Single: r7c8=7
Full House: r7c7=8
Hidden Single: r4c6=8
Hidden Single: r6c7=7
Locked Candidates Type 2 (Claiming): 4 in c4 => r5c56,r6c56<>4
Locked Candidates Type 2 (Claiming): 4 in r6 => r4c2<>4
Naked Pair: 1,4 in r3c36 => r3c25<>4, r3c5<>1
Naked Pair: 1,4 in r37c6 => r15c6<>1, r2c6<>4
Naked Single: r2c6=3
Hidden Single: r6c5=3
Skyscraper: 4 in r2c2,r8c1 (connected by r28c5) => r7c2<>4
Naked Single: r7c2=5
Naked Single: r4c2=6
Naked Single: r4c7=4
Full House: r5c7=6
Naked Single: r6c1=4
Full House: r6c3=5
Naked Single: r9c2=2
Full House: r9c1=6
Naked Single: r5c5=1
Naked Single: r8c1=1
Full House: r8c5=4
Full House: r1c1=2
Full House: r7c3=4
Full House: r7c6=1
Full House: r3c3=1
Naked Single: r6c8=2
Full House: r6c6=6
Naked Single: r1c2=8
Naked Single: r4c4=5
Full House: r4c8=1
Full House: r5c8=5
Naked Single: r2c5=9
Full House: r2c2=4
Full House: r3c2=9
Naked Single: r3c6=4
Full House: r3c5=8
Full House: r1c5=6
Naked Single: r1c6=5
Full House: r1c4=1
Full House: r5c4=4
Full House: r5c6=2
|
normal_sudoku_5220
|
...13..56..9....875..6.82...96.....2...24....8..965.7..2..1.....78....2.6..7.2..5
|
284137956169524387537698214396871542751243869842965173925416738478359621613782495
|
Basic 9x9 Sudoku 5220
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 1 3 . . 5 6
. . 9 . . . . 8 7
5 . . 6 . 8 2 . .
. 9 6 . . . . . 2
. . . 2 4 . . . .
8 . . 9 6 5 . 7 .
. 2 . . 1 . . . .
. 7 8 . . . . 2 .
6 . . 7 . 2 . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
284137956169524387537698214396871542751243869842965173925416738478359621613782495 #1 Extreme (2598)
Naked Single: r6c5=6
Naked Single: r2c6=4
Naked Single: r2c4=5
Naked Single: r2c5=2
Hidden Single: r4c7=5
Hidden Single: r6c3=2
Hidden Single: r1c2=8
Hidden Single: r2c2=6
Hidden Single: r7c7=7
Hidden Single: r5c2=5
Hidden Single: r7c3=5
Hidden Single: r8c5=5
Hidden Single: r1c1=2
Locked Candidates Type 1 (Pointing): 7 in b1 => r5c3<>7
Naked Triple: 1,3,4 in r4c8,r6c79 => r5c789<>1, r5c789<>3
2-String Kite: 9 in r1c7,r9c5 (connected by r1c6,r3c5) => r9c7<>9
Empty Rectangle: 1 in b7 (r2c17) => r9c7<>1
Empty Rectangle: 3 in b7 (r2c17) => r9c7<>3
Empty Rectangle: 4 in b7 (r4c18) => r9c8<>4
Finned Swordfish: 1 r268 c179 fr6c2 => r45c1<>1
XY-Chain: 4 4- r1c7 -9- r1c6 -7- r3c5 -9- r9c5 -8- r9c7 -4 => r68c7<>4
Naked Pair: 1,3 in r26c7 => r8c7<>1, r8c7<>3
Skyscraper: 1 in r2c7,r8c9 (connected by r28c1) => r3c9<>1
Swordfish: 1 c179 r268 => r6c2<>1
Hidden Single: r5c3=1
Hidden Single: r4c6=1
Empty Rectangle: 3 in b4 (r26c7) => r2c1<>3
Naked Single: r2c1=1
Full House: r2c7=3
Naked Single: r6c7=1
Hidden Single: r3c8=1
Hidden Single: r9c2=1
Hidden Single: r8c9=1
X-Wing: 4 r19 c37 => r3c3<>4
X-Wing: 4 r36 c29 => r7c9<>4
Skyscraper: 9 in r3c9,r9c8 (connected by r39c5) => r7c9<>9
Empty Rectangle: 3 in b4 (r67c9) => r7c1<>3
W-Wing: 8/3 in r4c4,r7c9 connected by 3 in r4c8,r6c9 => r7c4<>8
Hidden Single: r7c9=8
Naked Single: r5c9=9
Naked Single: r9c7=4
Naked Single: r3c9=4
Full House: r1c7=9
Full House: r6c9=3
Full House: r6c2=4
Full House: r3c2=3
Naked Single: r5c8=6
Naked Single: r9c3=3
Naked Single: r1c6=7
Full House: r1c3=4
Full House: r3c3=7
Full House: r3c5=9
Naked Single: r8c7=6
Full House: r5c7=8
Full House: r4c8=4
Naked Single: r9c8=9
Full House: r9c5=8
Full House: r7c8=3
Full House: r4c5=7
Naked Single: r5c6=3
Full House: r4c4=8
Full House: r4c1=3
Full House: r5c1=7
Naked Single: r7c4=4
Full House: r8c4=3
Naked Single: r8c6=9
Full House: r7c6=6
Full House: r7c1=9
Full House: r8c1=4
|
normal_sudoku_4233
|
8.6.5...22.96..5...5.......7...1.4.......7.2..2.8...76..37842...8.9....44...3..1.
|
876453192219678543354129687738216459645397821921845376193784265582961734467532918
|
Basic 9x9 Sudoku 4233
|
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 . 6 . 5 . . . 2
2 . 9 6 . . 5 . .
. 5 . . . . . . .
7 . . . 1 . 4 . .
. . . . . 7 . 2 .
. 2 . 8 . . . 7 6
. . 3 7 8 4 2 . .
. 8 . 9 . . . . 4
4 . . . 3 . . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
876453192219678543354129687738216459645397821921845376193784265582961734467532918 #1 Extreme (3302)
Hidden Single: r7c7=2
Hidden Single: r8c6=1
Locked Candidates Type 1 (Pointing): 5 in b8 => r9c39<>5
Skyscraper: 7 in r1c2,r8c3 (connected by r18c7) => r3c3,r9c2<>7
Hidden Pair: 2,7 in r89c3 => r8c3<>5
Locked Candidates Type 1 (Pointing): 5 in b7 => r56c1<>5
AIC: 2/5 2- r4c4 =2= r4c6 =6= r9c6 =5= r9c4 -5 => r9c4<>2, r4c4<>5
Naked Single: r9c4=5
AIC: 3 3- r3c1 -1- r3c3 -4- r6c3 =4= r6c5 -4- r5c4 -3 => r3c4,r5c1<>3
Discontinuous Nice Loop: 1 r1c2 -1- r3c3 -4- r6c3 =4= r6c5 -4- r2c5 -7- r2c2 =7= r1c2 => r1c2<>1
Discontinuous Nice Loop: 3 r1c2 -3- r3c1 -1- r3c3 -4- r6c3 =4= r6c5 -4- r2c5 -7- r2c2 =7= r1c2 => r1c2<>3
Discontinuous Nice Loop: 3 r1c4 -3- r5c4 -4- r6c5 =4= r6c3 -4- r3c3 -1- r3c4 =1= r1c4 => r1c4<>3
Locked Candidates Type 1 (Pointing): 3 in b2 => r46c6<>3
Finned Swordfish: 3 c249 r245 fr3c9 => r2c8<>3
AIC: 3 3- r5c4 -4- r6c5 =4= r6c3 -4- r3c3 -1- r3c1 -3- r6c1 =3= r6c7 -3 => r5c79<>3
Discontinuous Nice Loop: 7 r2c9 -7- r2c5 -4- r6c5 =4= r6c3 -4- r3c3 -1- r2c2 =1= r2c9 => r2c9<>7
Grouped AIC: 4 4- r2c8 -8- r2c6 -3- r1c6 =3= r1c78 -3- r23c9 =3= r4c9 -3- r6c7 =3= r6c1 -3- r3c1 -1- r3c3 -4 => r2c2,r3c8<>4
W-Wing: 7/4 in r1c2,r2c5 connected by 4 in r12c8 => r2c2<>7
Hidden Single: r2c5=7
Hidden Single: r1c2=7
Hidden Single: r2c8=4
Hidden Single: r5c2=4
Naked Single: r5c4=3
Naked Single: r4c4=2
Hidden Single: r3c3=4
Naked Single: r3c4=1
Full House: r1c4=4
Naked Single: r3c1=3
Full House: r2c2=1
Hidden Single: r6c5=4
Hidden Single: r1c7=1
Hidden Single: r4c2=3
Hidden Single: r6c7=3
Hidden Single: r5c9=1
Hidden Single: r7c1=1
Naked Single: r6c1=9
Naked Single: r5c1=6
Full House: r8c1=5
Naked Single: r6c6=5
Full House: r6c3=1
Naked Single: r5c5=9
Full House: r4c6=6
Naked Single: r3c5=2
Full House: r8c5=6
Full House: r9c6=2
Naked Single: r5c7=8
Full House: r5c3=5
Full House: r4c3=8
Naked Single: r8c7=7
Naked Single: r8c8=3
Full House: r8c3=2
Full House: r9c3=7
Naked Single: r1c8=9
Full House: r1c6=3
Naked Single: r3c7=6
Full House: r9c7=9
Naked Single: r4c8=5
Full House: r4c9=9
Naked Single: r2c6=8
Full House: r2c9=3
Full House: r3c6=9
Naked Single: r3c8=8
Full House: r7c8=6
Full House: r3c9=7
Naked Single: r7c9=5
Full House: r9c9=8
Full House: r9c2=6
Full House: r7c2=9
|
normal_sudoku_1306
|
.1.62..9...9.7...1.....38......4.1...2.9...7.43..12....76.8431..83....52..1......
|
314628795869475231752193846695847123128936574437512968576284319983761452241359687
|
Basic 9x9 Sudoku 1306
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . 6 2 . . 9 .
. . 9 . 7 . . . 1
. . . . . 3 8 . .
. . . . 4 . 1 . .
. 2 . 9 . . . 7 .
4 3 . . 1 2 . . .
. 7 6 . 8 4 3 1 .
. 8 3 . . . . 5 2
. . 1 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
314628795869475231752193846695847123128936574437512968576284319983761452241359687 #1 Easy (402)
Naked Single: r7c8=1
Naked Single: r7c9=9
Naked Single: r8c1=9
Naked Single: r8c5=6
Hidden Single: r3c5=9
Hidden Single: r3c4=1
Naked Single: r8c4=7
Naked Single: r8c6=1
Full House: r8c7=4
Hidden Single: r4c8=2
Hidden Single: r2c7=2
Hidden Single: r5c1=1
Hidden Single: r3c3=2
Hidden Single: r9c2=4
Hidden Single: r6c7=9
Hidden Single: r4c2=9
Hidden Single: r9c6=9
Hidden Single: r2c4=4
Hidden Single: r6c3=7
Hidden Single: r4c6=7
Hidden Single: r5c9=4
Hidden Single: r2c8=3
Hidden Single: r1c3=4
Hidden Single: r4c1=6
Hidden Single: r3c8=4
Hidden Single: r5c6=6
Naked Single: r5c7=5
Naked Single: r1c7=7
Full House: r9c7=6
Naked Single: r5c3=8
Full House: r5c5=3
Full House: r4c3=5
Full House: r9c5=5
Naked Single: r1c9=5
Full House: r3c9=6
Naked Single: r9c8=8
Full House: r6c8=6
Full House: r9c9=7
Naked Single: r4c4=8
Full House: r4c9=3
Full House: r6c9=8
Full House: r6c4=5
Naked Single: r7c4=2
Full House: r7c1=5
Full House: r9c1=2
Full House: r9c4=3
Naked Single: r1c6=8
Full House: r1c1=3
Full House: r2c6=5
Naked Single: r3c2=5
Full House: r3c1=7
Full House: r2c1=8
Full House: r2c2=6
|
normal_sudoku_2823
|
.5..7....41....2....3..5...1..25.7.4...841.9...8...1.5.9..3.4.6.7..2......4.6....
|
956472813417683259823915647139256784765841392248397165592138476671524938384769521
|
Basic 9x9 Sudoku 2823
|
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 . . 7 . . . .
4 1 . . . . 2 . .
. . 3 . . 5 . . .
1 . . 2 5 . 7 . 4
. . . 8 4 1 . 9 .
. . 8 . . . 1 . 5
. 9 . . 3 . 4 . 6
. 7 . . 2 . . . .
. . 4 . 6 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
956472813417683259823915647139256784765841392248397165592138476671524938384769521 #1 Extreme (1970)
Naked Single: r5c5=4
Naked Single: r6c5=9
Naked Single: r2c5=8
Full House: r3c5=1
Hidden Single: r4c8=8
Hidden Single: r2c8=5
Hidden Single: r1c6=2
Hidden Single: r6c2=4
Hidden Single: r4c3=9
Naked Single: r1c3=6
Naked Single: r2c3=7
Hidden Single: r8c6=4
Hidden Single: r8c1=6
Hidden Single: r5c1=7
Hidden Single: r5c3=5
Naked Single: r8c3=1
Full House: r7c3=2
Naked Single: r8c8=3
Locked Candidates Type 1 (Pointing): 6 in b3 => r3c4<>6
Locked Candidates Type 1 (Pointing): 3 in b6 => r5c2<>3
Locked Candidates Type 2 (Claiming): 8 in r8 => r9c79<>8
Naked Triple: 5,8,9 in r8c79,r9c7 => r9c9<>9
XYZ-Wing: 3/8/9 in r1c17,r2c9 => r1c9<>9
AIC: 8 8- r7c6 =8= r9c6 =9= r2c6 -9- r2c9 -3- r5c9 -2- r5c2 =2= r3c2 =8= r9c2 -8 => r7c1,r9c6<>8
Naked Single: r7c1=5
Hidden Single: r7c6=8
Uniqueness Test 6: 5/9 in r8c47,r9c47 => r8c7,r9c4<>5
Hidden Single: r8c4=5
Hidden Single: r9c7=5
XYZ-Wing: 3/8/9 in r18c7,r2c9 => r3c7<>9
W-Wing: 8/9 in r1c1,r8c9 connected by 9 in r18c7 => r1c9<>8
XY-Wing: 2/8/6 in r3c27,r5c2 => r5c7<>6
Naked Single: r5c7=3
Naked Single: r5c9=2
Full House: r5c2=6
Full House: r6c8=6
Naked Single: r4c2=3
Full House: r4c6=6
Full House: r6c1=2
Naked Single: r9c2=8
Full House: r3c2=2
Full House: r9c1=3
Hidden Single: r3c7=6
Hidden Single: r9c8=2
Hidden Single: r2c4=6
Naked Pair: 8,9 in r1c17 => r1c4<>9
XY-Chain: 3 3- r1c9 -1- r9c9 -7- r9c6 -9- r2c6 -3 => r1c4,r2c9<>3
Naked Single: r1c4=4
Naked Single: r2c9=9
Full House: r2c6=3
Full House: r3c4=9
Naked Single: r1c8=1
Naked Single: r1c7=8
Full House: r8c7=9
Full House: r8c9=8
Naked Single: r6c6=7
Full House: r6c4=3
Full House: r9c6=9
Naked Single: r3c1=8
Full House: r1c1=9
Full House: r1c9=3
Naked Single: r7c8=7
Full House: r3c8=4
Full House: r3c9=7
Full House: r7c4=1
Full House: r9c9=1
Full House: r9c4=7
|
normal_sudoku_5227
|
.824..6......2..5...7.68......9...8.8....4....94.8.2..3........7...4...1.68..29..
|
182495637643721859957368142276913584831254796594687213319576428725849361468132975
|
Basic 9x9 Sudoku 5227
|
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 4 . . 6 . .
. . . . 2 . . 5 .
. . 7 . 6 8 . . .
. . . 9 . . . 8 .
8 . . . . 4 . . .
. 9 4 . 8 . 2 . .
3 . . . . . . . .
7 . . . 4 . . . 1
. 6 8 . . 2 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
182495637643721859957368142276913584831254796594687213319576428725849361468132975 #1 Extreme (43938) bf
Hidden Single: r5c1=8
Hidden Single: r5c4=2
Hidden Single: r4c1=2
Locked Candidates Type 1 (Pointing): 9 in b7 => r2c3<>9
Brute Force: r5c7=7
Hidden Single: r4c2=7
Forcing Net Contradiction in c5 => r7c5<>1
r7c5=1 r7c5<>9 r1c5=9 r1c5<>5
r7c5=1 (r9c5<>1 r9c1=1 r9c1<>5) (r9c5<>1 r9c1=1 r1c1<>1) r7c5<>9 r1c5=9 (r1c5<>7 r9c5=7 r9c5<>5) r1c1<>9 r1c1=5 (r3c1<>5) r3c2<>5 r3c4=5 r9c4<>5 r9c9=5 (r7c7<>5) r8c7<>5 r4c7=5 r4c5<>5
r7c5=1 (r7c5<>9 r1c5=9 r1c1<>9 r1c1=5 r3c2<>5) (r9c4<>1) r9c5<>1 r9c1=1 r9c1<>4 r7c2=4 (r7c2<>5) r7c2<>2 r8c2=2 r8c2<>5 r5c2=5 r5c5<>5
r7c5=1 r7c5<>5
r7c5=1 (r7c5<>7) r7c5<>9 r1c5=9 r1c5<>7 r9c5=7 r9c5<>5
Forcing Net Contradiction in b9 => r9c4<>7
r9c4=7 (r7c4<>7) (r7c5<>7) (r7c6<>7) (r2c4<>7) r6c4<>7 r6c6=7 r2c6<>7 r2c9=7 r7c9<>7 r7c8=7 r7c8<>6
r9c4=7 (r2c4<>7) r6c4<>7 r6c6=7 r2c6<>7 r2c9=7 r2c9<>8 r7c9=8 r7c9<>6
r9c4=7 (r2c4<>7) r6c4<>7 r6c6=7 r2c6<>7 r2c9=7 (r7c9<>7 r7c8=7 r7c8<>2) r2c9<>8 r7c9=8 r7c9<>2 r7c2=2 r8c2<>2 r8c8=2 r8c8<>6
Brute Force: r5c8=9
Forcing Net Contradiction in r2c9 => r2c9<>3
r2c9=3 (r2c9<>7) (r2c9<>9) r2c9<>8 r7c9=8 (r7c9<>7) r7c9<>2 r3c9=2 r3c9<>9 r1c9=9 (r1c9<>7) r1c9<>7 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7 r7c5<>9 r1c5=9 r1c9<>9 r1c9=3 r2c9<>3
Forcing Net Contradiction in r7c5 => r2c9<>4
r2c9=4 (r9c9<>4) (r4c9<>4 r4c7=4 r7c7<>4) r2c9<>8 r2c7=8 (r8c7<>8) r7c7<>8 r7c7=5 (r9c9<>5) r8c7<>5 r8c7=3 r9c9<>3 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7
r2c9=4 (r2c9<>9) r2c9<>8 r7c9=8 r7c9<>2 r3c9=2 r3c9<>9 r1c9=9 r1c5<>9 r7c5=9
Forcing Net Contradiction in r2c9 => r3c9<>3
r3c9=3 (r3c9<>9 r3c1=9 r1c1<>9) (r3c9<>9 r3c1=9 r2c1<>9) r3c9<>2 r7c9=2 (r7c9<>7) r7c9<>8 r2c9=8 (r2c9<>7) r2c9<>9 r2c6=9 (r1c5<>9) r1c6<>9 r1c9=9 (r1c9<>7) r1c9<>7 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7 r7c5<>9 r1c5=9 r1c9<>9 r1c9=3 r3c9<>3
Forcing Net Contradiction in r7c5 => r3c9<>4
r3c9=4 (r3c9<>9 r3c1=9 r1c1<>9) (r3c9<>9 r3c1=9 r2c1<>9) r3c9<>2 r7c9=2 (r7c9<>7) r7c9<>8 r2c9=8 (r2c9<>7) r2c9<>9 r2c6=9 (r1c5<>9) r1c6<>9 r1c9=9 r1c9<>7 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7
r3c9=4 (r3c9<>9 r3c1=9 r2c1<>9) r3c9<>2 r7c9=2 r7c9<>8 r2c9=8 r2c9<>9 r2c6=9 r1c5<>9 r7c5=9
Forcing Net Contradiction in c9 => r4c9<>6
r4c9=6 (r4c9<>4 r4c7=4 r3c7<>4 r3c8=4 r3c8<>2 r3c9=2 r3c9<>9) (r4c9<>4 r4c7=4 r7c7<>4) (r4c9<>4 r4c7=4 r3c7<>4 r3c8=4 r7c8<>4) (r4c9<>4 r4c7=4 r2c7<>4) r5c9<>6 r5c3=6 r2c3<>6 r2c1=6 r2c1<>4 r2c2=4 r7c2<>4 r7c9=4 (r7c9<>7) r7c9<>8 r2c9=8 (r2c9<>7) r2c9<>9 r1c9=9 (r1c9<>7) r1c9<>7 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7 r7c5<>9 r1c5=9 r1c9<>9 r1c9=3
r4c9=6 (r6c9<>6) (r5c9<>6 r5c3=6 r6c1<>6) r4c9<>4 r4c7=4 r4c7<>1 r6c8=1 r6c1<>1 r6c1=5 r6c9<>5 r6c9=3
Forcing Net Contradiction in r4c9 => r6c8<>6
r6c8=6 (r5c9<>6 r5c3=6 r4c3<>6 r4c6=6 r8c6<>6 r8c4=6 r8c4<>8 r8c7=8 r7c7<>8 r7c4=8 r7c4<>7) (r5c9<>6) r6c9<>6 r7c9=6 (r7c9<>7) (r7c9<>7) (r7c9<>2 r3c9=2 r3c9<>9) r7c9<>8 r2c9=8 (r2c9<>7) r2c9<>9 (r2c6=9 r2c6<>7) (r2c6=9 r1c5<>9 r7c5=9 r7c5<>7) r1c9=9 r1c9<>7 r9c9=7 r7c8<>7 r7c6=7 r6c6<>7 r6c4=7 r2c4<>7 r2c9=7 r2c9<>8 r7c9=8 r7c9<>6 r78c8=6 r6c8<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r7c9<>6
Forcing Net Contradiction in r5c5 => r5c9<>3
r5c9=3 (r6c8<>3 r6c8=1 r6c4<>1) (r6c8<>3 r6c8=1 r6c1<>1) (r5c3<>3 r4c3=3 r2c3<>3) r5c9<>6 r5c3=6 r2c3<>6 r2c3=1 (r2c4<>1) (r2c7<>1 r3c7=1 r3c4<>1) (r1c1<>1) (r2c1<>1) r3c1<>1 r9c1=1 r9c4<>1 r7c4=1 (r7c4<>6) r7c4<>8 r8c4=8 r8c4<>6 r6c4=6 r6c9<>6 r5c9=6 r5c9<>3
Forcing Net Contradiction in r7c5 => r7c9<>4
r7c9=4 (r7c9<>7) (r9c8<>4 r3c8=4 r3c8<>2 r3c9=2 r3c9<>9) r7c9<>8 r2c9=8 (r2c9<>7) r2c9<>9 r1c9=9 r1c9<>7 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7
r7c9=4 (r9c8<>4 r3c8=4 r3c8<>2 r3c9=2 r3c9<>9) r7c9<>8 r2c9=8 r2c9<>9 r1c9=9 r1c5<>9 r7c5=9
Forcing Net Contradiction in r7c5 => r7c9<>5
r7c9=5 (r5c9<>5 r5c9=6 r6c9<>6 r6c9=3 r9c9<>3) (r9c9<>5) (r7c7<>5) r8c7<>5 r4c7=5 r4c7<>4 r4c9=4 r9c9<>4 r9c9=7 (r9c5<>7) (r7c8<>7) r9c8<>7 r1c8=7 r1c5<>7 r7c5=7
r7c9=5 (r7c9<>2 r3c9=2 r3c9<>9) r7c9<>8 r2c9=8 r2c9<>9 r1c9=9 r1c5<>9 r7c5=9
Brute Force: r5c5=5
Naked Single: r5c9=6
Locked Candidates Type 2 (Claiming): 1 in r5 => r4c3,r6c1<>1
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c3<>3
Finned Swordfish: 5 r169 c169 fr9c4 => r78c6<>5
Hidden Single: r1c6=5
AIC: 2 2- r7c9 =2= r3c9 =9= r3c1 =5= r3c2 -5- r8c2 -2 => r7c2,r8c8<>2
Hidden Single: r8c2=2
Discontinuous Nice Loop: 1 r3c2 -1- r5c2 -3- r5c3 =3= r2c3 =6= r2c1 -6- r6c1 -5- r3c1 =5= r3c2 => r3c2<>1
Almost Locked Set XZ-Rule: A=r6c1 {56}, B=r2369c4 {13567}, X=6, Z=5 => r9c1<>5
Discontinuous Nice Loop: 4 r2c1 -4- r9c1 =4= r7c2 =5= r3c2 -5- r3c1 =5= r6c1 =6= r2c1 => r2c1<>4
Finned X-Wing: 4 c18 r39 fr7c8 => r9c9<>4
Hidden Single: r4c9=4
Empty Rectangle: 5 in b7 (r4c37) => r7c7<>5
Discontinuous Nice Loop: 1 r3c8 -1- r6c8 -3- r6c9 -5- r6c1 =5= r3c1 =9= r3c9 =2= r3c8 => r3c8<>1
Grouped Discontinuous Nice Loop: 6 r8c4 -6- r8c8 =6= r7c8 =2= r3c8 =4= r23c7 -4- r7c7 -8- r7c4 =8= r8c4 => r8c4<>6
Almost Locked Set XY-Wing: A=r3c1247 {13459}, B=r1689c8 {13467}, C=r1269c1 {14569}, X,Y=4,9, Z=3 => r3c8<>3
Almost Locked Set XY-Wing: A=r6c19 {356}, B=r2369c4 {13567}, C=r12379c9 {235789}, X,Y=3,5, Z=6 => r6c6<>6
Grouped Discontinuous Nice Loop: 7 r7c6 -7- r6c6 =7= r6c4 =6= r6c1 =5= r3c1 =9= r3c9 =2= r7c9 =8= r2c9 =7= r1c89 -7- r1c5 =7= r79c5 -7- r7c6 => r7c6<>7
Discontinuous Nice Loop: 1 r6c6 -1- r6c8 =1= r1c8 -1- r1c1 -9- r1c5 =9= r2c6 =7= r6c6 => r6c6<>1
Almost Locked Set XY-Wing: A=r8c368 {3569}, B=r23679c4 {135678}, C=r7c2356789 {12456789}, X,Y=5,8, Z=3 => r8c4<>3
Forcing Chain Contradiction in r8c6 => r6c6=7
r6c6<>7 r6c6=3 r8c6<>3
r6c6<>7 r6c4=7 r6c4<>6 r7c4=6 r8c6<>6
r6c6<>7 r6c6=3 r6c9<>3 r6c9=5 r6c1<>5 r4c3=5 r8c3<>5 r8c3=9 r8c6<>9
Grouped Discontinuous Nice Loop: 3 r2c4 -3- r2c23 =3= r3c2 =5= r3c1 -5- r6c1 -6- r6c4 =6= r7c4 =7= r2c4 => r2c4<>3
Forcing Chain Contradiction in r9c4 => r2c4=7
r2c4<>7 r2c4=1 r9c4<>1
r2c4<>7 r2c4=1 r3c4<>1 r3c4=3 r9c4<>3
r2c4<>7 r7c4=7 r7c4<>6 r6c4=6 r6c1<>6 r6c1=5 r6c9<>5 r9c9=5 r9c4<>5
Almost Locked Set Chain: 1- r1c15 {139} -3- r3c4 {13} -1- r6c149 {1356} -3- r6c8 {13} -1 => r1c8<>1
Hidden Single: r6c8=1
Finned Swordfish: 1 r149 c156 fr9c4 => r7c6<>1
W-Wing: 3/1 in r3c4,r4c5 connected by 1 in r24c6 => r1c5,r6c4<>3
Naked Single: r6c4=6
Naked Single: r6c1=5
Full House: r6c9=3
Full House: r4c7=5
Naked Single: r4c3=6
Hidden Single: r2c1=6
Hidden Single: r3c2=5
Hidden Single: r9c9=5
Hidden Single: r1c8=3
Naked Single: r8c8=6
Hidden Single: r3c4=3
Naked Single: r9c4=1
Naked Single: r9c1=4
Naked Single: r7c2=1
Naked Single: r9c8=7
Full House: r9c5=3
Naked Single: r5c2=3
Full House: r2c2=4
Full House: r5c3=1
Naked Single: r4c5=1
Full House: r4c6=3
Naked Single: r8c6=9
Naked Single: r2c3=3
Naked Single: r1c5=9
Full House: r2c6=1
Full House: r7c5=7
Full House: r7c6=6
Naked Single: r8c3=5
Full House: r7c3=9
Naked Single: r1c1=1
Full House: r1c9=7
Full House: r3c1=9
Naked Single: r2c7=8
Full House: r2c9=9
Naked Single: r8c4=8
Full House: r8c7=3
Full House: r7c4=5
Naked Single: r3c9=2
Full House: r7c9=8
Naked Single: r7c7=4
Full House: r3c7=1
Full House: r3c8=4
Full House: r7c8=2
|
normal_sudoku_6883
|
2...1...8..98...7..31..75.....9....51...2.....9...37..31...4..7.6.....54..46..3..
|
247519638659832471831467592473986125186725943592143786315294867968371254724658319
|
Basic 9x9 Sudoku 6883
|
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 . . . 8
. . 9 8 . . . 7 .
. 3 1 . . 7 5 . .
. . . 9 . . . . 5
1 . . . 2 . . . .
. 9 . . . 3 7 . .
3 1 . . . 4 . . 7
. 6 . . . . . 5 4
. . 4 6 . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
247519638659832471831467592473986125186725943592143786315294867968371254724658319 #1 Extreme (12242)
Hidden Single: r3c3=1
Hidden Single: r3c1=8
Almost Locked Set XZ-Rule: A=r2c126 {2456}, B=r3c4 {24}, X=2, Z=4 => r2c5<>4
Forcing Chain Contradiction in r2 => r5c4<>4
r5c4=4 r3c4<>4 r3c4=2 r2c6<>2
r5c4=4 r5c4<>7 r8c4=7 r8c4<>3 r8c5=3 r2c5<>3 r2c9=3 r2c9<>1 r2c7=1 r2c7<>2
r5c4=4 r5c4<>7 r8c4=7 r8c4<>3 r8c5=3 r2c5<>3 r2c9=3 r2c9<>2
Forcing Chain Contradiction in r2 => r3c5<>4
r3c5=4 r3c4<>4 r3c4=2 r2c6<>2
r3c5=4 r13c4<>4 r6c4=4 r6c4<>1 r8c4=1 r8c4<>3 r8c5=3 r2c5<>3 r2c9=3 r2c9<>1 r2c7=1 r2c7<>2
r3c5=4 r13c4<>4 r6c4=4 r6c4<>1 r8c4=1 r8c4<>3 r8c5=3 r2c5<>3 r2c9=3 r2c9<>2
Locked Candidates Type 1 (Pointing): 4 in b2 => r6c4<>4
Forcing Chain Contradiction in c9 => r2c6<>6
r2c6=6 r3c5<>6 r3c5=9 r3c9<>9
r2c6=6 r2c6<>2 r3c4=2 r3c4<>4 r1c4=4 r1c4<>3 r1c8=3 r2c9<>3 r5c9=3 r5c9<>9
r2c6=6 r3c5<>6 r3c5=9 r7c5<>9 r7c78=9 r9c9<>9
Forcing Net Contradiction in r4 => r2c7<>6
r2c7=6 (r2c1<>6 r1c3=6 r4c3<>6) (r3c9<>6 r3c5=6 r4c5<>6) (r4c7<>6) (r7c7<>6 r7c8=6 r4c8<>6) (r5c7<>6) (r2c1<>6 r1c3=6 r5c3<>6) (r7c7<>6 r7c8=6 r5c8<>6) r2c7<>1 r2c9=1 r2c9<>3 r5c9=3 r5c9<>6 r5c6=6 r4c6<>6 r4c1=6 r4c1<>7
r2c7=6 r2c1<>6 r1c3=6 r1c3<>7 r1c2=7 r4c2<>7
r2c7=6 r2c7<>1 r2c9=1 r2c9<>3 r5c9=3 r4c8<>3 r4c3=3 r4c3<>7
r2c7=6 (r2c1<>6 r1c3=6 r1c3<>5) (r2c1<>6 r1c3=6 r1c3<>7 r1c2=7 r1c2<>5) (r3c8<>6) r3c9<>6 r3c5=6 r3c5<>9 r1c6=9 r1c6<>5 r1c4=5 r5c4<>5 r5c4=7 r4c5<>7
Forcing Net Contradiction in c3 => r2c9<>6
r2c9=6 r2c9<>3 r5c9=3 r4c8<>3 r4c3=3 r4c3<>2
r2c9=6 (r6c9<>6) r2c9<>3 r2c5=3 r8c5<>3 r8c4=3 r8c4<>1 r6c4=1 r6c9<>1 r6c9=2 r6c3<>2
r2c9=6 (r2c9<>1 r2c7=1 r2c7<>2 r2c6=2 r3c4<>2) r2c9<>3 r2c5=3 r8c5<>3 r8c4=3 r8c4<>2 r7c4=2 r7c3<>2
r2c9=6 (r2c1<>6 r1c3=6 r1c3<>7) r2c9<>3 (r5c9=3 r4c8<>3 r4c3=3 r4c3<>7) r2c5=3 r8c5<>3 r8c4=3 r8c4<>7 r5c4=7 r5c3<>7 r8c3=7 r8c3<>2
Forcing Net Verity => r4c3<>8
r9c2=2 r9c2<>8 r45c2=8 r4c3<>8
r9c6=2 (r2c6<>2 r2c6=5 r2c2<>5 r2c2=4 r1c2<>4) (r7c4<>2) r8c4<>2 r3c4=2 r3c4<>4 r3c8=4 (r1c7<>4) r1c8<>4 r1c4=4 r1c4<>3 r1c8=3 r4c8<>3 r4c3=3 r4c3<>8
r9c8=2 (r9c8<>1) (r7c7<>2) (r8c7<>2) r9c2<>2 r4c2=2 r4c7<>2 r2c7=2 r2c7<>1 r2c9=1 r9c9<>1 r9c6=1 (r4c6<>1) (r8c4<>1) r8c6<>1 r8c7=1 r4c7<>1 r4c8=1 r4c8<>3 r4c3=3 r4c3<>8
r9c9=2 (r7c7<>2) (r8c7<>2) r9c2<>2 r4c2=2 r4c7<>2 r2c7=2 r2c7<>1 r2c9=1 r2c9<>3 r5c9=3 r4c8<>3 r4c3=3 r4c3<>8
Forcing Net Contradiction in r6 => r4c7<>2
r4c7=2 (r7c7<>2) (r8c7<>2) r4c2<>2 r9c2=2 (r9c2<>5) (r9c8<>2) r9c9<>2 r7c8=2 r7c4<>2 r7c4=5 (r9c5<>5) r9c6<>5 r9c1=5 r6c1<>5
r4c7=2 (r6c8<>2) r6c9<>2 r6c3=2 r6c3<>5
r4c7=2 (r7c7<>2) (r8c7<>2) r4c2<>2 r9c2=2 (r9c8<>2) r9c9<>2 r7c8=2 r7c4<>2 r7c4=5 r6c4<>5
r4c7=2 (r7c7<>2) (r8c7<>2) r4c2<>2 r9c2=2 (r9c8<>2) r9c9<>2 r7c8=2 (r7c8<>9) r7c8<>6 r7c7=6 (r1c7<>6) r7c7<>9 r7c5=9 r3c5<>9 r3c5=6 (r2c5<>6) (r1c6<>6) r2c5<>6 r2c1=6 r1c3<>6 r1c8=6 r1c8<>3 r1c4=3 r2c5<>3 r2c5=5 r6c5<>5
Forcing Net Contradiction in c2 => r5c4=7
r5c4<>7 (r5c4=5 r6c4<>5 r6c4=1 r4c6<>1) r8c4=7 r8c4<>3 r8c5=3 r2c5<>3 r2c9=3 r2c9<>1 r2c7=1 r4c7<>1 r4c8=1 (r4c8<>2) r4c8<>3 r4c3=3 r4c3<>2 r4c2=2
r5c4<>7 r5c4=5 r7c4<>5 r7c4=2 (r9c6<>2) (r7c7<>2) (r8c6<>2) r9c6<>2 r2c6=2 r2c7<>2 r8c7=2 (r9c8<>2) r9c9<>2 r9c2=2
Forcing Net Contradiction in r9 => r2c1<>5
r2c1=5 (r9c1<>5) r2c1<>6 r2c5=6 (r3c5<>6 r3c5=9 r1c6<>9 r1c6=5 r9c6<>5) r2c5<>3 r8c5=3 r8c5<>7 r9c5=7 r9c5<>5 r9c2=5 r9c2<>2
r2c1=5 r2c6<>5 r2c6=2 r9c6<>2
r2c1=5 r2c6<>5 r2c6=2 r2c7<>2 r78c7=2 r9c8<>2
r2c1=5 r2c6<>5 r2c6=2 r2c7<>2 r78c7=2 r9c9<>2
Empty Rectangle: 5 in b5 (r69c1) => r9c6<>5
Forcing Chain Contradiction in r9 => r9c2<>5
r9c2=5 r9c2<>2
r9c2=5 r9c1<>5 r6c1=5 r5c23<>5 r5c6=5 r2c6<>5 r2c6=2 r9c6<>2
r9c2=5 r9c1<>5 r6c1=5 r5c23<>5 r5c6=5 r2c6<>5 r2c6=2 r2c7<>2 r78c7=2 r9c8<>2
r9c2=5 r9c1<>5 r6c1=5 r5c23<>5 r5c6=5 r2c6<>5 r2c6=2 r2c7<>2 r78c7=2 r9c9<>2
AIC: 7/9 9- r8c1 =9= r9c1 =5= r9c5 =7= r8c5 -7 => r8c1<>7, r8c5<>9
Naked Single: r8c1=9
Discontinuous Nice Loop: 6 r4c1 -6- r2c1 =6= r2c5 =3= r8c5 =7= r8c3 -7- r9c1 =7= r4c1 => r4c1<>6
Discontinuous Nice Loop: 7 r4c3 -7- r8c3 =7= r8c5 =3= r8c4 -3- r1c4 =3= r1c8 -3- r4c8 =3= r4c3 => r4c3<>7
Forcing Chain Verity => r2c5<>5
r1c2=5 r1c2<>7 r1c3=7 r8c3<>7 r8c5=7 r8c5<>3 r2c5=3 r2c5<>5
r2c2=5 r2c5<>5
r5c2=5 r5c6<>5 r12c6=5 r2c5<>5
Discontinuous Nice Loop: 6 r1c8 -6- r1c3 =6= r2c1 -6- r2c5 -3- r2c9 =3= r1c8 => r1c8<>6
Discontinuous Nice Loop: 6 r4c3 -6- r1c3 =6= r2c1 -6- r2c5 -3- r2c9 =3= r5c9 -3- r5c3 =3= r4c3 => r4c3<>6
Forcing Chain Contradiction in r5 => r4c3=3
r4c3<>3 r4c8=3 r1c8<>3 r1c4=3 r1c4<>4 r3c4=4 r3c4<>2 r2c6=2 r2c6<>5 r2c2=5 r5c2<>5
r4c3<>3 r5c3=3 r5c3<>5
r4c3<>3 r4c8=3 r1c8<>3 r1c4=3 r1c4<>5 r12c6=5 r5c6<>5
Forcing Chain Contradiction in c9 => r1c6<>6
r1c6=6 r1c6<>9 r3c5=9 r3c9<>9
r1c6=6 r2c5<>6 r2c5=3 r2c9<>3 r5c9=3 r5c9<>9
r1c6=6 r1c6<>9 r9c6=9 r9c9<>9
Locked Candidates Type 1 (Pointing): 6 in b2 => r46c5<>6
Finned Swordfish: 6 c159 r236 fr5c9 => r6c8<>6
Discontinuous Nice Loop: 6 r5c8 -6- r7c8 =6= r7c7 -6- r1c7 =6= r1c3 -6- r2c1 =6= r2c5 =3= r2c9 -3- r5c9 =3= r5c8 => r5c8<>6
Forcing Chain Contradiction in r9 => r3c8<>2
r3c8=2 r4c8<>2 r4c2=2 r9c2<>2
r3c8=2 r3c4<>2 r2c6=2 r9c6<>2
r3c8=2 r9c8<>2
r3c8=2 r2c7<>2 r78c7=2 r9c9<>2
Discontinuous Nice Loop: 6 r3c9 -6- r3c5 -9- r1c6 -5- r2c6 -2- r3c4 =2= r3c9 => r3c9<>6
Locked Candidates Type 2 (Claiming): 6 in c9 => r4c78,r5c7<>6
Hidden Single: r4c6=6
Hidden Single: r6c4=1
AIC: 9 9- r1c6 =9= r3c5 =6= r2c5 -6- r2c1 =6= r6c1 -6- r6c9 -2- r3c9 -9 => r1c78,r3c5<>9
Naked Single: r3c5=6
Naked Single: r2c5=3
Hidden Single: r1c6=9
Hidden Single: r2c1=6
Hidden Single: r7c8=6
Hidden Single: r1c7=6
Hidden Single: r1c8=3
Hidden Single: r8c4=3
Hidden Single: r5c9=3
Hidden Single: r5c3=6
Hidden Single: r6c9=6
Locked Candidates Type 1 (Pointing): 4 in b1 => r45c2<>4
Locked Candidates Type 1 (Pointing): 2 in b6 => r9c8<>2
Locked Candidates Type 2 (Claiming): 4 in r5 => r4c78,r6c8<>4
Naked Pair: 5,8 in r5c26 => r5c78<>8
Naked Pair: 4,9 in r35c8 => r9c8<>9
X-Wing: 5 r25 c26 => r1c2<>5
AIC: 2 2- r2c6 -5- r2c2 =5= r1c3 =7= r8c3 -7- r8c5 =7= r9c5 =9= r9c9 -9- r3c9 -2 => r2c79,r3c4<>2
Naked Single: r2c9=1
Naked Single: r3c4=4
Naked Single: r2c7=4
Naked Single: r1c4=5
Full House: r2c6=2
Full House: r2c2=5
Full House: r7c4=2
Naked Single: r3c8=9
Full House: r3c9=2
Full House: r9c9=9
Naked Single: r5c7=9
Naked Single: r1c3=7
Full House: r1c2=4
Naked Single: r5c2=8
Naked Single: r5c8=4
Full House: r5c6=5
Naked Single: r7c7=8
Naked Single: r4c7=1
Full House: r8c7=2
Full House: r9c8=1
Naked Single: r7c3=5
Full House: r7c5=9
Naked Single: r8c3=8
Full House: r6c3=2
Naked Single: r9c6=8
Full House: r8c6=1
Full House: r8c5=7
Full House: r9c5=5
Naked Single: r9c1=7
Full House: r9c2=2
Full House: r4c2=7
Naked Single: r6c8=8
Full House: r4c8=2
Naked Single: r4c1=4
Full House: r4c5=8
Full House: r6c5=4
Full House: r6c1=5
|
normal_sudoku_587
|
3864.7..57...291..........8..1398..7..21..8....7.6...1..4.....9.9..324.......6...
|
386417295745829163219653748451398627962175834837264951624581379598732416173946582
|
Basic 9x9 Sudoku 587
|
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 6 4 . 7 . . 5
7 . . . 2 9 1 . .
. . . . . . . . 8
. . 1 3 9 8 . . 7
. . 2 1 . . 8 . .
. . 7 . 6 . . . 1
. . 4 . . . . . 9
. 9 . . 3 2 4 . .
. . . . . 6 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
386417295745829163219653748451398627962175834837264951624581379598732416173946582 #1 Easy (262)
Naked Single: r1c4=4
Naked Single: r2c3=5
Naked Single: r8c9=6
Naked Single: r1c5=1
Naked Single: r2c2=4
Naked Single: r3c3=9
Naked Single: r8c3=8
Full House: r9c3=3
Naked Single: r3c5=5
Naked Single: r2c9=3
Naked Single: r9c9=2
Full House: r5c9=4
Naked Single: r3c4=6
Naked Single: r3c6=3
Full House: r2c4=8
Full House: r2c8=6
Naked Single: r5c5=7
Naked Single: r5c6=5
Naked Single: r7c5=8
Full House: r9c5=4
Naked Single: r6c4=2
Full House: r6c6=4
Full House: r7c6=1
Hidden Single: r6c1=8
Hidden Single: r9c4=9
Hidden Single: r3c8=4
Hidden Single: r4c1=4
Hidden Single: r4c7=6
Naked Single: r4c2=5
Full House: r4c8=2
Naked Single: r6c2=3
Naked Single: r1c8=9
Full House: r1c7=2
Full House: r3c7=7
Naked Single: r5c2=6
Full House: r5c1=9
Full House: r5c8=3
Naked Single: r6c8=5
Full House: r6c7=9
Naked Single: r9c7=5
Full House: r7c7=3
Naked Single: r7c8=7
Naked Single: r9c1=1
Naked Single: r7c2=2
Naked Single: r7c4=5
Full House: r7c1=6
Full House: r8c4=7
Naked Single: r8c8=1
Full House: r8c1=5
Full House: r3c1=2
Full House: r9c2=7
Full House: r9c8=8
Full House: r3c2=1
|
normal_sudoku_1600
|
1.48.....2..5.6..336.......8..2......237....4.4..1..6.....5..........92.78.49..56
|
154839672279546813368127549891264735623785194547913268916352487435678921782491356
|
Basic 9x9 Sudoku 1600
|
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 . 4 8 . . . . .
2 . . 5 . 6 . . 3
3 6 . . . . . . .
8 . . 2 . . . . .
. 2 3 7 . . . . 4
. 4 . . 1 . . 6 .
. . . . 5 . . . .
. . . . . . 9 2 .
7 8 . 4 9 . . 5 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
154839672279546813368127549891264735623785194547913268916352487435678921782491356 #1 Unfair (1310)
Naked Single: r9c1=7
Hidden Single: r8c1=4
Hidden Single: r1c7=6
Locked Candidates Type 1 (Pointing): 1 in b2 => r3c789<>1
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c789<>1
Locked Candidates Type 1 (Pointing): 6 in b5 => r8c5<>6
Locked Candidates Type 1 (Pointing): 2 in b8 => r13c6<>2
Locked Candidates Type 2 (Claiming): 5 in c1 => r4c23,r6c3<>5
Locked Candidates Type 2 (Claiming): 1 in c9 => r7c78,r9c7<>1
Naked Single: r9c7=3
Hidden Single: r4c8=3
Uniqueness Test 4: 1/2 in r7c36,r9c36 => r7c36<>1
Discontinuous Nice Loop: 7 r4c2 -7- r6c3 -9- r6c4 =9= r3c4 =1= r3c6 -1- r9c6 =1= r9c3 -1- r4c3 =1= r4c2 => r4c2<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r23c3<>7
AIC: 4 4- r2c5 -7- r2c2 =7= r1c2 =5= r1c9 =2= r1c5 =3= r8c5 =8= r5c5 =6= r4c5 =4= r4c6 -4 => r3c6,r4c5<>4
Naked Single: r4c5=6
Naked Single: r5c5=8
Hidden Single: r4c6=4
Hidden Single: r5c1=6
Naked Single: r7c1=9
Full House: r6c1=5
Hidden Single: r5c6=5
Naked Single: r5c7=1
Full House: r5c8=9
Naked Single: r1c8=7
Hidden Single: r2c8=1
Hidden Single: r2c2=7
Naked Single: r2c5=4
Naked Single: r2c7=8
Full House: r2c3=9
Naked Single: r3c8=4
Full House: r7c8=8
Naked Single: r1c2=5
Full House: r3c3=8
Naked Single: r6c3=7
Naked Single: r4c3=1
Full House: r4c2=9
Naked Single: r6c7=2
Naked Single: r9c3=2
Full House: r9c6=1
Naked Single: r3c7=5
Naked Single: r6c9=8
Naked Single: r7c3=6
Full House: r8c3=5
Naked Single: r4c7=7
Full House: r4c9=5
Full House: r7c7=4
Naked Single: r7c4=3
Naked Single: r6c4=9
Full House: r6c6=3
Naked Single: r7c2=1
Full House: r8c2=3
Naked Single: r8c4=6
Full House: r3c4=1
Naked Single: r8c5=7
Naked Single: r1c6=9
Naked Single: r7c9=7
Full House: r7c6=2
Full House: r8c6=8
Full House: r8c9=1
Full House: r3c6=7
Naked Single: r3c5=2
Full House: r1c5=3
Full House: r1c9=2
Full House: r3c9=9
|
normal_sudoku_5533
|
........7..9.6...41..8..6.5..35.1...9..32.5.1.......4.2....61.88.62...7..9..8....
|
468159327359762814127834695673541982984327561512698743245976138836215479791483256
|
Basic 9x9 Sudoku 5533
|
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 . 6 . . . 4
1 . . 8 . . 6 . 5
. . 3 5 . 1 . . .
9 . . 3 2 . 5 . 1
. . . . . . . 4 .
2 . . . . 6 1 . 8
8 . 6 2 . . . 7 .
. 9 . . 8 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
468159327359762814127834695673541982984327561512698743245976138836215479791483256 #1 Extreme (18036) bf
Almost Locked Set XZ-Rule: A=r8c679 {3459}, B=r3467c5 {34579}, X=5, Z=3,4,9 => r8c5<>3, r8c5<>4, r8c5<>9
Brute Force: r5c4=3
Hidden Single: r6c4=6
Empty Rectangle: 9 in b3 (r17c4) => r7c8<>9
Locked Candidates Type 1 (Pointing): 9 in b9 => r8c6<>9
Finned Franken Swordfish: 4 c14b5 r149 fr5c6 fr7c4 => r9c6<>4
Forcing Chain Contradiction in r7c8 => r6c7<>2
r6c7=2 r4c789<>2 r4c2=2 r4c2<>8 r4c78=8 r5c8<>8 r5c8=6 r9c8<>6 r9c9=6 r9c9<>2 r46c9=2 r6c7<>2
Forcing Chain Contradiction in c1 => r8c6<>4
r8c6=4 r79c4<>4 r1c4=4 r1c1<>4
r8c6=4 r5c6<>4 r4c5=4 r4c1<>4
r8c6=4 r8c7<>4 r9c7=4 r9c1<>4
Almost Locked Set XZ-Rule: A=r7c23,r8c2,r9c1 {13457}, B=r8c56,r9c6 {1357}, X=1, Z=7 => r9c3<>7
Forcing Chain Contradiction in r9c6 => r1c1<>5
r1c1=5 r1c5<>5 r78c5=5 r8c6<>5 r8c6=3 r9c6<>3
r1c1=5 r1c5<>5 r78c5=5 r9c6<>5
r1c1=5 r6c1<>5 r6c1=7 r5c23<>7 r5c6=7 r9c6<>7
Forcing Chain Contradiction in r4 => r1c5<>9
r1c5=9 r4c5<>9
r1c5=9 r6c5<>9 r6c5=7 r6c7<>7 r4c7=7 r4c7<>9
r1c5=9 r1c7<>9 r13c8=9 r4c8<>9
r1c5=9 r1c5<>5 r78c5=5 r8c6<>5 r8c6=3 r8c9<>3 r8c9=9 r4c9<>9
Forcing Chain Verity => r6c2<>5
r9c1=7 r6c1<>7 r6c1=5 r6c2<>5
r9c4=7 r9c4<>1 r9c3=1 r6c3<>1 r6c2=1 r6c2<>5
r9c6=7 r5c6<>7 r5c23=7 r6c1<>7 r6c1=5 r6c2<>5
Forcing Chain Contradiction in r1c4 => r6c2<>7
r6c2=7 r6c2<>1 r6c3=1 r9c3<>1 r9c4=1 r1c4<>1
r6c2=7 r5c23<>7 r5c6=7 r5c6<>4 r13c6=4 r1c4<>4
r6c2=7 r6c5<>7 r6c5=9 r6c6<>9 r13c6=9 r1c4<>9
Forcing Chain Contradiction in r9 => r6c9<>9
r6c9=9 r6c5<>9 r6c5=7 r6c1<>7 r6c1=5 r9c1<>5
r6c9=9 r8c9<>9 r8c7=9 r8c7<>4 r8c2=4 r8c2<>1 r9c3=1 r9c3<>5
r6c9=9 r8c9<>9 r8c9=3 r8c6<>3 r8c6=5 r9c6<>5
r6c9=9 r6c9<>3 r89c9=3 r7c8<>3 r7c8=5 r9c8<>5
Forcing Chain Contradiction in c1 => r9c6<>7
r9c6=7 r79c4<>7 r2c4=7 r2c1<>7
r9c6=7 r5c6<>7 r5c23=7 r4c1<>7
r9c6=7 r5c6<>7 r5c23=7 r6c1<>7
r9c6=7 r9c1<>7
Locked Pair: 3,5 in r89c6 => r123c6,r7c5<>3, r12c6,r78c5<>5
Naked Single: r8c5=1
Hidden Single: r1c5=5
Hidden Single: r6c2=1
Hidden Single: r9c3=1
Hidden Single: r3c5=3
AIC: 3 3- r6c7 =3= r6c9 =2= r6c3 =5= r7c3 -5- r7c8 -3 => r89c7<>3
XY-Chain: 2 2- r6c9 -3- r8c9 -9- r8c7 -4- r9c7 -2 => r4c7,r9c9<>2
Locked Candidates Type 2 (Claiming): 2 in c9 => r4c8<>2
Discontinuous Nice Loop: 3 r1c8 -3- r7c8 -5- r7c3 =5= r6c3 -5- r6c1 -7- r9c1 =7= r9c4 -7- r2c4 -1- r2c8 =1= r1c8 => r1c8<>3
Discontinuous Nice Loop: 2 r2c2 -2- r4c2 =2= r6c3 =5= r6c1 -5- r2c1 =5= r2c2 => r2c2<>2
Discontinuous Nice Loop: 3 r9c1 -3- r9c6 -5- r9c8 =5= r7c8 =3= r7c2 -3- r9c1 => r9c1<>3
Locked Candidates Type 1 (Pointing): 3 in b7 => r12c2<>3
AIC: 6 6- r5c8 =6= r5c2 -6- r1c2 =6= r1c1 =3= r1c7 -3- r6c7 =3= r6c9 -3- r9c9 -6 => r4c9,r9c8<>6
Hidden Single: r9c9=6
Continuous Nice Loop: 3/5/7/8 5= r6c3 =2= r6c9 =3= r8c9 -3- r7c8 -5- r7c3 =5= r6c3 =2 => r9c8<>3, r7c2<>5, r6c3<>7, r6c3<>8
Hidden Single: r9c6=3
Naked Single: r8c6=5
Hidden Single: r2c2=5
Locked Candidates Type 1 (Pointing): 8 in b1 => r1c78<>8
Sashimi Swordfish: 7 r259 c146 fr5c2 fr5c3 => r46c1<>7
Naked Single: r6c1=5
Naked Single: r6c3=2
Naked Single: r6c9=3
Naked Single: r8c9=9
Full House: r4c9=2
Naked Single: r8c7=4
Full House: r8c2=3
Naked Single: r9c7=2
Naked Single: r9c8=5
Full House: r7c8=3
Hidden Single: r7c3=5
2-String Kite: 4 in r4c5,r9c1 (connected by r7c5,r9c4) => r4c1<>4
Naked Single: r4c1=6
Hidden Single: r1c2=6
Hidden Single: r5c8=6
Hidden Single: r3c2=2
Naked Single: r3c8=9
Naked Single: r1c7=3
Naked Single: r4c8=8
Naked Single: r1c1=4
Naked Single: r2c7=8
Naked Single: r1c3=8
Naked Single: r3c3=7
Full House: r2c1=3
Full House: r9c1=7
Full House: r3c6=4
Full House: r5c3=4
Full House: r7c2=4
Full House: r9c4=4
Naked Single: r4c2=7
Full House: r5c2=8
Full House: r5c6=7
Naked Single: r4c7=9
Full House: r4c5=4
Full House: r6c7=7
Naked Single: r2c6=2
Naked Single: r6c5=9
Full House: r6c6=8
Full House: r1c6=9
Full House: r7c5=7
Full House: r7c4=9
Naked Single: r2c8=1
Full House: r1c8=2
Full House: r1c4=1
Full House: r2c4=7
|
normal_sudoku_3637
|
8.52.3.4.4..8....3.3......7.4.3.1.7.5.....3.2..9.6....7864.2.591.3.......5.7.....
|
875293641461875293932146587648321975517984362329567418786432159193658724254719836
|
Basic 9x9 Sudoku 3637
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 . 5 2 . 3 . 4 .
4 . . 8 . . . . 3
. 3 . . . . . . 7
. 4 . 3 . 1 . 7 .
5 . . . . . 3 . 2
. . 9 . 6 . . . .
7 8 6 4 . 2 . 5 9
1 . 3 . . . . . .
. 5 . 7 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
875293641461875293932146587648321975517984362329567418786432159193658724254719836 #1 Easy (208)
Naked Single: r7c6=2
Naked Single: r5c4=9
Naked Single: r6c4=5
Naked Single: r7c7=1
Full House: r7c5=3
Naked Single: r8c4=6
Full House: r3c4=1
Naked Single: r3c3=2
Naked Single: r4c3=8
Naked Single: r9c3=4
Naked Single: r4c5=2
Naked Single: r4c1=6
Naked Single: r3c1=9
Naked Single: r4c9=5
Full House: r4c7=9
Naked Single: r9c1=2
Full House: r6c1=3
Full House: r8c2=9
Naked Single: r1c7=6
Naked Single: r1c9=1
Naked Single: r3c8=8
Naked Single: r9c7=8
Naked Single: r1c2=7
Full House: r1c5=9
Naked Single: r3c7=5
Naked Single: r6c8=1
Naked Single: r8c8=2
Naked Single: r6c7=4
Naked Single: r8c9=4
Naked Single: r9c6=9
Naked Single: r9c9=6
Full House: r6c9=8
Full House: r5c8=6
Naked Single: r2c3=1
Full House: r2c2=6
Full House: r5c3=7
Naked Single: r5c2=1
Full House: r6c2=2
Full House: r6c6=7
Naked Single: r9c5=1
Full House: r9c8=3
Full House: r2c8=9
Full House: r2c7=2
Full House: r8c7=7
Naked Single: r3c5=4
Full House: r3c6=6
Naked Single: r2c6=5
Full House: r2c5=7
Naked Single: r5c5=8
Full House: r5c6=4
Full House: r8c6=8
Full House: r8c5=5
|
normal_sudoku_148
|
5...68...67.5..8.....1........7..1.6.9....5.8..3.9.274.8.......96.25...33.2...6..
|
521968347679534812438127965254783196796412538813695274185346729967251483342879651
|
Basic 9x9 Sudoku 148
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
5 . . . 6 8 . . .
6 7 . 5 . . 8 . .
. . . 1 . . . . .
. . . 7 . . 1 . 6
. 9 . . . . 5 . 8
. . 3 . 9 . 2 7 4
. 8 . . . . . . .
9 6 . 2 5 . . . 3
3 . 2 . . . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
521968347679534812438127965254783196796412538813695274185346729967251483342879651 #1 Medium (526)
Naked Single: r6c9=4
Naked Single: r5c8=3
Full House: r4c8=9
Hidden Single: r5c3=6
Naked Single: r5c4=4
Hidden Single: r8c8=8
Hidden Single: r3c8=6
Hidden Single: r5c1=7
Hidden Single: r3c9=5
Locked Candidates Type 1 (Pointing): 7 in b2 => r3c7<>7
Locked Candidates Type 1 (Pointing): 1 in b4 => r6c6<>1
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c56<>2
Locked Candidates Type 2 (Claiming): 3 in r2 => r1c4,r3c56<>3
Naked Single: r1c4=9
Naked Single: r9c4=8
Naked Single: r6c4=6
Full House: r7c4=3
Naked Single: r6c6=5
Naked Single: r4c6=3
Naked Single: r6c2=1
Full House: r6c1=8
Naked Single: r4c5=8
Hidden Single: r7c6=6
Hidden Single: r2c5=3
Hidden Single: r7c1=1
Hidden Single: r3c3=8
Hidden Single: r9c6=9
Hidden Single: r8c6=1
Naked Single: r5c6=2
Full House: r5c5=1
Naked Single: r2c6=4
Full House: r3c6=7
Full House: r3c5=2
Naked Single: r3c1=4
Full House: r4c1=2
Naked Single: r1c3=1
Naked Single: r3c2=3
Full House: r3c7=9
Naked Single: r2c3=9
Full House: r1c2=2
Naked Single: r1c8=4
Naked Single: r1c9=7
Full House: r1c7=3
Naked Single: r9c9=1
Naked Single: r2c9=2
Full House: r2c8=1
Full House: r7c9=9
Naked Single: r9c8=5
Full House: r7c8=2
Naked Single: r9c2=4
Full House: r4c2=5
Full House: r9c5=7
Full House: r4c3=4
Full House: r7c5=4
Naked Single: r8c3=7
Full House: r7c3=5
Full House: r7c7=7
Full House: r8c7=4
|
normal_sudoku_5629
|
7..3...41..1.5....43...1.5...3..7.899...8..1....9..4.....6..8....8..5.73.2.....6.
|
785326941261459738439871652143267589972584316856913427517632894698145273324798165
|
Basic 9x9 Sudoku 5629
|
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 . . . 4 1
. . 1 . 5 . . . .
4 3 . . . 1 . 5 .
. . 3 . . 7 . 8 9
9 . . . 8 . . 1 .
. . . 9 . . 4 . .
. . . 6 . . 8 . .
. . 8 . . 5 . 7 3
. 2 . . . . . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
785326941261459738439871652143267589972584316856913427517632894698145273324798165 #1 Extreme (25244) bf
Forcing Net Contradiction in r7c8 => r6c1<>6
r6c1=6 (r8c1<>6 r8c2=6 r2c2<>6) r6c1<>8 r6c2=8 r2c2<>8 r2c2=9 (r2c6<>9) (r1c3<>9) (r3c3<>9) r2c8<>9 r7c8=9 (r7c6<>9) r7c3<>9 r9c3=9 r9c6<>9 r1c6=9 r1c6<>8 r1c2=8 r6c2<>8 r6c1=8 r6c1<>6
Brute Force: r5c8=1
Forcing Chain Contradiction in c4 => r5c3<>5
r5c3=5 r5c4<>5 r4c4=5 r4c4<>1
r5c3=5 r6c123<>5 r6c9=5 r45c7<>5 r9c7=5 r9c7<>1 r8c7=1 r8c4<>1
r5c3=5 r1c3<>5 r1c2=5 r1c2<>8 r1c6=8 r9c6<>8 r9c4=8 r9c4<>1
Forcing Net Contradiction in b7 => r7c5<>9
r7c5=9 r7c2<>9
r7c5=9 r7c3<>9
r7c5=9 (r7c6<>9) r7c8<>9 r7c8=2 (r7c6<>2) r6c8<>2 r6c8=3 r5c7<>3 r5c6=3 r7c6<>3 r7c6=4 (r8c4<>4) r8c5<>4 r8c2=4 r8c2<>9
r7c5=9 (r3c5<>9) r7c8<>9 r2c8=9 r3c7<>9 r3c3=9 r9c3<>9
Brute Force: r5c9=6
Almost Locked Set XZ-Rule: A=r13489c7 {125679}, B=r23c9 {278}, X=7, Z=2 => r2c7<>2
Forcing Net Verity => r4c7=5
r4c7=5 r4c7=5
r5c7=5 (r5c7<>3 r2c7=3 r2c7<>7 r3c7=7 r3c7<>6 r1c7=6 r1c6<>6) (r5c7<>3 r2c7=3 r2c7<>7 r3c7=7 r3c7<>6 r1c7=6 r1c5<>6) (r5c7<>3 r2c7=3 r2c7<>7 r3c7=7 r3c7<>6 r1c7=6 r1c6<>6) (r5c7<>3 r2c7=3 r2c7<>7) r5c7<>7 r6c9=7 r2c9<>7 r2c4=7 r2c4<>4 r2c6=4 (r2c6<>6) r2c6<>6 r6c6=6 (r4c5<>6) r6c5<>6 r3c5=6 (r3c3<>6) r2c6<>6 r6c6=6 (r4c5<>6) r6c3<>6 r1c3=6 (r2c1<>6) r2c2<>6 r2c7=6 r2c7<>3 r2c8=3 r6c8<>3 r6c8=2 r4c7<>2 r4c7=5
r6c9=5 (r4c7<>5 r4c7=2 r4c1<>2) (r4c7<>5 r4c7=2 r6c8<>2) (r7c9<>5) r9c9<>5 r9c9=4 r7c9<>4 r7c9=2 r7c8<>2 r2c8=2 r2c1<>2 r6c1=2 (r6c1<>8 r6c2=8 r1c2<>8 r1c6=8 r9c6<>8 r9c4=8 r9c4<>1 r8c4=1 r8c7<>1 r9c7=1 r9c7<>5) (r6c1<>8 r6c2=8 r6c2<>1 r6c5=1 r4c5<>1) (r6c1<>1) r6c8<>2 r6c8=3 (r6c6<>3 r6c6=6 r4c5<>6) (r6c6<>3 r6c6=6 r2c6<>6) r2c8<>3 r2c7=3 r2c7<>6 r2c2=6 r4c2<>6 r4c1=6 (r4c1<>1) r8c1<>6 r8c1=1 (r7c1<>1) r7c2<>1 r7c5=1 r6c5<>1 r6c2=1 r4c2<>1 r4c4=1 r4c4<>5 r5c4=5 r5c7<>5 (r9c7=5 r9c7<>1 r8c7=1 r8c1<>1 r8c1=6 r2c1<>6) r4c7=5
Hidden Single: r5c4=5
Naked Triple: 1,2,9 in r7c8,r89c7 => r7c9<>2
Forcing Chain Contradiction in r5 => r2c8<>2
r2c8=2 r2c1<>2 r46c1=2 r5c3<>2
r2c8=2 r2c8<>3 r2c7=3 r5c7<>3 r5c6=3 r5c6<>2
r2c8=2 r7c8<>2 r8c7=2 r5c7<>2
Forcing Net Verity => r2c8=3
r1c7=2 (r1c7<>6) (r3c7<>2) (r2c9<>2) r3c9<>2 r6c9=2 (r6c9<>7 r5c7=7 r3c7<>7) r6c8<>2 r7c8=2 r7c8<>9 r2c8=9 r3c7<>9 r3c7=6 r3c3<>6 r1c3=6 (r2c1<>6) r1c2<>6 r1c5=6 (r1c3<>6) r2c6<>6 r6c6=6 (r2c6<>6) (r1c6<>6) (r1c6<>6) (r6c3<>6) r6c3<>6 r3c3=6 r2c2<>6 r2c7=6 r2c7<>3 r2c8=3
r3c7=2 (r3c9<>2 r6c9=2 r6c8<>2 r7c8=2 r7c8<>9 r2c8=9 r1c7<>9 r1c7=6 r1c3<>6 r3c3=6 r2c1<>6) r3c7<>6 r3c5=6 (r3c3<>6) r2c6<>6 r6c6=6 (r2c6<>6) (r1c6<>6) r6c3<>6 r1c3=6 r2c2<>6 r2c7=6 r2c7<>3 r2c8=3
r5c7=2 (r6c9<>2 r6c9=7 r2c9<>7) r6c8<>2 r6c8=3 r2c8<>3 (r2c8=9 r1c7<>9 r1c7=6 r1c6<>6) (r2c8=9 r1c7<>9 r1c7=6 r1c5<>6) (r2c8=9 r1c7<>9 r1c7=6 r1c6<>6) r2c7=3 r2c7<>7 r2c4=7 r2c4<>4 r2c6=4 (r2c6<>6) r2c6<>6 r6c6=6 (r4c5<>6) r6c5<>6 r3c5=6 (r3c3<>6) r2c6<>6 r6c6=6 (r4c5<>6) r6c3<>6 r1c3=6 (r2c1<>6) r2c2<>6 r2c7=6 r2c7<>3 r2c8=3
r8c7=2 r7c8<>2 r7c8=9 r2c8<>9 r2c8=3
Naked Single: r6c8=2
Full House: r7c8=9
Naked Single: r6c9=7
Full House: r5c7=3
Naked Single: r9c7=1
Naked Single: r8c7=2
Swordfish: 2 r157 c356 => r2c6,r3c35,r4c5<>2
Naked Triple: 6,7,9 in r3c357 => r3c4<>7
Uniqueness Test 1: 2/8 in r2c49,r3c49 => r2c4<>2, r2c4<>8
Sue de Coq: r1c56 - {2689} (r1c7 - {69}, r3c4 - {28}) => r2c6<>8, r1c23<>6, r1c23<>9
2-String Kite: 9 in r3c3,r8c5 (connected by r8c2,r9c3) => r3c5<>9
Empty Rectangle: 6 in b5 (r36c3) => r3c5<>6
Naked Single: r3c5=7
Naked Single: r2c4=4
Naked Single: r8c4=1
Naked Single: r4c4=2
Naked Single: r8c1=6
Naked Single: r3c4=8
Full House: r9c4=7
Naked Single: r5c6=4
Naked Single: r4c1=1
Naked Single: r3c9=2
Naked Single: r5c2=7
Full House: r5c3=2
Naked Single: r4c5=6
Full House: r4c2=4
Naked Single: r2c9=8
Naked Single: r1c3=5
Naked Single: r6c6=3
Full House: r6c5=1
Naked Single: r8c2=9
Full House: r8c5=4
Naked Single: r2c1=2
Naked Single: r1c2=8
Naked Single: r6c3=6
Naked Single: r7c6=2
Naked Single: r2c2=6
Full House: r3c3=9
Full House: r3c7=6
Naked Single: r9c3=4
Full House: r7c3=7
Naked Single: r6c2=5
Full House: r6c1=8
Full House: r7c2=1
Naked Single: r7c5=3
Naked Single: r2c6=9
Full House: r2c7=7
Full House: r1c7=9
Naked Single: r9c9=5
Full House: r7c9=4
Full House: r7c1=5
Full House: r9c1=3
Naked Single: r9c5=9
Full House: r1c5=2
Full House: r1c6=6
Full House: r9c6=8
|
normal_sudoku_6551
|
6138..5..8...........3...48..51..8.....5.64.3....4..1.9.7.8.3.......3..6....5.1..
|
613824579874965231592317648425139867189576423736248915947681352251493786368752194
|
Basic 9x9 Sudoku 6551
|
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 1 3 8 . . 5 . .
8 . . . . . . . .
. . . 3 . . . 4 8
. . 5 1 . . 8 . .
. . . 5 . 6 4 . 3
. . . . 4 . . 1 .
9 . 7 . 8 . 3 . .
. . . . . 3 . . 6
. . . . 5 . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
613824579874965231592317648425139867189576423736248915947681352251493786368752194 #1 Extreme (14306) bf
Hidden Single: r3c9=8
Hidden Single: r1c6=4
Hidden Single: r6c9=5
Hidden Single: r6c6=8
Hidden Single: r2c8=3
Hidden Single: r4c5=3
Hidden Single: r7c6=1
Hidden Single: r2c9=1
Hidden Single: r4c8=6
Hidden Single: r3c5=1
Hidden Single: r3c7=6
Hidden Single: r2c5=6
Brute Force: r6c2=3
Hidden Single: r9c1=3
Hidden Single: r6c3=6
Forcing Chain Contradiction in c5 => r8c7<>9
r8c7=9 r2c7<>9 r1c89=9 r1c5<>9
r8c7=9 r6c7<>9 r6c4=9 r5c5<>9
r8c7=9 r8c5<>9
Forcing Chain Contradiction in r4 => r2c2<>9
r2c2=9 r4c2<>9
r2c2=9 r3c23<>9 r3c6=9 r4c6<>9
r2c2=9 r2c7<>9 r6c7=9 r4c9<>9
Forcing Chain Verity => r5c8<>9
r8c4=9 r6c4<>9 r6c7=9 r5c8<>9
r8c5=9 r1c5<>9 r1c89=9 r2c7<>9 r6c7=9 r5c8<>9
r8c8=9 r5c8<>9
Almost Locked Set XY-Wing: A=r8c57 {279}, B=r2359c3 {12489}, C=r5c158 {1279}, X,Y=1,9, Z=2 => r8c3<>2
Forcing Chain Contradiction in c5 => r7c8=5
r7c8<>5 r7c8=2 r8c7<>2 r8c7=7 r2c7<>7 r1c89=7 r1c5<>7
r7c8<>5 r7c8=2 r5c8<>2 r5c8=7 r5c5<>7
r7c8<>5 r7c8=2 r8c7<>2 r8c7=7 r8c5<>7
Forcing Chain Contradiction in c5 => r6c7<>2
r6c7=2 r6c7<>9 r2c7=9 r2c7<>7 r1c89=7 r1c5<>7
r6c7=2 r5c8<>2 r5c8=7 r5c5<>7
r6c7=2 r8c7<>2 r8c7=7 r8c5<>7
Grouped Discontinuous Nice Loop: 2 r8c5 -2- r8c7 =2= r2c7 -2- r1c89 =2= r1c5 -2- r8c5 => r8c5<>2
Turbot Fish: 2 r1c5 =2= r5c5 -2- r5c8 =2= r4c9 => r1c9<>2
W-Wing: 7/2 in r5c8,r8c7 connected by 2 in r1c8,r2c7 => r6c7,r89c8<>7
Naked Single: r6c7=9
Locked Candidates Type 1 (Pointing): 9 in b3 => r1c5<>9
W-Wing: 7/2 in r1c5,r8c7 connected by 2 in r1c8,r2c7 => r8c5<>7
Naked Single: r8c5=9
Hidden Single: r4c6=9
Hidden Single: r2c4=9
Naked Pair: 2,7 in r5c58 => r5c123<>2, r5c12<>7
Naked Single: r5c1=1
Hidden Single: r8c3=1
X-Wing: 2 r15 c58 => r89c8<>2
Naked Single: r8c8=8
Naked Single: r9c8=9
Hidden Single: r1c9=9
Remote Pair: 2/7 r6c4 -7- r5c5 -2- r5c8 -7- r1c8 -2- r2c7 -7- r8c7 => r8c4<>2, r8c4<>7
Naked Single: r8c4=4
Hidden Single: r8c7=7
Full House: r2c7=2
Full House: r1c8=7
Full House: r1c5=2
Full House: r5c8=2
Full House: r5c5=7
Full House: r4c9=7
Full House: r6c4=2
Full House: r6c1=7
Naked Single: r2c3=4
Naked Single: r7c4=6
Full House: r9c4=7
Full House: r9c6=2
Naked Single: r9c3=8
Naked Single: r9c9=4
Full House: r7c9=2
Full House: r9c2=6
Full House: r7c2=4
Naked Single: r5c3=9
Full House: r3c3=2
Full House: r5c2=8
Naked Single: r4c2=2
Full House: r4c1=4
Naked Single: r3c1=5
Full House: r8c1=2
Full House: r8c2=5
Naked Single: r2c2=7
Full House: r2c6=5
Full House: r3c6=7
Full House: r3c2=9
|
normal_sudoku_701
|
..9.5.3....3.87..4.4..1..56......24.5....4..7.....9.38.2....8...96.....23.52....9
|
679452381153687924842913756917836245538124697264579138421795863796348512385261479
|
Basic 9x9 Sudoku 701
|
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 . 3 . .
. . 3 . 8 7 . . 4
. 4 . . 1 . . 5 6
. . . . . . 2 4 .
5 . . . . 4 . . 7
. . . . . 9 . 3 8
. 2 . . . . 8 . .
. 9 6 . . . . . 2
3 . 5 2 . . . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
679452381153687924842913756917836245538124697264579138421795863796348512385261479 #1 Hard (1056)
Naked Single: r3c9=6
Naked Single: r1c9=1
Naked Single: r2c7=9
Naked Single: r4c9=5
Full House: r7c9=3
Naked Single: r2c4=6
Naked Single: r2c8=2
Naked Single: r3c7=7
Full House: r1c8=8
Naked Single: r1c4=4
Naked Single: r1c6=2
Naked Single: r2c1=1
Full House: r2c2=5
Naked Single: r3c6=3
Full House: r3c4=9
Hidden Single: r4c1=9
Hidden Single: r7c5=9
Hidden Single: r5c8=9
Hidden Single: r6c4=5
Hidden Single: r8c7=5
Hidden Single: r7c6=5
Hidden Single: r9c7=4
Hidden Single: r7c8=6
Hidden Single: r8c5=4
Hidden Single: r8c4=3
Locked Candidates Type 1 (Pointing): 8 in b8 => r4c6<>8
Empty Rectangle: 1 in b5 (r7c34) => r4c3<>1
W-Wing: 7/8 in r4c3,r8c1 connected by 8 in r3c13 => r6c1,r7c3<>7
Locked Candidates Type 2 (Claiming): 7 in c3 => r46c2<>7
Naked Pair: 1,6 in r6c27 => r6c15<>6, r6c3<>1
Hidden Single: r1c1=6
Full House: r1c2=7
W-Wing: 8/1 in r5c4,r9c2 connected by 1 in r7c34 => r5c2<>8
W-Wing: 1/7 in r7c4,r8c8 connected by 7 in r9c58 => r8c6<>1
Naked Single: r8c6=8
Naked Single: r8c1=7
Full House: r8c8=1
Full House: r9c8=7
Naked Single: r7c1=4
Naked Single: r9c5=6
Naked Single: r6c1=2
Full House: r3c1=8
Full House: r3c3=2
Naked Single: r7c3=1
Full House: r7c4=7
Full House: r9c6=1
Full House: r9c2=8
Full House: r4c6=6
Naked Single: r6c5=7
Naked Single: r5c3=8
Naked Single: r4c5=3
Full House: r5c5=2
Naked Single: r6c3=4
Full House: r4c3=7
Naked Single: r5c4=1
Full House: r4c4=8
Full House: r4c2=1
Naked Single: r5c7=6
Full House: r5c2=3
Full House: r6c2=6
Full House: r6c7=1
|
normal_sudoku_4220
|
..41...6..96....21....9.4..8.3..7....4.9..67.........8....53.....7.1..5..2.4..1..
|
784125369396748521152396487813267945245981673679534218461853792937612854528479136
|
Basic 9x9 Sudoku 4220
|
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 1 . . . 6 .
. 9 6 . . . . 2 1
. . . . 9 . 4 . .
8 . 3 . . 7 . . .
. 4 . 9 . . 6 7 .
. . . . . . . . 8
. . . . 5 3 . . .
. . 7 . 1 . . 5 .
. 2 . 4 . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
784125369396748521152396487813267945245981673679534218461853792937612854528479136 #1 Extreme (29766) bf
Locked Candidates Type 1 (Pointing): 9 in b4 => r6c78<>9
Brute Force: r5c8=7
Forcing Net Contradiction in c9 => r3c4<>8
r3c4=8 (r8c4<>8) (r1c5<>8) (r1c6<>8) (r2c4<>8) (r2c5<>8) r2c6<>8 r2c7=8 (r8c7<>8) r1c7<>8 r1c2=8 r8c2<>8 r8c6=8 r5c6<>8 r5c5=8 r5c5<>3 r5c9=3
r3c4=8 (r3c8<>8 r3c8=3 r9c8<>3) (r3c8<>8 r3c8=3 r3c2<>3) (r1c5<>8) (r1c6<>8) (r2c4<>8) (r2c5<>8) r2c6<>8 r2c7=8 r1c7<>8 r1c2=8 r1c2<>3 r8c2=3 r9c1<>3 r9c9=3
Forcing Net Contradiction in r9 => r3c6<>8
r3c6=8 (r3c8<>8 r3c8=3 r3c2<>3) (r1c5<>8) (r1c6<>8) (r2c4<>8) (r2c5<>8) r2c6<>8 r2c7=8 r1c7<>8 r1c2=8 r1c2<>3 r8c2=3 r9c1<>3
r3c6=8 r3c8<>8 r3c8=3 r9c8<>3
r3c6=8 r5c6<>8 r5c5=8 r5c5<>3 r5c9=3 r9c9<>3
Forcing Net Contradiction in r9 => r6c2<>1
r6c2=1 (r7c2<>1) (r6c2<>6) r6c2<>7 r6c1=7 r6c1<>6 r4c2=6 (r8c2<>6) r7c2<>6 r7c2=8 r8c2<>8 r8c2=3 r9c1<>3
r6c2=1 (r7c2<>1) (r6c2<>6) r6c2<>7 r6c1=7 r6c1<>6 r4c2=6 r7c2<>6 r7c2=8 (r7c3<>8) r9c3<>8 r3c3=8 r3c8<>8 r3c8=3 r9c8<>3
r6c2=1 (r5c1<>1) r5c3<>1 r5c6=1 r5c6<>8 r5c5=8 r5c5<>3 r5c9=3 r9c9<>3
Brute Force: r5c9=3
Forcing Chain Contradiction in c2 => r1c2<>5
r1c2=5 r1c2<>3
r1c2=5 r1c2<>8 r3c23=8 r3c8<>8 r3c8=3 r3c2<>3
r1c2=5 r1c2<>8 r3c23=8 r3c8<>8 r3c8=3 r9c8<>3 r9c1=3 r8c2<>3
Grouped Discontinuous Nice Loop: 5 r3c6 -5- r3c2 =5= r46c2 -5- r5c13 =5= r5c6 -5- r3c6 => r3c6<>5
Grouped Discontinuous Nice Loop: 6 r6c6 -6- r46c5 =6= r9c5 =7= r9c9 -7- r3c9 -5- r3c2 =5= r46c2 -5- r5c13 =5= r5c6 =1= r6c6 => r6c6<>6
Grouped Discontinuous Nice Loop: 9 r7c7 =7= r12c7 -7- r3c9 -5- r3c2 =5= r46c2 -5- r5c13 =5= r5c6 =1= r6c6 -1- r6c8 =1= r4c8 =9= r79c8 -9- r7c7 => r7c7<>9
Grouped Discontinuous Nice Loop: 8 r9c5 -8- r5c5 =8= r5c6 =5= r5c13 -5- r46c2 =5= r3c2 -5- r3c9 -7- r9c9 =7= r9c5 => r9c5<>8
Forcing Chain Contradiction in c2 => r1c2<>7
r1c2=7 r1c2<>3
r1c2=7 r1c2<>8 r3c23=8 r3c8<>8 r3c8=3 r3c2<>3
r1c2=7 r1c2<>8 r3c23=8 r3c8<>8 r3c8=3 r9c8<>3 r9c1=3 r8c2<>3
Forcing Chain Contradiction in r4c4 => r4c5<>2
r4c5=2 r4c4<>2
r4c5=2 r4c79<>2 r6c7=2 r6c7<>5 r4c79=5 r4c4<>5
r4c5=2 r4c5<>4 r4c89=4 r6c8<>4 r6c8=1 r6c6<>1 r5c6=1 r5c6<>5 r5c13=5 r46c2<>5 r3c2=5 r3c9<>5 r3c9=7 r9c9<>7 r9c5=7 r9c5<>6 r46c5=6 r4c4<>6
Forcing Chain Contradiction in r1c6 => r6c3<>5
r6c3=5 r6c7<>5 r6c7=2 r4c79<>2 r4c4=2 r78c4<>2 r8c6=2 r1c6<>2
r6c3=5 r5c13<>5 r5c6=5 r1c6<>5
r6c3=5 r9c3<>5 r9c1=5 r9c1<>3 r9c8=3 r3c8<>3 r3c8=8 r2c7<>8 r2c456=8 r1c6<>8
Forcing Chain Contradiction in b9 => r8c7<>9
r8c7=9 r79c8<>9 r4c8=9 r4c8<>1 r4c2=1 r5c13<>1 r5c6=1 r5c6<>5 r5c13=5 r46c2<>5 r3c2=5 r3c9<>5 r3c9=7 r12c7<>7 r7c7=7 r7c7<>8
r8c7=9 r8c7<>3 r9c8=3 r3c8<>3 r3c8=8 r7c8<>8
r8c7=9 r8c7<>8
r8c7=9 r8c7<>3 r9c8=3 r9c8<>8
Forcing Net Verity => r1c9=9
r3c2=5 (r2c1<>5) r3c9<>5 r3c9=7 (r3c4<>7) (r1c7<>7) r2c7<>7 r7c7=7 r7c4<>7 r2c4=7 r2c1<>7 r2c1=3 (r2c7<>3) (r1c2<>3) r3c2<>3 r8c2=3 r8c7<>3 r1c7=3 r1c7<>9 r1c9=9
r4c2=5 (r4c2<>6) r4c2<>1 r4c8=1 (r4c8<>4) r6c8<>1 r6c8=4 r4c9<>4 r4c5=4 (r4c5<>6) r4c5<>6 r4c4=6 r6c5<>6 r9c5=6 r9c5<>7 r9c9=7 (r1c9<>7) r3c9<>7 r3c9=5 r1c9<>5 r1c9=9
r6c2=5 (r5c3<>5 r5c6=5 r1c6<>5) r6c2<>7 (r6c1=7 r2c1<>7) r3c2=7 r3c9<>7 r3c9=5 (r1c7<>5) r1c9<>5 r1c1=5 r2c1<>5 r2c1=3 (r2c7<>3) (r1c2<>3) r3c2<>3 r8c2=3 r8c7<>3 r1c7=3 r1c7<>9 r1c9=9
Hidden Single: r4c7=9
Locked Pair: 1,4 in r46c8 => r4c9,r7c8<>4
Naked Pair: 6,7 in r9c59 => r9c16<>6
Empty Rectangle: 2 in b8 (r4c49) => r8c9<>2
Hidden Rectangle: 4/6 in r7c19,r8c19 => r7c1<>6
Discontinuous Nice Loop: 5 r6c2 -5- r6c7 =5= r4c9 -5- r3c9 -7- r3c2 =7= r6c2 => r6c2<>5
X-Wing: 5 c29 r34 => r3c134,r4c4<>5
Multi Colors 1: 5 (r2c4) / (r6c4), (r3c2,r4c9) / (r3c9,r4c2,r6c7) => r2c1<>5
Grouped AIC: 6 6- r4c4 -2- r78c4 =2= r8c6 =9= r8c1 =6= r6c1 -6 => r4c2,r6c45<>6
Naked Triple: 1,2,5 in r4c2,r5c13 => r6c13<>1, r6c13<>2, r6c1<>5
Naked Single: r6c3=9
Locked Candidates Type 1 (Pointing): 2 in b4 => r5c56<>2
Naked Single: r5c5=8
W-Wing: 6/2 in r3c6,r4c4 connected by 2 in r16c5 => r3c4<>6
Hidden Single: r3c6=6
AIC: 7 7- r3c9 -5- r4c9 -2- r4c4 -6- r4c5 =6= r9c5 =7= r7c4 -7 => r3c4,r7c9<>7
Sue de Coq: r12c5 - {2347} (r49c5 - {467}, r3c4 - {23}) => r1c6<>2, r2c4<>3, r6c5<>4
Naked Triple: 2,3,5 in r6c457 => r6c6<>2, r6c6<>5
Hidden Single: r8c6=2
Hidden Single: r8c1=9
Hidden Single: r9c6=9
Hidden Single: r7c8=9
Hidden Single: r8c9=4
Hidden Single: r7c1=4
Hidden Single: r6c1=6
Naked Single: r6c2=7
Locked Candidates Type 1 (Pointing): 8 in b8 => r2c4<>8
Naked Pair: 3,8 in r8c7,r9c8 => r7c7<>8
2-String Kite: 3 in r3c8,r8c2 (connected by r8c7,r9c8) => r3c2<>3
Sue de Coq: r2c45 - {3457} (r2c1 - {37}, r12c6 - {458}) => r2c7<>3, r2c7<>7
X-Wing: 3 c27 r18 => r1c15<>3
Skyscraper: 7 in r1c7,r2c4 (connected by r7c47) => r1c5<>7
Naked Single: r1c5=2
Naked Single: r3c4=3
Naked Single: r6c5=3
Naked Single: r3c8=8
Naked Single: r2c7=5
Naked Single: r9c8=3
Naked Single: r2c4=7
Naked Single: r3c9=7
Full House: r1c7=3
Naked Single: r6c7=2
Naked Single: r8c7=8
Full House: r7c7=7
Naked Single: r9c1=5
Naked Single: r2c1=3
Naked Single: r2c5=4
Full House: r2c6=8
Full House: r1c6=5
Naked Single: r9c9=6
Full House: r7c9=2
Full House: r4c9=5
Naked Single: r1c2=8
Full House: r1c1=7
Naked Single: r6c4=5
Naked Single: r8c4=6
Full House: r8c2=3
Naked Single: r9c3=8
Full House: r9c5=7
Full House: r4c5=6
Full House: r7c4=8
Full House: r4c4=2
Naked Single: r5c6=1
Full House: r6c6=4
Full House: r6c8=1
Full House: r4c8=4
Full House: r4c2=1
Naked Single: r7c3=1
Full House: r7c2=6
Full House: r3c2=5
Naked Single: r5c1=2
Full House: r3c1=1
Full House: r3c3=2
Full House: r5c3=5
|
normal_sudoku_5468
|
..37..9.28....9.34...4..6..9..........8..4.93.3.95..2.2.41....8..9.......8...2.4.
|
413786952826519734795423681942371865578264193631958427264195378359847216187632549
|
Basic 9x9 Sudoku 5468
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 7 . . 9 . 2
8 . . . . 9 . 3 4
. . . 4 . . 6 . .
9 . . . . . . . .
. . 8 . . 4 . 9 3
. 3 . 9 5 . . 2 .
2 . 4 1 . . . . 8
. . 9 . . . . . .
. 8 . . . 2 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
413786952826519734795423681942371865578264193631958427264195378359847216187632549 #1 Extreme (16546) bf
Hidden Single: r6c4=9
Hidden Single: r3c2=9
Hidden Single: r7c5=9
Hidden Single: r9c9=9
Hidden Single: r8c7=2
Hidden Single: r8c5=4
Locked Candidates Type 1 (Pointing): 8 in b3 => r4c8<>8
Hidden Pair: 4,8 in r46c7 => r46c7<>1, r4c7<>5, r46c7<>7
Brute Force: r5c1=5
Grouped Discontinuous Nice Loop: 1 r8c1 -1- r3c1 -7- r2c23 =7= r2c7 -7- r5c7 -1- r9c7 =1= r8c89 -1- r8c1 => r8c1<>1
Forcing Net Contradiction in r3c8 => r2c2<>5
r2c2=5 (r2c7<>5) (r2c3<>5) r3c3<>5 r9c3=5 (r9c4<>5) r9c7<>5 r7c7=5 r7c7<>3 r7c6=3 r9c4<>3 r9c4=6 (r2c4<>6) r5c4<>6 r5c4=2 r2c4<>2 r2c4=5 r2c2<>5
Forcing Net Contradiction in r9 => r7c7<>7
r7c7=7 (r5c7<>7 r5c7=1 r2c7<>1 r2c7=5 r2c3<>5) r7c7<>3 r7c6=3 r3c6<>3 r3c5=3 r3c5<>2 r3c3=2 r3c3<>5 r9c3=5
r7c7=7 r7c7<>3 r9c7=3 r9c7<>5 r9c4=5
Forcing Net Contradiction in r8c1 => r8c2<>1
r8c2=1 (r9c3<>1) (r2c2<>1) (r5c2<>1) (r9c1<>1) r9c3<>1 r9c7=1 (r2c7<>1) r5c7<>1 r5c5=1 r2c5<>1 r2c3=1 (r2c3<>7) r3c1<>1 r3c1=7 r2c2<>7 r2c7=7 r5c7<>7 r5c7=1 r9c7<>1 r9c1=1 r8c2<>1
Locked Candidates Type 1 (Pointing): 1 in b7 => r9c7<>1
Forcing Chain Contradiction in b3 => r8c9<>5
r8c9=5 r8c9<>1 r8c8=1 r1c8<>1
r8c9=5 r79c7<>5 r2c7=5 r2c7<>1
r8c9=5 r8c9<>1 r8c8=1 r3c8<>1
r8c9=5 r79c7<>5 r2c7=5 r2c7<>7 r2c23=7 r3c1<>7 r3c1=1 r3c9<>1
Forcing Net Contradiction in c3 => r1c1<>1
r1c1=1 r3c1<>1 r3c1=7 r2c3<>7
r1c1=1 r3c1<>1 r3c1=7 r3c3<>7
r1c1=1 (r9c1<>1 r9c3=1 r9c3<>7) r3c1<>1 r3c1=7 (r9c1<>7) (r2c2<>7) r2c3<>7 r2c7=7 (r5c7<>7) r9c7<>7 r9c5=7 r5c5<>7 r5c2=7 r4c3<>7
r1c1=1 (r9c1<>1 r9c3=1 r9c3<>7) r3c1<>1 r3c1=7 (r9c1<>7) (r2c2<>7) r2c3<>7 r2c7=7 (r5c7<>7) r9c7<>7 r9c5=7 r5c5<>7 r5c2=7 r6c3<>7
r1c1=1 r9c1<>1 r9c3=1 r9c3<>7
Forcing Net Contradiction in r4 => r1c2<>5
r1c2=5 r1c2<>4 r4c2=4 r4c2<>2
r1c2=5 (r2c3<>5) r3c3<>5 r9c3=5 (r9c7<>5) r9c3<>1 r9c1=1 r3c1<>1 r3c1=7 (r2c2<>7) r2c3<>7 r2c7=7 r9c7<>7 r9c7=3 r7c7<>3 r7c6=3 r3c6<>3 r3c5=3 r3c5<>2 r3c3=2 r4c3<>2
r1c2=5 (r2c3<>5) r3c3<>5 r9c3=5 (r9c7<>5) r9c3<>1 r9c1=1 r3c1<>1 r3c1=7 (r2c2<>7) r2c3<>7 r2c7=7 r9c7<>7 r9c7=3 r7c7<>3 r7c6=3 (r4c6<>3) r3c6<>3 r3c5=3 r4c5<>3 r4c4=3 r4c4<>2
r1c2=5 (r2c3<>5) (r2c3<>5) r3c3<>5 r9c3=5 r9c3<>1 r9c1=1 r3c1<>1 r3c1=7 (r2c2<>7) r2c3<>7 r2c7=7 r2c7<>5 r2c4=5 r2c4<>2 r45c4=2 r4c5<>2
Locked Candidates Type 1 (Pointing): 5 in b1 => r9c3<>5
Forcing Net Contradiction in c4 => r1c5<>6
r1c5=6 (r1c6<>6) r1c1<>6 r1c1=4 (r1c2<>4 r1c2=1 r1c6<>1) r6c1<>4 r6c7=4 r6c7<>8 r6c6=8 r1c6<>8 r1c6=5 r2c4<>5
r1c5=6 r1c1<>6 r1c1=4 r6c1<>4 r6c7=4 r6c7<>8 r6c6=8 r8c6<>8 r8c4=8 r8c4<>5
r1c5=6 (r1c5<>8) r1c1<>6 r1c1=4 r1c2<>4 (r1c2=1 r3c1<>1 r3c1=7 r2c3<>7 r2c7=7 r2c7<>5) r4c2=4 r4c7<>4 r4c7=8 r4c5<>8 r3c5=8 r3c5<>3 r3c6=3 r7c6<>3 r7c7=3 r7c7<>5 r9c7=5 r9c4<>5
Forcing Net Contradiction in r2c5 => r2c3<>7
r2c3=7 (r2c3<>5 r3c3=5 r3c9<>5 r3c9=7 r6c9<>7) (r6c3<>7) r3c1<>7 r3c1=1 r9c1<>1 r9c3=1 r6c3<>1 r6c3=6 r6c9<>6 r6c9=1 r5c7<>1 r2c7=1 r2c5<>1
r2c3=7 r2c3<>5 r3c3=5 r3c3<>2 r3c5=2 r2c5<>2
r2c3=7 (r3c1<>7 r3c1=1 r9c1<>1 r9c3=1 r6c3<>1 r6c3=6 r5c2<>6) (r2c3<>2) r2c3<>5 r3c3=5 r3c3<>2 (r3c5=2 r5c5<>2) r4c3=2 r5c2<>2 r5c4=2 r5c4<>6 r5c5=6 r2c5<>6
Finned Swordfish: 7 r259 c257 fr9c1 fr9c3 => r78c2<>7
Locked Pair: 5,6 in r78c2 => r1245c2,r89c1,r9c3<>6
Locked Candidates Type 2 (Claiming): 6 in r5 => r4c456,r6c6<>6
Locked Candidates Type 2 (Claiming): 6 in r9 => r78c6,r8c4<>6
Hidden Single: r1c6=6
Naked Single: r1c1=4
Naked Single: r1c2=1
Naked Single: r1c5=8
Full House: r1c8=5
Naked Single: r3c1=7
Naked Single: r2c2=2
Naked Single: r3c9=1
Naked Single: r8c1=3
Naked Single: r2c4=5
Naked Single: r2c5=1
Naked Single: r3c3=5
Full House: r2c3=6
Full House: r2c7=7
Full House: r3c8=8
Naked Single: r5c2=7
Naked Single: r9c1=1
Full House: r6c1=6
Naked Single: r3c6=3
Full House: r3c5=2
Naked Single: r8c4=8
Naked Single: r5c7=1
Naked Single: r4c2=4
Naked Single: r6c3=1
Full House: r4c3=2
Full House: r9c3=7
Naked Single: r6c9=7
Naked Single: r5c5=6
Full House: r5c4=2
Naked Single: r4c7=8
Naked Single: r4c4=3
Full House: r9c4=6
Naked Single: r4c8=6
Naked Single: r6c6=8
Full House: r6c7=4
Full House: r4c9=5
Full House: r8c9=6
Naked Single: r9c5=3
Full House: r4c5=7
Full House: r9c7=5
Full House: r4c6=1
Full House: r7c7=3
Naked Single: r7c8=7
Full House: r8c8=1
Naked Single: r8c2=5
Full House: r7c2=6
Full House: r7c6=5
Full House: r8c6=7
|
normal_sudoku_1998
|
...9..7.69...72.5.4..6.529..4.79...5...2.4.......56...6....9.2.38.....4.....6.5..
|
521948736963172854478635291842793165756214983139856472615489327387521649294367518
|
Basic 9x9 Sudoku 1998
|
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 . . 7 . 6
9 . . . 7 2 . 5 .
4 . . 6 . 5 2 9 .
. 4 . 7 9 . . . 5
. . . 2 . 4 . . .
. . . . 5 6 . . .
6 . . . . 9 . 2 .
3 8 . . . . . 4 .
. . . . 6 . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
521948736963172854478635291842793165756214983139856472615489327387521649294367518 #1 Extreme (16488) bf
Hidden Single: r1c4=9
Hidden Single: r6c9=2
Hidden Single: r8c7=6
Hidden Single: r8c5=2
Hidden Single: r1c5=4
Hidden Single: r6c7=4
Hidden Single: r2c9=4
Hidden Single: r5c7=9
Brute Force: r5c9=3
Locked Candidates Type 1 (Pointing): 7 in b6 => r9c8<>7
Skyscraper: 3 in r2c7,r3c5 (connected by r7c57) => r2c4<>3
Turbot Fish: 3 r3c5 =3= r1c6 -3- r4c6 =3= r4c3 => r3c3<>3
Forcing Net Verity => r3c5=3
r7c7=1 r3c5=3
r7c7=3 r7c5<>3 r3c5=3
r7c7=8 (r4c7<>8 r4c7=1 r4c6<>1) (r7c5<>8) (r7c9<>8) r9c9<>8 r3c9=8 r3c5<>8 r5c5=8 r4c6<>8 r4c6=3 r1c6<>3 r3c5=3
Finned Franken Swordfish: 1 c57b2 r247 fr1c6 fr5c5 => r4c6<>1
W-Wing: 8/1 in r2c4,r7c5 connected by 1 in r5c5,r6c4 => r79c4<>8
Sashimi Swordfish: 8 c457 r247 fr5c5 fr6c4 => r4c6<>8
Naked Single: r4c6=3
Naked Pair: 1,8 in r26c4 => r789c4<>1
Naked Single: r8c4=5
Naked Triple: 1,7,8 in r6c148 => r6c23<>1, r6c23<>7, r6c3<>8
Grouped Discontinuous Nice Loop: 8 r5c3 -8- r5c5 =8= r7c5 -8- r9c6 =8= r1c6 -8- r1c1 =8= r456c1 -8- r5c3 => r5c3<>8
Finned Franken Swordfish: 1 r38b2 c369 fr2c4 fr3c2 => r2c3<>1
Forcing Chain Contradiction in b3 => r1c1<>8
r1c1=8 r1c6<>8 r1c6=1 r1c8<>1
r1c1=8 r456c1<>8 r4c3=8 r4c7<>8 r4c7=1 r2c7<>1
r1c1=8 r3c3<>8 r3c9=8 r3c9<>1
Locked Candidates Type 1 (Pointing): 8 in b1 => r4c3<>8
Forcing Chain Verity => r1c8<>1
r9c6=8 r1c6<>8 r1c6=1 r1c8<>1
r9c8=8 r9c8<>3 r1c8=3 r1c8<>1
r9c9=8 r3c9<>8 r3c9=1 r1c8<>1
Multi Colors 1: 1 (r1c6,r6c4,r7c5) / (r2c4,r5c5), (r2c7) / (r3c9) => r7c9<>1
XY-Wing: 1/8/7 in r3c29,r7c9 => r7c2<>7
XY-Wing: 1/8/7 in r7c59,r8c6 => r8c9<>7
Discontinuous Nice Loop: 8 r2c3 -8- r2c4 -1- r2c7 =1= r3c9 =8= r3c3 -8- r2c3 => r2c3<>8
W-Wing: 1/8 in r4c7,r6c4 connected by 8 in r2c47 => r6c8<>1
Turbot Fish: 1 r1c6 =1= r2c4 -1- r6c4 =1= r6c1 => r1c1<>1
Finned Swordfish: 8 c369 r139 fr7c9 => r9c8<>8
XY-Wing: 3/8/1 in r1c68,r9c8 => r9c6<>1
XY-Wing: 3/8/1 in r19c8,r3c9 => r89c9<>1
Naked Single: r8c9=9
Hidden Single: r3c9=1
Naked Single: r3c2=7
Full House: r3c3=8
Locked Candidates Type 2 (Claiming): 8 in c9 => r7c7<>8
Naked Pair: 7,8 in r9c69 => r9c13<>7
Locked Candidates Type 1 (Pointing): 7 in b7 => r5c3<>7
Skyscraper: 1 in r2c2,r6c1 (connected by r26c4) => r5c2<>1
Skyscraper: 1 in r4c7,r5c5 (connected by r7c57) => r5c8<>1
Locked Candidates Type 1 (Pointing): 1 in b6 => r4c13<>1
Skyscraper: 8 in r4c7,r6c4 (connected by r2c47) => r6c8<>8
Naked Single: r6c8=7
Hidden Single: r5c1=7
Hidden Single: r1c1=5
Swordfish: 8 c147 r246 => r4c8<>8
Skyscraper: 1 in r5c5,r8c6 (connected by r58c3) => r7c5<>1
Naked Single: r7c5=8
Full House: r5c5=1
Full House: r6c4=8
Naked Single: r7c9=7
Full House: r9c9=8
Naked Single: r9c6=7
Naked Single: r2c4=1
Full House: r1c6=8
Full House: r8c6=1
Full House: r8c3=7
Naked Single: r6c1=1
Naked Single: r1c8=3
Full House: r2c7=8
Naked Single: r9c1=2
Full House: r4c1=8
Naked Single: r9c8=1
Full House: r7c7=3
Full House: r4c7=1
Naked Single: r4c8=6
Full House: r4c3=2
Full House: r5c8=8
Naked Single: r9c2=9
Naked Single: r7c4=4
Full House: r9c4=3
Full House: r9c3=4
Naked Single: r1c3=1
Full House: r1c2=2
Naked Single: r6c2=3
Full House: r6c3=9
Naked Single: r7c3=5
Full House: r7c2=1
Naked Single: r2c2=6
Full House: r2c3=3
Full House: r5c3=6
Full House: r5c2=5
|
normal_sudoku_1164
|
.3.....8....17.2...15......14.35......2....5...8.6...7.....96.8.694..3....38..7..
|
736294581984175236215683479147358962692741853358962147471539628869427315523816794
|
Basic 9x9 Sudoku 1164
|
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 .
. . . 1 7 . 2 . .
. 1 5 . . . . . .
1 4 . 3 5 . . . .
. . 2 . . . . 5 .
. . 8 . 6 . . . 7
. . . . . 9 6 . 8
. 6 9 4 . . 3 . .
. . 3 8 . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
736294581984175236215683479147358962692741853358962147471539628869427315523816794 #1 Easy (364)
Naked Single: r6c3=8
Hidden Single: r7c5=3
Hidden Single: r7c3=1
Hidden Single: r8c1=8
Hidden Single: r9c6=6
Hidden Single: r3c8=7
Hidden Single: r1c7=5
Hidden Single: r2c2=8
Hidden Single: r8c6=7
Hidden Single: r7c4=5
Hidden Single: r2c6=5
Hidden Single: r1c9=1
Hidden Single: r4c3=7
Naked Single: r5c2=9
Naked Single: r5c4=7
Naked Single: r6c2=5
Naked Single: r6c1=3
Full House: r5c1=6
Naked Single: r9c2=2
Full House: r7c2=7
Naked Single: r9c5=1
Full House: r8c5=2
Naked Single: r7c1=4
Full House: r7c8=2
Full House: r9c1=5
Naked Single: r8c8=1
Full House: r8c9=5
Naked Single: r2c1=9
Naked Single: r3c1=2
Full House: r1c1=7
Hidden Single: r3c6=3
Hidden Single: r6c4=9
Naked Single: r3c4=6
Full House: r1c4=2
Naked Single: r6c8=4
Naked Single: r1c6=4
Naked Single: r5c9=3
Naked Single: r6c7=1
Full House: r6c6=2
Naked Single: r9c8=9
Full House: r9c9=4
Naked Single: r1c3=6
Full House: r1c5=9
Full House: r2c3=4
Full House: r3c5=8
Full House: r5c5=4
Naked Single: r5c7=8
Full House: r5c6=1
Full House: r4c6=8
Naked Single: r4c8=6
Full House: r2c8=3
Full House: r2c9=6
Naked Single: r3c9=9
Full House: r3c7=4
Full House: r4c7=9
Full House: r4c9=2
|
normal_sudoku_1443
|
.......8..9.5......2.13....6..42.3.99..8.3....34....2..4.38.26.86.........3..94..
|
375692184196548732428137596681425379952873641734916825549381267867254913213769458
|
Basic 9x9 Sudoku 1443
|
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 .
. 9 . 5 . . . . .
. 2 . 1 3 . . . .
6 . . 4 2 . 3 . 9
9 . . 8 . 3 . . .
. 3 4 . . . . 2 .
. 4 . 3 8 . 2 6 .
8 6 . . . . . . .
. . 3 . . 9 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
375692184196548732428137596681425379952873641734916825549381267867254913213769458 #1 Extreme (13012) bf
Hidden Single: r5c6=3
Hidden Single: r5c3=2
Hidden Single: r4c2=8
Hidden Single: r9c1=2
Hidden Single: r7c3=9
Hidden Single: r9c9=8
Hidden Single: r6c7=8
Locked Candidates Type 1 (Pointing): 9 in b2 => r1c7<>9
Brute Force: r5c2=5
Skyscraper: 5 in r4c6,r9c5 (connected by r49c8) => r6c5,r78c6<>5
Forcing Chain Contradiction in r4c6 => r7c1<>1
r7c1=1 r6c1<>1 r4c3=1 r4c6<>1
r7c1=1 r7c1<>5 r7c9=5 r6c9<>5 r6c6=5 r4c6<>5
r7c1=1 r7c6<>1 r7c6=7 r4c6<>7
W-Wing: 7/1 in r1c2,r4c3 connected by 1 in r8c3,r9c2 => r123c3<>7
Finned Franken Swordfish: 1 r47b7 c368 fr7c9 fr9c2 => r9c8<>1
W-Wing: 7/1 in r1c2,r7c6 connected by 1 in r9c25 => r1c6<>7
Forcing Chain Contradiction in r4c8 => r1c2=7
r1c2<>7 r1c2=1 r9c2<>1 r9c5=1 r5c5<>1 r5c789=1 r4c8<>1
r1c2<>7 r9c2=7 r9c8<>7 r9c8=5 r4c8<>5
r1c2<>7 r9c2=7 r8c3<>7 r4c3=7 r4c8<>7
Full House: r9c2=1
W-Wing: 1/7 in r4c3,r7c6 connected by 7 in r67c1 => r4c6<>1
W-Wing: 7/5 in r8c3,r9c8 connected by 5 in r7c19 => r8c789<>7
Sashimi X-Wing: 7 c14 r67 fr8c4 fr9c4 => r7c6<>7
Naked Single: r7c6=1
Naked Pair: 5,7 in r7c9,r9c8 => r8c789<>5
Locked Candidates Type 2 (Claiming): 5 in c7 => r13c9,r3c8<>5
XY-Chain: 5 5- r4c6 -7- r4c3 -1- r6c1 -7- r7c1 -5- r7c9 -7- r9c8 -5 => r4c8<>5
Hidden Single: r4c6=5
Hidden Single: r9c8=5
Naked Single: r7c9=7
Full House: r7c1=5
Full House: r8c3=7
Naked Single: r3c1=4
Naked Single: r4c3=1
Full House: r4c8=7
Full House: r6c1=7
Naked Single: r8c4=2
Naked Single: r3c9=6
Naked Single: r3c8=9
Naked Single: r6c6=6
Naked Single: r8c6=4
Naked Single: r6c4=9
Naked Single: r1c6=2
Naked Single: r8c5=5
Naked Single: r1c4=6
Full House: r9c4=7
Full House: r9c5=6
Naked Single: r6c5=1
Full House: r5c5=7
Full House: r6c9=5
Naked Single: r1c3=5
Naked Single: r2c5=4
Full House: r1c5=9
Naked Single: r1c7=1
Naked Single: r3c3=8
Full House: r2c3=6
Naked Single: r1c1=3
Full House: r1c9=4
Full House: r2c1=1
Naked Single: r2c7=7
Naked Single: r2c8=3
Naked Single: r5c7=6
Naked Single: r8c7=9
Full House: r3c7=5
Full House: r3c6=7
Full House: r2c6=8
Full House: r2c9=2
Naked Single: r5c9=1
Full House: r5c8=4
Full House: r8c8=1
Full House: r8c9=3
|
normal_sudoku_1259
|
2...53......92.7.64......2....6..51.81.........4..73.9.7834..9..4.7.1.5.....6...3
|
267153948185924736493876125732689514819435267654217389578342691346791852921568473
|
Basic 9x9 Sudoku 1259
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . 5 3 . . .
. . . 9 2 . 7 . 6
4 . . . . . . 2 .
. . . 6 . . 5 1 .
8 1 . . . . . . .
. . 4 . . 7 3 . 9
. 7 8 3 4 . . 9 .
. 4 . 7 . 1 . 5 .
. . . . 6 . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
267153948185924736493876125732689514819435267654217389578342691346791852921568473 #1 Easy (402)
Naked Single: r7c5=4
Hidden Single: r4c1=7
Hidden Single: r1c3=7
Hidden Single: r3c5=7
Hidden Single: r3c9=5
Hidden Single: r3c6=6
Hidden Single: r2c8=3
Hidden Single: r9c8=7
Hidden Single: r5c9=7
Hidden Single: r1c2=6
Hidden Single: r6c5=1
Hidden Single: r8c1=3
Hidden Single: r2c6=4
Hidden Single: r9c7=4
Hidden Single: r1c7=9
Hidden Single: r9c1=9
Hidden Single: r5c4=4
Naked Single: r5c8=6
Naked Single: r5c7=2
Naked Single: r6c8=8
Full House: r1c8=4
Full House: r4c9=4
Hidden Single: r2c2=8
Hidden Single: r8c5=9
Naked Single: r5c5=3
Full House: r4c5=8
Hidden Single: r9c3=1
Naked Single: r2c3=5
Full House: r2c1=1
Naked Single: r5c3=9
Full House: r5c6=5
Naked Single: r3c3=3
Full House: r3c2=9
Naked Single: r6c4=2
Full House: r4c6=9
Naked Single: r7c6=2
Full House: r9c6=8
Full House: r9c4=5
Full House: r9c2=2
Naked Single: r4c3=2
Full House: r4c2=3
Full House: r6c2=5
Full House: r8c3=6
Full House: r6c1=6
Full House: r7c1=5
Naked Single: r7c9=1
Full House: r7c7=6
Naked Single: r8c7=8
Full House: r3c7=1
Full House: r1c9=8
Full House: r8c9=2
Full House: r3c4=8
Full House: r1c4=1
|
normal_sudoku_140
|
......9..47..1..2...2......24...7.1.1.8.4.....3.......6.4.217.5..3.762..7..4...6.
|
315264987479518623862739154246397518198645372537182496684921735953876241721453869
|
Basic 9x9 Sudoku 140
|
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 7 . . 1 . . 2 .
. . 2 . . . . . .
2 4 . . . 7 . 1 .
1 . 8 . 4 . . . .
. 3 . . . . . . .
6 . 4 . 2 1 7 . 5
. . 3 . 7 6 2 . .
7 . . 4 . . . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
315264987479518623862739154246397518198645372537182496684921735953876241721453869 #1 Extreme (23898) bf
Hidden Single: r4c2=4
Hidden Single: r6c4=1
Hidden Single: r9c2=2
Hidden Single: r6c3=7
Skyscraper: 1 in r1c3,r3c7 (connected by r9c37) => r1c9,r3c2<>1
Brute Force: r4c9=8
Finned Swordfish: 8 r269 c567 fr2c4 => r1c56,r3c56<>8
Almost Locked Set XZ-Rule: A=r2456c7 {34568}, B=r13c5,r2c46,r3c6 {345689}, X=8, Z=4 => r3c7<>4
Hidden Single: r6c7=4
Naked Pair: 5,9 in r6c18 => r6c56<>5, r6c569<>9
Forcing Net Contradiction in c4 => r1c4<>3
r1c4=3 r1c4<>6
r1c4=3 (r1c4<>8) (r1c4<>7 r3c4=7 r3c4<>8) r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r2c6<>8 r2c4=8 r2c4<>6
r1c4=3 r1c4<>7 r3c4=7 r3c4<>6
r1c4=3 r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r6c5<>8 r6c5=6 r4c4<>6
r1c4=3 r1c4<>2 r5c4=2 r5c4<>6
Forcing Net Contradiction in c4 => r1c4<>5
r1c4=5 r1c4<>6
r1c4=5 (r1c4<>8) (r1c4<>7 r3c4=7 r3c4<>8) r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r2c6<>8 r2c4=8 r2c4<>6
r1c4=5 r1c4<>7 r3c4=7 r3c4<>6
r1c4=5 r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r6c5<>8 r6c5=6 r4c4<>6
r1c4=5 r1c4<>2 r5c4=2 r5c4<>6
Forcing Net Contradiction in b2 => r2c4<>3
r2c4=3 (r2c6<>3) (r1c5<>3) r2c9<>3 r2c9=6 r6c9<>6 (r6c9=2 r6c6<>2 r6c6=8 r2c6<>8) r6c5=6 r1c5<>6 r1c5=5 r2c6<>5 r2c6=9
r2c4=3 (r3c5<>3) (r1c5<>3) r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 (r3c5<>6) r1c5<>6 r1c5=5 r3c5<>5 r3c5=9
Forcing Net Contradiction in r2c4 => r1c9<>3
r1c9=3 (r1c5<>3) r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r2c4<>5
r1c9=3 r2c9<>3 r2c9=6 r2c4<>6
r1c9=3 (r9c9<>3) r2c9<>3 (r2c6=3 r9c6<>3) r2c9=6 r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 (r9c7<>8) r9c5<>3 r9c7=3 r9c7<>1 r3c7=1 r3c7<>8 r2c7=8 r2c4<>8
r1c9=3 (r1c1<>3 r3c1=3 r3c5<>3) (r1c5<>3) r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 (r3c5<>6) r1c5<>6 r1c5=5 r3c5<>5 r3c5=9 r2c4<>9
Forcing Net Contradiction in c4 => r3c4<>3
r3c4=3 r3c4<>7 r1c4=7 r1c4<>6
r3c4=3 (r3c4<>8) r3c4<>7 r1c4=7 (r1c4<>8) r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r2c6<>8 r2c4=8 r2c4<>6
r3c4=3 r3c4<>6
r3c4=3 r3c4<>7 r1c4=7 r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r6c5<>8 r6c5=6 r4c4<>6
r3c4=3 r3c4<>7 r1c4=7 r1c4<>2 r5c4=2 r5c4<>6
Forcing Chain Contradiction in c8 => r5c6<>3
r5c6=3 r2c6<>3 r2c79=3 r1c8<>3
r5c6=3 r2c6<>3 r2c79=3 r3c8<>3
r5c6=3 r5c8<>3
r5c6=3 r45c4<>3 r7c4=3 r7c8<>3
Forcing Net Contradiction in c4 => r3c4<>5
r3c4=5 r3c4<>7 r1c4=7 r1c4<>6
r3c4=5 (r3c4<>8) r3c4<>7 r1c4=7 (r1c4<>8) r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r2c6<>8 r2c4=8 r2c4<>6
r3c4=5 r3c4<>6
r3c4=5 r3c4<>7 r1c4=7 r1c4<>2 r1c6=2 r6c6<>2 r6c6=8 r6c5<>8 r6c5=6 r4c4<>6
r3c4=5 r3c4<>7 r1c4=7 r1c4<>2 r5c4=2 r5c4<>6
Forcing Net Contradiction in r6 => r3c4<>9
r3c4=9 (r7c4<>9) (r2c6<>9 r2c3=9 r4c3<>9 r4c5=9 r4c5<>3) r3c4<>7 r1c4=7 r1c4<>2 r5c4=2 r5c4<>3 r4c4=3 r7c4<>3 r7c4=8 r9c5<>8 r6c5=8
r3c4=9 r3c4<>7 r1c4=7 r1c4<>2 r1c6=2 r6c6<>2 r6c6=8
Forcing Net Contradiction in b2 => r3c7<>3
r3c7=3 (r3c7<>1 r9c7=1 r9c7<>8 r2c7=8 r2c4<>8) r2c9<>3 (r2c6=3 r1c5<>3) r2c9=6 (r2c4<>6) r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r2c4<>5 r2c4=9
r3c7=3 (r3c5<>3) r2c9<>3 (r2c6=3 r1c5<>3) r2c9=6 r6c9<>6 r6c5=6 (r3c5<>6) r1c5<>6 r1c5=5 r3c5<>5 r3c5=9
Forcing Net Contradiction in r2c4 => r3c9<>3
r3c9=3 r2c9<>3 (r2c6=3 r1c5<>3) r2c9=6 r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r2c4<>5
r3c9=3 r2c9<>3 r2c9=6 r2c4<>6
r3c9=3 (r3c9<>1 r3c7=1 r3c7<>8) r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r2c7=8 r2c4<>8
r3c9=3 (r3c5<>3) r2c9<>3 (r2c6=3 r1c5<>3) r2c9=6 r6c9<>6 r6c5=6 (r3c5<>6) r1c5<>6 r1c5=5 r3c5<>5 r3c5=9 r2c4<>9
Forcing Net Contradiction in r3c5 => r3c9<>6
r3c9=6 (r3c9<>1 r3c7=1 r9c7<>1) r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r9c7=3 r9c6<>3 r123c6=3 r3c5<>3
r3c9=6 (r2c9<>6 r2c9=3 r1c8<>3) (r2c9<>6 r2c9=3 r3c8<>3) (r3c9<>1 r3c7=1 r9c7<>1) r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r9c7=3 (r9c6<>3 r123c6=3 r1c5<>3) r7c8<>3 r5c8=3 r5c8<>7 r5c9=7 r5c9<>2 r6c9=2 r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r3c5<>5
r3c9=6 r3c5<>6
r3c9=6 (r2c9<>6 r2c9=3 r1c8<>3) (r2c9<>6 r2c9=3 r3c8<>3) (r3c9<>1 r3c7=1 r9c7<>1) r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r9c7=3 r7c8<>3 (r7c4=3 r7c4<>9) r5c8=3 (r5c8<>9) r5c8<>7 r5c9=7 r5c9<>9 r6c8=9 (r6c1<>9) r7c8<>9 r7c2=9 r8c1<>9 r3c1=9 r3c5<>9
Forcing Net Contradiction in c7 => r5c4<>9
r5c4=9 (r4c5<>9 r4c3=9 r2c3<>9 r2c6=9 r2c6<>8) r5c4<>2 r1c4=2 (r1c4<>8) r1c4<>7 r3c4=7 r3c4<>8 r2c4=8 r2c7<>8
r5c4=9 (r4c5<>9) (r2c4<>9) (r4c4<>9) r4c5<>9 r4c3=9 r2c3<>9 r2c6=9 r3c5<>9 r9c5=9 (r9c9<>9) r9c5<>8 r6c5=8 r6c5<>6 r6c9=6 r2c9<>6 r2c9=3 r9c9<>3 r9c9=1 r3c9<>1 r3c7=1 r3c7<>8
r5c4=9 (r4c5<>9 r4c3=9 r6c1<>9 r6c8=9 r7c8<>9 r7c2=9 r7c2<>8) (r4c5<>9 r4c3=9 r2c3<>9 r2c6=9 r2c6<>8) r5c4<>2 r1c4=2 (r1c4<>8) r1c4<>7 r3c4=7 r3c4<>8 r2c4=8 r7c4<>8 r7c8=8 r9c7<>8
Forcing Net Contradiction in c4 => r4c5<>6
r4c5=6 r6c5<>6 r6c5=8 r6c6<>8 r6c6=2 r1c6<>2 r1c4=2 r1c4<>6
r4c5=6 (r4c3<>6 r5c2=6 r5c2<>9) r6c5<>6 r6c5=8 r6c6<>8 r6c6=2 (r5c4<>2) r5c6<>2 r5c9=2 (r5c9<>9) r5c9<>7 r5c8=7 r5c8<>9 r5c6=9 (r2c6<>9) (r4c4<>9) r4c5<>9 r4c3=9 r2c3<>9 r2c4=9 r2c4<>6
r4c5=6 r6c5<>6 r6c5=8 r6c6<>8 r6c6=2 r1c6<>2 r1c4=2 r1c4<>7 r3c4=7 r3c4<>6
r4c5=6 r4c4<>6
r4c5=6 r5c4<>6
Forcing Net Verity => r1c3<>6
r4c3=5 (r4c7<>5) (r6c1<>5 r6c8=5 r5c7<>5) r4c3<>6 r5c2=6 (r3c2<>6) r5c7<>6 r5c7=3 r4c7<>3 r4c7=6 (r3c7<>6) r6c9<>6 r6c5=6 (r1c5<>6) r3c5<>6 r3c4=6 (r3c4<>8) (r3c4<>7 r1c4=7 r1c4<>8) r3c5<>6 r6c5=6 (r1c5<>6) r6c5<>8 r9c5=8 (r9c7<>8) (r7c4<>8) r8c4<>8 r2c4=8 r2c7<>8 r3c7=8 r3c7<>1 r9c7=1 r9c3<>1 r1c3=1 r1c3<>6
r4c3=6 r1c3<>6
r4c3=9 (r6c1<>9 r6c8=9 r8c8<>9) (r6c1<>9 r6c8=9 r7c8<>9) (r2c3<>9) (r4c4<>9) r4c5<>9 r5c6=9 r2c6<>9 r2c4=9 (r8c4<>9) r7c4<>9 r7c2=9 (r8c1<>9) r8c2<>9 r8c9=9 r8c9<>1 r8c2=1 r1c2<>1 r1c3=1 r1c3<>6
Forcing Net Verity => r7c8=3
r1c8=3 (r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 r5c4<>6 r5c7=6 r5c7<>3) (r5c8<>3) (r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r1c2<>5) (r2c9<>3 r2c6=3 r2c6<>5) (r2c9<>3 r2c9=6 r6c9<>6 r6c5=6 r1c5<>6 r1c5=5 r2c4<>5) (r1c5<>3) (r1c1<>3 r3c1=3 r3c5<>3) r7c8<>3 r7c4=3 r9c5<>3 r4c5=3 r4c7<>3 r4c7=5 r2c7<>5 r2c3=5 (r3c2<>5) r1c3<>5 r1c3=1 r1c2<>1 r8c2=1 r8c2<>5 r5c2=5 (r6c1<>5 r8c1=5 r8c4<>5 r4c4=5 r4c7<>5) r5c2<>6 r4c3=6 (r4c7<>6) r4c7<>6 r4c7=3 r5c9<>3 r5c4=3 r7c4<>3 r7c8=3
r3c8=3 (r7c8<>3 r7c4=3 r9c5<>3 r4c5=3 r4c7<>3 r4c7=5 r2c7<>5 r2c3=5 r1c3<>5 r1c3=1 r9c3<>1 r9c3=9 r7c2<>9 r7c2=8 r7c8<>8) (r7c8<>3 r7c4=3 r5c4<>3) (r5c8<>3) r2c9<>3 r2c9=6 (r2c3<>6 r4c3=6 r4c3<>9) (r2c3<>6 r4c3=6 r5c2<>6) (r5c9<>6) r6c9<>6 r6c5=6 r5c4<>6 r5c7=6 r5c7<>3 r5c9=3 r5c9<>7 r5c8=7 r5c8<>9 r6c8=9 (r5c9<>9) r6c1<>9 r5c2=9 r6c1<>9 r6c8=9 (r5c9<>9) r7c8<>9 r7c8=3
r5c8=3 (r1c8<>3) (r3c8<>3) (r7c8<>3 r7c4=3 r4c4<>3 r4c5=3 r4c5<>9) (r5c8<>9) (r7c8<>3 r7c4=3 r7c4<>9) (r5c8<>9) r5c8<>7 r5c9=7 (r5c9<>9) r5c9<>9 r6c8=9 r7c8<>9 r7c2=9 r5c2<>9 r5c6=9 (r2c6<>9) (r4c4<>9) r4c5<>9 r4c3=9 r2c3<>9 r2c4=9 r3c5<>9 r9c5=9 r9c5<>8 r6c5=8 r6c6<>8 r6c6=2 (r5c4<>2) r5c6<>2 r5c9=2 r5c9<>7 r5c8=7 r5c8<>3 r7c8=3
r7c8=3 r7c8=3
Locked Candidates Type 1 (Pointing): 3 in b3 => r2c6<>3
Locked Candidates Type 2 (Claiming): 3 in c4 => r4c5<>3
Discontinuous Nice Loop: 7 r3c9 -7- r3c4 =7= r1c4 =2= r1c6 -2- r6c6 -8- r6c5 =8= r9c5 -8- r9c7 -1- r3c7 =1= r3c9 => r3c9<>7
Naked Triple: 1,4,9 in r389c9 => r1c9<>4, r5c9<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r8c8<>9
Forcing Chain Contradiction in b7 => r6c1=5
r6c1<>5 r6c1=9 r6c8<>9 r5c8=9 r5c8<>7 r5c9=7 r5c9<>2 r6c9=2 r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r7c4<>8 r7c4=9 r7c2<>9
r6c1<>5 r6c1=9 r8c1<>9
r6c1<>5 r6c1=9 r6c8<>9 r5c8=9 r5c8<>7 r5c9=7 r5c9<>2 r6c9=2 r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r9c7=1 r9c3<>1 r8c2=1 r8c2<>9
r6c1<>5 r6c1=9 r6c8<>9 r5c8=9 r5c8<>7 r5c9=7 r5c9<>2 r6c9=2 r6c9<>6 r6c5=6 r6c5<>8 r9c5=8 r9c7<>8 r9c7=1 r9c9<>1 r9c9=9 r9c3<>9
Naked Single: r6c8=9
Naked Pair: 8,9 in r7c2,r8c1 => r8c2<>8, r8c2,r9c3<>9
Naked Pair: 1,5 in r19c3 => r2c3<>5
Skyscraper: 9 in r5c6,r7c4 (connected by r57c2) => r4c4,r9c6<>9
2-String Kite: 9 in r2c3,r5c6 (connected by r4c3,r5c2) => r2c6<>9
Skyscraper: 9 in r2c4,r4c5 (connected by r24c3) => r3c5<>9
Skyscraper: 9 in r2c3,r7c2 (connected by r27c4) => r3c2<>9
2-String Kite: 9 in r2c4,r8c1 (connected by r2c3,r3c1) => r8c4<>9
Discontinuous Nice Loop: 2/3/5 r1c6 =4= r1c8 -4- r8c8 -8- r8c1 -9- r3c1 =9= r3c6 =4= r1c6 => r1c6<>2, r1c6<>3, r1c6<>5
Naked Single: r1c6=4
Hidden Single: r1c4=2
Hidden Single: r3c4=7
Locked Candidates Type 1 (Pointing): 8 in b2 => r2c7<>8
Naked Triple: 3,5,6 in r245c7 => r3c7<>5, r3c7<>6
Swordfish: 6 r136 c259 => r25c9,r5c2<>6
Naked Single: r2c9=3
Naked Single: r5c2=9
Full House: r4c3=6
Naked Single: r7c2=8
Full House: r7c4=9
Naked Single: r2c3=9
Naked Single: r8c1=9
Hidden Single: r4c5=9
Hidden Single: r3c6=9
Hidden Single: r9c9=9
Hidden Single: r9c6=3
Naked Triple: 2,5,7 in r5c689 => r5c47<>5
Skyscraper: 5 in r4c7,r5c6 (connected by r2c67) => r4c4,r5c8<>5
Naked Single: r4c4=3
Full House: r4c7=5
Naked Single: r5c8=7
Naked Single: r5c4=6
Naked Single: r2c7=6
Naked Single: r5c9=2
Naked Single: r5c7=3
Full House: r5c6=5
Full House: r6c9=6
Naked Single: r6c5=8
Full House: r6c6=2
Full House: r2c6=8
Full House: r2c4=5
Full House: r8c4=8
Full House: r9c5=5
Naked Single: r1c9=7
Naked Single: r8c8=4
Naked Single: r9c3=1
Full House: r1c3=5
Full House: r8c2=5
Full House: r8c9=1
Full House: r9c7=8
Full House: r3c9=4
Full House: r3c7=1
Naked Single: r1c8=8
Full House: r3c8=5
Naked Single: r3c2=6
Full House: r1c2=1
Naked Single: r1c1=3
Full House: r1c5=6
Full House: r3c5=3
Full House: r3c1=8
|
normal_sudoku_1883
|
.7.2.8...862.3..19.....1..819...3.8.6...9412...31....4..9..2.315.....8.2......9..
|
971248356862537419435961278194723685657894123283156794749682531516379842328415967
|
Basic 9x9 Sudoku 1883
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . 2 . 8 . . .
8 6 2 . 3 . . 1 9
. . . . . 1 . . 8
1 9 . . . 3 . 8 .
6 . . . 9 4 1 2 .
. . 3 1 . . . . 4
. . 9 . . 2 . 3 1
5 . . . . . 8 . 2
. . . . . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
971248356862537419435961278194723685657894123283156794749682531516379842328415967 #1 Hard (824)
Hidden Single: r2c1=8
Hidden Single: r1c3=1
Hidden Single: r3c4=9
Hidden Single: r3c7=2
Hidden Single: r4c5=2
Hidden Single: r5c9=3
Hidden Single: r4c3=4
Naked Single: r3c3=5
Hidden Single: r1c1=9
Hidden Single: r6c8=9
Hidden Single: r8c6=9
Hidden Single: r1c7=3
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c58<>4
Locked Candidates Type 1 (Pointing): 6 in b2 => r6789c5<>6
Hidden Triple: 1,2,3 in r89c2,r9c1 => r89c2,r9c1<>4, r9c1<>7, r9c2<>8
Locked Candidates Type 1 (Pointing): 4 in b7 => r7c457<>4
Hidden Single: r2c7=4
Hidden Single: r1c5=4
Hidden Single: r3c8=7
Naked Single: r3c5=6
Hidden Pair: 3,4 in r89c4 => r89c4<>6, r89c4<>7, r9c4<>5, r9c4<>8
Skyscraper: 6 in r6c6,r7c4 (connected by r67c7) => r4c4,r9c6<>6
Hidden Single: r7c4=6
Hidden Single: r6c6=6
Hidden Single: r5c4=8
Naked Single: r5c2=5
Full House: r5c3=7
Naked Single: r6c1=2
Full House: r6c2=8
Naked Single: r8c3=6
Full House: r9c3=8
Naked Single: r9c1=3
Naked Single: r7c2=4
Naked Single: r8c8=4
Naked Single: r3c1=4
Full House: r3c2=3
Full House: r7c1=7
Naked Single: r8c2=1
Full House: r9c2=2
Naked Single: r9c4=4
Naked Single: r8c4=3
Full House: r8c5=7
Naked Single: r7c7=5
Full House: r7c5=8
Naked Single: r6c5=5
Full House: r6c7=7
Full House: r4c4=7
Full House: r9c5=1
Full House: r9c6=5
Full House: r4c7=6
Full House: r2c4=5
Full House: r2c6=7
Full House: r4c9=5
Naked Single: r9c8=6
Full House: r1c8=5
Full House: r1c9=6
Full House: r9c9=7
|
normal_sudoku_903
|
..3......68...93..91..2..6...9..861...1.7.5...5......74..5..1....8..6.9.....8.4.6
|
523864971684719352917325864279458613341672589856931247462597138138246795795183426
|
Basic 9x9 Sudoku 903
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 . . . . . .
6 8 . . . 9 3 . .
9 1 . . 2 . . 6 .
. . 9 . . 8 6 1 .
. . 1 . 7 . 5 . .
. 5 . . . . . . 7
4 . . 5 . . 1 . .
. . 8 . . 6 . 9 .
. . . . 8 . 4 . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
523864971684719352917325864279458613341672589856931247462597138138246795795183426 #1 Extreme (36246) bf
Brute Force: r5c7=5
Hidden Single: r4c5=5
Forcing Net Contradiction in c3 => r1c5=6
r1c5<>6 r1c4=6 (r1c4<>7) r1c4<>8 r3c4=8 (r3c4<>7) (r3c7<>8 r3c7=7 r3c6<>7) r3c4<>3 r3c6=3 r3c6<>5 r1c6=5 r1c6<>7 r2c4=7 r2c3<>7
r1c5<>6 r1c4=6 r1c4<>8 r3c4=8 r3c7<>8 r3c7=7 r3c3<>7
r1c5<>6 r1c4=6 r5c4<>6 r5c2=6 r7c2<>6 r7c3=6 r7c3<>7
r1c5<>6 r1c4=6 (r1c4<>8 r3c4=8 r3c7<>8 r3c7=7 r8c7<>7 r8c7=2 r8c2<>2) r1c5<>6 r6c5=6 (r6c5<>3) r6c5<>9 r7c5=9 r7c5<>3 r8c5=3 r8c2<>3 r8c2=7 r9c3<>7
Almost Locked Set XY-Wing: A=r6c135678 {1234689}, B=r123489c4 {1234789}, C=r7c35689 {236789}, X,Y=6,9, Z=1,2,3,4 => r6c4<>1, r6c4<>2, r6c4<>3, r6c4<>4
Forcing Chain Verity => r1c9<>5
r1c4=1 r1c4<>8 r3c4=8 r3c4<>3 r3c6=3 r3c6<>5 r1c6=5 r1c9<>5
r2c4=1 r2c9<>1 r1c9=1 r1c9<>5
r8c4=1 r8c4<>4 r8c5=4 r2c5<>4 r2c5=1 r2c9<>1 r1c9=1 r1c9<>5
r9c4=1 r9c1<>1 r8c1=1 r8c1<>5 r8c9=5 r1c9<>5
Forcing Net Contradiction in r4 => r1c7<>2
r1c7=2 (r2c9<>2 r2c3=2 r6c3<>2) r1c7<>9 r6c7=9 r6c4<>9 r6c4=6 r6c3<>6 r6c3=4 r4c2<>4
r1c7=2 r1c7<>9 (r6c7=9 r6c4<>9 r6c4=6 r6c3<>6 r6c3=4 r6c6<>4) r1c9=9 r1c9<>1 r2c9=1 r2c5<>1 r2c5=4 (r1c6<>4) r3c6<>4 r5c6=4 r4c4<>4
r1c7=2 (r8c7<>2 r8c7=7 r3c7<>7 r3c7=8 r3c9<>8) (r2c9<>2 r2c3=2 r2c3<>5) r1c7<>9 r1c9=9 r1c9<>1 r2c9=1 r2c9<>5 r2c8=5 r3c9<>5 r3c9=4 r4c9<>4
Almost Locked Set Chain: 2- r8c7 {27} -7- r136c7 {2789} -2- r4c9,r56c8 {2348} -8- r79c8,r8c79 {23578} -2 => r7c9<>2
Forcing Net Contradiction in c3 => r1c9<>8
r1c9=8 r1c9<>1 r2c9=1 r2c5<>1 r2c5=4 r2c3<>4
r1c9=8 (r3c9<>8) (r7c9<>8 r7c9=3 r8c9<>3) r3c7<>8 r3c7=7 r8c7<>7 r8c7=2 r8c9<>2 r8c9=5 r3c9<>5 r3c9=4 r3c3<>4
r1c9=8 (r3c7<>8 r6c7=8 r6c7<>9) r7c9<>8 r7c9=3 r7c5<>3 r7c5=9 r6c5<>9 r6c4=9 r6c4<>6 r6c3=6 r6c3<>4
Forcing Net Contradiction in r3c9 => r5c9<>4
r5c9=4 r3c9<>4
r5c9=4 (r6c8<>4) (r3c9<>4) r5c9<>9 r1c9=9 r1c9<>1 r2c9=1 r2c5<>1 r2c5=4 (r6c5<>4) (r3c4<>4) r3c6<>4 r3c3=4 r6c3<>4 r6c6=4 r6c6<>1 r6c5=1 (r8c5<>1) r2c5<>1 r2c5=4 (r6c5<>4) (r3c4<>4) r8c5<>4 r8c4=4 r8c4<>1 r8c1=1 r8c1<>5 r8c9=5 r3c9<>5
r5c9=4 r5c9<>9 r5c4=9 (r6c4<>9) r6c5<>9 r6c7=9 r6c7<>8 r13c7=8 r3c9<>8
Forcing Net Contradiction in r9c3 => r6c6<>2
r6c6=2 (r4c4<>2) (r5c4<>2) r6c7<>2 r8c7=2 r8c4<>2 r9c4=2 r9c3<>2
r6c6=2 (r4c4<>2) (r6c6<>4) r6c6<>1 r6c5=1 r2c5<>1 r2c5=4 (r1c6<>4) r3c6<>4 r5c6=4 r4c4<>4 r4c4=3 r3c4<>3 r3c6=3 r3c6<>5 r1c6=5 r1c1<>5 r89c1=5 r9c3<>5
r6c6=2 (r6c7<>2 r8c7=2 r8c2<>2) r6c6<>1 r6c5=1 (r8c5<>1) r2c5<>1 r2c5=4 r8c5<>4 r8c5=3 r8c2<>3 r8c2=7 r9c3<>7
Forcing Net Contradiction in c3 => r5c9<>8
r5c9=8 r5c9<>9 r1c9=9 r1c9<>1 r2c9=1 r2c5<>1 r2c5=4 r2c3<>4
r5c9=8 (r3c9<>8) (r7c9<>8 r7c9=3 r8c9<>3) r5c9<>9 r5c4=9 (r6c4<>9) r6c5<>9 r6c7=9 r6c7<>2 r8c7=2 r8c9<>2 r8c9=5 r3c9<>5 r3c9=4 r3c3<>4
r5c9=8 (r6c8<>8 r6c1=8 r6c1<>2) (r5c9<>2) r5c9<>9 (r1c9=9 r1c9<>2) (r1c9=9 r1c9<>1 r2c9=1 r2c9<>2) r5c4=9 (r6c4<>9) r6c5<>9 r6c7=9 (r6c7<>2) r6c7<>2 r8c7=2 r8c9<>2 r4c9=2 r6c8<>2 r6c3=2 r6c3<>4
Forcing Net Contradiction in r8 => r7c2<>7
r7c2=7 r8c1<>7
r7c2=7 r8c2<>7
r7c2=7 (r7c2<>9 r7c5=9 r6c5<>9) r7c2<>6 r7c3=6 r6c3<>6 r6c4=6 r6c4<>9 r6c7=9 r1c7<>9 r1c9=9 r1c9<>1 r2c9=1 (r2c4<>1) r2c5<>1 r2c5=4 r2c4<>4 r2c4=7 r8c4<>7
r7c2=7 (r7c2<>9 r7c5=9 r6c5<>9) r7c2<>6 r7c3=6 r6c3<>6 r6c4=6 r6c4<>9 r6c7=9 r6c7<>2 r8c7=2 r8c7<>7
Forcing Net Contradiction in r9c1 => r8c1<>2
r8c1=2 (r8c9<>2) (r7c3<>2) (r9c3<>2) r8c7<>2 (r8c7=7 r3c7<>7 r3c7=8 r1c8<>8 r1c4=8 r1c4<>1) r6c7=2 (r4c9<>2) (r5c9<>2) r6c3<>2 r2c3=2 r2c9<>2 r1c9=2 r1c9<>1 r1c6=1 (r6c6<>1 r6c5=1 r8c5<>1) r2c5<>1 r2c5=4 r8c5<>4 r8c4=4 r8c4<>1 r8c1=1 r8c1<>2
Forcing Net Verity => r8c4<>3
r7c2=3 (r7c5<>3 r7c5=9 r6c5<>9) r7c2<>6 r7c3=6 r6c3<>6 r6c4=6 r6c4<>9 r6c7=9 r1c7<>9 r1c9=9 r1c9<>1 r2c9=1 r2c5<>1 r2c5=4 r8c5<>4 r8c4=4 r8c4<>3
r8c1=3 r8c4<>3
r8c2=3 r8c4<>3
r9c1=3 (r9c1<>5) r9c1<>1 r8c1=1 r8c1<>5 (r8c9=5 r3c9<>5) r1c1=5 r3c3<>5 r3c6=5 r3c6<>3 r3c4=3 r8c4<>3
r9c2=3 r9c2<>9 r9c4=9 r7c5<>9 r7c5=3 r8c4<>3
Brute Force: r5c9=9
Hidden Single: r1c7=9
Continuous Nice Loop: 2/3 9= r7c2 =6= r7c3 -6- r6c3 =6= r6c4 =9= r6c5 -9- r7c5 =9= r7c2 =6 => r7c2<>2, r7c2<>3
Forcing Net Verity => r1c6<>7
r7c3=7 r23c3<>7 r1c12=7 r1c6<>7
r7c6=7 r1c6<>7
r7c8=7 (r8c7<>7 r3c7=7 r3c7<>8) r7c8<>8 r7c9=8 r3c9<>8 r3c4=8 r3c4<>3 r3c6=3 r3c6<>5 r1c6=5 r1c6<>7
Empty Rectangle: 7 in b2 (r38c7) => r8c4<>7
Forcing Chain Verity => r7c9=8
r1c1=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c9<>8 r7c9=8
r1c2=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c9<>8 r7c9=8
r1c4=7 r1c4<>8 r1c8=8 r7c8<>8 r7c9=8
r1c8=7 r3c7<>7 r3c7=8 r3c9<>8 r7c9=8
Almost Locked Set XZ-Rule: A=r1c6,r2c45 {1457}, B=r123c9,r2c8 {12457}, X=7, Z=5 => r1c8<>5
Forcing Chain Verity => r1c4<>1
r1c1=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c4<>8 r1c4=8 r1c4<>1
r1c2=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c4<>8 r1c4=8 r1c4<>1
r1c4=7 r1c4<>1
r1c8=7 r1c8<>8 r1c4=8 r1c4<>1
Discontinuous Nice Loop: 4 r1c9 -4- r3c9 -5- r3c6 =5= r1c6 =1= r1c9 => r1c9<>4
Forcing Chain Contradiction in c3 => r1c9=1
r1c9<>1 r1c9=2 r1c12<>2 r2c3=2 r2c3<>4
r1c9<>1 r1c6=1 r1c6<>5 r3c6=5 r3c9<>5 r3c9=4 r3c3<>4
r1c9<>1 r1c6=1 r6c6<>1 r6c5=1 r6c5<>9 r6c4=9 r6c4<>6 r6c3=6 r6c3<>4
Forcing Chain Contradiction in c3 => r6c6=1
r6c6<>1 r6c5=1 r2c5<>1 r2c5=4 r2c3<>4
r6c6<>1 r9c6=1 r9c1<>1 r8c1=1 r8c1<>5 r8c9=5 r3c9<>5 r3c9=4 r3c3<>4
r6c6<>1 r6c5=1 r6c5<>9 r6c4=9 r6c4<>6 r6c3=6 r6c3<>4
Forcing Chain Verity => r1c4<>4
r1c1=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c4<>8 r1c4=8 r1c4<>4
r1c2=7 r23c3<>7 r79c3=7 r8c12<>7 r8c7=7 r3c7<>7 r3c7=8 r3c4<>8 r1c4=8 r1c4<>4
r1c4=7 r1c4<>4
r1c8=7 r1c8<>8 r1c4=8 r1c4<>4
Forcing Chain Verity => r4c2<>3
r8c1=3 r8c9<>3 r4c9=3 r4c2<>3
r8c2=3 r4c2<>3
r9c1=3 r9c1<>1 r8c1=1 r8c1<>5 r8c9=5 r8c9<>3 r4c9=3 r4c2<>3
r9c2=3 r4c2<>3
Forcing Chain Contradiction in r1c1 => r6c1<>2
r6c1=2 r1c1<>2
r6c1=2 r6c7<>2 r6c7=8 r3c7<>8 r3c4=8 r3c4<>3 r3c6=3 r3c6<>5 r1c6=5 r1c1<>5
r6c1=2 r6c7<>2 r6c7=8 r3c7<>8 r3c4=8 r1c4<>8 r1c4=7 r1c1<>7
Forcing Chain Contradiction in r9c3 => r4c9<>2
r4c9=2 r6c78<>2 r6c3=2 r9c3<>2
r4c9=2 r4c9<>3 r8c9=3 r8c9<>5 r8c1=5 r9c3<>5
r4c9=2 r6c7<>2 r8c7=2 r8c7<>7 r8c12=7 r9c3<>7
Finned Swordfish: 2 c379 r268 fr7c3 fr9c3 => r8c2<>2
XY-Chain: 3 3- r6c1 -8- r6c7 -2- r8c7 -7- r8c2 -3 => r5c2,r89c1<>3
AIC: 3 3- r4c9 =3= r8c9 -3- r8c2 -7- r8c7 -2- r6c7 -8- r6c1 -3 => r4c1,r6c8<>3
Hidden Pair: 3,8 in r56c1 => r5c1<>2
Discontinuous Nice Loop: 3 r8c5 -3- r8c2 =3= r9c2 =9= r9c4 -9- r7c5 -3- r8c5 => r8c5<>3
Naked Pair: 1,4 in r28c5 => r6c5<>4
Empty Rectangle: 4 in b1 (r6c38) => r1c8<>4
Discontinuous Nice Loop: 4 r3c3 -4- r3c9 -5- r3c6 =5= r1c6 =4= r1c2 -4- r3c3 => r3c3<>4
Sashimi Swordfish: 4 r134 c249 fr1c6 fr3c6 => r2c4<>4
Sashimi Swordfish: 4 c368 r256 fr1c6 fr3c6 => r2c5<>4
Naked Single: r2c5=1
Naked Single: r2c4=7
Naked Single: r8c5=4
Naked Single: r1c4=8
Hidden Single: r3c7=8
Naked Single: r6c7=2
Full House: r8c7=7
Naked Single: r8c2=3
Hidden Single: r3c3=7
Hidden Single: r1c8=7
Hidden Single: r4c9=3
Hidden Single: r7c6=7
Locked Candidates Type 1 (Pointing): 2 in b3 => r2c3<>2
Locked Candidates Type 1 (Pointing): 4 in b6 => r2c8<>4
Locked Candidates Type 2 (Claiming): 2 in c3 => r9c12<>2
Naked Triple: 2,3,5 in r9c368 => r9c1<>5, r9c4<>2, r9c4<>3
X-Wing: 5 c38 r29 => r2c9<>5
Skyscraper: 4 in r1c6,r4c4 (connected by r14c2) => r3c4,r5c6<>4
Naked Single: r3c4=3
W-Wing: 4/2 in r1c2,r4c4 connected by 2 in r14c1 => r4c2<>4
Hidden Single: r4c4=4
Locked Candidates Type 1 (Pointing): 2 in b5 => r5c2<>2
Bivalue Universal Grave + 1 => r9c8<>3, r9c8<>5
Naked Single: r9c8=2
Naked Single: r2c8=5
Naked Single: r7c8=3
Full House: r8c9=5
Naked Single: r9c3=5
Naked Single: r9c6=3
Naked Single: r2c3=4
Full House: r2c9=2
Full House: r3c9=4
Full House: r3c6=5
Full House: r1c6=4
Full House: r5c6=2
Naked Single: r7c5=9
Full House: r6c5=3
Naked Single: r8c1=1
Full House: r8c4=2
Full House: r9c4=1
Naked Single: r1c2=2
Full House: r1c1=5
Naked Single: r6c3=6
Full House: r7c3=2
Full House: r7c2=6
Naked Single: r5c4=6
Full House: r6c4=9
Naked Single: r6c1=8
Full House: r6c8=4
Full House: r5c8=8
Naked Single: r9c1=7
Full House: r9c2=9
Naked Single: r4c2=7
Full House: r5c2=4
Full House: r5c1=3
Full House: r4c1=2
|
normal_sudoku_2729
|
..5...37..1......57....561...1..3..7...21.9..8...9.....4.3..7....7.46..32....1.4.
|
685129374412637895739485612921563487374218956856794231148352769597846123263971548
|
Basic 9x9 Sudoku 2729
|
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 7 .
. 1 . . . . . . 5
7 . . . . 5 6 1 .
. . 1 . . 3 . . 7
. . . 2 1 . 9 . .
8 . . . 9 . . . .
. 4 . 3 . . 7 . .
. . 7 . 4 6 . . 3
2 . . . . 1 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
685129374412637895739485612921563487374218956856794231148352769597846123263971548 #1 Extreme (29084) bf
Locked Candidates Type 1 (Pointing): 2 in b8 => r7c89<>2
Brute Force: r5c5=1
Hidden Single: r1c4=1
Brute Force: r5c6=8
Hidden Single: r5c2=7
Finned Franken Swordfish: 4 r35b5 c349 fr5c1 fr6c6 => r6c3<>4
Almost Locked Set XY-Wing: A=r4c1245 {24569}, B=r5c9 {46}, C=r5c13,r6c23 {23456}, X,Y=2,4, Z=6 => r4c8<>6
Almost Locked Set XY-Wing: A=r9c4579 {56789}, B=r46c2,r5c13,r6c3 {234569}, C=r5c9 {46}, X,Y=4,6, Z=9 => r9c2<>9
Forcing Chain Contradiction in r7c1 => r6c8<>2
r6c8=2 r8c8<>2 r8c7=2 r8c7<>1 r8c1=1 r7c1<>1
r6c8=2 r6c8<>3 r5c8=3 r5c8<>5 r5c1=5 r7c1<>5
r6c8=2 r4c78<>2 r4c2=2 r4c2<>9 r4c1=9 r4c1<>4 r5c13=4 r5c9<>4 r5c9=6 r9c9<>6 r7c89=6 r7c1<>6
r6c8=2 r4c78<>2 r4c2=2 r4c2<>9 r4c1=9 r7c1<>9
Almost Locked Set XY-Wing: A=r4c1245 {24569}, B=r5c89,r6c8 {3456}, C=r5c13,r6c23 {23456}, X,Y=2,4, Z=5 => r4c78<>5
Almost Locked Set XZ-Rule: A=r8c124 {1589}, B=r2489c7 {12458}, X=1, Z=5 => r8c8<>5
Naked Triple: 2,8,9 in r248c8 => r7c8<>8, r7c8<>9
Grouped Discontinuous Nice Loop: 6 r7c1 -6- r7c8 -5- r89c7 =5= r6c7 =1= r6c9 -1- r7c9 =1= r7c1 => r7c1<>6
Almost Locked Set XZ-Rule: A=r7c13,r8c12 {15689}, B=r7c8,r9c7 {568}, X=6, Z=8 => r9c23<>8
Forcing Net Verity => r7c6=2
r7c1=9 r7c6<>9 r7c6=2
r7c3=9 r7c6<>9 r7c6=2
r8c1=9 (r1c1<>9) (r4c1<>9 r4c2=9 r1c2<>9) r8c8<>9 r2c8=9 r1c9<>9 r1c6=9 r7c6<>9 r7c6=2
r8c2=9 (r1c2<>9) (r4c2<>9 r4c1=9 r1c1<>9) r8c8<>9 r2c8=9 r1c9<>9 r1c6=9 r7c6<>9 r7c6=2
r9c3=9 (r9c3<>6) r9c3<>3 r9c2=3 r9c2<>6 r9c9=6 (r7c9<>6 r7c3=6 r7c3<>8) r7c8<>6 r7c8=5 r9c7<>5 r9c7=8 r7c9<>8 r7c5=8 r7c5<>2 r7c6=2
Locked Candidates Type 1 (Pointing): 9 in b8 => r23c4<>9
Forcing Chain Contradiction in r1 => r7c8=6
r7c8<>6 r56c8=6 r5c9<>6 r5c9=4 r5c3<>4 r45c1=4 r1c1<>4
r7c8<>6 r7c8=5 r89c7<>5 r6c7=5 r6c7<>1 r8c7=1 r8c7<>2 r8c8=2 r8c8<>9 r2c8=9 r2c6<>9 r1c6=9 r1c6<>4
r7c8<>6 r56c8=6 r5c9<>6 r5c9=4 r1c9<>4
Locked Candidates Type 1 (Pointing): 5 in b9 => r6c7<>5
Hidden Pair: 3,6 in r9c23 => r9c2<>5, r9c3<>9
Forcing Chain Contradiction in r1 => r1c1<>9
r1c1=9 r23c3<>9 r7c3=9 r7c3<>8 r8c2=8 r1c2<>8
r1c1=9 r1c6<>9 r1c6=4 r3c4<>4 r3c4=8 r1c5<>8
r1c1=9 r3c23<>9 r3c9=9 r9c9<>9 r9c9=8 r1c9<>8
Almost Locked Set XY-Wing: A=r1c1 {46}, B=r5c39 {346}, C=r23679c3 {234689}, X,Y=3,4, Z=6 => r5c1<>6
Forcing Chain Contradiction in r1 => r1c2<>9
r1c2=9 r1c2<>8
r1c2=9 r1c6<>9 r1c6=4 r3c4<>4 r3c4=8 r1c5<>8
r1c2=9 r3c23<>9 r3c9=9 r9c9<>9 r9c9=8 r1c9<>8
Forcing Chain Verity => r2c3<>6
r2c3=8 r2c3<>6
r3c3=8 r3c4<>8 r3c4=4 r46c4<>4 r6c6=4 r6c6<>7 r6c4=7 r6c4<>6 r4c45=6 r4c1<>6 r12c1=6 r2c3<>6
r7c3=8 r7c5<>8 r7c5=5 r4c5<>5 r4c5=6 r4c1<>6 r12c1=6 r2c3<>6
Forcing Chain Contradiction in r1 => r8c4<>5
r8c4=5 r7c5<>5 r7c5=8 r7c3<>8 r8c2=8 r1c2<>8
r8c4=5 r7c5<>5 r7c5=8 r1c5<>8
r8c4=5 r8c4<>9 r9c4=9 r9c9<>9 r9c9=8 r1c9<>8
AIC: 9 9- r1c6 -4- r3c4 -8- r8c4 -9- r8c8 =9= r2c8 -9 => r1c9,r2c6<>9
Hidden Single: r1c6=9
Empty Rectangle: 4 in b3 (r26c6) => r6c9<>4
Empty Rectangle: 4 in b4 (r1c19) => r5c9<>4
Naked Single: r5c9=6
Locked Candidates Type 1 (Pointing): 4 in b6 => r2c7<>4
Locked Candidates Type 2 (Claiming): 4 in r5 => r4c1<>4
W-Wing: 8/2 in r2c7,r4c8 connected by 2 in r8c78 => r2c8,r4c7<>8
Hidden Single: r4c8=8
Discontinuous Nice Loop: 9 r2c1 -9- r2c8 -2- r8c8 =2= r8c7 -2- r4c7 =2= r4c2 =9= r4c1 -9- r2c1 => r2c1<>9
Discontinuous Nice Loop: 6 r4c1 -6- r4c5 -5- r7c5 =5= r7c1 =1= r7c9 -1- r6c9 -2- r4c7 =2= r4c2 =9= r4c1 => r4c1<>6
Locked Candidates Type 2 (Claiming): 6 in c1 => r1c2<>6
Naked Triple: 1,5,9 in r478c1 => r5c1<>5
Hidden Single: r5c8=5
Naked Single: r6c8=3
W-Wing: 8/2 in r1c2,r2c7 connected by 2 in r4c27 => r1c9,r2c3<>8
2-String Kite: 8 in r1c5,r7c3 (connected by r1c2,r3c3) => r7c5<>8
Naked Single: r7c5=5
Naked Single: r4c5=6
Hidden Single: r9c7=5
Hidden Single: r1c1=6
Hidden Single: r2c4=6
Hidden Single: r1c9=4
2-String Kite: 2 in r3c9,r4c2 (connected by r4c7,r6c9) => r3c2<>2
Uniqueness Test 1: 3/4 in r2c13,r5c13 => r2c3<>3, r2c3<>4
Naked Pair: 2,9 in r2c38 => r2c57<>2
Naked Single: r2c7=8
Skyscraper: 8 in r1c5,r8c4 (connected by r18c2) => r3c4,r9c5<>8
Naked Single: r3c4=4
Naked Single: r9c5=7
Naked Single: r2c6=7
Full House: r6c6=4
Naked Single: r4c4=5
Full House: r6c4=7
Naked Single: r2c5=3
Naked Single: r4c1=9
Naked Single: r2c1=4
Naked Single: r4c2=2
Full House: r4c7=4
Naked Single: r7c1=1
Naked Single: r5c1=3
Full House: r8c1=5
Full House: r5c3=4
Naked Single: r1c2=8
Full House: r1c5=2
Full House: r3c5=8
Naked Single: r6c3=6
Full House: r6c2=5
Naked Single: r8c2=9
Naked Single: r9c3=3
Naked Single: r3c2=3
Full House: r9c2=6
Full House: r7c3=8
Full House: r7c9=9
Naked Single: r8c4=8
Full House: r9c4=9
Full House: r9c9=8
Naked Single: r8c8=2
Full House: r2c8=9
Full House: r3c9=2
Full House: r8c7=1
Full House: r2c3=2
Full House: r3c3=9
Full House: r6c9=1
Full House: r6c7=2
|
normal_sudoku_5957
|
76...3..2..54..6......6....1.8...94...967.3.16....1.2535...72.82...5...7.......53
|
764593812835412679912768534178235946529674381643981725356147298281359467497826153
|
Basic 9x9 Sudoku 5957
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 6 . . . 3 . . 2
. . 5 4 . . 6 . .
. . . . 6 . . . .
1 . 8 . . . 9 4 .
. . 9 6 7 . 3 . 1
6 . . . . 1 . 2 5
3 5 . . . 7 2 . 8
2 . . . 5 . . . 7
. . . . . . . 5 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
764593812835412679912768534178235946529674381643981725356147298281359467497826153 #1 Easy (204)
Naked Single: r6c9=5
Naked Single: r5c8=8
Naked Single: r2c9=9
Naked Single: r4c9=6
Full House: r6c7=7
Full House: r3c9=4
Naked Single: r1c8=1
Naked Single: r2c1=8
Naked Single: r1c3=4
Naked Single: r2c6=2
Naked Single: r3c1=9
Naked Single: r6c3=3
Naked Single: r2c5=1
Naked Single: r4c6=5
Naked Single: r9c1=4
Full House: r5c1=5
Naked Single: r6c2=4
Naked Single: r2c2=3
Full House: r2c8=7
Naked Single: r3c6=8
Naked Single: r5c6=4
Full House: r5c2=2
Full House: r4c2=7
Naked Single: r9c7=1
Naked Single: r3c8=3
Naked Single: r1c5=9
Naked Single: r3c7=5
Full House: r1c7=8
Full House: r8c7=4
Full House: r1c4=5
Full House: r3c4=7
Naked Single: r3c2=1
Full House: r3c3=2
Naked Single: r6c5=8
Full House: r6c4=9
Naked Single: r7c5=4
Naked Single: r9c5=2
Full House: r4c5=3
Full House: r4c4=2
Naked Single: r7c4=1
Naked Single: r9c4=8
Full House: r8c4=3
Naked Single: r7c3=6
Full House: r7c8=9
Full House: r8c8=6
Naked Single: r9c2=9
Full House: r8c2=8
Naked Single: r8c3=1
Full House: r9c3=7
Full House: r8c6=9
Full House: r9c6=6
|
normal_sudoku_2158
|
..2...4.6.5...27.973...9.2.....5....5.7..3.4..8.1....5..3..4.6.9...8.1...6.9.....
|
892715436651432789734869521349258617517693842286147395173524968925386174468971253
|
Basic 9x9 Sudoku 2158
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . . . 4 . 6
. 5 . . . 2 7 . 9
7 3 . . . 9 . 2 .
. . . . 5 . . . .
5 . 7 . . 3 . 4 .
. 8 . 1 . . . . 5
. . 3 . . 4 . 6 .
9 . . . 8 . 1 . .
. 6 . 9 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
892715436651432789734869521349258617517693842286147395173524968925386174468971253 #1 Hard (1230)
Hidden Single: r5c1=5
Hidden Single: r1c2=9
Hidden Single: r7c7=9
Hidden Single: r5c5=9
Hidden Single: r7c4=5
Hidden Single: r3c7=5
Hidden Single: r1c6=5
Hidden Single: r9c6=1
Hidden Single: r4c6=8
Locked Candidates Type 1 (Pointing): 3 in b3 => r4689c8<>3
W-Wing: 1/8 in r1c1,r3c9 connected by 8 in r7c19 => r1c8,r3c3<>1
X-Wing: 1 c38 r24 => r2c15,r4c129<>1
Hidden Pair: 1,9 in r4c38 => r4c3<>4, r4c3<>6, r4c8<>7
2-String Kite: 7 in r4c9,r8c6 (connected by r4c4,r6c6) => r8c9<>7
W-Wing: 8/1 in r1c1,r3c9 connected by 1 in r2c38 => r1c8,r3c3<>8
Naked Single: r1c8=3
X-Wing: 8 c38 r29 => r2c14,r9c179<>8
Hidden Single: r5c7=8
Hidden Single: r5c4=6
Naked Single: r6c6=7
Full House: r8c6=6
Naked Single: r6c8=9
Naked Single: r4c8=1
Naked Single: r2c8=8
Full House: r3c9=1
Naked Single: r4c3=9
Naked Single: r5c9=2
Full House: r5c2=1
Hidden Single: r4c9=7
Naked Single: r7c9=8
Hidden Single: r2c3=1
Naked Single: r1c1=8
Naked Single: r1c4=7
Full House: r1c5=1
Hidden Single: r9c3=8
Hidden Single: r3c4=8
Hidden Single: r9c7=2
Naked Single: r9c1=4
Naked Single: r2c1=6
Full House: r3c3=4
Full House: r3c5=6
Naked Single: r8c3=5
Full House: r6c3=6
Naked Single: r9c9=3
Full House: r8c9=4
Naked Single: r8c8=7
Full House: r9c8=5
Full House: r9c5=7
Naked Single: r6c7=3
Full House: r4c7=6
Naked Single: r8c2=2
Full House: r8c4=3
Full House: r7c5=2
Naked Single: r6c1=2
Full House: r6c5=4
Full House: r2c5=3
Full House: r2c4=4
Full House: r4c4=2
Naked Single: r4c2=4
Full House: r7c2=7
Full House: r7c1=1
Full House: r4c1=3
|
normal_sudoku_4071
|
.2..9.3....12...9.7.........8.42...3..58.124.2....6.8....6....58..7..4...5..4..3.
|
426598317531267894798314652189425763365871249274936581942683175813759426657142938
|
Basic 9x9 Sudoku 4071
|
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 2 . . . 9 .
7 . . . . . . . .
. 8 . 4 2 . . . 3
. . 5 8 . 1 2 4 .
2 . . . . 6 . 8 .
. . . 6 . . . . 5
8 . . 7 . . 4 . .
. 5 . . 4 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
426598317531267894798314652189425763365871249274936581942683175813759426657142938 #1 Extreme (30432) bf
Brute Force: r5c4=8
Grouped Discontinuous Nice Loop: 7 r2c5 -7- r56c5 =7= r4c6 =9= r6c4 -9- r9c4 -1- r13c4 =1= r3c5 =6= r2c5 => r2c5<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r4c6<>7
Forcing Chain Contradiction in r8 => r6c2<>9
r6c2=9 r8c2<>9
r6c2=9 r3c2<>9 r3c3=9 r8c3<>9
r6c2=9 r6c4<>9 r9c4=9 r8c6<>9
r6c2=9 r5c12<>9 r5c9=9 r8c9<>9
Forcing Chain Contradiction in r8 => r6c3<>9
r6c3=9 r3c3<>9 r3c2=9 r8c2<>9
r6c3=9 r8c3<>9
r6c3=9 r6c4<>9 r9c4=9 r8c6<>9
r6c3=9 r5c12<>9 r5c9=9 r8c9<>9
Forcing Net Verity => r2c1<>6
r9c1=1 (r4c1<>1) r9c4<>1 r9c4=9 (r7c6<>9) (r8c6<>9) r9c6<>9 r4c6=9 r4c1<>9 r4c1=6 r2c1<>6
r9c1=6 r2c1<>6
r9c1=9 r9c4<>9 r9c4=1 r1c4<>1 r1c4=5 r1c1<>5 r2c1=5 r2c1<>6
Forcing Net Contradiction in r7c2 => r4c1<>9
r4c1=9 (r4c1<>1 r6c2=1 r6c2<>4 r6c3=4 r7c3<>4) (r4c1<>1) r4c6<>9 r6c4=9 r9c4<>9 r9c4=1 r9c1<>1 r7c1=1 r7c1<>4 r7c2=4
r4c1=9 (r4c6<>9 r6c4=9 r6c9<>9) r4c1<>1 r6c2=1 (r6c2<>7) r6c9<>1 r6c9=7 (r4c7<>7) r4c8<>7 r4c3=7 r5c2<>7 r7c2=7
Forcing Net Contradiction in r4c3 => r7c1<>1
r7c1=1 (r7c1<>4) (r7c2<>1) r8c2<>1 r6c2=1 r6c2<>4 r6c3=4 r7c3<>4 r7c2=4 r7c2<>7 r56c2=7 r4c3<>7
r7c1=1 r4c1<>1 r4c1=6 (r4c3<>6) (r9c1<>6 r9c1=9 r5c1<>9) (r5c1<>6) r5c2<>6 r5c9=6 r5c9<>9 r5c2=9 r4c3<>9 r4c3=7
Forcing Net Contradiction in b6 => r9c3<>9
r9c3=9 (r4c3<>9) r9c4<>9 r6c4=9 r4c6<>9 r4c7=9 r4c7<>6
r9c3=9 (r9c1<>9 r5c1=9 r5c9<>9) (r9c9<>9) r9c4<>9 (r9c4=1 r9c1<>1 r9c1=6 r8c2<>6) (r9c4=1 r9c1<>1 r9c1=6 r8c3<>6) r6c4=9 r6c9<>9 r8c9=9 r8c9<>6 r8c8=6 r4c8<>6
r9c3=9 (r3c3<>9 r3c2=9 r3c2<>6) r9c4<>9 r9c4=1 (r9c1<>1 r9c1=6 r8c2<>6) (r7c5<>1) r8c5<>1 r3c5=1 r3c5<>6 r2c5=6 r2c2<>6 r5c2=6 r5c9<>6
Brute Force: r5c5=7
Locked Candidates Type 1 (Pointing): 3 in b5 => r6c23<>3
Grouped Discontinuous Nice Loop: 6 r2c9 -6- r2c5 =6= r3c5 =1= r13c4 -1- r9c4 -9- r6c4 =9= r6c79 -9- r5c9 -6- r2c9 => r2c9<>6
Forcing Chain Contradiction in c8 => r3c9<>6
r3c9=6 r5c9<>6 r5c9=9 r6c79<>9 r6c4=9 r9c4<>9 r9c4=1 r1c4<>1 r1c4=5 r1c8<>5
r3c9=6 r3c9<>2 r3c8=2 r3c8<>5
r3c9=6 r5c9<>6 r5c9=9 r5c12<>9 r4c3=9 r4c6<>9 r4c6=5 r4c8<>5
Forcing Chain Contradiction in c1 => r5c1<>6
r5c1=6 r5c9<>6 r5c9=9 r6c79<>9 r6c4=9 r9c4<>9 r9c4=1 r1c4<>1 r1c4=5 r1c1<>5 r2c1=5 r2c1<>3
r5c1=6 r5c1<>3
r5c1=6 r5c9<>6 r5c9=9 r6c79<>9 r6c4=9 r6c4<>3 r3c4=3 r3c3<>3 r78c3=3 r7c1<>3
Forcing Chain Contradiction in r5c2 => r7c2<>3
r7c2=3 r5c2<>3
r7c2=3 r78c3<>3 r3c3=3 r3c4<>3 r6c4=3 r6c4<>9 r6c79=9 r5c9<>9 r5c9=6 r5c2<>6
r7c2=3 r78c3<>3 r3c3=3 r3c3<>9 r3c2=9 r5c2<>9
Forcing Chain Contradiction in r5c2 => r8c2<>3
r8c2=3 r5c2<>3
r8c2=3 r78c3<>3 r3c3=3 r3c4<>3 r6c4=3 r6c4<>9 r6c79=9 r5c9<>9 r5c9=6 r5c2<>6
r8c2=3 r78c3<>3 r3c3=3 r3c3<>9 r3c2=9 r5c2<>9
Forcing Net Verity => r1c9<>1
r9c1=1 (r4c1<>1 r4c1=6 r1c1<>6) (r7c2<>1) r8c2<>1 r6c2=1 (r6c2<>4 r6c3=4 r7c3<>4) r6c2<>7 r7c2=7 r7c2<>4 r7c1=4 r1c1<>4 r1c1=5 r1c4<>5 r1c4=1 r1c9<>1
r9c4=1 (r9c1<>1 r4c1=1 r6c2<>1) (r1c4<>1 r1c4=5 r6c4<>5) r9c4<>9 r6c4=9 r4c6<>9 r4c6=5 r6c5<>5 r6c7=5 r6c7<>1 r6c9=1 r1c9<>1
r9c7=1 (r6c7<>1) r9c1<>1 r4c1=1 r6c2<>1 r6c9=1 r1c9<>1
r9c9=1 r1c9<>1
Forcing Net Contradiction in r8c9 => r1c9<>6
r1c9=6 r5c9<>6 (r5c2=6 r8c2<>6) r5c9=9 (r5c1<>9) r5c2<>9 r4c3=9 r3c3<>9 r3c2=9 r8c2<>9 r8c2=1 r8c9<>1
r1c9=6 r5c9<>6 r5c9=9 (r6c7<>9) r6c9<>9 r6c4=9 (r6c4<>3 r3c4=3 r3c4<>5) (r9c4<>9 r9c4=1 r1c4<>1 r1c4=5 r3c5<>5) (r6c4<>5) r4c6<>9 r4c6=5 (r3c6<>5) r6c5<>5 r6c7=5 r3c7<>5 r3c8=5 r3c8<>2 r3c9=2 r8c9<>2
r1c9=6 r8c9<>6
r1c9=6 r5c9<>6 r5c9=9 r8c9<>9
Forcing Chain Contradiction in c2 => r8c8<>6
r8c8=6 r1c8<>6 r1c13=6 r2c2<>6
r8c8=6 r1c8<>6 r1c13=6 r3c2<>6
r8c8=6 r89c9<>6 r5c9=6 r5c2<>6
r8c8=6 r8c2<>6
Grouped Discontinuous Nice Loop: 6 r2c7 -6- r2c5 =6= r3c5 =1= r13c4 -1- r9c4 -9- r6c4 =9= r6c79 -9- r5c9 -6- r4c8 =6= r13c8 -6- r2c7 => r2c7<>6
Grouped Discontinuous Nice Loop: 1 r9c7 -1- r9c4 -9- r6c4 =9= r6c79 -9- r5c9 -6- r89c9 =6= r9c7 => r9c7<>1
Almost Locked Set Chain: 1- r4c1 {16} -6- r12579c1 {134569} -1- r23578c2 {134679} -7- r78c8 {127} -1 => r4c8<>1
Forcing Chain Verity => r3c7<>1
r9c1=1 r4c1<>1 r4c7=1 r3c7<>1
r9c4=1 r1c4<>1 r1c8=1 r3c7<>1
r9c9=1 r6c9<>1 r46c7=1 r3c7<>1
Sue de Coq: r13c8 - {12567} (r8c8 - {12}, r12c9,r23c7 - {45678}) => r3c9<>4, r3c9<>8, r7c8<>1, r7c8<>2
Naked Single: r7c8=7
Hidden Single: r6c2=7
Naked Single: r6c3=4
Hidden Single: r9c3=7
Hidden Single: r4c7=7
Hidden Single: r4c1=1
Hidden Pair: 4,7 in r12c9 => r12c9<>8
Hidden Single: r9c9=8
Hidden Single: r9c4=1
Naked Single: r1c4=5
Naked Single: r3c4=3
Full House: r6c4=9
Naked Single: r4c6=5
Full House: r6c5=3
Naked Single: r6c9=1
Full House: r6c7=5
Naked Single: r4c8=6
Full House: r4c3=9
Full House: r5c9=9
Naked Single: r7c5=8
Naked Single: r8c5=5
Naked Single: r3c9=2
Naked Single: r2c7=8
Naked Single: r1c8=1
Naked Single: r5c1=3
Full House: r5c2=6
Naked Single: r2c5=6
Full House: r3c5=1
Naked Single: r8c9=6
Naked Single: r3c7=6
Naked Single: r3c8=5
Full House: r8c8=2
Naked Single: r9c7=9
Full House: r7c7=1
Naked Single: r3c3=8
Naked Single: r8c3=3
Naked Single: r9c1=6
Full House: r9c6=2
Naked Single: r1c3=6
Full House: r7c3=2
Naked Single: r3c6=4
Full House: r3c2=9
Naked Single: r8c6=9
Full House: r8c2=1
Full House: r7c6=3
Naked Single: r1c1=4
Naked Single: r2c6=7
Full House: r1c6=8
Full House: r1c9=7
Full House: r2c9=4
Naked Single: r7c2=4
Full House: r2c2=3
Full House: r2c1=5
Full House: r7c1=9
|
normal_sudoku_822
|
...463.8..8.........2.5....53...9..8....2..5.1276.5394.5.....2...8...4.7.41..89..
|
975463182486192573312857649534719268869324751127685394753941826298536417641278935
|
Basic 9x9 Sudoku 822
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 4 6 3 . 8 .
. 8 . . . . . . .
. . 2 . 5 . . . .
5 3 . . . 9 . . 8
. . . . 2 . . 5 .
1 2 7 6 . 5 3 9 4
. 5 . . . . . 2 .
. . 8 . . . 4 . 7
. 4 1 . . 8 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
975463182486192573312857649534719268869324751127685394753941826298536417641278935 #1 Extreme (2318)
Naked Single: r6c2=2
Full House: r6c5=8
Hidden Single: r5c4=3
Hidden Single: r4c7=2
Hidden Single: r5c1=8
Hidden Single: r8c4=5
Hidden Single: r3c4=8
Hidden Single: r7c7=8
Hidden Single: r9c9=5
Hidden Single: r1c9=2
Locked Candidates Type 1 (Pointing): 9 in b2 => r2c139<>9
Hidden Single: r3c9=9
Locked Candidates Type 1 (Pointing): 4 in b4 => r2c3<>4
Locked Candidates Type 1 (Pointing): 7 in b7 => r123c1<>7
Naked Single: r1c1=9
Naked Single: r1c3=5
Hidden Single: r2c7=5
Naked Pair: 6,9 in r58c2 => r3c2<>6
Naked Pair: 1,7 in r3c26 => r3c78<>1, r3c78<>7
Naked Single: r3c7=6
X-Wing: 3 c39 r27 => r2c18,r7c15<>3
Swordfish: 6 r249 c138 => r57c3,r78c1,r8c8<>6
Naked Single: r7c1=7
Swordfish: 7 r135 c267 => r2c6<>7
XYZ-Wing: 1/3/9 in r7c4,r8c58 => r8c6<>1
Sue de Coq: r8c12 - {2369} (r8c6 - {26}, r7c3 - {39}) => r9c1<>3
XY-Wing: 2/6/3 in r89c1,r9c8 => r8c8<>3
Naked Single: r8c8=1
Locked Candidates Type 1 (Pointing): 1 in b6 => r5c6<>1
XY-Wing: 3/6/7 in r49c8,r9c5 => r4c5<>7
XY-Wing: 4/7/1 in r35c6,r4c5 => r2c5<>1
Naked Triple: 3,7,9 in r289c5 => r7c5<>9
XY-Chain: 7 7- r2c8 -4- r2c1 -6- r2c3 -3- r7c3 -9- r8c2 -6- r8c6 -2- r2c6 -1- r3c6 -7 => r2c45<>7
Naked Single: r2c5=9
Naked Single: r8c5=3
Naked Single: r8c1=2
Naked Single: r9c5=7
Naked Single: r8c6=6
Full House: r8c2=9
Naked Single: r9c1=6
Full House: r7c3=3
Naked Single: r9c4=2
Full House: r9c8=3
Full House: r7c9=6
Naked Single: r5c2=6
Naked Single: r2c1=4
Full House: r3c1=3
Naked Single: r2c3=6
Naked Single: r2c4=1
Naked Single: r3c8=4
Naked Single: r5c9=1
Full House: r2c9=3
Naked Single: r4c3=4
Full House: r5c3=9
Naked Single: r2c8=7
Full House: r2c6=2
Full House: r3c6=7
Full House: r1c7=1
Full House: r5c7=7
Full House: r4c8=6
Full House: r3c2=1
Full House: r5c6=4
Full House: r1c2=7
Full House: r7c6=1
Naked Single: r4c4=7
Full House: r7c4=9
Full House: r4c5=1
Full House: r7c5=4
|
normal_sudoku_6027
|
.94..3...3...6...4..2....3.4....2.6...9.5...8...1..7..2....9.8.58.7....19...8.5..
|
694273815318965274752418936475892163169357428823146759241539687586724391937681542
|
Basic 9x9 Sudoku 6027
|
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 . . 3 . . .
3 . . . 6 . . . 4
. . 2 . . . . 3 .
4 . . . . 2 . 6 .
. . 9 . 5 . . . 8
. . . 1 . . 7 . .
2 . . . . 9 . 8 .
5 8 . 7 . . . . 1
9 . . . 8 . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
694273815318965274752418936475892163169357428823146759241539687586724391937681542 #1 Extreme (8204)
Hidden Single: r9c1=9
Hidden Single: r7c4=5
Locked Candidates Type 2 (Claiming): 5 in r1 => r2c8,r3c9<>5
Forcing Chain Contradiction in c6 => r2c3<>7
r2c3=7 r2c6<>7
r2c3=7 r2c3<>8 r13c1=8 r6c1<>8 r6c1=6 r13c1<>6 r3c2=6 r3c2<>5 r3c6=5 r3c6<>7
r2c3=7 r13c1<>7 r5c1=7 r5c6<>7
Forcing Chain Contradiction in c6 => r3c2<>1
r3c2=1 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r13c1<>8 r2c3=8 r2c6<>8
r3c2=1 r3c2<>5 r3c6=5 r3c6<>8
r3c2=1 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r6c6<>8
Forcing Chain Contradiction in c6 => r3c2<>7
r3c2=7 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r13c1<>8 r2c3=8 r2c6<>8
r3c2=7 r3c2<>5 r3c6=5 r3c6<>8
r3c2=7 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r6c6<>8
Forcing Chain Contradiction in c6 => r3c6<>1
r3c6=1 r3c6<>5 r2c6=5 r2c6<>8
r3c6=1 r3c6<>8
r3c6=1 r3c6<>5 r3c2=5 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r6c6<>8
Forcing Chain Contradiction in r6c6 => r3c6<>4
r3c6=4 r6c6<>4
r3c6=4 r8c6<>4 r8c6=6 r6c6<>6
r3c6=4 r3c6<>5 r3c2=5 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r6c6<>8
Forcing Chain Contradiction in c6 => r3c6<>7
r3c6=7 r3c6<>5 r2c6=5 r2c6<>8
r3c6=7 r3c6<>8
r3c6=7 r3c6<>5 r3c2=5 r3c2<>6 r13c1=6 r6c1<>6 r6c1=8 r6c6<>8
Empty Rectangle: 7 in b1 (r25c6) => r5c1<>7
Locked Candidates Type 2 (Claiming): 7 in c1 => r2c2<>7
Grouped Discontinuous Nice Loop: 4 r9c6 -4- r8c6 -6- r6c6 =6= r5c46 -6- r5c1 -1- r13c1 =1= r2c23 -1- r2c6 =1= r9c6 => r9c6<>4
Grouped Discontinuous Nice Loop: 1 r2c6 -1- r9c6 -6- r9c4 =6= r5c4 -6- r5c1 -1- r13c1 =1= r2c23 -1- r2c6 => r2c6<>1
Hidden Single: r9c6=1
XY-Wing: 4/6/3 in r7c5,r8c36 => r7c23,r8c5<>3
Finned Swordfish: 1 r247 c237 fr2c8 => r13c7<>1
Discontinuous Nice Loop: 8 r3c4 -8- r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r3c1 =1= r3c5 =4= r3c4 => r3c4<>8
Discontinuous Nice Loop: 4 r9c4 -4- r3c4 =4= r3c5 =1= r3c1 -1- r5c1 -6- r5c4 =6= r9c4 => r9c4<>4
Grouped Discontinuous Nice Loop: 2 r1c8 -2- r1c4 -8- r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r13c1 =1= r2c23 -1- r2c78 =1= r1c8 => r1c8<>2
Grouped Discontinuous Nice Loop: 2 r1c9 -2- r1c4 -8- r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r13c1 =1= r2c23 -1- r2c78 =1= r1c8 =5= r1c9 => r1c9<>2
Grouped Discontinuous Nice Loop: 9 r3c5 -9- r23c4 =9= r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r3c1 =1= r3c5 => r3c5<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r4c4<>9
Discontinuous Nice Loop: 2 r2c4 -2- r1c4 -8- r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r3c1 =1= r3c5 =4= r3c4 =9= r2c4 => r2c4<>2
Locked Candidates Type 1 (Pointing): 2 in b2 => r1c7<>2
Discontinuous Nice Loop: 8 r2c4 -8- r4c4 =8= r4c3 -8- r6c1 -6- r5c1 -1- r3c1 =1= r3c5 =4= r3c4 =9= r2c4 => r2c4<>8
Naked Single: r2c4=9
Naked Single: r3c4=4
Discontinuous Nice Loop: 2 r8c7 -2- r2c7 =2= r2c8 =7= r2c6 -7- r5c6 =7= r5c2 =2= r6c2 -2- r6c9 =2= r9c9 -2- r8c7 => r8c7<>2
Grouped AIC: 1/7 7- r2c8 =7= r2c6 -7- r5c6 =7= r4c5 =9= r6c5 =4= r78c5 -4- r8c6 -6- r6c6 =6= r5c46 -6- r5c1 -1- r13c1 =1= r2c23 -1- r2c78 =1= r1c8 -1 => r2c8<>1, r1c8<>7
Swordfish: 1 r247 c237 => r5c27<>1
AIC: 2/5 2- r6c2 =2= r5c2 -2- r5c7 =2= r2c7 =1= r1c8 =5= r6c8 -5 => r6c8<>2, r6c2<>5
AIC: 8 8- r4c4 =8= r1c4 =2= r1c5 -2- r8c5 =2= r8c8 =9= r6c8 =5= r1c8 =1= r5c8 -1- r5c1 -6- r6c1 -8 => r4c3,r6c6<>8
Hidden Single: r4c4=8
Naked Single: r1c4=2
Hidden Single: r8c5=2
Locked Pair: 1,7 in r13c5 => r2c6,r4c5<>7
Hidden Single: r5c6=7
Hidden Single: r2c8=7
Hidden Single: r2c7=2
Hidden Single: r4c7=1
Hidden Single: r1c8=1
Naked Single: r1c5=7
Naked Single: r3c5=1
Hidden Single: r5c1=1
Hidden Single: r1c9=5
Hidden Single: r6c8=5
Hidden Single: r3c1=7
Hidden Single: r8c8=9
Hidden Single: r3c7=9
Naked Single: r3c9=6
Full House: r1c7=8
Full House: r1c1=6
Full House: r6c1=8
Naked Single: r3c2=5
Full House: r3c6=8
Full House: r2c6=5
Naked Single: r2c2=1
Full House: r2c3=8
Hidden Single: r4c3=5
Hidden Single: r7c3=1
Hidden Single: r4c2=7
Hidden Single: r9c3=7
Hidden Single: r7c9=7
X-Wing: 6 r59 c24 => r67c2<>6
Naked Single: r7c2=4
Naked Single: r7c5=3
Full House: r7c7=6
Naked Single: r4c5=9
Full House: r4c9=3
Full House: r6c5=4
Naked Single: r9c4=6
Full House: r5c4=3
Full House: r6c6=6
Full House: r8c6=4
Naked Single: r5c7=4
Full House: r8c7=3
Full House: r8c3=6
Full House: r9c2=3
Full House: r6c3=3
Naked Single: r9c9=2
Full House: r6c9=9
Full House: r5c8=2
Full House: r6c2=2
Full House: r9c8=4
Full House: r5c2=6
|
normal_sudoku_6646
|
3...1..4..574.3..1..69...37...8......6.5....37...3.4...9..2.78.2...7...4..13.8.2.
|
329715648857463291146982537534897162962541873718236459693124785285679314471358926
|
Basic 9x9 Sudoku 6646
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 . . . 1 . . 4 .
. 5 7 4 . 3 . . 1
. . 6 9 . . . 3 7
. . . 8 . . . . .
. 6 . 5 . . . . 3
7 . . . 3 . 4 . .
. 9 . . 2 . 7 8 .
2 . . . 7 . . . 4
. . 1 3 . 8 . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
329715648857463291146982537534897162962541873718236459693124785285679314471358926 #1 Easy (318)
Hidden Single: r2c3=7
Hidden Single: r1c4=7
Hidden Single: r9c2=7
Hidden Single: r7c3=3
Naked Single: r8c2=8
Naked Single: r1c2=2
Naked Single: r8c3=5
Naked Single: r6c2=1
Naked Single: r3c2=4
Full House: r4c2=3
Hidden Single: r8c7=3
Hidden Single: r2c7=2
Hidden Single: r6c4=2
Hidden Single: r3c6=2
Hidden Single: r4c1=5
Hidden Single: r3c1=1
Hidden Single: r8c8=1
Naked Single: r8c4=6
Full House: r7c4=1
Full House: r8c6=9
Naked Single: r6c6=6
Naked Single: r1c6=5
Naked Single: r3c5=8
Full House: r2c5=6
Full House: r3c7=5
Naked Single: r7c6=4
Full House: r9c5=5
Naked Single: r2c8=9
Full House: r2c1=8
Full House: r1c3=9
Naked Single: r7c1=6
Full House: r7c9=5
Full House: r9c1=4
Full House: r5c1=9
Naked Single: r5c8=7
Naked Single: r6c8=5
Full House: r4c8=6
Naked Single: r6c3=8
Full House: r6c9=9
Naked Single: r5c5=4
Full House: r4c5=9
Naked Single: r5c6=1
Full House: r4c6=7
Naked Single: r4c7=1
Naked Single: r4c9=2
Full House: r5c7=8
Full House: r5c3=2
Full House: r4c3=4
Naked Single: r9c9=6
Full House: r1c9=8
Full House: r1c7=6
Full House: r9c7=9
|
normal_sudoku_3253
|
...67.....74..38.636.2.417.......48.8..46..17..7.1...3.5.....6......63.1.9.8...4.
|
981675234274193856365284179516739482839462517427518693152347968748956321693821745
|
Basic 9x9 Sudoku 3253
|
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 . . . .
. 7 4 . . 3 8 . 6
3 6 . 2 . 4 1 7 .
. . . . . . 4 8 .
8 . . 4 6 . . 1 7
. . 7 . 1 . . . 3
. 5 . . . . . 6 .
. . . . . 6 3 . 1
. 9 . 8 . . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
981675234274193856365284179516739482839462517427518693152347968748956321693821745 #1 Extreme (6022)
Hidden Single: r2c9=6
Hidden Single: r6c7=6
Hidden Single: r1c8=3
Hidden Single: r6c6=8
Hidden Single: r3c5=8
Hidden Single: r7c9=8
Hidden Single: r1c9=4
Locked Candidates Type 1 (Pointing): 3 in b5 => r4c23<>3
Hidden Single: r5c2=3
Empty Rectangle: 2 in b5 (r49c9) => r9c6<>2
Hidden Rectangle: 2/8 in r1c23,r8c23 => r1c2<>2
Finned X-Wing: 2 r26 c18 fr6c2 => r4c1<>2
Almost Locked Set XZ-Rule: A=r4c123569 {1235679}, B=r9c579 {2357}, X=3, Z=7 => r9c6<>7
Almost Locked Set XZ-Rule: A=r12c1,r3c3 {1259}, B=r78c1,r8c23 {12478}, X=1, Z=2 => r9c1<>2
Forcing Chain Contradiction in r8 => r2c4<>5
r2c4=5 r6c4<>5 r6c4=9 r8c4<>9
r2c4=5 r2c5<>5 r2c5=9 r8c5<>9
r2c4=5 r2c4<>1 r7c4=1 r9c6<>1 r9c6=5 r8c45<>5 r8c8=5 r8c8<>9
Forcing Chain Contradiction in r5 => r2c8<>9
r2c8=9 r3c9<>9 r3c3=9 r5c3<>9
r2c8=9 r2c45<>9 r1c6=9 r5c6<>9
r2c8=9 r8c8<>9 r7c7=9 r5c7<>9
Forcing Chain Contradiction in r1c6 => r1c1<>5
r1c1=5 r3c3<>5 r3c3=9 r3c9<>9 r4c9=9 r6c8<>9 r8c8=9 r8c8<>5 r8c45=5 r9c6<>5 r9c6=1 r1c6<>1
r1c1=5 r1c6<>5
r1c1=5 r3c3<>5 r3c3=9 r3c9<>9 r1c7=9 r1c6<>9
Forcing Chain Contradiction in r5c3 => r1c3<>5
r1c3=5 r1c6<>5 r2c5=5 r2c8<>5 r2c8=2 r6c8<>2 r6c12=2 r5c3<>2
r1c3=5 r5c3<>5
r1c3=5 r3c3<>5 r3c3=9 r5c3<>9
Forcing Chain Contradiction in r5 => r2c4=1
r2c4<>1 r2c1=1 r2c1<>5 r3c3=5 r5c3<>5
r2c4<>1 r2c4=9 r6c4<>9 r6c4=5 r5c6<>5
r2c4<>1 r1c6=1 r1c6<>5 r1c7=5 r5c7<>5
Forcing Chain Contradiction in r5 => r9c6=1
r9c6<>1 r9c6=5 r1c6<>5 r1c7=5 r3c9<>5 r3c3=5 r5c3<>5
r9c6<>1 r9c6=5 r5c6<>5
r9c6<>1 r9c6=5 r1c6<>5 r1c7=5 r5c7<>5
Grouped Discontinuous Nice Loop: 9 r4c5 -9- r2c5 -5- r1c6 =5= r45c6 -5- r6c4 -9- r4c5 => r4c5<>9
Grouped Discontinuous Nice Loop: 9 r8c5 -9- r8c8 =9= r6c8 -9- r6c4 -5- r8c4 =5= r89c5 -5- r2c5 -9- r8c5 => r8c5<>9
Forcing Chain Verity => r1c6=5
r4c1=9 r2c1<>9 r2c5=9 r2c5<>5 r1c6=5
r4c3=9 r4c3<>6 r4c1=6 r9c1<>6 r9c1=7 r8c1<>7 r8c4=7 r8c4<>5 r46c4=5 r45c6<>5 r1c6=5
r4c4=9 r6c4<>9 r6c4=5 r45c6<>5 r1c6=5
r4c6=9 r1c6<>9 r1c6=5
r4c9=9 r3c9<>9 r3c9=5 r1c7<>5 r1c6=5
Full House: r2c5=9
Skyscraper: 5 in r3c9,r5c7 (connected by r35c3) => r4c9<>5
XY-Wing: 5/9/2 in r1c7,r39c9 => r79c7<>2
XY-Wing: 5/9/2 in r2c8,r34c9 => r6c8<>2
Locked Candidates Type 2 (Claiming): 2 in r6 => r4c23,r5c3<>2
Naked Single: r4c2=1
Naked Single: r1c2=8
Hidden Single: r8c3=8
Naked Pair: 5,9 in r6c48 => r6c1<>5, r6c1<>9
Naked Pair: 5,9 in r35c3 => r14c3<>9, r4c3<>5
Naked Single: r4c3=6
Hidden Single: r9c1=6
Hidden Single: r9c7=7
Naked Single: r7c7=9
Naked Single: r1c7=2
Full House: r5c7=5
Naked Single: r1c3=1
Full House: r1c1=9
Naked Single: r2c8=5
Full House: r2c1=2
Full House: r3c3=5
Full House: r3c9=9
Naked Single: r5c3=9
Full House: r5c6=2
Naked Single: r6c8=9
Full House: r8c8=2
Full House: r4c9=2
Full House: r9c9=5
Naked Single: r4c1=5
Naked Single: r6c1=4
Full House: r6c2=2
Full House: r6c4=5
Full House: r8c2=4
Naked Single: r7c6=7
Full House: r4c6=9
Naked Single: r4c5=3
Full House: r4c4=7
Naked Single: r8c1=7
Full House: r7c1=1
Naked Single: r8c5=5
Full House: r8c4=9
Full House: r7c4=3
Naked Single: r9c5=2
Full House: r7c5=4
Full House: r7c3=2
Full House: r9c3=3
|
normal_sudoku_766
|
..5.1........9..3....7.....3.....6..5....412.92..7.354.635...8.2.4.3...6.....9...
|
835216497672495831419783265341952678587364129926178354763541982294837516158629743
|
Basic 9x9 Sudoku 766
|
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 . 1 . . . .
. . . . 9 . . 3 .
. . . 7 . . . . .
3 . . . . . 6 . .
5 . . . . 4 1 2 .
9 2 . . 7 . 3 5 4
. 6 3 5 . . . 8 .
2 . 4 . 3 . . . 6
. . . . . 9 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
835216497672495831419783265341952678587364129926178354763541982294837516158629743 #1 Hard (584)
Hidden Single: r6c9=4
Hidden Single: r4c2=4
Hidden Single: r5c4=3
Hidden Single: r9c9=3
Hidden Single: r3c3=9
Hidden Single: r8c2=9
Hidden Single: r5c9=9
Naked Single: r4c8=7
Full House: r4c9=8
Naked Single: r8c8=1
Naked Single: r4c3=1
Naked Single: r8c4=8
Naked Single: r9c8=4
Naked Single: r8c6=7
Full House: r8c7=5
Naked Single: r3c8=6
Full House: r1c8=9
Hidden Single: r4c4=9
Hidden Single: r2c3=2
Hidden Single: r9c2=5
Hidden Single: r7c7=9
Hidden Single: r7c5=4
Locked Candidates Type 1 (Pointing): 1 in b7 => r23c1<>1
Naked Pair: 2,7 in r17c9 => r2c9<>7, r3c9<>2
Skyscraper: 2 in r7c9,r9c4 (connected by r1c49) => r7c6,r9c7<>2
Naked Single: r7c6=1
Naked Single: r9c7=7
Full House: r7c9=2
Full House: r7c1=7
Naked Single: r9c3=8
Full House: r9c1=1
Naked Single: r1c9=7
Naked Single: r6c3=6
Full House: r5c3=7
Full House: r5c2=8
Full House: r5c5=6
Naked Single: r6c4=1
Full House: r6c6=8
Naked Single: r1c2=3
Naked Single: r9c5=2
Full House: r9c4=6
Naked Single: r3c2=1
Full House: r2c2=7
Naked Single: r4c5=5
Full House: r3c5=8
Full House: r4c6=2
Naked Single: r2c4=4
Full House: r1c4=2
Naked Single: r3c9=5
Full House: r2c9=1
Naked Single: r3c1=4
Naked Single: r1c6=6
Naked Single: r2c7=8
Naked Single: r3c6=3
Full House: r3c7=2
Full House: r2c6=5
Full House: r1c7=4
Full House: r1c1=8
Full House: r2c1=6
|
normal_sudoku_3421
|
.4..3..12......3..3..1...845......9..2.8.41..71..69...........5..6.7.....3.4..8..
|
948537612162948357375126984584713296629854173713269548491682735856371429237495861
|
Basic 9x9 Sudoku 3421
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 . . 3 . . 1 2
. . . . . . 3 . .
3 . . 1 . . . 8 4
5 . . . . . . 9 .
. 2 . 8 . 4 1 . .
7 1 . . 6 9 . . .
. . . . . . . . 5
. . 6 . 7 . . . .
. 3 . 4 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
948537612162948357375126984584713296629854173713269548491682735856371429237495861 #1 Extreme (18796) bf
Brute Force: r5c6=4
Naked Single: r5c5=5
Hidden Single: r2c5=4
Hidden Single: r7c5=8
Locked Candidates Type 1 (Pointing): 4 in b4 => r7c3<>4
Locked Candidates Type 1 (Pointing): 7 in b5 => r4c79<>7
Hidden Triple: 2,4,5 in r46c7,r6c8 => r4c7<>6, r6c8<>3
Discontinuous Nice Loop: 9 r7c1 -9- r5c1 -6- r4c2 -8- r8c2 =8= r8c1 =4= r7c1 => r7c1<>9
Discontinuous Nice Loop: 9 r8c1 -9- r5c1 -6- r4c2 -8- r8c2 =8= r8c1 => r8c1<>9
Almost Locked Set Chain: 9- r15c1 {689} -8- r123579c3 {1235789} -3- r46c3 {348} -8- r4c2,r5c1 {689} -9 => r29c1<>9
Forcing Chain Contradiction in r3 => r2c9<>6
r2c9=6 r4c9<>6 r4c2=6 r3c2<>6
r2c9=6 r13c7<>6 r7c7=6 r7c4<>6 r12c4=6 r3c6<>6
r2c9=6 r3c7<>6
Grouped Discontinuous Nice Loop: 9 r2c2 -9- r2c9 -7- r13c7 =7= r7c7 -7- r7c2 -9- r2c2 => r2c2<>9
Sashimi X-Wing: 9 c25 r39 fr7c2 fr8c2 => r9c3<>9
Grouped Discontinuous Nice Loop: 9 r7c4 -9- r7c2 -7- r7c7 =7= r13c7 -7- r2c9 -9- r9c9 =9= r9c5 -9- r7c4 => r7c4<>9
Forcing Chain Contradiction in b1 => r2c1<>8
r2c1=8 r2c1<>2
r2c1=8 r2c1<>1 r2c3=1 r2c3<>2
r2c1=8 r8c1<>8 r8c2=8 r8c2<>5 r9c3=5 r9c3<>7 r7c23=7 r7c7<>7 r13c7=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9 r3c5=2 r3c3<>2
Forcing Chain Contradiction in b1 => r2c3<>7
r2c3=7 r2c3<>1 r2c1=1 r2c1<>2
r2c3=7 r2c3<>2
r2c3=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9 r3c5=2 r3c3<>2
Forcing Chain Contradiction in b2 => r5c8<>3
r5c8=3 r5c3<>3 r5c3=9 r5c1<>9 r1c1=9 r1c4<>9
r5c8=3 r5c8<>7 r5c9=7 r2c9<>7 r2c9=9 r2c4<>9
r5c8=3 r5c8<>7 r5c9=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9
Locked Candidates Type 1 (Pointing): 3 in b6 => r8c9<>3
Grouped Discontinuous Nice Loop: 1 r8c1 -1- r8c9 -9- r2c9 -7- r13c7 =7= r7c7 -7- r7c23 =7= r9c3 =5= r8c2 =8= r8c1 => r8c1<>1
Almost Locked Set XY-Wing: A=r1345679c3 {12345789}, B=r259c8 {2567}, C=r9c1 {12}, X,Y=1,2, Z=5 => r2c3<>5
Forcing Chain Contradiction in b1 => r7c1<>1
r7c1=1 r9c1<>1 r9c1=2 r2c1<>2
r7c1=1 r2c1<>1 r2c3=1 r2c3<>2
r7c1=1 r7c1<>4 r8c1=4 r8c1<>8 r8c2=8 r8c2<>5 r9c3=5 r9c3<>7 r7c23=7 r7c7<>7 r13c7=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9 r3c5=2 r3c3<>2
Forcing Chain Contradiction in b1 => r7c1=4
r7c1<>4 r7c1=2 r2c1<>2
r7c1<>4 r7c1=2 r9c1<>2 r9c1=1 r2c1<>1 r2c3=1 r2c3<>2
r7c1<>4 r8c1=4 r8c1<>8 r8c2=8 r8c2<>5 r9c3=5 r9c3<>7 r7c23=7 r7c7<>7 r13c7=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9 r3c5=2 r3c3<>2
Forcing Chain Contradiction in b1 => r8c1=8
r8c1<>8 r8c1=2 r2c1<>2
r8c1<>8 r8c1=2 r9c1<>2 r9c1=1 r2c1<>1 r2c3=1 r2c3<>2
r8c1<>8 r8c2=8 r8c2<>5 r9c3=5 r9c3<>7 r7c23=7 r7c7<>7 r13c7=7 r2c9<>7 r2c9=9 r9c9<>9 r9c5=9 r3c5<>9 r3c5=2 r3c3<>2
Naked Pair: 6,9 in r15c1 => r2c1<>6
Grouped Discontinuous Nice Loop: 6 r7c7 -6- r7c46 =6= r9c6 =5= r9c3 -5- r8c2 -9- r7c23 =9= r7c7 => r7c7<>6
Locked Candidates Type 2 (Claiming): 6 in c7 => r2c8<>6
Discontinuous Nice Loop: 5 r2c2 -5- r2c8 -7- r5c8 -6- r5c1 =6= r4c2 =8= r2c2 => r2c2<>5
2-String Kite: 5 in r3c2,r9c6 (connected by r8c2,r9c3) => r3c6<>5
Discontinuous Nice Loop: 5 r3c7 -5- r2c8 -7- r5c8 -6- r5c1 =6= r1c1 -6- r1c7 =6= r3c7 => r3c7<>5
Locked Candidates Type 2 (Claiming): 5 in r3 => r1c3<>5
Discontinuous Nice Loop: 2 r3c3 -2- r3c5 -9- r9c5 =9= r8c4 -9- r8c2 -5- r3c2 =5= r3c3 => r3c3<>2
Locked Candidates Type 1 (Pointing): 2 in b1 => r2c46<>2
Hidden Pair: 1,2 in r2c13 => r2c3<>8, r2c3<>9
Skyscraper: 9 in r2c4,r9c5 (connected by r29c9) => r3c5,r8c4<>9
Naked Single: r3c5=2
Naked Single: r4c5=1
Full House: r9c5=9
Uniqueness Test 1: 1/2 in r2c13,r9c13 => r9c3<>1, r9c3<>2
Naked Triple: 5,7,9 in r78c2,r9c3 => r7c3<>7, r7c3<>9
Locked Candidates Type 1 (Pointing): 9 in b7 => r3c2<>9
Continuous Nice Loop: 6/7/9 9= r3c7 =6= r1c7 -6- r1c1 -9- r3c3 =9= r3c7 =6 => r1c46<>6, r3c7<>7, r1c3<>9
Turbot Fish: 7 r1c7 =7= r7c7 -7- r7c2 =7= r9c3 => r1c3<>7
Naked Single: r1c3=8
Hidden Single: r2c6=8
Hidden Single: r4c2=8
Hidden Single: r6c9=8
Hidden Single: r4c9=6
Naked Single: r5c8=7
Naked Single: r2c8=5
Naked Single: r5c9=3
Naked Single: r5c3=9
Full House: r5c1=6
Naked Single: r1c1=9
Hidden Single: r6c7=5
Hidden Single: r3c7=9
Naked Single: r2c9=7
Full House: r1c7=6
Naked Single: r2c2=6
Naked Single: r9c9=1
Full House: r8c9=9
Naked Single: r2c4=9
Naked Single: r9c1=2
Full House: r2c1=1
Full House: r2c3=2
Naked Single: r8c2=5
Naked Single: r7c3=1
Naked Single: r9c8=6
Naked Single: r3c2=7
Full House: r3c3=5
Full House: r3c6=6
Full House: r7c2=9
Full House: r9c3=7
Full House: r9c6=5
Naked Single: r1c6=7
Full House: r1c4=5
Hidden Single: r7c7=7
Hidden Single: r7c4=6
Hidden Single: r8c6=1
Hidden Single: r4c4=7
Remote Pair: 2/3 r6c4 -3- r8c4 -2- r7c6 -3- r7c8 => r6c8<>2
Naked Single: r6c8=4
Full House: r4c7=2
Full House: r8c7=4
Naked Single: r6c3=3
Full House: r4c3=4
Full House: r4c6=3
Full House: r6c4=2
Full House: r7c6=2
Full House: r8c4=3
Full House: r7c8=3
Full House: r8c8=2
|
normal_sudoku_5143
|
....7...8.6.82.9.1..81.9.43..93.8.14.......9......2.3..4.2.......39.14..5........
|
914673528365824971278159643759368214432517896186492735847235169623981457591746382
|
Basic 9x9 Sudoku 5143
|
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
. 6 . 8 2 . 9 . 1
. . 8 1 . 9 . 4 3
. . 9 3 . 8 . 1 4
. . . . . . . 9 .
. . . . . 2 . 3 .
. 4 . 2 . . . . .
. . 3 9 . 1 4 . .
5 . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
914673528365824971278159643759368214432517896186492735847235169623981457591746382 #1 Hard (1470)
Hidden Single: r2c4=8
Hidden Single: r6c5=9
Hidden Single: r5c5=1
Hidden Single: r9c5=4
Hidden Single: r7c5=3
Hidden Single: r9c7=3
Hidden Single: r8c5=8
Hidden Single: r7c7=1
Hidden Single: r7c6=5
Locked Candidates Type 1 (Pointing): 6 in b8 => r9c389<>6
Locked Candidates Type 1 (Pointing): 7 in b8 => r9c2389<>7
Naked Triple: 2,6,7 in r7c3,r8c12 => r7c1<>6, r7c1<>7, r9c23<>2
Naked Single: r9c3=1
Locked Candidates Type 1 (Pointing): 2 in b7 => r8c89<>2
Naked Triple: 2,6,7 in r348c1 => r15c1<>2, r256c1<>7, r56c1<>6
Naked Pair: 3,4 in r2c16 => r2c3<>4
Naked Triple: 2,5,7 in r2c3,r3c12 => r1c23<>2, r1c23<>5
Naked Single: r1c3=4
Naked Single: r2c1=3
Naked Single: r2c6=4
Hidden Single: r5c3=2
Hidden Single: r1c6=3
Hidden Single: r5c2=3
Hidden Single: r4c7=2
Hidden Single: r9c9=2
Naked Single: r9c8=8
Naked Single: r9c2=9
Naked Single: r1c2=1
Naked Single: r7c1=8
Naked Single: r1c1=9
Naked Single: r5c1=4
Naked Single: r6c1=1
Hidden Single: r1c8=2
Hidden Single: r7c9=9
Hidden Single: r6c2=8
Hidden Single: r5c7=8
Hidden Single: r6c4=4
Locked Candidates Type 1 (Pointing): 6 in b3 => r6c7<>6
Locked Candidates Type 1 (Pointing): 7 in b5 => r5c9<>7
Locked Candidates Type 1 (Pointing): 6 in b6 => r8c9<>6
Locked Candidates Type 1 (Pointing): 7 in b6 => r6c3<>7
X-Wing: 5 c25 r34 => r3c7<>5
X-Wing: 7 r27 c38 => r8c8<>7
Skyscraper: 5 in r1c7,r5c9 (connected by r15c4) => r6c7<>5
Naked Single: r6c7=7
Naked Single: r3c7=6
Full House: r1c7=5
Full House: r1c4=6
Full House: r3c5=5
Full House: r2c8=7
Full House: r4c5=6
Full House: r2c3=5
Naked Single: r9c4=7
Full House: r5c4=5
Full House: r5c6=7
Full House: r9c6=6
Full House: r5c9=6
Full House: r6c9=5
Full House: r6c3=6
Full House: r8c9=7
Full House: r7c3=7
Full House: r7c8=6
Full House: r8c8=5
Naked Single: r4c1=7
Full House: r4c2=5
Naked Single: r8c2=2
Full House: r3c2=7
Full House: r3c1=2
Full House: r8c1=6
|
normal_sudoku_1019
|
4.....7.1....1..2........3.3..957.1.....823.6.2.6.......8.24...9..73.....51.9....
|
493268751867315924215479638386957412574182396129643587638524179942731865751896243
|
Basic 9x9 Sudoku 1019
|
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 . . . . . 7 . 1
. . . . 1 . . 2 .
. . . . . . . 3 .
3 . . 9 5 7 . 1 .
. . . . 8 2 3 . 6
. 2 . 6 . . . . .
. . 8 . 2 4 . . .
9 . . 7 3 . . . .
. 5 1 . 9 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
493268751867315924215479638386957412574182396129643587638524179942731865751896243 #1 Medium (454)
Naked Single: r4c6=7
Naked Single: r9c4=8
Naked Single: r1c5=6
Naked Single: r6c5=4
Full House: r3c5=7
Naked Single: r9c6=6
Naked Single: r5c4=1
Full House: r6c6=3
Naked Single: r7c4=5
Full House: r8c6=1
Hidden Single: r9c9=3
Hidden Single: r7c2=3
Hidden Single: r3c2=1
Hidden Single: r6c1=1
Hidden Single: r7c7=1
Hidden Single: r4c2=8
Naked Single: r1c2=9
Hidden Single: r4c3=6
Locked Candidates Type 1 (Pointing): 6 in b3 => r8c7<>6
Locked Candidates Type 1 (Pointing): 4 in b4 => r5c8<>4
Locked Candidates Type 1 (Pointing): 4 in b7 => r8c789<>4
Hidden Single: r9c8=4
Naked Single: r9c7=2
Full House: r9c1=7
Naked Single: r4c7=4
Full House: r4c9=2
Naked Single: r5c1=5
Naked Single: r7c1=6
Naked Single: r2c1=8
Full House: r3c1=2
Naked Single: r8c2=4
Full House: r8c3=2
Naked Single: r3c3=5
Naked Single: r3c4=4
Naked Single: r5c2=7
Full House: r2c2=6
Naked Single: r1c3=3
Full House: r2c3=7
Naked Single: r2c4=3
Full House: r1c4=2
Naked Single: r5c8=9
Full House: r5c3=4
Full House: r6c3=9
Naked Single: r7c8=7
Full House: r7c9=9
Naked Single: r3c9=8
Naked Single: r1c8=5
Full House: r1c6=8
Naked Single: r3c6=9
Full House: r2c6=5
Full House: r3c7=6
Naked Single: r8c9=5
Naked Single: r2c7=9
Full House: r2c9=4
Full House: r6c9=7
Naked Single: r6c8=8
Full House: r6c7=5
Full House: r8c7=8
Full House: r8c8=6
|
normal_sudoku_1029
|
.5.2...1....5....6..3.8.9...4..978.....1...7......2..5536..8..7798.2.....14.6.3..
|
459236718821579436673481952145697823982153674367842195536918247798324561214765389
|
Basic 9x9 Sudoku 1029
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 5 . 2 . . . 1 .
. . . 5 . . . . 6
. . 3 . 8 . 9 . .
. 4 . . 9 7 8 . .
. . . 1 . . . 7 .
. . . . . 2 . . 5
5 3 6 . . 8 . . 7
7 9 8 . 2 . . . .
. 1 4 . 6 . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
459236718821579436673481952145697823982153674367842195536918247798324561214765389 #1 Easy (342)
Naked Single: r8c1=7
Full House: r9c1=2
Hidden Single: r3c8=5
Hidden Single: r4c3=5
Hidden Single: r6c4=8
Hidden Single: r5c5=5
Hidden Single: r8c7=5
Hidden Single: r9c4=7
Hidden Single: r9c6=5
Hidden Single: r8c8=6
Hidden Single: r3c2=7
Naked Single: r1c3=9
Naked Single: r6c2=6
Naked Single: r5c3=2
Naked Single: r2c3=1
Full House: r6c3=7
Naked Single: r5c2=8
Full House: r2c2=2
Hidden Single: r7c4=9
Hidden Single: r3c9=2
Hidden Single: r2c6=9
Hidden Single: r4c4=6
Naked Single: r3c4=4
Full House: r8c4=3
Naked Single: r3c1=6
Full House: r3c6=1
Naked Single: r8c6=4
Full House: r7c5=1
Full House: r8c9=1
Naked Single: r5c6=3
Full House: r1c6=6
Full House: r6c5=4
Naked Single: r4c9=3
Naked Single: r5c1=9
Naked Single: r6c7=1
Naked Single: r4c1=1
Full House: r4c8=2
Full House: r6c1=3
Full House: r6c8=9
Naked Single: r5c9=4
Full House: r5c7=6
Naked Single: r7c8=4
Full House: r7c7=2
Naked Single: r9c8=8
Full House: r2c8=3
Full House: r9c9=9
Full House: r1c9=8
Naked Single: r2c5=7
Full House: r1c5=3
Naked Single: r1c1=4
Full House: r1c7=7
Full House: r2c7=4
Full House: r2c1=8
|
normal_sudoku_2522
|
25....86..........79......2.7..9..2.6.5148.933..2..154....75....1.......5.74.1.39
|
253914867846732915791856342174593628625148793389267154932675481418329576567481239
|
Basic 9x9 Sudoku 2522
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 5 . . . . 8 6 .
. . . . . . . . .
7 9 . . . . . . 2
. 7 . . 9 . . 2 .
6 . 5 1 4 8 . 9 3
3 . . 2 . . 1 5 4
. . . . 7 5 . . .
. 1 . . . . . . .
5 . 7 4 . 1 . 3 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
253914867846732915791856342174593628625148793389267154932675481418329576567481239 #1 Easy (224)
Naked Single: r5c1=6
Naked Single: r4c7=6
Naked Single: r6c5=6
Naked Single: r5c2=2
Full House: r5c7=7
Full House: r4c9=8
Naked Single: r6c2=8
Naked Single: r4c6=3
Naked Single: r9c7=2
Naked Single: r6c6=7
Full House: r6c3=9
Full House: r4c4=5
Naked Single: r9c2=6
Full House: r9c5=8
Naked Single: r7c7=4
Naked Single: r7c2=3
Full House: r2c2=4
Naked Single: r8c7=5
Naked Single: r3c7=3
Full House: r2c7=9
Hidden Single: r7c3=2
Hidden Single: r1c6=4
Naked Single: r3c6=6
Naked Single: r2c6=2
Full House: r8c6=9
Naked Single: r3c4=8
Naked Single: r7c4=6
Naked Single: r3c3=1
Naked Single: r7c9=1
Naked Single: r8c4=3
Full House: r8c5=2
Naked Single: r1c3=3
Naked Single: r2c1=8
Full House: r2c3=6
Naked Single: r3c5=5
Full House: r3c8=4
Naked Single: r4c3=4
Full House: r4c1=1
Full House: r8c3=8
Naked Single: r1c9=7
Naked Single: r7c8=8
Full House: r7c1=9
Full House: r8c1=4
Naked Single: r2c4=7
Full House: r1c4=9
Full House: r1c5=1
Full House: r2c5=3
Naked Single: r8c8=7
Full House: r2c8=1
Full House: r2c9=5
Full House: r8c9=6
|
normal_sudoku_5457
|
.8.5...4.....7.1......9...5.489...5.35.86..9...6.....3..5.49.2..2..85..4...2.....
|
683521947592476138417398265248937651351864792976152483135749826729685314864213579
|
Basic 9x9 Sudoku 5457
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 . 5 . . . 4 .
. . . . 7 . 1 . .
. . . . 9 . . . 5
. 4 8 9 . . . 5 .
3 5 . 8 6 . . 9 .
. . 6 . . . . . 3
. . 5 . 4 9 . 2 .
. 2 . . 8 5 . . 4
. . . 2 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
683521947592476138417398265248937651351864792976152483135749826729685314864213579 #1 Extreme (25550) bf
Hidden Single: r5c2=5
Hidden Single: r6c5=5
Hidden Single: r9c7=5
Hidden Single: r2c1=5
Brute Force: r5c6=4
Hidden Single: r6c7=4
Hidden Single: r6c8=8
Locked Candidates Type 1 (Pointing): 1 in b6 => r79c9<>1
2-String Kite: 2 in r1c5,r6c1 (connected by r4c5,r6c6) => r1c1<>2
Finned Franken Swordfish: 2 r25b5 c369 fr4c5 fr5c7 => r4c9<>2
Forcing Net Contradiction in c6 => r2c9<>6
r2c9=6 (r2c9<>2) r2c9<>8 r2c6=8 (r3c6<>8 r3c7=8 r3c7<>2) r2c6<>2 r2c3=2 (r3c1<>2) r3c3<>2 r3c6=2
r2c9=6 (r2c2<>6) r2c8<>6 r2c8=3 r2c2<>3 r2c2=9 r6c2<>9 r6c1=9 r6c1<>2 r6c6=2
Forcing Net Contradiction in c2 => r8c8<>3
r8c8=3 (r3c8<>3) r2c8<>3 r2c8=6 r3c8<>6 r3c8=7 r3c2<>7
r8c8=3 r8c8<>1 r9c8=1 r9c5<>1 r9c5=3 r4c5<>3 r4c6=3 r4c6<>7 r6c46=7 r6c2<>7
r8c8=3 (r7c7<>3) r8c8<>1 r9c8=1 r9c5<>1 r9c5=3 r7c4<>3 r7c2=3 r7c2<>7
r8c8=3 r8c8<>1 r9c8=1 (r9c5<>1 r9c5=3 r4c5<>3 r4c6=3 r4c6<>7) r9c56<>1 r78c4=1 r6c4<>1 r6c4=7 r6c6<>7 r9c6=7 r9c2<>7
Forcing Net Contradiction in c2 => r8c3<>1
r8c3=1 (r8c3<>3) (r7c1<>1) r7c2<>1 r7c4=1 (r6c4<>1 r6c4=7 r6c2<>7) (r6c4<>1 r6c4=7 r6c6<>7 r9c6=7 r9c2<>7) (r7c4<>3) r9c5<>1 r9c5=3 r8c4<>3 r8c7=3 r7c7<>3 r7c2=3 r7c2<>7 r3c2=7 r3c2<>1
r8c3=1 (r8c3<>9) (r8c3<>3) (r7c1<>1) r7c2<>1 r7c4=1 r9c5<>1 r9c5=3 r8c4<>3 r8c7=3 r8c7<>9 r8c1=9 r6c1<>9 r6c2=9 r6c2<>1
r8c3=1 r7c2<>1
r8c3=1 r9c2<>1
Forcing Net Contradiction in c2 => r8c8<>6
r8c8=6 (r3c8<>6) r2c8<>6 r2c8=3 r3c8<>3 r3c8=7 r3c2<>7
r8c8=6 r8c8<>1 r9c8=1 r9c5<>1 r9c5=3 r4c5<>3 r4c6=3 r4c6<>7 r6c46=7 r6c2<>7
r8c8=6 (r2c8<>6 r2c8=3 r2c2<>3) (r2c8<>6 r2c8=3 r2c4<>3) r8c8<>1 r9c8=1 r9c5<>1 r9c5=3 (r9c2<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c2<>3 r7c2=3 r7c2<>7
r8c8=6 r8c8<>1 r9c8=1 (r9c5<>1 r9c5=3 r4c5<>3 r4c6=3 r4c6<>7) r9c56<>1 r78c4=1 r6c4<>1 r6c4=7 r6c6<>7 r9c6=7 r9c2<>7
Forcing Net Contradiction in r8c7 => r2c4<>6
r2c4=6 (r8c4<>6) (r1c6<>6) (r2c8<>6) (r1c6<>6) (r2c6<>6) r3c6<>6 r9c6=6 r9c8<>6 r3c8=6 (r1c7<>6) r1c9<>6 r1c1=6 r8c1<>6 r8c7=6
r2c4=6 r2c4<>4 r2c3=4 r9c3<>4 r9c1=4 r9c1<>8 r9c9=8 r9c9<>9 r8c7=9
Forcing Net Contradiction in r1 => r2c4=4
r2c4<>4 (r2c4=3 r8c4<>3) r2c3=4 r9c3<>4 r9c1=4 r9c1<>8 r9c9=8 r9c9<>9 r8c7=9 r8c7<>3 r8c3=3 r1c3<>3
r2c4<>4 r2c4=3 r1c5<>3
r2c4<>4 r2c4=3 r1c6<>3
r2c4<>4 r2c4=3 r78c4<>3 r9c56=3 r9c8<>3 r78c7=3 r1c7<>3
Forcing Net Contradiction in r7 => r8c4<>1
r8c4=1 r9c5<>1 r9c5=3 r7c4<>3 r7c2=3
r8c4=1 (r8c8<>1 r8c8=7 r7c7<>7) (r8c8<>1 r8c8=7 r7c9<>7) (r7c4<>1) (r6c4<>1 r6c4=7 r7c4<>7) r9c5<>1 r9c5=3 r7c4<>3 r7c4=6 (r7c7<>6) r7c9<>6 r7c9=8 r7c7<>8 r7c7=3
Forcing Net Contradiction in b9 => r9c1<>1
r9c1=1 r9c5<>1 r9c5=3 (r8c4<>3) (r1c5<>3) (r4c5<>3 r4c6=3 r1c6<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r1c7<>3 r1c3=3 r8c3<>3 r8c7=3 r8c7<>9
r9c1=1 r9c1<>8 r9c9=8 r9c9<>9
Forcing Net Verity => r9c1<>7
r9c6=1 r9c5<>1 r9c5=3 (r8c4<>3) (r1c5<>3) (r4c5<>3 r4c6=3 r1c6<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r1c7<>3 r1c3=3 r8c3<>3 r8c7=3 r8c7<>9 r1c7=9 (r1c9<>9) r2c9<>9 r9c9=9 r9c9<>8 r9c1=8 r9c1<>7
r9c6=3 (r9c5<>3 r9c5=1 r7c4<>1) (r9c2<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 (r3c2<>3) r3c8<>3 r2c8=3 r2c2<>3 r7c2=3 r7c2<>1 r7c1=1 r7c1<>8 r9c1=8 r9c1<>7
r9c6=6 (r8c4<>6) (r1c6<>6) (r9c8<>6) (r7c4<>6) r8c4<>6 r3c4=6 r3c8<>6 r2c8=6 (r1c7<>6) r1c9<>6 r1c1=6 r8c1<>6 r8c7=6 r8c7<>9 r1c7=9 (r1c9<>9) r2c9<>9 r9c9=9 r9c9<>8 r9c1=8 r9c1<>7
r9c6=7 r9c1<>7
Forcing Net Contradiction in c2 => r9c2<>1
r9c2=1 (r8c1<>1 r8c8=1 r8c8<>7) (r7c1<>1) r7c2<>1 r7c4=1 r6c4<>1 r6c4=7 (r4c6<>7) r6c6<>7 r9c6=7 r9c8<>7 r3c8=7 r3c2<>7
r9c2=1 (r7c1<>1) r7c2<>1 r7c4=1 r6c4<>1 r6c4=7 r6c2<>7
r9c2=1 (r9c2<>3) r9c5<>1 r9c5=3 (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 (r3c2<>3) r3c8<>3 r2c8=3 r2c2<>3 r7c2=3 r7c2<>7
r9c2=1 r9c2<>7
Forcing Net Contradiction in r9c2 => r4c5<>1
r4c5=1 r9c5<>1 r9c5=3 r9c2<>3
r4c5=1 (r9c5<>1 r9c5=3 r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r2c8<>6) (r4c9<>1 r5c9=1 r5c9<>2) r4c5<>2 r1c5=2 r1c9<>2 r2c9=2 r2c9<>8 r2c6=8 r2c6<>6 r2c2=6 r9c2<>6
r4c5=1 r6c4<>1 r6c4=7 (r4c6<>7) r6c6<>7 r9c6=7 r9c2<>7
r4c5=1 (r4c5<>3 r4c6=3 r1c6<>3) r9c5<>1 r9c5=3 (r8c4<>3) (r1c5<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r1c7<>3 r1c3=3 r8c3<>3 r8c7=3 r8c7<>9 r8c13=9 r9c2<>9
Forcing Chain Contradiction in r9 => r9c3<>1
r9c3=1 r9c3<>4 r9c1=4 r9c1<>9
r9c3=1 r9c5<>1 r9c5=3 r4c5<>3 r4c5=2 r6c6<>2 r6c1=2 r6c1<>9 r6c2=9 r9c2<>9
r9c3=1 r9c3<>9
r9c3=1 r9c3<>4 r9c1=4 r9c1<>8 r9c9=8 r9c9<>9
Forcing Net Contradiction in r7c2 => r8c8=1
r8c8<>1 r9c8=1 (r9c8<>3) r9c5<>1 r9c5=3 (r9c2<>3) (r7c4<>3) r8c4<>3 r3c4=3 (r3c2<>3) r3c8<>3 r2c8=3 r2c2<>3 r7c2=3
r8c8<>1 (r8c1=1 r7c2<>1 r7c4=1 r7c4<>7) (r8c8=7 r7c7<>7) (r8c8=7 r7c9<>7) (r8c1=1 r4c1<>1) r9c8=1 r9c5<>1 r9c5=3 r4c5<>3 r4c5=2 r4c1<>2 r4c1=7 r7c1<>7 r7c2=7
Locked Candidates Type 1 (Pointing): 1 in b7 => r7c4<>1
Forcing Chain Contradiction in c2 => r6c1<>1
r6c1=1 r6c4<>1 r6c4=7 r78c4<>7 r9c6=7 r9c8<>7 r3c8=7 r3c2<>7
r6c1=1 r6c1<>9 r6c2=9 r6c2<>7
r6c1=1 r7c1<>1 r7c2=1 r7c2<>7
r6c1=1 r6c4<>1 r6c4=7 r78c4<>7 r9c6=7 r9c2<>7
Forcing Net Verity => r1c7=9
r9c6=1 r9c5<>1 r9c5=3 (r8c4<>3) (r1c5<>3) (r4c5<>3 r4c6=3 r1c6<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r1c7<>3 r1c3=3 r8c3<>3 r8c7=3 r8c7<>9 r1c7=9
r9c6=3 (r8c4<>3) (r1c6<>3) (r4c6<>3 r4c5=3 r1c5<>3) (r9c8<>3) (r7c4<>3) r8c4<>3 r3c4=3 r3c8<>3 r2c8=3 r1c7<>3 r1c3=3 r8c3<>3 r8c7=3 r8c7<>9 r1c7=9
r9c6=6 (r8c4<>6) (r1c6<>6) (r9c8<>6) (r7c4<>6) r8c4<>6 r3c4=6 r3c8<>6 r2c8=6 (r1c7<>6) r1c9<>6 r1c1=6 r8c1<>6 r8c7=6 r8c7<>9 r1c7=9
r9c6=7 (r8c4<>7) (r8c4<>7 r6c4=7 r6c2<>7) (r9c2<>7) r9c8<>7 r3c8=7 r3c2<>7 r7c2=7 (r8c1<>7) r8c3<>7 r8c7=7 r8c7<>9 r1c7=9
Hidden Single: r9c9=9
Hidden Single: r9c1=8
Hidden Single: r9c3=4
Hidden Single: r3c1=4
Locked Candidates Type 1 (Pointing): 2 in b1 => r5c3<>2
Locked Candidates Type 2 (Claiming): 2 in r5 => r4c7<>2
Finned Swordfish: 3 c347 r378 fr1c3 fr2c3 => r3c2<>3
Forcing Chain Contradiction in r3c2 => r3c7<>6
r3c7=6 r4c7<>6 r4c7=7 r5c79<>7 r5c3=7 r5c3<>1 r13c3=1 r3c2<>1
r3c7=6 r3c2<>6
r3c7=6 r23c8<>6 r9c8=6 r9c8<>7 r3c8=7 r3c2<>7
Finned Swordfish: 6 r239 c268 fr3c4 => r1c6<>6
Forcing Net Verity => r1c5=2
r9c6=1 (r6c6<>1 r6c4=1 r6c2<>1) r9c5<>1 r9c5=3 r4c5<>3 (r4c6=3 r1c6<>3 r1c6=2 r1c3<>2) (r4c6=3 r1c6<>3 r1c6=2 r1c9<>2) (r4c6=3 r1c6<>3 r1c6=2 r1c3<>2) (r4c6=3 r1c6<>3 r1c3=3 r2c3<>3) (r4c6=3 r1c6<>3 r1c3=3 r8c3<>3) r4c5=2 r6c6<>2 r6c1=2 r6c1<>9 r8c1=9 r8c3<>9 r8c3=7 (r9c2<>7) r8c3<>9 r8c1=9 r6c1<>9 r6c2=9 r6c2<>7 r3c2=7 r3c2<>1 r7c2=1 (r7c2<>3) r7c1<>1 r1c1=1 r1c1<>6 r1c9=6 (r1c9<>7 r1c3=7 r1c3<>3) r2c8<>6 r2c8=3 r2c2<>3 (r7c2=3 r7c2<>1 r7c1=1 r4c1<>1) (r7c2=3 r7c2<>7) r9c2=3 r8c3<>3 r3c3=3 r3c3<>2 r2c3=2 r2c3<>9 r2c2=9 r6c2<>9 r6c1=9 r6c1<>2 r6c6=2 r1c6<>2 r1c5=2
r9c6=3 (r9c5<>3 r9c5=1 r1c5<>1) r4c6<>3 r4c5=3 r1c5<>3 r1c5=2
r9c6=6 (r9c2<>6) (r9c8<>6) (r7c4<>6) r8c4<>6 r3c4=6 (r3c2<>6) r3c8<>6 r2c8=6 r2c2<>6 r7c2=6 (r7c2<>1 r7c1=1 r4c1<>1) (r7c9<>6) r8c1<>6 r1c1=6 (r7c1<>6) r1c9<>6 r4c9=6 r4c7<>6 r4c7=7 r4c1<>7 r4c1=2 r4c5<>2 r1c5=2
r9c6=7 (r9c6<>1 r9c5=1 r1c5<>1) (r8c4<>7 r6c4=7 r6c4<>1 r3c4=1 r3c2<>1) (r8c4<>7 r6c4=7 r6c2<>7) (r9c2<>7) r9c8<>7 r3c8=7 r3c2<>7 r7c2=7 r7c2<>1 (r7c1=1 r4c1<>1) r6c2=1 r5c3<>1 r5c9=1 r4c9<>1 r4c6=1 r4c6<>3 r4c5=3 r1c5<>3 r1c5=2
Naked Single: r4c5=3
Full House: r9c5=1
Naked Triple: 3,6,7 in r1c9,r23c8 => r3c7<>3, r3c7<>7
Locked Candidates Type 1 (Pointing): 3 in b3 => r9c8<>3
Skyscraper: 3 in r1c3,r9c2 (connected by r19c6) => r2c2,r8c3<>3
Discontinuous Nice Loop: 1 r3c3 -1- r5c3 -7- r5c7 -2- r3c7 =2= r3c3 => r3c3<>1
Discontinuous Nice Loop: 1 r4c1 -1- r5c3 -7- r8c3 -9- r8c1 =9= r6c1 =2= r4c1 => r4c1<>1
Hidden Rectangle: 2/7 in r4c16,r6c16 => r6c6<>7
W-Wing: 6/7 in r4c7,r9c8 connected by 7 in r49c6 => r78c7<>6
Hidden Single: r4c7=6
Empty Rectangle: 6 in b1 (r17c9) => r7c2<>6
Swordfish: 6 r178 c149 => r3c4<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r9c6<>6
Naked Pair: 1,3 in r1c6,r3c4 => r23c6<>3, r3c6<>1
XY-Chain: 3 3- r2c8 -6- r9c8 -7- r9c6 -3- r1c6 -1- r3c4 -3 => r3c8<>3
Hidden Single: r2c8=3
XY-Chain: 7 7- r5c7 -2- r3c7 -8- r2c9 -2- r2c3 -9- r8c3 -7 => r5c3,r8c7<>7
Naked Single: r5c3=1
Naked Single: r8c7=3
Hidden Single: r4c9=1
W-Wing: 7/9 in r6c2,r8c3 connected by 9 in r2c23 => r79c2<>7
XY-Wing: 3/7/6 in r8c4,r9c26 => r8c1<>6
Hidden Single: r8c4=6
Locked Candidates Type 2 (Claiming): 7 in r8 => r7c1<>7
Naked Triple: 2,7,9 in r468c1 => r1c1<>7
Uniqueness Test 4: 2/7 in r4c16,r6c16 => r6c1<>7
Sashimi Swordfish: 7 c248 r367 fr9c8 => r7c79<>7
Naked Single: r7c7=8
Naked Single: r3c7=2
Full House: r5c7=7
Full House: r5c9=2
Naked Single: r7c9=6
Full House: r9c8=7
Full House: r3c8=6
Naked Single: r2c9=8
Full House: r1c9=7
Naked Single: r7c1=1
Naked Single: r9c6=3
Full House: r7c4=7
Full House: r7c2=3
Full House: r9c2=6
Naked Single: r3c6=8
Naked Single: r2c6=6
Naked Single: r1c3=3
Naked Single: r1c1=6
Full House: r1c6=1
Full House: r3c4=3
Full House: r6c4=1
Naked Single: r2c2=9
Full House: r2c3=2
Naked Single: r3c3=7
Full House: r3c2=1
Full House: r6c2=7
Full House: r8c3=9
Full House: r8c1=7
Naked Single: r6c6=2
Full House: r4c6=7
Full House: r4c1=2
Full House: r6c1=9
|
normal_sudoku_2361
|
.2.35..1...1..72..6..2.1..32..536..45...981..9......5.......9..1...7..4..4.12.5..
|
728354619431967285695281473217536894564798132983412756376845921152679348849123567
|
Basic 9x9 Sudoku 2361
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . 3 5 . . 1 .
. . 1 . . 7 2 . .
6 . . 2 . 1 . . 3
2 . . 5 3 6 . . 4
5 . . . 9 8 1 . .
9 . . . . . . 5 .
. . . . . . 9 . .
1 . . . 7 . . 4 .
. 4 . 1 2 . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
728354619431967285695281473217536894564798132983412756376845921152679348849123567 #1 Medium (398)
Naked Single: r4c6=6
Hidden Single: r4c2=1
Hidden Single: r4c8=9
Hidden Single: r6c5=1
Hidden Single: r7c9=1
Hidden Single: r6c6=2
Hidden Single: r2c9=5
Hidden Single: r1c9=9
Naked Single: r1c6=4
Naked Single: r3c5=8
Naked Single: r2c5=6
Full House: r2c4=9
Full House: r7c5=4
Naked Single: r3c8=7
Naked Single: r2c8=8
Naked Single: r3c7=4
Full House: r1c7=6
Naked Single: r2c2=3
Full House: r2c1=4
Hidden Single: r9c9=7
Locked Candidates Type 1 (Pointing): 3 in b4 => r789c3<>3
Locked Candidates Type 1 (Pointing): 8 in b9 => r8c234<>8
Naked Single: r8c4=6
Naked Single: r7c4=8
Hidden Single: r6c2=8
Naked Single: r4c3=7
Full House: r4c7=8
Naked Single: r6c9=6
Naked Single: r1c3=8
Full House: r1c1=7
Naked Single: r5c2=6
Naked Single: r8c7=3
Full House: r6c7=7
Naked Single: r5c9=2
Full House: r5c8=3
Full House: r8c9=8
Naked Single: r7c1=3
Full House: r9c1=8
Naked Single: r9c8=6
Full House: r7c8=2
Naked Single: r6c4=4
Full House: r5c4=7
Full House: r5c3=4
Full House: r6c3=3
Naked Single: r7c6=5
Naked Single: r9c3=9
Full House: r9c6=3
Full House: r8c6=9
Naked Single: r7c2=7
Full House: r7c3=6
Naked Single: r3c3=5
Full House: r3c2=9
Full House: r8c2=5
Full House: r8c3=2
|
normal_sudoku_2166
|
.2..9...81..7.2...93..6.2.......4.27..92......5.8...6..7..1.582....86..9......1..
|
724395618168742395935168274381654927649271853257839461476913582512486739893527146
|
Basic 9x9 Sudoku 2166
|
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 . . 9 . . . 8
1 . . 7 . 2 . . .
9 3 . . 6 . 2 . .
. . . . . 4 . 2 7
. . 9 2 . . . . .
. 5 . 8 . . . 6 .
. 7 . . 1 . 5 8 2
. . . . 8 6 . . 9
. . . . . . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
724395618168742395935168274381654927649271853257839461476913582512486739893527146 #1 Medium (530)
Hidden Single: r3c7=2
Hidden Single: r3c6=8
Hidden Single: r9c5=2
Hidden Single: r4c4=6
Hidden Single: r9c2=9
Hidden Single: r2c8=9
Hidden Single: r9c9=6
Hidden Single: r2c5=4
Hidden Single: r9c6=7
Hidden Single: r4c5=5
Hidden Single: r4c7=9
Hidden Single: r6c6=9
Naked Single: r7c6=3
Naked Single: r5c6=1
Full House: r1c6=5
Naked Single: r3c4=1
Full House: r1c4=3
Hidden Single: r7c4=9
Hidden Single: r5c7=8
Hidden Single: r6c9=1
Hidden Single: r1c8=1
Locked Candidates Type 1 (Pointing): 5 in b1 => r89c3<>5
Locked Candidates Type 2 (Claiming): 3 in r4 => r56c1,r6c3<>3
Locked Candidates Type 2 (Claiming): 4 in r7 => r8c123,r9c13<>4
Naked Single: r8c2=1
Naked Single: r4c2=8
Naked Single: r2c2=6
Full House: r5c2=4
Naked Single: r4c1=3
Full House: r4c3=1
Naked Single: r2c7=3
Naked Single: r2c9=5
Full House: r2c3=8
Naked Single: r6c7=4
Naked Single: r3c9=4
Full House: r5c9=3
Full House: r5c8=5
Naked Single: r9c3=3
Naked Single: r8c7=7
Full House: r1c7=6
Full House: r3c8=7
Full House: r3c3=5
Naked Single: r5c5=7
Full House: r5c1=6
Full House: r6c5=3
Naked Single: r8c3=2
Naked Single: r9c8=4
Full House: r8c8=3
Naked Single: r7c1=4
Full House: r7c3=6
Naked Single: r6c3=7
Full House: r1c3=4
Full House: r1c1=7
Full House: r6c1=2
Naked Single: r8c1=5
Full House: r8c4=4
Full House: r9c4=5
Full House: r9c1=8
|
normal_sudoku_6339
|
4.5.1...9.6.......2.1..6..4.5..4...6....28.9...976.3........8....76...31.1..5...2
|
475213689968574213231986574853149726746328195129765348692431857587692431314857962
|
Basic 9x9 Sudoku 6339
|
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 . . . 9
. 6 . . . . . . .
2 . 1 . . 6 . . 4
. 5 . . 4 . . . 6
. . . . 2 8 . 9 .
. . 9 7 6 . 3 . .
. . . . . . 8 . .
. . 7 6 . . . 3 1
. 1 . . 5 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
475213689968574213231986574853149726746328195129765348692431857587692431314857962 #1 Easy (260)
Naked Single: r6c5=6
Hidden Single: r2c9=3
Naked Single: r2c3=8
Hidden Single: r6c9=8
Naked Single: r6c1=1
Naked Single: r6c6=5
Hidden Single: r4c1=8
Hidden Single: r8c2=8
Naked Single: r8c5=9
Naked Single: r2c5=7
Naked Single: r8c1=5
Naked Single: r2c1=9
Naked Single: r7c5=3
Full House: r3c5=8
Naked Single: r8c7=4
Full House: r8c6=2
Naked Single: r7c1=6
Naked Single: r1c6=3
Naked Single: r2c6=4
Naked Single: r9c1=3
Full House: r5c1=7
Naked Single: r1c2=7
Full House: r3c2=3
Naked Single: r1c4=2
Naked Single: r9c6=7
Naked Single: r9c3=4
Naked Single: r5c9=5
Full House: r7c9=7
Naked Single: r5c2=4
Naked Single: r1c7=6
Full House: r1c8=8
Naked Single: r2c4=5
Full House: r3c4=9
Naked Single: r7c6=1
Full House: r4c6=9
Naked Single: r9c8=6
Naked Single: r7c3=2
Full House: r7c2=9
Full House: r6c2=2
Full House: r6c8=4
Naked Single: r9c4=8
Full House: r9c7=9
Full House: r7c8=5
Full House: r7c4=4
Naked Single: r5c7=1
Naked Single: r4c3=3
Full House: r5c3=6
Full House: r5c4=3
Full House: r4c4=1
Naked Single: r3c8=7
Full House: r3c7=5
Naked Single: r2c7=2
Full House: r2c8=1
Full House: r4c8=2
Full House: r4c7=7
|
normal_sudoku_2009
|
....8...3.2.7..6.....635.....24...974....72...7.....6...8....1..4.9..7..5.7..1...
|
695284173823719645714635829182456397456397281379128564938572416241963758567841932
|
Basic 9x9 Sudoku 2009
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 8 . . . 3
. 2 . 7 . . 6 . .
. . . 6 3 5 . . .
. . 2 4 . . . 9 7
4 . . . . 7 2 . .
. 7 . . . . . 6 .
. . 8 . . . . 1 .
. 4 . 9 . . 7 . .
5 . 7 . . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
695284173823719645714635829182456397456397281379128564938572416241963758567841932 #1 Extreme (36612) bf
Locked Candidates Type 1 (Pointing): 2 in b2 => r1c8<>2
Brute Force: r5c6=7
Hidden Single: r7c5=7
Finned X-Wing: 4 c58 r29 fr1c8 fr3c8 => r2c9<>4
Brute Force: r5c5=9
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c12<>6
Brute Force: r5c8=8
Locked Candidates Type 1 (Pointing): 3 in b6 => r79c7<>3
Finned Swordfish: 8 r248 c169 fr4c2 => r6c1<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r4c6<>8
Forcing Chain Contradiction in r9c4 => r1c7<>5
r1c7=5 r2c8<>5 r2c8=4 r2c5<>4 r2c5=1 r1c4<>1 r1c4=2 r9c4<>2
r1c7=5 r12c8<>5 r8c8=5 r8c8<>3 r9c8=3 r9c4<>3
r1c7=5 r1c23<>5 r2c3=5 r2c3<>3 r2c1=3 r2c1<>8 r2c9=8 r8c9<>8 r8c6=8 r9c4<>8
Forcing Chain Contradiction in r4 => r2c9<>1
r2c9=1 r2c9<>8 r2c1=8 r4c1<>8 r4c2=8 r4c2<>5
r2c9=1 r5c9<>1 r5c9=5 r46c7<>5 r7c7=5 r7c4<>5 r8c5=5 r4c5<>5
r2c9=1 r5c9<>1 r5c9=5 r4c7<>5
Almost Locked Set XY-Wing: A=r4689c5 {12456}, B=r13467c7 {134589}, C=r2c5689 {14589}, X,Y=1,8, Z=4 => r9c7<>4
Forcing Chain Contradiction in r2c9 => r6c4<>2
r6c4=2 r1c4<>2 r1c4=1 r2c5<>1 r2c5=4 r2c8<>4 r2c8=5 r2c9<>5
r6c4=2 r6c4<>8 r6c6=8 r8c6<>8 r8c9=8 r2c9<>8
r6c4=2 r1c4<>2 r1c6=2 r1c6<>9 r2c6=9 r2c9<>9
Discontinuous Nice Loop: 1 r6c5 -1- r2c5 =1= r1c4 =2= r1c6 -2- r6c6 =2= r6c5 => r6c5<>1
Discontinuous Nice Loop: 2 r9c5 -2- r6c5 =2= r6c6 -2- r1c6 =2= r1c4 =1= r2c5 =4= r9c5 => r9c5<>2
Forcing Chain Contradiction in c4 => r6c5=2
r6c5<>2 r6c6=2 r1c6<>2 r1c4=2 r1c4<>1
r6c5<>2 r6c5=5 r8c5<>5 r7c4=5 r7c7<>5 r46c7=5 r5c9<>5 r5c9=1 r5c4<>1
r6c5<>2 r6c6=2 r6c6<>8 r6c4=8 r6c4<>1
Discontinuous Nice Loop: 3 r4c2 -3- r4c7 =3= r6c7 -3- r6c6 -8- r6c4 =8= r9c4 -8- r9c7 =8= r3c7 -8- r3c2 =8= r4c2 => r4c2<>3
Discontinuous Nice Loop: 3 r6c3 -3- r6c6 -8- r8c6 =8= r8c9 -8- r2c9 =8= r2c1 =3= r2c3 -3- r6c3 => r6c3<>3
Forcing Chain Contradiction in r7 => r4c7<>1
r4c7=1 r4c5<>1 r2c5=1 r2c5<>4 r9c5=4 r7c6<>4
r4c7=1 r5c9<>1 r5c9=5 r46c7<>5 r7c7=5 r7c7<>4
r4c7=1 r4c7<>3 r6c7=3 r6c7<>4 r6c9=4 r7c9<>4
Finned Swordfish: 1 r248 c135 fr4c2 => r56c3,r6c1<>1
Discontinuous Nice Loop: 5 r2c3 -5- r6c3 -9- r6c1 -3- r2c1 =3= r2c3 => r2c3<>5
Locked Candidates Type 1 (Pointing): 5 in b1 => r1c8<>5
Discontinuous Nice Loop: 9 r2c1 -9- r6c1 -3- r6c6 -8- r8c6 =8= r8c9 -8- r2c9 =8= r2c1 => r2c1<>9
Discontinuous Nice Loop: 5 r4c2 -5- r6c3 -9- r6c1 -3- r6c6 -8- r6c4 =8= r9c4 -8- r9c7 =8= r3c7 -8- r3c2 =8= r4c2 => r4c2<>5
Turbot Fish: 5 r4c7 =5= r4c5 -5- r8c5 =5= r7c4 => r7c7<>5
Locked Candidates Type 2 (Claiming): 5 in c7 => r56c9<>5
Naked Single: r5c9=1
Naked Single: r6c9=4
Hidden Single: r6c4=1
Naked Single: r1c4=2
Hidden Single: r2c5=1
Hidden Single: r6c6=8
Hidden Single: r9c4=8
Naked Single: r9c7=9
Naked Single: r7c7=4
Naked Single: r1c7=1
Naked Single: r3c7=8
Hidden Single: r9c5=4
Hidden Single: r8c9=8
Hidden Single: r2c1=8
Hidden Single: r4c2=8
Hidden Single: r2c3=3
Hidden Single: r4c1=1
Hidden Single: r3c2=1
Hidden Single: r8c3=1
Locked Candidates Type 2 (Claiming): 2 in r9 => r7c9,r8c8<>2
Turbot Fish: 3 r6c1 =3= r5c2 -3- r5c4 =3= r7c4 => r7c1<>3
Hidden Rectangle: 5/6 in r1c23,r5c23 => r1c2<>6
XY-Chain: 3 3- r6c1 -9- r6c3 -5- r6c7 -3- r4c7 -5- r4c5 -6- r8c5 -5- r8c8 -3- r9c8 -2- r9c9 -6- r9c2 -3 => r5c2,r8c1<>3
Hidden Single: r5c4=3
Full House: r7c4=5
Naked Single: r4c6=6
Full House: r4c5=5
Full House: r8c5=6
Full House: r4c7=3
Full House: r6c7=5
Naked Single: r7c9=6
Naked Single: r8c1=2
Naked Single: r6c3=9
Full House: r6c1=3
Naked Single: r9c9=2
Naked Single: r7c1=9
Naked Single: r8c6=3
Full House: r7c6=2
Full House: r7c2=3
Full House: r8c8=5
Full House: r9c8=3
Full House: r9c2=6
Naked Single: r3c3=4
Naked Single: r3c9=9
Full House: r2c9=5
Naked Single: r3c1=7
Full House: r1c1=6
Full House: r3c8=2
Naked Single: r2c8=4
Full House: r1c8=7
Full House: r2c6=9
Full House: r1c6=4
Naked Single: r5c2=5
Full House: r1c2=9
Full House: r1c3=5
Full House: r5c3=6
|
normal_sudoku_2495
|
...5.48.35..........13...2.2..7.......9.317...7...9.3.........68479...1.3621...74
|
726514893534892167981376425213748659659231748478659231195427386847963512362185974
|
Basic 9x9 Sudoku 2495
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 5 . 4 8 . 3
5 . . . . . . . .
. . 1 3 . . . 2 .
2 . . 7 . . . . .
. . 9 . 3 1 7 . .
. 7 . . . 9 . 3 .
. . . . . . . . 6
8 4 7 9 . . . 1 .
3 6 2 1 . . . 7 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
726514893534892167981376425213748659659231748478659231195427386847963512362185974 #1 Hard (532)
Naked Single: r8c1=8
Naked Single: r1c3=6
Naked Single: r7c3=5
Naked Single: r1c8=9
Naked Single: r1c1=7
Naked Single: r1c2=2
Full House: r1c5=1
Naked Single: r7c8=8
Hidden Single: r9c7=9
Hidden Single: r4c9=9
Locked Candidates Type 1 (Pointing): 5 in b9 => r8c56<>5
Locked Candidates Type 2 (Claiming): 5 in c8 => r46c7,r56c9<>5
Hidden Single: r6c5=5
Naked Single: r9c5=8
Full House: r9c6=5
Locked Candidates Type 1 (Pointing): 2 in b5 => r27c4<>2
Naked Single: r7c4=4
Hidden Single: r4c5=4
Skyscraper: 4 in r3c7,r5c8 (connected by r35c1) => r2c8,r6c7<>4
Naked Single: r2c8=6
Naked Single: r2c4=8
Naked Single: r4c8=5
Full House: r5c8=4
Naked Single: r5c1=6
Naked Single: r5c4=2
Full House: r6c4=6
Full House: r4c6=8
Naked Single: r5c9=8
Full House: r5c2=5
Naked Single: r4c3=3
Naked Single: r2c3=4
Full House: r6c3=8
Naked Single: r4c2=1
Full House: r4c7=6
Full House: r6c1=4
Naked Single: r2c7=1
Naked Single: r3c1=9
Full House: r7c1=1
Full House: r7c2=9
Naked Single: r2c9=7
Naked Single: r6c7=2
Full House: r6c9=1
Naked Single: r2c2=3
Full House: r3c2=8
Naked Single: r2c6=2
Full House: r2c5=9
Naked Single: r3c9=5
Full House: r3c7=4
Full House: r8c9=2
Naked Single: r7c7=3
Full House: r8c7=5
Naked Single: r8c5=6
Full House: r8c6=3
Naked Single: r7c6=7
Full House: r3c6=6
Full House: r3c5=7
Full House: r7c5=2
|
normal_sudoku_5891
|
....4.1....31.....1...8..39..2.9...779.2......31..529.....2135...593..72.........
|
987346125253179846164582739542893617796214583831765294479621358615938472328457961
|
Basic 9x9 Sudoku 5891
|
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 . 1 . .
. . 3 1 . . . . .
1 . . . 8 . . 3 9
. . 2 . 9 . . . 7
7 9 . 2 . . . . .
. 3 1 . . 5 2 9 .
. . . . 2 1 3 5 .
. . 5 9 3 . . 7 2
. . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
987346125253179846164582739542893617796214583831765294479621358615938472328457961 #1 Extreme (24954) bf
Hidden Single: r6c8=9
Hidden Single: r4c8=1
Hidden Single: r5c5=1
Hidden Single: r5c9=3
Hidden Single: r9c7=9
Hidden Single: r9c1=3
Hidden Single: r8c2=1
Hidden Single: r9c9=1
Hidden Single: r5c7=5
Hidden Single: r9c2=2
Hidden Single: r3c6=2
Brute Force: r4c6=3
Hidden Single: r1c4=3
Brute Force: r4c7=6
Skyscraper: 6 in r5c3,r8c1 (connected by r58c6) => r6c1,r79c3<>6
Hidden Single: r5c3=6
Naked Pair: 4,8 in r4c4,r5c6 => r6c4<>4, r6c4<>8
Naked Pair: 4,7 in r3c37 => r3c2<>4, r3c24<>7
Discontinuous Nice Loop: 6 r9c5 -6- r6c5 =6= r6c4 -6- r3c4 -5- r9c4 =5= r9c5 => r9c5<>6
Forcing Chain Contradiction in r8 => r2c1<>4
r2c1=4 r8c1<>4
r2c1=4 r6c1<>4 r6c9=4 r5c8<>4 r5c6=4 r8c6<>4
r2c1=4 r3c3<>4 r3c7=4 r8c7<>4
Forcing Chain Contradiction in c9 => r2c1<>6
r2c1=6 r3c2<>6 r3c2=5 r1c12<>5 r1c9=5 r1c9<>6
r2c1=6 r2c9<>6
r2c1=6 r8c1<>6 r7c12=6 r7c9<>6
Forcing Chain Contradiction in r7c9 => r8c1<>4
r8c1=4 r6c1<>4 r6c9=4 r7c9<>4
r8c1=4 r8c1<>6 r7c12=6 r7c9<>6
r8c1=4 r8c7<>4 r8c7=8 r7c9<>8
Skyscraper: 4 in r5c8,r8c7 (connected by r58c6) => r9c8<>4
Turbot Fish: 4 r3c3 =4= r3c7 -4- r8c7 =4= r7c9 => r7c3<>4
Sashimi Swordfish: 4 r389 c347 fr8c6 fr9c6 => r7c4<>4
AIC: 8 8- r2c7 =8= r8c7 =4= r7c9 -4- r6c9 -8 => r12c9<>8
Grouped AIC: 4/8 4- r2c2 =4= r3c3 -4- r9c3 =4= r7c12 -4- r7c9 =4= r8c7 =8= r2c7 -8 => r2c7<>4, r2c2<>8
Almost Locked Set Chain: 8- r5c6 {48} -4- r5c8 {48} -8- r6c9 {48} -4- r68c1 {468} -6- r58c6 {468} -8 => r9c6<>8
Forcing Chain Contradiction in r9c6 => r2c7=8
r2c7<>8 r8c7=8 r8c7<>4 r8c6=4 r9c6<>4
r2c7<>8 r8c7=8 r9c8<>8 r9c8=6 r9c6<>6
r2c7<>8 r2c7=7 r2c5<>7 r12c6=7 r9c6<>7
Naked Single: r8c7=4
Full House: r3c7=7
Naked Single: r3c3=4
Skyscraper: 8 in r8c6,r9c8 (connected by r5c68) => r9c4<>8
2-String Kite: 8 in r4c4,r8c1 (connected by r7c4,r8c6) => r4c1<>8
Turbot Fish: 8 r6c1 =8= r4c2 -8- r4c4 =8= r7c4 => r7c1<>8
Turbot Fish: 8 r4c2 =8= r6c1 -8- r6c9 =8= r7c9 => r7c2<>8
W-Wing: 6/8 in r7c9,r8c1 connected by 8 in r6c19 => r7c12<>6
Hidden Single: r8c1=6
Full House: r8c6=8
Naked Single: r5c6=4
Full House: r5c8=8
Full House: r6c9=4
Naked Single: r4c4=8
Naked Single: r9c8=6
Full House: r7c9=8
Naked Single: r6c1=8
Naked Single: r1c8=2
Full House: r2c8=4
Naked Single: r9c6=7
Naked Single: r7c4=6
Naked Single: r9c3=8
Naked Single: r9c5=5
Full House: r9c4=4
Naked Single: r3c4=5
Full House: r6c4=7
Full House: r3c2=6
Full House: r6c5=6
Full House: r2c5=7
Naked Single: r2c2=5
Naked Single: r1c1=9
Naked Single: r2c9=6
Full House: r1c9=5
Naked Single: r4c2=4
Full House: r4c1=5
Naked Single: r1c3=7
Full House: r7c3=9
Naked Single: r1c6=6
Full House: r2c6=9
Full House: r2c1=2
Full House: r7c1=4
Full House: r7c2=7
Full House: r1c2=8
|
normal_sudoku_2981
|
..82....6.2.5.63.7.....4...2.6..8...85..4..2..14.2....6..8.1...14......5..2.5....
|
578213496429586317361974258296138574853749621714625839635891742147362985982457163
|
Basic 9x9 Sudoku 2981
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 8 2 . . . . 6
. 2 . 5 . 6 3 . 7
. . . . . 4 . . .
2 . 6 . . 8 . . .
8 5 . . 4 . . 2 .
. 1 4 . 2 . . . .
6 . . 8 . 1 . . .
1 4 . . . . . . 5
. . 2 . 5 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
578213496429586317361974258296138574853749621714625839635891742147362985982457163 #1 Extreme (12956) bf
Hidden Single: r4c1=2
Hidden Single: r3c2=6
Hidden Single: r9c4=4
Hidden Single: r9c2=8
Hidden Single: r8c6=2
Hidden Single: r6c6=5
Hidden Single: r7c3=5
Hidden Single: r8c5=6
Brute Force: r5c3=3
Skyscraper: 3 in r7c2,r9c6 (connected by r1c26) => r7c5,r9c1<>3
Hidden Single: r7c2=3
Naked Pair: 7,9 in r69c1 => r13c1<>7, r123c1<>9
Naked Single: r2c1=4
Empty Rectangle: 3 in b5 (r8c48) => r4c8<>3
Finned Franken Swordfish: 9 r27b7 c358 fr7c7 fr7c9 fr9c1 => r9c8<>9
Forcing Chain Contradiction in r1c6 => r4c5<>7
r4c5=7 r4c5<>3 r13c5=3 r1c6<>3
r4c5=7 r4c2<>7 r1c2=7 r1c6<>7
r4c5=7 r5c6<>7 r5c6=9 r1c6<>9
Forcing Chain Contradiction in r8c4 => r1c6<>7
r1c6=7 r1c6<>3 r9c6=3 r8c4<>3
r1c6=7 r5c6<>7 r456c4=7 r8c4<>7
r1c6=7 r1c2<>7 r1c2=9 r23c3<>9 r8c3=9 r8c4<>9
Skyscraper: 7 in r5c6,r6c1 (connected by r9c16) => r6c4<>7
W-Wing: 9/7 in r4c2,r7c5 connected by 7 in r1c25 => r4c5<>9
Discontinuous Nice Loop: 7 r8c4 -7- r8c3 =7= r3c3 -7- r1c2 -9- r1c6 -3- r9c6 =3= r8c4 => r8c4<>7
Multi Colors 2: 7 (r1c2,r6c1,r8c3) / (r1c5,r3c3,r4c2,r9c1), (r5c6,r7c5) / (r9c6) => r1c5,r3c3,r4c2,r9c1<>7
Naked Single: r4c2=9
Full House: r1c2=7
Full House: r6c1=7
Naked Single: r9c1=9
Full House: r8c3=7
XY-Wing: 3/7/9 in r19c6,r7c5 => r123c5<>9
Hidden Single: r7c5=9
Naked Single: r8c4=3
Full House: r9c6=7
Naked Single: r5c6=9
Full House: r1c6=3
Naked Single: r5c9=1
Naked Single: r6c4=6
Naked Single: r1c1=5
Full House: r3c1=3
Naked Single: r1c5=1
Naked Single: r9c9=3
Naked Single: r5c4=7
Full House: r5c7=6
Naked Single: r2c5=8
Naked Single: r4c5=3
Full House: r4c4=1
Full House: r3c4=9
Full House: r3c5=7
Naked Single: r4c9=4
Naked Single: r9c7=1
Full House: r9c8=6
Naked Single: r3c3=1
Full House: r2c3=9
Full House: r2c8=1
Naked Single: r7c9=2
Naked Single: r3c9=8
Full House: r6c9=9
Naked Single: r3c8=5
Full House: r3c7=2
Naked Single: r6c7=8
Full House: r6c8=3
Naked Single: r4c8=7
Full House: r4c7=5
Naked Single: r8c7=9
Full House: r8c8=8
Naked Single: r7c8=4
Full House: r1c8=9
Full House: r1c7=4
Full House: r7c7=7
|
normal_sudoku_1876
|
..8.2...32..1...9......65..1...9..7..8.6.79....7..1..4......4.57.5..2.6..3.......
|
568924713243175698971386542154893276382647951697251384826719435715432869439568127
|
Basic 9x9 Sudoku 1876
|
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 . . . 3
2 . . 1 . . . 9 .
. . . . . 6 5 . .
1 . . . 9 . . 7 .
. 8 . 6 . 7 9 . .
. . 7 . . 1 . . 4
. . . . . . 4 . 5
7 . 5 . . 2 . 6 .
. 3 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
568924713243175698971386542154893276382647951697251384826719435715432869439568127 #1 Extreme (39472) bf
Locked Candidates Type 1 (Pointing): 7 in b9 => r9c45<>7
Brute Force: r5c7=9
Finned Swordfish: 2 r357 c389 fr7c2 => r9c3<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c8<>2
Grouped Discontinuous Nice Loop: 1 r8c9 -1- r5c9 -2- r46c7 =2= r9c7 =7= r9c9 =9= r8c9 => r8c9<>1
Grouped Discontinuous Nice Loop: 1 r9c9 -1- r5c9 -2- r46c7 =2= r9c7 =7= r9c9 => r9c9<>1
Brute Force: r5c8=5
Hidden Single: r5c9=1
Hidden Single: r5c3=2
Hidden Single: r7c2=2
Forcing Net Contradiction in r8c2 => r1c1<>9
r1c1=9 (r6c1<>9 r6c2=9 r6c2<>5) (r1c1<>6) (r6c1<>9 r6c2=9 r6c2<>6) r1c1<>5 r6c1=5 (r4c2<>5) r6c1<>6 r6c7=6 r1c7<>6 r1c2=6 r1c2<>5 r2c2=5 (r2c5<>5) r1c1<>5 r6c1=5 (r4c2<>5) r6c5<>5 r9c5=5 (r9c5<>1) r9c5<>6 r7c5=6 r7c5<>1 r8c5=1 r8c2<>1
r1c1=9 (r1c1<>6) (r6c1<>9 r6c2=9 r6c2<>6) r1c1<>5 r6c1=5 (r4c2<>5) r6c1<>6 r6c7=6 r1c7<>6 r1c2=6 r4c2<>6 r4c2=4 r8c2<>4
r1c1=9 r6c1<>9 r6c2=9 r8c2<>9
Forcing Net Contradiction in r8 => r6c1<>3
r6c1=3 (r5c1<>3 r5c5=3 r8c5<>3) r6c8<>3 r7c8=3 r8c7<>3 r8c4=3 r8c4<>8
r6c1=3 (r6c5<>3) (r6c1<>5 r1c1=5 r2c2<>5) (r5c1<>3 r5c5=3 r4c6<>3) r6c8<>3 r7c8=3 r7c6<>3 r2c6=3 r2c6<>5 r2c5=5 r6c5<>5 r6c5=8 r8c5<>8
r6c1=3 (r5c1<>3 r5c1=4 r4c3<>4 r4c3=6 r4c9<>6 r2c9=6 r2c9<>8) (r6c1<>5 r1c1=5 r2c2<>5) (r5c1<>3 r5c5=3 r4c6<>3) r6c8<>3 r7c8=3 r7c6<>3 r2c6=3 (r2c6<>8) r2c6<>5 r2c5=5 r2c5<>8 r2c7=8 r8c7<>8
r6c1=3 (r6c1<>9 r6c2=9 r8c2<>9) (r5c1<>3 r5c5=3 r8c5<>3) r6c8<>3 r7c8=3 r8c7<>3 r8c4=3 r8c4<>9 r8c9=9 r8c9<>8
Forcing Net Contradiction in b1 => r2c5<>4
r2c5=4 (r2c3<>4) r5c5<>4 (r5c1=4 r1c1<>4) r5c5=3 r5c1<>3 r3c1=3 r2c3<>3 r2c3=6 r1c1<>6 r1c1=5
r2c5=4 (r2c5<>5) (r2c5<>3) r5c5<>4 r5c5=3 r5c1<>3 r3c1=3 r2c3<>3 r2c6=3 r2c6<>5 r2c2=5
Forcing Net Verity => r3c3<>4
r1c1=4 r3c3<>4
r3c1=4 r3c3<>4
r5c1=4 (r5c5<>4 r5c5=3 r2c5<>3) r5c1<>3 r3c1=3 r2c3<>3 r2c6=3 r2c6<>4 r2c23=4 r3c3<>4
r9c1=4 (r8c2<>4) (r3c1<>4) r5c1<>4 r5c1=3 r3c1<>3 r3c1=9 r6c1<>9 r6c2=9 r8c2<>9 r8c2=1 (r7c3<>1) r9c3<>1 r3c3=1 r3c3<>4
Forcing Net Contradiction in b4 => r6c5<>3
r6c5=3 (r5c5<>3 r5c5=4 r8c5<>4) (r8c5<>3) r6c8<>3 r7c8=3 r8c7<>3 r8c4=3 r8c4<>4 r8c2=4 r4c2<>4
r6c5=3 (r5c5<>3 r5c5=4 r8c5<>4) (r8c5<>3) r6c8<>3 r7c8=3 (r7c6<>3 r2c6=3 r2c6<>4) r8c7<>3 r8c4=3 r8c4<>4 r8c2=4 r2c2<>4 r2c3=4 r4c3<>4
r6c5=3 r5c5<>3 r5c5=4 r5c1<>4
Forcing Net Contradiction in c8 => r7c5<>8
r7c5=8 (r7c4<>8) (r8c4<>8) (r9c4<>8) (r7c6<>8) (r9c6<>8) r6c5<>8 r6c5=5 (r2c5<>5) (r4c4<>5) r4c6<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>8 r4c6=8 (r4c4<>8) r6c4<>8 r3c4=8 r3c8<>8
r7c5=8 (r7c6<>8) (r9c6<>8) r6c5<>8 r6c5=5 (r2c5<>5) (r4c6<>5) (r2c5<>5) (r4c4<>5) r4c6<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>8 r4c6=8 (r4c6<>3) r6c5<>8 r6c5=5 (r2c5<>5) (r4c6<>5) (r2c5<>5) (r4c4<>5) r4c4<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>3 r7c6=3 r7c8<>3 r6c8=3 r6c8<>8
r7c5=8 r7c8<>8
r7c5=8 r7c1<>8 r9c1=8 r9c8<>8
Forcing Net Contradiction in c8 => r9c5<>8
r9c5=8 (r7c4<>8) (r8c4<>8) (r9c4<>8) (r7c6<>8) (r9c6<>8) r6c5<>8 r6c5=5 (r2c5<>5) (r4c4<>5) r4c6<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>8 r4c6=8 (r4c4<>8) r6c4<>8 r3c4=8 r3c8<>8
r9c5=8 (r7c6<>8) (r9c6<>8) r6c5<>8 r6c5=5 (r2c5<>5) (r4c6<>5) (r2c5<>5) (r4c4<>5) r4c6<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>8 r4c6=8 (r4c6<>3) r6c5<>8 r6c5=5 (r2c5<>5) (r4c6<>5) (r2c5<>5) (r4c4<>5) r4c4<>5 r4c2=5 r2c2<>5 r2c6=5 r2c6<>3 r7c6=3 r7c8<>3 r6c8=3 r6c8<>8
r9c5=8 r9c1<>8 r7c1=8 r7c8<>8
r9c5=8 r9c8<>8
Brute Force: r5c5=4
Full House: r5c1=3
Finned Swordfish: 4 r248 c234 fr2c6 => r13c4<>4
Locked Candidates Type 1 (Pointing): 4 in b2 => r9c6<>4
Almost Locked Set XZ-Rule: A=r2c23579 {345678}, B=r3c12345 {134789}, X=4, Z=8 => r2c6<>8
Forcing Chain Contradiction in c8 => r1c1=5
r1c1<>5 r6c1=5 r6c5<>5 r6c5=8 r2c5<>8 r2c79=8 r3c8<>8
r1c1<>5 r6c1=5 r6c5<>5 r6c5=8 r6c8<>8
r1c1<>5 r6c1=5 r6c5<>5 r6c5=8 r4c6<>8 r79c6=8 r8c45<>8 r8c79=8 r7c8<>8
r1c1<>5 r6c1=5 r6c5<>5 r6c5=8 r4c6<>8 r79c6=8 r8c45<>8 r8c79=8 r9c8<>8
2-String Kite: 6 in r1c2,r4c9 (connected by r1c7,r2c9) => r4c2<>6
W-Wing: 9/4 in r1c6,r3c1 connected by 4 in r13c8 => r1c2,r3c4<>9
XY-Wing: 6/9/4 in r36c1,r4c3 => r2c3<>4
Discontinuous Nice Loop: 6 r9c1 -6- r9c5 =6= r7c5 =7= r7c4 -7- r1c4 -9- r1c6 -4- r1c8 =4= r3c8 -4- r3c1 =4= r9c1 => r9c1<>6
Grouped Discontinuous Nice Loop: 3 r2c5 =5= r2c6 =4= r2c2 -4- r3c1 -9- r6c1 -6- r6c2 =6= r12c2 -6- r2c3 -3- r2c5 => r2c5<>3
Grouped Discontinuous Nice Loop: 6 r2c3 =3= r2c6 =4= r2c2 -4- r3c1 -9- r6c1 -6- r6c2 =6= r12c2 -6- r2c3 => r2c3<>6
Naked Single: r2c3=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r6c2<>6
Skyscraper: 3 in r4c6,r6c8 (connected by r7c68) => r4c7,r6c4<>3
Discontinuous Nice Loop: 7 r1c2 -7- r1c4 -9- r1c6 -4- r2c6 =4= r2c2 =6= r1c2 => r1c2<>7
AIC: 7 7- r1c4 -9- r1c6 -4- r2c6 =4= r2c2 =7= r3c2 -7 => r3c45<>7
Locked Pair: 3,8 in r3c45 => r2c5,r3c89<>8
Finned Swordfish: 8 c168 r479 fr6c8 => r4c79<>8
Locked Pair: 2,6 in r4c79 => r4c3,r6c7<>6, r4c4,r6c78<>2
Naked Single: r4c3=4
Naked Single: r4c2=5
Naked Single: r6c2=9
Full House: r6c1=6
Hidden Single: r6c4=2
Hidden Single: r6c5=5
Naked Single: r2c5=7
Naked Single: r1c4=9
Naked Single: r1c6=4
Naked Single: r1c8=1
Naked Single: r2c6=5
Naked Single: r1c2=6
Full House: r1c7=7
Naked Single: r2c2=4
Naked Single: r3c9=2
Naked Single: r3c1=9
Naked Single: r8c2=1
Full House: r3c2=7
Full House: r3c3=1
Naked Single: r3c8=4
Naked Single: r4c9=6
Naked Single: r7c1=8
Full House: r9c1=4
Naked Single: r2c9=8
Full House: r2c7=6
Naked Single: r4c7=2
Naked Single: r7c8=3
Naked Single: r8c9=9
Full House: r9c9=7
Naked Single: r6c8=8
Full House: r6c7=3
Full House: r9c8=2
Naked Single: r7c4=7
Naked Single: r7c6=9
Naked Single: r8c7=8
Full House: r9c7=1
Naked Single: r7c3=6
Full House: r7c5=1
Full House: r9c3=9
Naked Single: r9c6=8
Full House: r4c6=3
Full House: r4c4=8
Naked Single: r8c5=3
Full House: r8c4=4
Naked Single: r9c5=6
Full House: r9c4=5
Full House: r3c4=3
Full House: r3c5=8
|
normal_sudoku_1138
|
......51.53..91...1685.7.9..9..7......7..3.26..5..8....53.....89.18.....7...65.3.
|
479386512532491687168527493396172854847953126215648379653719248921834765784265931
|
Basic 9x9 Sudoku 1138
|
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 .
5 3 . . 9 1 . . .
1 6 8 5 . 7 . 9 .
. 9 . . 7 . . . .
. . 7 . . 3 . 2 6
. . 5 . . 8 . . .
. 5 3 . . . . . 8
9 . 1 8 . . . . .
7 . . . 6 5 . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
479386512532491687168527493396172854847953126215648379653719248921834765784265931 #1 Hard (858)
Hidden Single: r2c1=5
Hidden Single: r5c5=5
Hidden Single: r1c3=9
Hidden Single: r1c5=8
Hidden Single: r1c2=7
Hidden Single: r7c4=7
Hidden Single: r9c2=8
Hidden Single: r4c3=6
Hidden Single: r7c1=6
Naked Single: r7c8=4
Naked Single: r6c8=7
Hidden Single: r7c6=9
Hidden Single: r8c5=3
Hidden Single: r1c4=3
Hidden Single: r1c6=6
Hidden Single: r6c4=6
Hidden Single: r5c4=9
Naked Pair: 2,4 in r2c34 => r2c79<>2, r2c79<>4
Naked Single: r2c9=7
Hidden Single: r8c7=7
Hidden Single: r8c8=6
Naked Single: r2c8=8
Full House: r4c8=5
Naked Single: r2c7=6
Hidden Single: r8c9=5
X-Wing: 4 r29 c34 => r4c4<>4
Remote Pair: 2/4 r1c1 -4- r2c3 -2- r9c3 -4- r8c2 -2- r8c6 -4- r4c6 => r4c1<>2, r4c1<>4
Locked Candidates Type 1 (Pointing): 2 in b4 => r6c5<>2
Remote Pair: 2/4 r2c4 -4- r2c3 -2- r9c3 -4- r8c2 -2- r8c6 -4- r4c6 => r4c4<>2
Naked Single: r4c4=1
Naked Single: r6c5=4
Full House: r4c6=2
Full House: r8c6=4
Full House: r8c2=2
Full House: r9c3=4
Full House: r2c3=2
Full House: r1c1=4
Full House: r2c4=4
Full House: r3c5=2
Full House: r9c4=2
Full House: r1c9=2
Full House: r7c5=1
Full House: r7c7=2
Naked Single: r6c2=1
Full House: r5c2=4
Naked Single: r5c1=8
Full House: r5c7=1
Naked Single: r4c1=3
Full House: r6c1=2
Naked Single: r9c7=9
Full House: r9c9=1
Naked Single: r4c9=4
Full House: r4c7=8
Naked Single: r6c7=3
Full House: r3c7=4
Full House: r3c9=3
Full House: r6c9=9
|
normal_sudoku_2990
|
...58.....3..1.7.49..7..6....9..8..7....4...35..2.3916.6.8.........9....4.7...1.8
|
746589231835612794912734685329168547671945823584273916263851479158497362497326158
|
Basic 9x9 Sudoku 2990
|
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 . . . .
. 3 . . 1 . 7 . 4
9 . . 7 . . 6 . .
. . 9 . . 8 . . 7
. . . . 4 . . . 3
5 . . 2 . 3 9 1 6
. 6 . 8 . . . . .
. . . . 9 . . . .
4 . 7 . . . 1 . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
746589231835612794912734685329168547671945823584273916263851479158497362497326158 #1 Medium (580)
Naked Single: r6c9=6
Naked Single: r6c5=7
Hidden Single: r3c5=3
Hidden Single: r4c1=3
Hidden Single: r9c2=9
Hidden Single: r8c4=4
Hidden Single: r5c7=8
Hidden Single: r9c4=3
Locked Candidates Type 1 (Pointing): 2 in b2 => r789c6<>2
Locked Candidates Type 1 (Pointing): 6 in b4 => r5c46<>6
Locked Candidates Type 1 (Pointing): 4 in b6 => r4c2<>4
Locked Candidates Type 1 (Pointing): 1 in b8 => r5c6<>1
Naked Triple: 2,5,6 in r79c5,r9c6 => r78c6<>5, r8c6<>6
Hidden Single: r8c8=6
Hidden Single: r8c6=7
Naked Single: r7c6=1
Naked Single: r7c1=2
Naked Single: r7c5=5
Naked Single: r4c5=6
Full House: r9c5=2
Full House: r9c6=6
Full House: r9c8=5
Naked Single: r7c3=3
Naked Single: r7c9=9
Naked Single: r4c4=1
Naked Single: r5c8=2
Naked Single: r8c9=2
Naked Single: r7c7=4
Full House: r7c8=7
Full House: r8c7=3
Naked Single: r4c2=2
Naked Single: r5c4=9
Full House: r2c4=6
Full House: r5c6=5
Naked Single: r3c8=8
Naked Single: r4c8=4
Full House: r4c7=5
Full House: r1c7=2
Naked Single: r1c9=1
Full House: r3c9=5
Naked Single: r2c1=8
Naked Single: r2c8=9
Full House: r1c8=3
Naked Single: r8c1=1
Naked Single: r2c6=2
Full House: r2c3=5
Naked Single: r3c6=4
Full House: r1c6=9
Naked Single: r8c3=8
Full House: r8c2=5
Naked Single: r3c2=1
Full House: r3c3=2
Naked Single: r6c3=4
Full House: r6c2=8
Naked Single: r5c2=7
Full House: r1c2=4
Naked Single: r1c3=6
Full House: r1c1=7
Full House: r5c1=6
Full House: r5c3=1
|
normal_sudoku_592
|
..5.8..32.29.7....6..2..5.......17.....43..9.1...9...3.4386...52..1....8...3.....
|
715986432429573816638214579392651784576438291184792653943867125257149368861325947
|
Basic 9x9 Sudoku 592
|
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 . . 3 2
. 2 9 . 7 . . . .
6 . . 2 . . 5 . .
. . . . . 1 7 . .
. . . 4 3 . . 9 .
1 . . . 9 . . . 3
. 4 3 8 6 . . . 5
2 . . 1 . . . . 8
. . . 3 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
715986432429573816638214579392651784576438291184792653943867125257149368861325947 #1 Easy (390)
Hidden Single: r2c2=2
Hidden Single: r3c5=1
Hidden Single: r8c7=3
Hidden Single: r6c4=7
Hidden Single: r1c4=9
Hidden Single: r9c3=1
Hidden Single: r1c2=1
Hidden Single: r3c9=9
Hidden Single: r1c1=7
Naked Single: r7c1=9
Hidden Single: r9c9=7
Hidden Single: r3c8=7
Hidden Single: r4c2=9
Hidden Single: r9c7=9
Hidden Single: r8c6=9
Hidden Single: r7c6=7
Hidden Single: r4c1=3
Hidden Single: r3c2=3
Naked Single: r3c6=4
Full House: r3c3=8
Full House: r2c1=4
Naked Single: r1c6=6
Full House: r1c7=4
Naked Single: r2c4=5
Full House: r2c6=3
Full House: r4c4=6
Naked Single: r4c9=4
Naked Single: r4c3=2
Naked Single: r4c5=5
Full House: r4c8=8
Naked Single: r8c5=4
Full House: r9c5=2
Full House: r9c6=5
Naked Single: r8c8=6
Naked Single: r9c1=8
Full House: r5c1=5
Naked Single: r2c8=1
Naked Single: r8c3=7
Full House: r8c2=5
Full House: r9c2=6
Full House: r9c8=4
Naked Single: r2c9=6
Full House: r2c7=8
Full House: r5c9=1
Naked Single: r7c8=2
Full House: r6c8=5
Full House: r7c7=1
Naked Single: r5c3=6
Full House: r6c3=4
Naked Single: r6c2=8
Full House: r5c2=7
Naked Single: r5c7=2
Full House: r5c6=8
Full House: r6c6=2
Full House: r6c7=6
|
normal_sudoku_5178
|
...6....1.4....38.7.98.....9......6...8.7..35..53..1....25...1..9..3.2..4...62...
|
823645971541729386769813542934251768218976435675384129382597614196438257457162893
|
Basic 9x9 Sudoku 5178
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 6 . . . . 1
. 4 . . . . 3 8 .
7 . 9 8 . . . . .
9 . . . . . . 6 .
. . 8 . 7 . . 3 5
. . 5 3 . . 1 . .
. . 2 5 . . . 1 .
. 9 . . 3 . 2 . .
4 . . . 6 2 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
823645971541729386769813542934251768218976435675384129382597614196438257457162893 #1 Extreme (13882) bf
Forcing Net Contradiction in r1 => r3c6<>5
r3c6=5 (r2c6<>5 r2c1=5 r1c1<>5) r3c6<>3 r3c2=3 (r1c1<>3) r1c3<>3 r1c3=8 r1c1<>8 r1c1=2
r3c6=5 (r2c6<>5 r2c1=5 r1c2<>5) r3c6<>3 r3c2=3 (r1c2<>3) r1c3<>3 r1c3=8 r1c2<>8 r1c2=2
Brute Force: r5c3=8
Naked Single: r1c3=3
Hidden Single: r4c3=4
Hidden Single: r7c1=3
Hidden Single: r3c6=3
Hidden Single: r4c2=3
Hidden Single: r9c9=3
Hidden Single: r6c2=7
Locked Candidates Type 1 (Pointing): 1 in b4 => r5c46<>1
Finned Swordfish: 7 r147 c679 fr1c8 => r2c9<>7
Locked Candidates Type 1 (Pointing): 7 in b3 => r1c6<>7
Grouped AIC: 6 6- r6c1 -2- r5c12 =2= r5c4 -2- r4c4 -1- r89c4 =1= r8c6 =8= r7c56 -8- r7c2 -6 => r5c2,r8c1<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r2c1<>6
X-Wing: 6 r28 c39 => r37c9<>6
Discontinuous Nice Loop: 8 r8c9 -8- r9c7 =8= r9c2 -8- r7c2 -6- r7c7 =6= r8c9 => r8c9<>8
Forcing Chain Contradiction in r3 => r5c6=6
r5c6<>6 r5c1=6 r6c1<>6 r6c1=2 r5c12<>2 r5c4=2 r4c4<>2 r4c4=1 r89c4<>1 r8c6=1 r8c6<>8 r8c1=8 r8c1<>5 r9c2=5 r3c2<>5
r5c6<>6 r5c1=6 r5c1<>1 r5c2=1 r3c2<>1 r3c5=1 r3c5<>5
r5c6<>6 r5c1=6 r6c1<>6 r6c1=2 r5c12<>2 r5c4=2 r4c4<>2 r4c4=1 r89c4<>1 r8c6=1 r8c6<>8 r8c1=8 r7c2<>8 r7c2=6 r7c7<>6 r3c7=6 r3c7<>5
r5c6<>6 r5c1=6 r6c1<>6 r6c1=2 r5c12<>2 r5c4=2 r4c4<>2 r4c4=1 r89c4<>1 r8c6=1 r8c6<>8 r8c1=8 r8c1<>5 r8c8=5 r3c8<>5
Hidden Single: r6c1=6
Locked Candidates Type 1 (Pointing): 2 in b4 => r5c4<>2
Empty Rectangle: 9 in b8 (r5c47) => r7c7<>9
Finned Swordfish: 9 r159 c478 fr1c5 fr1c6 => r2c4<>9
Almost Locked Set XY-Wing: A=r4c7 {78}, B=r9c34 {179}, C=r79c7,r8c89,r9c8 {456789}, X,Y=8,9, Z=7 => r9c7<>7
Forcing Chain Contradiction in r7c7 => r1c8=7
r1c8<>7 r1c7=7 r4c7<>7 r4c7=8 r79c7<>8 r7c9=8 r7c9<>9 r7c56=9 r9c4<>9 r5c4=9 r5c4<>4 r5c7=4 r7c7<>4
r1c8<>7 r1c7=7 r4c7<>7 r4c7=8 r9c7<>8 r9c2=8 r7c2<>8 r7c2=6 r7c7<>6
r1c8<>7 r1c7=7 r7c7<>7
r1c8<>7 r1c7=7 r4c7<>7 r4c7=8 r7c7<>8
Skyscraper: 9 in r5c4,r6c8 (connected by r9c48) => r5c7,r6c56<>9
Naked Single: r5c7=4
Naked Single: r5c4=9
Hidden Single: r8c4=4
Naked Single: r8c8=5
Naked Single: r9c8=9
Naked Single: r6c8=2
Full House: r3c8=4
Naked Single: r9c7=8
Naked Single: r3c9=2
Naked Single: r4c7=7
Naked Single: r4c9=8
Full House: r6c9=9
Naked Single: r7c7=6
Naked Single: r2c9=6
Naked Single: r3c7=5
Full House: r1c7=9
Naked Single: r7c2=8
Naked Single: r8c9=7
Full House: r7c9=4
Naked Single: r2c3=1
Naked Single: r3c5=1
Full House: r3c2=6
Naked Single: r7c5=9
Full House: r7c6=7
Naked Single: r8c1=1
Naked Single: r8c3=6
Full House: r9c3=7
Full House: r8c6=8
Full House: r9c4=1
Full House: r9c2=5
Naked Single: r5c1=2
Full House: r5c2=1
Full House: r1c2=2
Naked Single: r6c6=4
Full House: r6c5=8
Naked Single: r4c4=2
Full House: r2c4=7
Naked Single: r2c1=5
Full House: r1c1=8
Naked Single: r1c6=5
Full House: r1c5=4
Naked Single: r4c5=5
Full House: r2c5=2
Full House: r2c6=9
Full House: r4c6=1
|
normal_sudoku_4882
|
61......2..82...4.2....79.85..3724......86.....24....3....5..3...39..8..1..7.....
|
619548372758239641234617958591372486347186529862495713926854137473921865185763294
|
Basic 9x9 Sudoku 4882
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
6 1 . . . . . . 2
. . 8 2 . . . 4 .
2 . . . . 7 9 . 8
5 . . 3 7 2 4 . .
. . . . 8 6 . . .
. . 2 4 . . . . 3
. . . . 5 . . 3 .
. . 3 9 . . 8 . .
1 . . 7 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
619548372758239641234617958591372486347186529862495713926854137473921865185763294 #1 Extreme (22790) bf
Hidden Single: r4c6=2
Locked Candidates Type 1 (Pointing): 9 in b5 => r6c128<>9
Grouped Discontinuous Nice Loop: 4 r9c2 -4- r78c1 =4= r5c1 =3= r5c2 -3- r3c2 =3= r3c5 -3- r9c5 =3= r9c6 =8= r9c2 => r9c2<>4
Brute Force: r5c9=9
Hidden Single: r9c8=9
Forcing Net Contradiction in c8 => r3c4<>5
r3c4=5 (r3c3<>5 r3c3=4 r1c3<>4) (r3c3<>5 r3c3=4 r7c3<>4) (r3c4<>6 r7c4=6 r7c3<>6) (r3c3<>5 r3c3=4 r5c3<>4) r5c4<>5 r5c4=1 r5c3<>1 r5c3=7 (r1c3<>7) r7c3<>7 r7c3=9 r1c3<>9 r1c3=5 r1c8<>5
r3c4=5 r3c8<>5
r3c4=5 (r3c4<>6 r7c4=6 r8c5<>6) (r3c4<>6 r7c4=6 r7c3<>6) r5c4<>5 r5c4=1 r5c3<>1 r4c3=1 (r4c9<>1 r4c9=6 r8c9<>6) r4c3<>6 r9c3=6 r8c2<>6 r8c8=6 r8c8<>2 r5c8=2 r5c8<>5
r3c4=5 (r1c6<>5) r2c6<>5 r6c6=5 r6c8<>5
r3c4=5 (r3c4<>6 r7c4=6 r8c5<>6) (r3c4<>6 r7c4=6 r7c3<>6) r5c4<>5 r5c4=1 r5c3<>1 r4c3=1 (r4c9<>1 r4c9=6 r8c9<>6) r4c3<>6 r9c3=6 r8c2<>6 r8c8=6 r8c8<>5
Forcing Chain Contradiction in c8 => r5c8<>5
r5c8=5 r5c4<>5 r5c4=1 r3c4<>1 r3c4=6 r3c8<>6
r5c8=5 r5c4<>5 r5c4=1 r5c3<>1 r4c3=1 r4c9<>1 r4c9=6 r4c8<>6
r5c8=5 r5c4<>5 r5c4=1 r5c3<>1 r4c3=1 r4c9<>1 r4c9=6 r6c8<>6
r5c8=5 r5c8<>2 r8c8=2 r8c8<>6
Forcing Chain Contradiction in b6 => r6c7<>1
r6c7=1 r6c56<>1 r5c4=1 r5c4<>5 r5c7=5 r5c7<>7
r6c7=1 r6c56<>1 r5c4=1 r5c4<>5 r5c7=5 r5c7<>2 r5c8=2 r5c8<>7
r6c7=1 r6c7<>7
r6c7=1 r6c56<>1 r5c4=1 r5c4<>5 r1c4=5 r1c8<>5 r1c8=7 r6c8<>7
Forcing Net Contradiction in c3 => r4c8=8
r4c8<>8 r4c2=8 r4c2<>9 r4c3=9 r4c3<>6
r4c8<>8 r4c2=8 r6c1<>8 (r7c1=8 r7c4<>8) r6c1=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r7c4<>1 r7c4=6 r7c3<>6
r4c8<>8 r4c2=8 (r6c1<>8 r6c1=7 r6c2<>7 r6c2=6 r6c7<>6 r6c7=5 r9c7<>5) (r6c1<>8 r7c1=8 r7c1<>9) r4c2<>9 r4c3=9 r7c3<>9 r7c2=9 r7c2<>2 r7c7=2 r9c7<>2 r9c7=6 r9c3<>6
Forcing Net Contradiction in c8 => r6c1=8
r6c1<>8 (r7c1=8 r7c4<>8) r6c1=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r7c4<>1 r7c4=6 r3c4<>6 r3c4=1 r3c8<>1
r6c1<>8 r6c1=7 (r5c3<>7) (r5c2<>7) (r5c1<>7) r8c1<>7 r8c1=4 r5c1<>4 r5c1=3 r5c2<>3 r5c2=4 r5c3<>4 r5c3=1 r5c8<>1
r6c1<>8 (r7c1=8 r7c4<>8) r6c1=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 (r8c5<>1) r7c4<>1 r7c4=6 r3c4<>6 r3c4=1 (r2c5<>1) r3c5<>1 r6c5=1 r6c8<>1
r6c1<>8 r6c1=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r8c8<>1
Almost Locked Set XY-Wing: A=r9c379 {2456}, B=r2345678c2 {23456789}, C=r7c134679 {1246789}, X,Y=2,8, Z=5,6 => r9c2<>5, r9c2<>6
Forcing Net Contradiction in r5c4 => r1c3<>5
r1c3=5 (r3c2<>5 r8c2=5 r8c9<>5 r9c9=5 r9c7<>5 r9c7=2 r9c5<>2) (r3c3<>5 r3c3=4 r9c3<>4 r9c3=6 r9c5<>6) (r1c4<>5 r5c4=5 r6c6<>5 r2c6=5 r2c6<>3) (r1c7<>5) r1c8<>5 r1c8=7 r1c7<>7 r1c7=3 r1c6<>3 r9c6=3 r9c5<>3 r9c5=4 r8c6<>4 r8c6=1 r6c6<>1 r6c8=1 r6c56<>1 r5c4=1
r1c3=5 r1c4<>5 r5c4=5
Forcing Net Contradiction in b8 => r1c6<>4
r1c6=4 (r8c6<>4 r8c6=1 r7c4<>1) r1c6<>8 r1c4=8 r7c4<>8 r7c4=6
r1c6=4 (r8c6<>4 r8c6=1 r8c8<>1) (r8c6<>4 r8c6=1 r8c5<>1) (r8c6<>4 r8c6=1 r7c4<>1) r1c6<>8 r1c4=8 r7c4<>8 r7c4=6 r3c4<>6 r3c4=1 (r3c8<>1) (r2c5<>1) r3c5<>1 r6c5=1 r6c8<>1 r5c8=1 (r5c8<>2 r8c8=2 r8c8<>6) r4c9<>1 r4c9=6 (r8c9<>6) (r6c7<>6) r6c8<>6 r6c2=6 r8c2<>6 r8c5=6
Locked Candidates Type 1 (Pointing): 4 in b2 => r89c5<>4
Forcing Net Contradiction in r7c1 => r1c5<>3
r1c5=3 (r9c5<>3 r9c6=3 r9c6<>4) r1c5<>4 r1c3=4 (r3c3<>4 r3c3=5 r9c3<>5) r9c3<>4 r9c9=4 r9c9<>5 r9c7=5 (r1c7<>5) (r6c7<>5) r5c7<>5 r5c4=5 r6c6<>5 r6c8=5 r1c8<>5 r1c8=7 r1c7<>7 r1c7=3 r1c5<>3
Forcing Net Contradiction in c7 => r1c7<>5
r1c7=5 r1c7<>3 r2c7=3 r2c7<>6
r1c7=5 (r5c7<>5 r5c4=5 r6c6<>5 r2c6=5 r2c6<>1) (r5c7<>5 r5c4=5 r6c6<>5 r2c6=5 r2c6<>9) r1c7<>3 (r2c7=3 r2c7<>1) r1c6=3 r1c6<>9 r6c6=9 r6c5<>9 r6c5=1 r2c5<>1 r2c9=1 r4c9<>1 r4c9=6 r6c7<>6
r1c7=5 (r5c7<>5 r5c4=5 r6c6<>5 r2c6=5 r2c6<>1) (r5c7<>5 r5c4=5 r6c6<>5 r2c6=5 r2c6<>9) r1c7<>3 (r2c7=3 r2c7<>1) r1c6=3 r1c6<>9 r6c6=9 r6c5<>9 r6c5=1 (r3c5<>1) r2c5<>1 r2c9=1 r3c8<>1 r3c4=1 r3c4<>6 r7c4=6 r7c7<>6
r1c7=5 (r1c6<>5) r1c7<>3 r1c6=3 (r1c6<>9 r6c6=9 r6c5<>9 r6c5=1 r2c5<>1 r2c9=1 r3c8<>1 r3c4=1 r3c4<>6 r7c4=6 r7c2<>6) (r1c6<>9 r6c6=9 r6c5<>9 r6c5=1 r2c5<>1 r2c9=1 r3c8<>1 r3c4=1 r3c4<>6 r7c4=6 r7c3<>6) (r3c5<>3 r3c2=3 r3c2<>5) r1c6<>8 r1c4=8 r1c4<>5 r5c4=5 r6c6<>5 r2c6=5 r2c2<>5 r8c2=5 r8c2<>6 r9c3=6 r9c7<>6
Forcing Net Contradiction in r9 => r1c7=3
r1c7<>3 (r1c7=7 r1c8<>7 r1c8=5 r6c8<>5) r1c6=3 (r9c6<>3 r9c5=3 r9c5<>6) (r3c5<>3 r3c2=3 r3c2<>5 r3c3=5 r9c3<>5) r1c6<>8 r1c4=8 r1c4<>5 r5c4=5 r6c6<>5 r6c7=5 r9c7<>5 r9c9=5 r9c9<>6 r9c3=6
r1c7<>3 (r2c7=3 r2c7<>6) (r1c7=7 r1c8<>7 r1c8=5 r6c8<>5) r1c6=3 (r9c6<>3 r9c5=3 r9c5<>2 r8c5=2 r8c5<>6 r7c4=6 r7c7<>6) r1c6<>8 r1c4=8 r1c4<>5 r5c4=5 r6c6<>5 r6c7=5 r6c7<>6 r9c7=6
Forcing Net Verity => r2c9<>7
r1c8=7 r2c9<>7
r5c8=7 (r6c8<>7 r6c2=7 r6c2<>6) (r1c8<>7 r1c8=5 r6c8<>5) r5c8<>2 r5c7=2 r5c7<>5 r5c4=5 r6c6<>5 r6c7=5 (r9c7<>5 r9c7=6 r7c9<>6) (r9c7<>5 r9c7=6 r8c9<>6) (r9c7<>5 r9c7=6 r9c9<>6) r6c7<>6 r6c8=6 r4c9<>6 r2c9=6 r2c9<>7
r6c8=7 (r1c8<>7 r1c8=5 r1c4<>5 r1c4=8 r1c6<>8 r1c6=9 r2c5<>9 r2c1=9 r7c1<>9 r7c3=9 r7c3<>6 r9c3=6 r9c3<>5 r9c79=5 r8c9<>5) (r1c8<>7 r1c8=5 r1c4<>5 r1c4=8 r1c6<>8 r1c6=9 r2c5<>9 r2c1=9 r7c1<>9 r7c3=9 r7c3<>6 r9c3=6 r9c7<>6) (r1c8<>7 r1c8=5 r1c4<>5 r1c4=8 r1c6<>8 r1c6=9 r2c5<>9 r2c1=9 r7c1<>9 r7c3=9 r7c3<>6 r9c3=6 r9c5<>6) (r1c8<>7 r1c3=7 r5c3<>7) r6c2<>7 r6c2=6 (r4c3<>6) r4c2<>6 r4c2=9 r4c3<>9 r4c3=1 r5c3<>1 r5c3=4 (r3c3<>4) r1c3<>4 r1c5=4 r3c5<>4 r3c2=4 r3c2<>3 r3c5=3 r9c5<>3 r9c5=2 r9c7<>2 r9c7=5 r9c9<>5 r2c9=5 r2c9<>7
r8c8=7 (r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r6c6<>1) r1c8<>7 r1c8=5 r1c4<>5 r5c4=5 r6c6<>5 r6c6=9 (r1c6<>9) r6c6<>5 r5c4=5 r1c4<>5 r1c4=8 r1c6<>8 r1c6=5 r1c8<>5 r1c8=7 r2c9<>7
Locked Candidates Type 2 (Claiming): 7 in c9 => r7c7,r8c8<>7
Forcing Chain Contradiction in c4 => r7c9<>6
r7c9=6 r7c4<>6 r3c4=6 r3c4<>1
r7c9=6 r4c9<>6 r4c9=1 r4c3<>1 r5c3=1 r5c4<>1
r7c9=6 r7c9<>7 r8c9=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r7c4<>1
Forcing Net Verity => r3c5<>6
r3c8=1 r3c4<>1 r3c4=6 r3c5<>6
r3c8=5 (r8c8<>5) r3c3<>5 (r3c3=4 r7c3<>4) (r3c3=4 r1c3<>4 r1c3=9 r7c3<>9) r9c3=5 r8c2<>5 r8c9=5 r8c9<>7 r7c9=7 r7c3<>7 r7c3=6 r7c4<>6 r3c4=6 r3c5<>6
r3c8=6 r3c5<>6
Forcing Net Verity => r1c8=7
r5c1=7 (r6c2<>7 r6c2=6 r4c2<>6 r4c2=9 r4c3<>9) (r7c1<>7) r8c1<>7 r8c1=4 r7c1<>4 r7c1=9 r7c3<>9 r1c3=9 r1c3<>7 r1c8=7
r5c2=7 (r5c2<>4) r5c2<>3 r5c1=3 r5c1<>4 r5c3=4 (r3c3<>4 r3c3=5 r3c2<>5 r8c2=5 r8c9<>5) (r3c3<>4 r3c3=5 r9c3<>5 r9c3=6 r9c7<>6) (r3c3<>4 r3c3=5 r9c3<>5 r9c3=6 r9c5<>6) (r3c3<>4) r1c3<>4 r1c5=4 r3c5<>4 r3c2=4 r3c2<>3 r3c5=3 r9c5<>3 r9c5=2 r9c7<>2 r9c7=5 r9c9<>5 r2c9=5 r1c8<>5 r1c8=7
r5c3=7 r1c3<>7 r1c8=7
r5c7=7 (r5c8<>7) r6c8<>7 r1c8=7
r5c8=7 (r6c8<>7 r6c2=7 r6c2<>6) (r1c8<>7 r1c8=5 r6c8<>5) r5c8<>2 r5c7=2 (r5c7<>1) r5c7<>5 r5c4=5 r6c6<>5 r6c7=5 r6c7<>6 r6c8=6 (r3c8<>6 r3c4=6 r3c4<>1) r4c9<>6 r4c9=1 r4c3<>1 r5c3=1 r5c4<>1 r7c4=1 r7c7<>1 r2c7=1 r2c7<>7 r1c8=7
Locked Candidates Type 2 (Claiming): 5 in r1 => r2c6<>5
Naked Pair: 4,9 in r1c35 => r1c6<>9
Discontinuous Nice Loop: 9 r7c2 -9- r7c1 =9= r2c1 =7= r2c2 -7- r6c2 -6- r4c2 -9- r7c2 => r7c2<>9
Discontinuous Nice Loop: 6 r8c9 -6- r4c9 -1- r4c3 =1= r5c3 =7= r7c3 -7- r7c9 =7= r8c9 => r8c9<>6
Forcing Chain Contradiction in c4 => r2c9<>6
r2c9=6 r2c5<>6 r3c4=6 r3c4<>1
r2c9=6 r4c9<>6 r4c9=1 r4c3<>1 r5c3=1 r5c4<>1
r2c9=6 r4c9<>6 r4c9=1 r4c3<>1 r5c3=1 r5c3<>7 r7c3=7 r8c1<>7 r8c1=4 r8c6<>4 r8c6=1 r7c4<>1
2-String Kite: 6 in r2c7,r7c4 (connected by r2c5,r3c4) => r7c7<>6
Grouped Discontinuous Nice Loop: 6 r9c3 -6- r7c23 =6= r7c4 -6- r3c4 =6= r3c8 -6- r8c8 =6= r9c79 -6- r9c3 => r9c3<>6
Naked Pair: 4,5 in r39c3 => r157c3<>4
Naked Single: r1c3=9
Naked Single: r1c5=4
Hidden Single: r7c1=9
Hidden Single: r4c2=9
Naked Triple: 1,6,7 in r45c3,r6c2 => r5c12<>7
Hidden Rectangle: 1/9 in r2c56,r6c56 => r2c6<>1
XY-Wing: 1/3/9 in r2c6,r36c5 => r2c5,r6c6<>9
Hidden Single: r2c6=9
Hidden Single: r6c5=9
Hidden Single: r9c6=3
Hidden Single: r9c2=8
Multi Colors 1: 6 (r2c5,r3c8,r7c4) / (r2c7,r3c4), (r4c3,r9c9) / (r4c9,r6c2,r7c3) => r9c7<>6
XY-Chain: 6 6- r4c9 -1- r4c3 -6- r7c3 -7- r8c1 -4- r8c6 -1- r6c6 -5- r5c4 -1- r5c3 -7- r6c2 -6 => r4c3,r6c78<>6
Naked Single: r4c3=1
Full House: r4c9=6
Naked Single: r5c3=7
Naked Single: r6c2=6
Naked Single: r7c3=6
Hidden Single: r2c7=6
Hidden Single: r9c5=6
Hidden Single: r8c8=6
Hidden Single: r6c7=7
Hidden Single: r3c4=6
Hidden Single: r9c7=2
Naked Single: r7c7=1
Full House: r5c7=5
Naked Single: r7c4=8
Naked Single: r5c4=1
Full House: r1c4=5
Full House: r6c6=5
Full House: r6c8=1
Full House: r5c8=2
Full House: r1c6=8
Full House: r3c8=5
Full House: r2c9=1
Naked Single: r7c6=4
Full House: r8c6=1
Full House: r8c5=2
Naked Single: r3c3=4
Full House: r9c3=5
Full House: r9c9=4
Naked Single: r2c5=3
Full House: r3c5=1
Full House: r3c2=3
Naked Single: r7c9=7
Full House: r7c2=2
Full House: r8c9=5
Naked Single: r2c1=7
Full House: r2c2=5
Naked Single: r5c2=4
Full House: r5c1=3
Full House: r8c1=4
Full House: r8c2=7
|
normal_sudoku_688
|
8..6..4...2...4.7...4.....5....1...7.7.4.23..6..8...2..3.7...9...1.9....9....3..6
|
893675412526184973714329685352916847178452369649837521435761298261598734987243156
|
Basic 9x9 Sudoku 688
|
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 . . 6 . . 4 . .
. 2 . . . 4 . 7 .
. . 4 . . . . . 5
. . . . 1 . . . 7
. 7 . 4 . 2 3 . .
6 . . 8 . . . 2 .
. 3 . 7 . . . 9 .
. . 1 . 9 . . . .
9 . . . . 3 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
893675412526184973714329685352916847178452369649837521435761298261598734987243156 #1 Extreme (20850) bf
Brute Force: r5c4=4
Brute Force: r5c5=5
Naked Single: r5c1=1
Hidden Single: r5c8=6
Hidden Single: r7c5=6
Hidden Single: r4c6=6
Hidden Single: r2c3=6
Hidden Single: r8c2=6
Hidden Single: r9c5=4
Hidden Single: r3c7=6
Hidden Single: r1c9=2
Hidden Single: r3c5=2
Hidden Single: r2c5=8
Hidden Single: r3c8=8
Locked Candidates Type 1 (Pointing): 9 in b3 => r2c4<>9
Locked Candidates Type 1 (Pointing): 4 in b7 => r4c1<>4
Turbot Fish: 1 r1c8 =1= r9c8 -1- r9c4 =1= r7c6 => r1c6<>1
Finned Swordfish: 1 r267 c479 fr7c6 => r9c4<>1
Hidden Single: r7c6=1
Hidden Single: r8c6=8
Hidden Single: r1c6=5
Hidden Single: r2c1=5
Locked Pair: 1,9 in r13c2 => r1c3,r46c2<>9
Hidden Single: r1c2=9
Naked Single: r3c2=1
Hidden Single: r1c8=1
Naked Single: r2c7=9
Full House: r2c9=3
Full House: r2c4=1
Naked Single: r9c8=5
Naked Single: r8c9=4
Naked Single: r4c8=4
Full House: r8c8=3
Naked Single: r9c2=8
Naked Single: r9c4=2
Full House: r8c4=5
Naked Single: r7c9=8
Naked Single: r4c2=5
Full House: r6c2=4
Naked Single: r9c3=7
Full House: r9c7=1
Naked Single: r5c9=9
Full House: r5c3=8
Full House: r6c9=1
Naked Single: r7c7=2
Full House: r8c7=7
Full House: r8c1=2
Naked Single: r4c7=8
Full House: r6c7=5
Naked Single: r1c3=3
Full House: r1c5=7
Full House: r3c1=7
Full House: r6c5=3
Naked Single: r7c1=4
Full House: r7c3=5
Full House: r4c1=3
Naked Single: r6c3=9
Full House: r4c3=2
Full House: r4c4=9
Full House: r6c6=7
Full House: r3c6=9
Full House: r3c4=3
|
normal_sudoku_2433
|
..1.5.........76..4561..378...74......4..85379.5......6.....8.2.9.......2..3..79.
|
731856429829437651456192378382745916164928537975613284613579842597284163248361795
|
Basic 9x9 Sudoku 2433
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 . 5 . . . .
. . . . . 7 6 . .
4 5 6 1 . . 3 7 8
. . . 7 4 . . . .
. . 4 . . 8 5 3 7
9 . 5 . . . . . .
6 . . . . . 8 . 2
. 9 . . . . . . .
2 . . 3 . . 7 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
731856429829437651456192378382745916164928537975613284613579842597284163248361795 #1 Easy (336)
Naked Single: r3c1=4
Naked Single: r5c1=1
Naked Single: r9c3=8
Hidden Single: r4c6=5
Hidden Single: r6c2=7
Hidden Single: r2c3=9
Hidden Single: r8c1=5
Hidden Single: r8c9=3
Naked Single: r8c3=7
Naked Single: r7c3=3
Full House: r4c3=2
Naked Single: r5c2=6
Hidden Single: r9c9=5
Hidden Single: r1c1=7
Hidden Single: r6c8=8
Hidden Single: r7c4=5
Hidden Single: r7c5=7
Hidden Single: r2c8=5
Hidden Single: r8c8=6
Naked Single: r4c8=1
Naked Single: r4c7=9
Naked Single: r7c8=4
Full House: r1c8=2
Full House: r8c7=1
Naked Single: r4c9=6
Naked Single: r7c2=1
Full House: r7c6=9
Full House: r9c2=4
Naked Single: r1c7=4
Full House: r6c7=2
Full House: r6c9=4
Naked Single: r3c6=2
Full House: r3c5=9
Naked Single: r1c9=9
Full House: r2c9=1
Naked Single: r6c4=6
Naked Single: r8c6=4
Naked Single: r5c5=2
Full House: r5c4=9
Naked Single: r1c4=8
Naked Single: r8c5=8
Full House: r8c4=2
Full House: r2c4=4
Naked Single: r1c2=3
Full House: r1c6=6
Full House: r2c5=3
Naked Single: r2c1=8
Full House: r2c2=2
Full House: r4c2=8
Full House: r4c1=3
Naked Single: r9c6=1
Full House: r6c6=3
Full House: r6c5=1
Full House: r9c5=6
|
normal_sudoku_2900
|
.........1..9.648...37.592..9...25.......3...36......17....8..3..5......9...6..4.
|
659824317127936485483715926891672534574183269362459871746298153215347698938561742
|
Basic 9x9 Sudoku 2900
|
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 . 6 4 8 .
. . 3 7 . 5 9 2 .
. 9 . . . 2 5 . .
. . . . . 3 . . .
3 6 . . . . . . 1
7 . . . . 8 . . 3
. . 5 . . . . . .
9 . . . 6 . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
659824317127936485483715926891672534574183269362459871746298153215347698938561742 #1 Easy (442)
Naked Single: r2c6=6
Naked Single: r3c9=6
Hidden Single: r3c5=1
Naked Single: r1c6=4
Hidden Single: r2c5=3
Hidden Single: r4c8=3
Hidden Single: r1c7=3
Hidden Single: r1c3=9
Hidden Single: r4c4=6
Hidden Single: r1c8=1
Hidden Single: r1c1=6
Hidden Single: r7c3=6
Hidden Single: r4c3=1
Hidden Single: r5c4=1
Hidden Single: r7c8=5
Hidden Single: r5c1=5
Hidden Single: r9c4=5
Hidden Single: r7c5=9
Hidden Single: r6c5=5
Hidden Single: r8c1=2
Naked Single: r9c3=8
Hidden Single: r9c2=3
Hidden Single: r8c4=3
Hidden Single: r6c6=9
Naked Single: r6c8=7
Hidden Single: r1c5=2
Full House: r1c4=8
Naked Single: r6c4=4
Full House: r7c4=2
Naked Single: r6c3=2
Full House: r6c7=8
Naked Single: r7c7=1
Full House: r7c2=4
Full House: r8c2=1
Naked Single: r2c3=7
Full House: r5c3=4
Naked Single: r4c9=4
Naked Single: r3c2=8
Full House: r3c1=4
Full House: r4c1=8
Full House: r5c2=7
Full House: r4c5=7
Full House: r5c5=8
Full House: r8c5=4
Naked Single: r8c6=7
Full House: r9c6=1
Naked Single: r1c2=5
Full House: r1c9=7
Full House: r2c9=5
Full House: r2c2=2
Naked Single: r8c7=6
Naked Single: r9c9=2
Full House: r9c7=7
Full House: r5c7=2
Naked Single: r8c8=9
Full House: r5c8=6
Full House: r5c9=9
Full House: r8c9=8
|
normal_sudoku_1206
|
.785....15.1..26...6..1..5..4..3.5.....67...4..7....3..14.9...57.....9..2..85..4.
|
978563421531482679462917358149238567823675194657149832314796285785324916296851743
|
Basic 9x9 Sudoku 1206
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 8 5 . . . . 1
5 . 1 . . 2 6 . .
. 6 . . 1 . . 5 .
. 4 . . 3 . 5 . .
. . . 6 7 . . . 4
. . 7 . . . . 3 .
. 1 4 . 9 . . . 5
7 . . . . . 9 . .
2 . . 8 5 . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
978563421531482679462917358149238567823675194657149832314796285785324916296851743 #1 Unfair (932)
Hidden Single: r2c3=1
Hidden Single: r3c3=2
Locked Candidates Type 2 (Claiming): 4 in r2 => r1c56,r3c46<>4
Naked Single: r1c5=6
Naked Pair: 3,9 in r29c2 => r58c2<>3, r56c2<>9
Finned X-Wing: 2 c59 r68 fr4c9 => r6c7<>2
Finned Swordfish: 2 r147 c478 fr4c9 => r5c78<>2
Hidden Single: r5c2=2
Locked Pair: 1,8 in r56c7 => r37c7,r4c89,r5c8,r6c9<>8, r45c8,r9c7<>1
Naked Single: r5c8=9
Naked Single: r1c8=2
Hidden Single: r9c6=1
Hidden Single: r8c8=1
Hidden Single: r7c7=2
Locked Candidates Type 1 (Pointing): 7 in b8 => r7c8<>7
Skyscraper: 6 in r6c1,r9c3 (connected by r69c9) => r4c3,r7c1<>6
Naked Single: r4c3=9
Naked Single: r4c6=8
Naked Single: r5c6=5
Naked Single: r5c3=3
Naked Single: r9c3=6
Full House: r8c3=5
Naked Single: r8c2=8
Naked Single: r6c2=5
Naked Single: r7c1=3
Full House: r9c2=9
Full House: r2c2=3
Naked Single: r7c4=7
Naked Single: r7c6=6
Full House: r7c8=8
Naked Single: r2c8=7
Full House: r4c8=6
Naked Single: r4c1=1
Naked Single: r6c9=2
Naked Single: r4c4=2
Full House: r4c9=7
Naked Single: r5c1=8
Full House: r5c7=1
Full House: r6c1=6
Full House: r6c7=8
Naked Single: r6c5=4
Naked Single: r9c9=3
Full House: r9c7=7
Full House: r8c9=6
Naked Single: r2c5=8
Full House: r8c5=2
Naked Single: r6c6=9
Full House: r6c4=1
Naked Single: r2c9=9
Full House: r2c4=4
Full House: r3c9=8
Naked Single: r1c6=3
Naked Single: r8c4=3
Full House: r3c4=9
Full House: r3c6=7
Full House: r8c6=4
Naked Single: r1c7=4
Full House: r1c1=9
Full House: r3c1=4
Full House: r3c7=3
|
normal_sudoku_5132
|
7.2.3..6......6..8....9..5.9..6..13.....18..9..5..3..6...36..1.3..5..89..5.......
|
712835964594176328836294751948657132623418579175923486487369215361542897259781643
|
Basic 9x9 Sudoku 5132
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 . 2 . 3 . . 6 .
. . . . . 6 . . 8
. . . . 9 . . 5 .
9 . . 6 . . 1 3 .
. . . . 1 8 . . 9
. . 5 . . 3 . . 6
. . . 3 6 . . 1 .
3 . . 5 . . 8 9 .
. 5 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
712835964594176328836294751948657132623418579175923486487369215361542897259781643 #1 Extreme (15370) bf
Hidden Single: r6c6=3
Hidden Single: r5c7=5
Hidden Single: r6c8=8
Hidden Single: r9c5=8
Hidden Single: r9c7=6
Hidden Single: r1c6=5
Hidden Single: r2c1=5
Hidden Single: r6c4=9
Hidden Single: r7c9=5
Hidden Single: r9c9=3
Hidden Single: r4c5=5
Brute Force: r5c2=2
Hidden Single: r5c3=3
Hidden Single: r5c1=6
Finned X-Wing: 2 r48 c69 fr8c5 => r79c6<>2
Finned X-Wing: 2 c48 r29 fr3c4 => r2c5<>2
2-String Kite: 2 in r4c9,r8c5 (connected by r4c6,r6c5) => r8c9<>2
Locked Candidates Type 2 (Claiming): 2 in r8 => r9c4<>2
Locked Candidates Type 2 (Claiming): 2 in c4 => r3c6<>2
Discontinuous Nice Loop: 1/4 r1c4 =8= r1c2 -8- r3c1 =8= r7c1 =2= r7c7 -2- r9c8 =2= r2c8 -2- r2c4 =2= r3c4 =8= r1c4 => r1c4<>1, r1c4<>4
Naked Single: r1c4=8
Forcing Chain Contradiction in r2c8 => r3c4<>4
r3c4=4 r3c4<>2 r2c4=2 r2c8<>2
r3c4=4 r5c4<>4 r5c8=4 r2c8<>4
r3c4=4 r2c5<>4 r2c5=7 r2c8<>7
Forcing Chain Contradiction in r2c8 => r3c4<>7
r3c4=7 r3c4<>2 r2c4=2 r2c8<>2
r3c4=7 r2c5<>7 r2c5=4 r2c8<>4
r3c4=7 r5c4<>7 r5c8=7 r2c8<>7
Forcing Chain Contradiction in r2c8 => r6c5<>4
r6c5=4 r6c5<>2 r6c7=2 r7c7<>2 r9c8=2 r2c8<>2
r6c5=4 r5c4<>4 r5c8=4 r2c8<>4
r6c5=4 r2c5<>4 r2c5=7 r2c8<>7
Sashimi Swordfish: 4 c458 r259 fr8c5 => r9c6<>4
Discontinuous Nice Loop: 7 r4c9 -7- r5c8 -4- r5c4 =4= r4c6 =2= r4c9 => r4c9<>7
Discontinuous Nice Loop: 7 r8c6 -7- r8c9 -4- r4c9 -2- r4c6 =2= r8c6 => r8c6<>7
Finned Franken Swordfish: 7 c59b6 r268 fr3c9 fr5c8 => r2c8<>7
AIC: 2 2- r4c9 =2= r3c9 -2- r2c8 -4- r2c5 -7- r6c5 -2 => r4c6,r6c7<>2
Hidden Single: r4c9=2
Hidden Single: r8c6=2
Hidden Single: r6c5=2
Locked Candidates Type 1 (Pointing): 1 in b8 => r9c13<>1
Naked Pair: 4,7 in r8c59 => r8c23<>4, r8c23<>7
Skyscraper: 7 in r2c5,r3c9 (connected by r8c59) => r2c7,r3c6<>7
Turbot Fish: 7 r4c6 =7= r5c4 -7- r5c8 =7= r9c8 => r9c6<>7
Empty Rectangle: 7 in b4 (r47c6) => r7c2<>7
Locked Candidates Type 1 (Pointing): 7 in b7 => r4c3<>7
W-Wing: 4/7 in r5c4,r8c5 connected by 7 in r2c45 => r9c4<>4
Turbot Fish: 4 r2c4 =4= r5c4 -4- r5c8 =4= r6c7 => r2c7<>4
W-Wing: 4/7 in r6c7,r8c9 connected by 7 in r3c79 => r7c7<>4
Turbot Fish: 4 r2c5 =4= r8c5 -4- r8c9 =4= r9c8 => r2c8<>4
Naked Single: r2c8=2
Hidden Single: r3c4=2
Hidden Single: r7c7=2
Hidden Single: r9c1=2
Remote Pair: 4/7 r2c5 -7- r8c5 -4- r8c9 -7- r9c8 -4- r5c8 -7- r5c4 => r2c4<>4, r2c4<>7
Naked Single: r2c4=1
Naked Single: r3c6=4
Full House: r2c5=7
Full House: r8c5=4
Naked Single: r9c4=7
Full House: r5c4=4
Full House: r4c6=7
Full House: r5c8=7
Full House: r9c8=4
Full House: r8c9=7
Full House: r6c7=4
Naked Single: r7c6=9
Full House: r9c6=1
Full House: r9c3=9
Naked Single: r3c9=1
Full House: r1c9=4
Naked Single: r1c7=9
Full House: r1c2=1
Naked Single: r6c1=1
Full House: r6c2=7
Naked Single: r2c3=4
Naked Single: r3c1=8
Full House: r7c1=4
Naked Single: r2c7=3
Full House: r2c2=9
Full House: r3c7=7
Naked Single: r8c2=6
Full House: r8c3=1
Naked Single: r4c3=8
Full House: r4c2=4
Naked Single: r3c3=6
Full House: r3c2=3
Full House: r7c2=8
Full House: r7c3=7
|
normal_sudoku_839
|
.6......1..3..25..8..7...3..3..1..8.4..5.8.....73....6.5..9......82..4..3....5.9.
|
762953841193482567845761932539617284416528379287349156651894723978236415324175698
|
Basic 9x9 Sudoku 839
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . . . . . . 1
. . 3 . . 2 5 . .
8 . . 7 . . . 3 .
. 3 . . 1 . . 8 .
4 . . 5 . 8 . . .
. . 7 3 . . . . 6
. 5 . . 9 . . . .
. . 8 2 . . 4 . .
3 . . . . 5 . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
762953841193482567845761932539617284416528379287349156651894723978236415324175698 #1 Extreme (20550) bf
Hidden Pair: 4,5 in r4c9,r6c8 => r4c9,r6c8<>2, r4c9<>7, r4c9<>9, r6c8<>1
Brute Force: r5c6=8
Hidden Single: r6c2=8
Brute Force: r5c5=2
Naked Single: r6c5=4
Naked Single: r6c6=9
Naked Single: r6c8=5
Naked Single: r4c4=6
Full House: r4c6=7
Naked Single: r4c9=4
Hidden Single: r5c3=6
Hidden Single: r8c9=5
Locked Candidates Type 1 (Pointing): 2 in b6 => r1379c7<>2
Locked Candidates Type 1 (Pointing): 3 in b9 => r7c6<>3
Skyscraper: 6 in r2c8,r9c7 (connected by r29c5) => r3c7,r78c8<>6
Naked Single: r3c7=9
Naked Single: r3c9=2
Naked Single: r4c7=2
Naked Single: r6c7=1
Full House: r6c1=2
Naked Single: r5c8=7
Naked Single: r1c8=4
Naked Single: r5c7=3
Full House: r5c9=9
Full House: r5c2=1
Naked Single: r8c8=1
Naked Single: r1c6=3
Naked Single: r2c8=6
Full House: r7c8=2
Naked Single: r3c2=4
Naked Single: r8c6=6
Naked Single: r2c5=8
Naked Single: r3c6=1
Full House: r7c6=4
Naked Single: r1c4=9
Naked Single: r1c5=5
Naked Single: r2c9=7
Full House: r1c7=8
Naked Single: r9c5=7
Naked Single: r3c3=5
Full House: r3c5=6
Full House: r2c4=4
Full House: r8c5=3
Naked Single: r7c3=1
Naked Single: r1c1=7
Full House: r1c3=2
Naked Single: r2c2=9
Full House: r2c1=1
Naked Single: r9c9=8
Full House: r7c9=3
Naked Single: r9c2=2
Full House: r8c2=7
Full House: r8c1=9
Naked Single: r9c7=6
Full House: r7c7=7
Naked Single: r4c3=9
Full House: r9c3=4
Full House: r7c1=6
Full House: r7c4=8
Full House: r9c4=1
Full House: r4c1=5
|
normal_sudoku_1592
|
..56.8..7...7.5.193....2..415.....8...8.71......8..6...........54.3.......6.5794.
|
915648327462735819387912564153496782628571493794823651879264135541389276236157948
|
Basic 9x9 Sudoku 1592
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 5 6 . 8 . . 7
. . . 7 . 5 . 1 9
3 . . . . 2 . . 4
1 5 . . . . . 8 .
. . 8 . 7 1 . . .
. . . 8 . . 6 . .
. . . . . . . . .
5 4 . 3 . . . . .
. . 6 . 5 7 9 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
915648327462735819387912564153496782628571493794823651879264135541389276236157948 #1 Easy (380)
Naked Single: r9c6=7
Hidden Single: r3c8=6
Hidden Single: r6c9=1
Hidden Single: r5c4=5
Hidden Single: r3c7=5
Hidden Single: r6c8=5
Hidden Single: r7c9=5
Hidden Single: r3c2=8
Hidden Single: r2c7=8
Hidden Single: r4c7=7
Hidden Single: r5c8=9
Hidden Single: r8c9=6
Naked Single: r8c6=9
Hidden Single: r3c3=7
Hidden Single: r2c5=3
Hidden Single: r5c7=4
Hidden Single: r8c5=8
Hidden Single: r9c9=8
Naked Single: r9c1=2
Naked Single: r5c1=6
Naked Single: r8c3=1
Naked Single: r9c4=1
Full House: r9c2=3
Naked Single: r2c1=4
Naked Single: r8c7=2
Full House: r8c8=7
Naked Single: r3c4=9
Full House: r3c5=1
Full House: r1c5=4
Naked Single: r5c2=2
Full House: r5c9=3
Full House: r4c9=2
Naked Single: r7c3=9
Naked Single: r1c1=9
Naked Single: r2c3=2
Full House: r2c2=6
Full House: r1c2=1
Naked Single: r1c7=3
Full House: r1c8=2
Full House: r7c8=3
Full House: r7c7=1
Naked Single: r4c4=4
Full House: r7c4=2
Naked Single: r7c2=7
Full House: r6c2=9
Full House: r7c1=8
Full House: r6c1=7
Naked Single: r4c3=3
Full House: r6c3=4
Naked Single: r6c6=3
Full House: r6c5=2
Naked Single: r7c5=6
Full House: r4c5=9
Full House: r4c6=6
Full House: r7c6=4
|
normal_sudoku_5057
|
9...8..1...83..4...5...7..8..28567...8.4....5....3.......2..6..1......9..7...3.84
|
927684513618325479453197268392856741786412935541739826839241657164578392275963184
|
Basic 9x9 Sudoku 5057
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . . . 8 . . 1 .
. . 8 3 . . 4 . .
. 5 . . . 7 . . 8
. . 2 8 5 6 7 . .
. 8 . 4 . . . . 5
. . . . 3 . . . .
. . . 2 . . 6 . .
1 . . . . . . 9 .
. 7 . . . 3 . 8 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
927684513618325479453197268392856741786412935541739826839241657164578392275963184 #1 Extreme (11212)
Hidden Single: r4c4=8
Hidden Single: r6c7=8
Hidden Single: r7c1=8
Hidden Single: r8c6=8
Naked Pair: 3,4 in r4c18 => r4c29<>3, r4c2<>4
Hidden Pair: 5,7 in r27c8 => r2c8<>2, r2c8<>6, r7c8<>3
Forcing Chain Contradiction in r3 => r3c1<>2
r3c1=2 r3c1<>3
r3c1=2 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c2=1 r2c2<>1 r3c3=1 r3c3<>3
r3c1=2 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r5c7<>9 r3c7=9 r3c7<>3
r3c1=2 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r5c7<>3 r45c8=3 r3c8<>3
Forcing Chain Contradiction in r3 => r6c1<>4
r6c1=4 r4c1<>4 r4c1=3 r3c1<>3
r6c1=4 r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c2=1 r2c2<>1 r3c3=1 r3c3<>3
r6c1=4 r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r5c7<>9 r3c7=9 r3c7<>3
r6c1=4 r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r5c7<>3 r45c8=3 r3c8<>3
Forcing Chain Contradiction in c4 => r6c2<>1
r6c2=1 r2c2<>1 r3c3=1 r3c4<>1
r6c2=1 r6c4<>1
r6c2=1 r4c2<>1 r4c9=1 r7c9<>1 r9c7=1 r9c4<>1
Forcing Chain Contradiction in c4 => r6c9<>1
r6c9=1 r4c9<>1 r4c2=1 r2c2<>1 r3c3=1 r3c4<>1
r6c9=1 r6c4<>1
r6c9=1 r7c9<>1 r9c7=1 r9c4<>1
Forcing Chain Contradiction in r3 => r5c3<>9
r5c3=9 r5c3<>3 r45c1=3 r3c1<>3
r5c3=9 r4c2<>9 r4c2=1 r2c2<>1 r3c3=1 r3c3<>3
r5c3=9 r5c7<>9 r3c7=9 r3c7<>3
r5c3=9 r4c2<>9 r4c2=1 r4c9<>1 r5c7=1 r5c7<>3 r45c8=3 r3c8<>3
Forcing Chain Contradiction in c2 => r8c3<>3
r8c3=3 r78c2<>3 r1c2=3 r1c2<>2
r8c3=3 r7c23<>3 r7c9=3 r7c9<>1 r4c9=1 r4c2<>1 r2c2=1 r2c2<>2
r8c3=3 r7c23<>3 r7c9=3 r7c9<>1 r9c7=1 r9c7<>2 r9c1=2 r8c2<>2
Forcing Chain Contradiction in c4 => r9c4<>1
r9c4=1 r9c7<>1 r5c7=1 r5c7<>9 r3c7=9 r3c4<>9
r9c4=1 r9c7<>1 r5c7=1 r5c7<>9 r5c56=9 r6c4<>9
r9c4=1 r9c4<>9
Simple Colors Trap: 1 (r2c2,r4c9,r9c7) / (r3c3,r4c2,r5c7,r7c9,r9c5) => r2c5<>1
Forcing Chain Contradiction in c2 => r1c6<>2
r1c6=2 r1c2<>2
r1c6=2 r23c5<>2 r5c5=2 r5c5<>7 r6c4=7 r6c4<>1 r3c4=1 r3c3<>1 r2c2=1 r2c2<>2
r1c6=2 r23c5<>2 r5c5=2 r5c5<>7 r6c4=7 r6c4<>1 r3c4=1 r3c3<>1 r2c2=1 r4c2<>1 r4c9=1 r7c9<>1 r9c7=1 r9c7<>2 r9c1=2 r8c2<>2
Grouped Discontinuous Nice Loop: 4 r1c2 -4- r1c6 =4= r3c5 =2= r2c56 -2- r2c12 =2= r1c2 => r1c2<>4
Forcing Chain Contradiction in r6 => r6c1<>6
r6c1=6 r6c1<>7
r6c1=6 r6c1<>5 r6c3=5 r6c3<>7
r6c1=6 r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c2=1 r2c2<>1 r2c6=1 r3c4<>1 r6c4=1 r6c4<>7
Forcing Chain Contradiction in r6 => r6c3<>9
r6c3=9 r6c3<>5 r6c1=5 r6c1<>7
r6c3=9 r6c3<>7
r6c3=9 r4c2<>9 r4c2=1 r2c2<>1 r2c6=1 r3c4<>1 r6c4=1 r6c4<>7
Locked Candidates Type 1 (Pointing): 9 in b4 => r7c2<>9
Forcing Chain Contradiction in c3 => r6c1=5
r6c1<>5 r6c1=7 r2c1<>7 r1c3=7 r1c3<>4
r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c2=1 r2c2<>1 r3c3=1 r3c3<>4
r6c1<>5 r6c3=5 r6c3<>4
r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c9=9 r4c2<>9 r6c2=9 r6c2<>4 r78c2=4 r7c3<>4
r6c1<>5 r9c1=5 r9c1<>2 r9c7=2 r9c7<>1 r5c7=1 r4c9<>1 r4c9=9 r4c2<>9 r6c2=9 r6c2<>4 r78c2=4 r8c3<>4
Discontinuous Nice Loop: 2 r2c1 -2- r9c1 =2= r9c7 =1= r5c7 -1- r4c9 =1= r4c2 -1- r2c2 =1= r2c6 -1- r3c4 =1= r6c4 =7= r6c3 -7- r1c3 =7= r2c1 => r2c1<>2
Hidden Single: r9c1=2
Discontinuous Nice Loop: 2 r1c9 -2- r1c2 =2= r2c2 =1= r2c6 -1- r3c4 =1= r6c4 =7= r6c3 -7- r1c3 =7= r1c9 => r1c9<>2
Forcing Chain Contradiction in r8c7 => r1c2=2
r1c2<>2 r1c7=2 r8c7<>2
r1c2<>2 r2c2=2 r2c2<>1 r2c6=1 r3c4<>1 r6c4=1 r6c4<>7 r6c3=7 r1c3<>7 r1c9=7 r1c9<>3 r78c9=3 r8c7<>3
r1c2<>2 r2c2=2 r2c2<>1 r4c2=1 r4c9<>1 r7c9=1 r9c7<>1 r9c7=5 r8c7<>5
Locked Candidates Type 2 (Claiming): 3 in c2 => r7c3<>3
Discontinuous Nice Loop: 3 r1c3 -3- r1c7 -5- r2c8 -7- r2c1 =7= r1c3 => r1c3<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r3c78<>3
Locked Candidates Type 2 (Claiming): 3 in c8 => r5c7<>3
Discontinuous Nice Loop: 7 r8c9 -7- r7c8 -5- r2c8 =5= r1c7 =3= r8c7 =2= r8c9 => r8c9<>7
Locked Candidates Type 1 (Pointing): 7 in b9 => r7c5<>7
Almost Locked Set XZ-Rule: A=r2c1 {67}, B=r1789c3 {45679}, X=7, Z=6 => r3c3<>6
Forcing Chain Contradiction in r1c3 => r7c2=3
r7c2<>3 r7c2=4 r7c6<>4 r1c6=4 r1c3<>4
r7c2<>3 r8c2=3 r8c2<>6 r89c3=6 r1c3<>6
r7c2<>3 r7c2=4 r7c56<>4 r8c5=4 r8c5<>7 r8c4=7 r6c4<>7 r6c3=7 r1c3<>7
Naked Triple: 1,5,7 in r7c89,r9c7 => r8c7<>5
XY-Chain: 6 6- r2c1 -7- r2c8 -5- r7c8 -7- r7c9 -1- r4c9 -9- r4c2 -1- r2c2 -6 => r1c3,r2c59,r3c1<>6
Naked Pair: 3,4 in r34c1 => r5c1<>3
XY-Chain: 7 7- r2c1 -6- r2c2 -1- r4c2 -9- r4c9 -1- r7c9 -7 => r2c9<>7
Naked Pair: 2,9 in r2c9,r3c7 => r3c8<>2
Naked Single: r3c8=6
Hidden Single: r1c4=6
Hidden Single: r6c9=6
Locked Candidates Type 1 (Pointing): 5 in b2 => r7c6<>5
Locked Candidates Type 2 (Claiming): 2 in c8 => r5c7<>2
Naked Pair: 2,9 in r2c59 => r2c6<>2, r2c6<>9
Locked Candidates Type 1 (Pointing): 2 in b2 => r5c5<>2
2-String Kite: 9 in r2c5,r5c7 (connected by r2c9,r3c7) => r5c5<>9
Sue de Coq: r6c46 - {1279} (r6c28 - {249}, r5c5 - {17}) => r5c6<>1, r6c3<>4
Sue de Coq: r13c3 - {1347} (r6c3 - {17}, r3c1 - {34}) => r5c3<>1, r5c3<>7
X-Wing: 1 r59 c57 => r37c5<>1
Naked Triple: 2,4,9 in r237c5 => r8c5<>4, r9c5<>9
Locked Candidates Type 1 (Pointing): 4 in b8 => r7c3<>4
X-Wing: 1 c34 r36 => r6c6<>1
Locked Pair: 2,9 in r56c6 => r6c4,r7c6<>9
W-Wing: 9/1 in r3c4,r5c7 connected by 1 in r5c5,r6c4 => r3c7<>9
Naked Single: r3c7=2
Naked Single: r2c9=9
Naked Single: r8c7=3
Naked Single: r2c5=2
Naked Single: r4c9=1
Naked Single: r1c7=5
Naked Single: r8c9=2
Naked Single: r4c2=9
Naked Single: r5c7=9
Full House: r9c7=1
Naked Single: r7c9=7
Full House: r1c9=3
Full House: r2c8=7
Full House: r7c8=5
Naked Single: r1c6=4
Full House: r1c3=7
Naked Single: r6c2=4
Naked Single: r5c6=2
Naked Single: r9c5=6
Naked Single: r2c1=6
Naked Single: r7c3=9
Naked Single: r3c5=9
Naked Single: r7c6=1
Full House: r7c5=4
Naked Single: r6c3=1
Naked Single: r4c1=3
Full House: r4c8=4
Naked Single: r6c8=2
Full House: r5c8=3
Naked Single: r8c2=6
Full House: r2c2=1
Full House: r2c6=5
Full House: r6c6=9
Full House: r3c4=1
Full House: r6c4=7
Full House: r5c5=1
Full House: r8c5=7
Naked Single: r5c1=7
Full House: r3c1=4
Full House: r5c3=6
Full House: r3c3=3
Naked Single: r9c3=5
Full House: r8c3=4
Full House: r8c4=5
Full House: r9c4=9
|
normal_sudoku_931
|
4...3.....6..5....725......9..1....581....3.2.56...4...9.3815.....4...3....52...1
|
489632157163759824725814693942163785817945362356278419294381576571496238638527941
|
Basic 9x9 Sudoku 931
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . . 3 . . . .
. 6 . . 5 . . . .
7 2 5 . . . . . .
9 . . 1 . . . . 5
8 1 . . . . 3 . 2
. 5 6 . . . 4 . .
. 9 . 3 8 1 5 . .
. . . 4 . . . 3 .
. . . 5 2 . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
489632157163759824725814693942163785817945362356278419294381576571496238638527941 #1 Unfair (1740)
Naked Single: r5c1=8
Naked Single: r1c2=8
Naked Single: r8c2=7
Hidden Single: r3c5=1
Hidden Single: r1c8=5
Hidden Single: r3c9=3
Hidden Single: r5c6=5
Hidden Single: r8c1=5
Hidden Single: r6c8=1
Hidden Single: r9c6=7
Hidden Single: r8c3=1
Naked Single: r1c3=9
Naked Single: r2c3=3
Full House: r2c1=1
Hidden Single: r1c7=1
Hidden Single: r8c7=2
Hidden Single: r9c3=8
Hidden Single: r2c8=2
Hidden Single: r8c9=8
Locked Candidates Type 1 (Pointing): 4 in b2 => r4c6<>4
Locked Candidates Type 1 (Pointing): 7 in b2 => r56c4<>7
Locked Candidates Type 1 (Pointing): 8 in b6 => r4c6<>8
Naked Pair: 7,9 in r6c59 => r6c46<>9
Hidden Triple: 2,3,8 in r46c6,r6c4 => r4c6<>6
XY-Chain: 7 7- r5c3 -4- r4c2 -3- r4c6 -2- r1c6 -6- r1c9 -7- r6c9 -9- r6c5 -7 => r5c5<>7
Discontinuous Nice Loop: 6/8/9 r3c6 =4= r3c8 -4- r9c8 =4= r9c2 =3= r4c2 -3- r4c6 -2- r1c6 -6- r1c9 =6= r7c9 =4= r2c9 -4- r2c6 =4= r3c6 => r3c6<>6, r3c6<>8, r3c6<>9
Naked Single: r3c6=4
Hidden Single: r2c9=4
Hidden Single: r6c9=9
Naked Single: r6c5=7
W-Wing: 6/7 in r1c9,r5c8 connected by 7 in r7c89 => r3c8<>6
XYZ-Wing: 6/8/9 in r2c6,r35c4 => r2c4<>9
XYZ-Wing: 6/8/9 in r3c78,r9c7 => r2c7<>9
Hidden Single: r2c6=9
Naked Single: r8c6=6
Full House: r8c5=9
Naked Single: r1c6=2
Naked Single: r4c6=3
Full House: r6c6=8
Naked Single: r4c2=4
Full House: r9c2=3
Naked Single: r6c4=2
Full House: r6c1=3
Naked Single: r4c5=6
Full House: r5c5=4
Full House: r5c4=9
Naked Single: r5c3=7
Full House: r4c3=2
Full House: r5c8=6
Full House: r7c3=4
Naked Single: r9c1=6
Full House: r7c1=2
Naked Single: r7c8=7
Full House: r7c9=6
Full House: r1c9=7
Full House: r1c4=6
Naked Single: r9c7=9
Full House: r9c8=4
Naked Single: r4c8=8
Full House: r3c8=9
Full House: r4c7=7
Naked Single: r2c7=8
Full House: r2c4=7
Full House: r3c4=8
Full House: r3c7=6
|
normal_sudoku_611
|
6.235...4..5.1..6..43..7..5.....1..6.6....95...7...1...7..26.8....58....4.6......
|
612358794795412368843697215254971836168243957937865142579126483321584679486739521
|
Basic 9x9 Sudoku 611
|
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 . 2 3 5 . . . 4
. . 5 . 1 . . 6 .
. 4 3 . . 7 . . 5
. . . . . 1 . . 6
. 6 . . . . 9 5 .
. . 7 . . . 1 . .
. 7 . . 2 6 . 8 .
. . . 5 8 . . . .
4 . 6 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
612358794795412368843697215254971836168243957937865142579126483321584679486739521 #1 Unfair (1590)
Hidden Single: r1c1=6
Hidden Single: r6c6=5
Hidden Single: r8c7=6
Hidden Single: r9c2=8
Naked Single: r2c2=9
Naked Single: r1c2=1
Naked Single: r3c1=8
Full House: r2c1=7
Naked Single: r3c7=2
Hidden Single: r9c7=5
Hidden Single: r4c2=5
Hidden Single: r7c1=5
Hidden Single: r3c8=1
Hidden Single: r1c8=9
Naked Single: r1c6=8
Full House: r1c7=7
Locked Pair: 1,9 in r78c3 => r4c3,r8c1<>9, r5c3,r8c1<>1
Hidden Single: r5c1=1
Locked Candidates Type 1 (Pointing): 2 in b7 => r8c89<>2
Locked Candidates Type 1 (Pointing): 3 in b7 => r8c689<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r9c89<>3
Locked Candidates Type 1 (Pointing): 7 in b8 => r9c89<>7
Naked Single: r9c8=2
Locked Candidates Type 2 (Claiming): 4 in c5 => r456c4,r5c6<>4
Locked Candidates Type 2 (Claiming): 9 in c6 => r79c4,r9c5<>9
Locked Candidates Type 2 (Claiming): 3 in c8 => r4c7,r56c9<>3
Locked Candidates Type 2 (Claiming): 3 in r5 => r46c5<>3
Naked Pair: 4,8 in r4c37 => r4c4<>8, r4c58<>4
W-Wing: 9/1 in r7c3,r9c9 connected by 1 in r8c39 => r7c9<>9
Hidden Single: r7c3=9
Naked Single: r8c3=1
Uniqueness Test 1: 2/3 in r6c12,r8c12 => r6c1<>2, r6c1<>3
Naked Single: r6c1=9
Sue de Coq: r5c45 - {23478} (r5c3 - {48}, r4c45,r5c6 - {2379}) => r6c4<>2, r5c9<>8
XY-Chain: 7 7- r4c5 -9- r3c5 -6- r6c5 -4- r6c8 -3- r4c8 -7- r8c8 -4- r8c6 -9- r9c6 -3- r5c6 -2- r5c9 -7 => r4c8,r5c45<>7
Naked Single: r4c8=3
Naked Single: r4c1=2
Full House: r8c1=3
Full House: r8c2=2
Full House: r6c2=3
Naked Single: r6c8=4
Full House: r8c8=7
Naked Single: r4c7=8
Naked Single: r6c5=6
Naked Single: r8c9=9
Full House: r8c6=4
Naked Single: r2c7=3
Full House: r2c9=8
Full House: r7c7=4
Naked Single: r4c3=4
Full House: r5c3=8
Naked Single: r6c9=2
Full House: r6c4=8
Full House: r5c9=7
Naked Single: r3c5=9
Full House: r3c4=6
Naked Single: r9c9=1
Full House: r7c9=3
Full House: r7c4=1
Naked Single: r2c6=2
Full House: r2c4=4
Naked Single: r5c4=2
Naked Single: r4c5=7
Full House: r4c4=9
Full House: r9c4=7
Naked Single: r5c6=3
Full House: r5c5=4
Full House: r9c5=3
Full House: r9c6=9
|
normal_sudoku_1868
|
.4..7.1....52...7.1..9....851..8.....3...528.6.....5.....8.643...4.2..17......8.5
|
942378156385261974176954328519482763437615289628739541751896432894523617263147895
|
Basic 9x9 Sudoku 1868
|
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 . . 7 . 1 . .
. . 5 2 . . . 7 .
1 . . 9 . . . . 8
5 1 . . 8 . . . .
. 3 . . . 5 2 8 .
6 . . . . . 5 . .
. . . 8 . 6 4 3 .
. . 4 . 2 . . 1 7
. . . . . . 8 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
942378156385261974176954328519482763437615289628739541751896432894523617263147895 #1 Extreme (4302)
Hidden Single: r4c1=5
Hidden Single: r4c7=7
Hidden Single: r5c1=4
Locked Candidates Type 1 (Pointing): 3 in b6 => r12c9<>3
Locked Candidates Type 1 (Pointing): 7 in b8 => r9c123<>7
Hidden Single: r7c1=7
Skyscraper: 2 in r7c9,r9c1 (connected by r1c19) => r7c23,r9c8<>2
Hidden Single: r7c9=2
Naked Triple: 3,6,9 in r1c9,r23c7 => r13c8,r2c9<>6, r1c8,r2c9<>9
Naked Single: r2c9=4
XY-Wing: 6/9/3 in r38c7,r8c6 => r3c6<>3
Naked Single: r3c6=4
Discontinuous Nice Loop: 3 r3c5 -3- r3c7 -6- r8c7 =6= r8c2 =5= r8c4 -5- r1c4 =5= r3c5 => r3c5<>3
Discontinuous Nice Loop: 3 r9c5 -3- r8c6 -9- r8c7 =9= r9c8 -9- r6c8 -4- r6c5 =4= r9c5 => r9c5<>3
Almost Locked Set XY-Wing: A=r4c36 {239}, B=r9c8 {69}, C=r8c67 {369}, X,Y=3,6, Z=9 => r4c8<>9
Empty Rectangle: 9 in b4 (r69c8) => r9c3<>9
Almost Locked Set XY-Wing: A=r6c45689 {123479}, B=r134579c3 {1236789}, C=r148c6 {2389}, X,Y=2,8, Z=7,9 => r6c3<>7, r6c3<>9
Almost Locked Set XY-Wing: A=r9c1238 {12369}, B=r1248c6 {12389}, C=r457c3 {1279}, X,Y=1,2, Z=3,9 => r9c6<>3, r9c6<>9
Forcing Chain Contradiction in r5 => r3c7=3
r3c7<>3 r3c3=3 r3c3<>7 r5c3=7 r5c3<>9
r3c7<>3 r3c7=6 r8c7<>6 r8c7=9 r8c6<>9 r79c5=9 r5c5<>9
r3c7<>3 r3c7=6 r1c9<>6 r1c9=9 r5c9<>9
Grouped Discontinuous Nice Loop: 6 r1c3 -6- r1c9 =6= r2c7 -6- r8c7 =6= r8c2 =5= r8c4 -5- r1c4 =5= r3c5 =6= r3c23 -6- r1c3 => r1c3<>6
Empty Rectangle: 6 in b5 (r1c49) => r5c9<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c4<>6
AIC: 7 7- r3c2 =7= r3c3 =6= r9c3 -6- r9c8 =6= r4c8 -6- r4c9 =6= r1c9 -6- r1c4 =6= r5c4 =7= r5c3 -7 => r3c3,r6c2<>7
Hidden Single: r3c2=7
Hidden Single: r5c3=7
2-String Kite: 9 in r5c5,r9c8 (connected by r5c9,r6c8) => r9c5<>9
XY-Wing: 1/9/6 in r15c9,r5c4 => r1c4<>6
Hidden Single: r1c9=6
Naked Single: r2c7=9
Full House: r8c7=6
Full House: r9c8=9
Naked Single: r6c8=4
Naked Single: r4c8=6
Hidden Single: r5c4=6
Hidden Single: r4c4=4
Hidden Single: r9c5=4
Naked Pair: 3,5 in r18c4 => r69c4<>3
Locked Pair: 1,7 in r9c46 => r7c5,r9c3<>1
Hidden Single: r7c3=1
Locked Candidates Type 1 (Pointing): 3 in b8 => r8c1<>3
W-Wing: 6/2 in r3c3,r9c2 connected by 2 in r19c1 => r2c2,r9c3<>6
Naked Single: r2c2=8
Naked Single: r2c1=3
Naked Single: r2c6=1
Full House: r2c5=6
Naked Single: r9c1=2
Naked Single: r9c6=7
Naked Single: r3c5=5
Naked Single: r1c1=9
Full House: r8c1=8
Naked Single: r9c2=6
Naked Single: r9c3=3
Full House: r9c4=1
Naked Single: r1c4=3
Full House: r1c6=8
Naked Single: r3c8=2
Full House: r1c8=5
Full House: r1c3=2
Full House: r3c3=6
Naked Single: r7c5=9
Full House: r7c2=5
Full House: r8c2=9
Full House: r6c2=2
Naked Single: r6c4=7
Full House: r8c4=5
Full House: r8c6=3
Naked Single: r4c3=9
Full House: r6c3=8
Naked Single: r5c5=1
Full House: r5c9=9
Full House: r6c5=3
Naked Single: r6c6=9
Full House: r4c6=2
Full House: r4c9=3
Full House: r6c9=1
|
normal_sudoku_5717
|
82.43.7...94.....3.....98.49......7..372...4.24...83.9...91....4..86............2
|
825436791694187523713529864981643275537291648246758319372915486459862137168374952
|
Basic 9x9 Sudoku 5717
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 2 . 4 3 . 7 . .
. 9 4 . . . . . 3
. . . . . 9 8 . 4
9 . . . . . . 7 .
. 3 7 2 . . . 4 .
2 4 . . . 8 3 . 9
. . . 9 1 . . . .
4 . . 8 6 . . . .
. . . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
825436791694187523713529864981643275537291648246758319372915486459862137168374952 #1 Extreme (12462) bf
Hidden Single: r3c9=4
Hidden Single: r5c9=8
Hidden Single: r1c8=9
Hidden Single: r5c5=9
Hidden Single: r2c5=8
Hidden Single: r4c7=2
Hidden Single: r3c5=2
Hidden Single: r2c8=2
Brute Force: r6c5=5
Naked Single: r4c5=4
Full House: r9c5=7
Hidden Single: r6c4=7
Hidden Single: r2c6=7
Avoidable Rectangle Type 1: 7/5 in r6c45,r9c45 => r9c4<>5
Naked Single: r9c4=3
Hidden Single: r4c6=3
Locked Candidates Type 1 (Pointing): 5 in b8 => r1c6<>5
Naked Triple: 1,5,6 in r259c1 => r3c1<>1, r37c1<>5, r37c1<>6
Hidden Rectangle: 2/5 in r7c36,r8c36 => r7c3<>5
Hidden Rectangle: 4/5 in r7c67,r9c67 => r7c7<>5
Finned Franken Swordfish: 1 r16b5 c369 fr4c4 fr6c8 => r4c9<>1
W-Wing: 6/1 in r5c6,r6c3 connected by 1 in r5c7,r6c8 => r5c1<>6
Sashimi Swordfish: 6 r156 c369 fr5c7 fr6c8 => r4c9<>6
Naked Single: r4c9=5
Hidden Single: r1c3=5
Hidden Single: r5c1=5
Remote Pair: 1/6 r1c9 -6- r1c6 -1- r5c6 -6- r5c7 => r2c7<>1, r2c7<>6
Naked Single: r2c7=5
Hidden Single: r3c4=5
Naked Pair: 1,6 in r36c8 => r79c8<>6, r89c8<>1
Remote Pair: 1/6 r6c3 -6- r6c8 -1- r5c7 -6- r5c6 -1- r1c6 -6- r2c4 -1- r2c1 -6- r9c1 => r89c3,r9c7<>1, r79c3,r9c7<>6
Locked Candidates Type 1 (Pointing): 1 in b9 => r8c2<>1
Locked Candidates Type 1 (Pointing): 6 in b9 => r7c2<>6
Hidden Pair: 1,6 in r9c12 => r9c2<>5, r9c2<>8
XY-Wing: 5/7/3 in r7c1,r8c28 => r7c8,r8c3<>3
Hidden Single: r8c8=3
XY-Chain: 9 9- r8c3 -2- r8c6 -5- r9c6 -4- r9c7 -9 => r8c7,r9c3<>9
Naked Single: r8c7=1
Naked Single: r9c3=8
Naked Single: r5c7=6
Full House: r5c6=1
Full House: r6c8=1
Full House: r4c4=6
Full House: r6c3=6
Full House: r2c4=1
Full House: r1c6=6
Full House: r2c1=6
Full House: r1c9=1
Full House: r3c8=6
Naked Single: r8c9=7
Full House: r7c9=6
Naked Single: r9c8=5
Full House: r7c8=8
Naked Single: r7c7=4
Full House: r9c7=9
Naked Single: r4c3=1
Full House: r4c2=8
Naked Single: r9c1=1
Naked Single: r8c2=5
Naked Single: r9c6=4
Full House: r9c2=6
Naked Single: r3c3=3
Naked Single: r7c2=7
Full House: r3c2=1
Full House: r3c1=7
Full House: r7c1=3
Naked Single: r8c6=2
Full House: r7c6=5
Full House: r7c3=2
Full House: r8c3=9
|
normal_sudoku_1009
|
..49.25.1..3....8..6...34....7..42...4.2..1..2...5......8.1...9..68..35.3....67..
|
784962531523741986169583472897134265645278193231659847478315629916827354352496718
|
Basic 9x9 Sudoku 1009
|
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 . 2 5 . 1
. . 3 . . . . 8 .
. 6 . . . 3 4 . .
. . 7 . . 4 2 . .
. 4 . 2 . . 1 . .
2 . . . 5 . . . .
. . 8 . 1 . . . 9
. . 6 8 . . 3 5 .
3 . . . . 6 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
784962531523741986169583472897134265645278193231659847478315629916827354352496718 #1 Easy (366)
Naked Single: r8c7=3
Naked Single: r7c7=6
Naked Single: r2c7=9
Full House: r6c7=8
Hidden Single: r1c8=3
Hidden Single: r9c8=1
Hidden Single: r9c9=8
Hidden Single: r7c4=3
Hidden Single: r5c6=8
Hidden Single: r1c5=6
Hidden Single: r2c9=6
Hidden Single: r3c5=8
Hidden Single: r2c2=2
Hidden Single: r9c3=2
Hidden Single: r7c8=2
Full House: r8c9=4
Naked Single: r3c8=7
Full House: r3c9=2
Hidden Single: r8c5=2
Hidden Single: r7c1=4
Hidden Single: r6c8=4
Hidden Single: r6c4=6
Naked Single: r4c4=1
Naked Single: r3c4=5
Naked Single: r9c4=4
Full House: r2c4=7
Naked Single: r9c5=9
Full House: r9c2=5
Naked Single: r2c5=4
Full House: r2c6=1
Full House: r2c1=5
Naked Single: r4c5=3
Full House: r5c5=7
Full House: r6c6=9
Naked Single: r8c6=7
Full House: r7c6=5
Full House: r7c2=7
Naked Single: r4c9=5
Naked Single: r6c3=1
Naked Single: r1c2=8
Full House: r1c1=7
Naked Single: r5c9=3
Full House: r6c9=7
Full House: r6c2=3
Naked Single: r3c3=9
Full House: r3c1=1
Full House: r5c3=5
Naked Single: r4c2=9
Full House: r8c2=1
Full House: r8c1=9
Naked Single: r4c8=6
Full House: r4c1=8
Full House: r5c1=6
Full House: r5c8=9
|
normal_sudoku_2010
|
..49...7.5...3....6...1.9...5..482.6.6.....1..921...87..54..7...4..8..2..3..7..54
|
314962578529837641678514932153748296867293415492156387985421763746385129231679854
|
Basic 9x9 Sudoku 2010
|
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 . . . 7 .
5 . . . 3 . . . .
6 . . . 1 . 9 . .
. 5 . . 4 8 2 . 6
. 6 . . . . . 1 .
. 9 2 1 . . . 8 7
. . 5 4 . . 7 . .
. 4 . . 8 . . 2 .
. 3 . . 7 . . 5 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
314962578529837641678514932153748296867293415492156387985421763746385129231679854 #1 Hard (1028)
Naked Single: r6c2=9
Hidden Single: r2c3=9
Hidden Single: r4c8=9
Locked Candidates Type 1 (Pointing): 4 in b6 => r2c7<>4
Locked Candidates Type 2 (Claiming): 7 in c2 => r3c3<>7
Hidden Rectangle: 3/4 in r5c17,r6c17 => r5c7<>3
Sashimi X-Wing: 6 c48 r27 fr8c4 fr9c4 => r7c56<>6
Hidden Single: r7c8=6
Naked Single: r2c8=4
Full House: r3c8=3
Naked Single: r3c3=8
Hidden Single: r3c6=4
Hidden Single: r1c1=3
Naked Single: r6c1=4
Hidden Single: r7c2=8
Hidden Single: r2c4=8
Hidden Single: r5c1=8
Hidden Single: r5c7=4
Hidden Single: r9c7=8
Hidden Single: r1c9=8
Locked Candidates Type 2 (Claiming): 6 in c4 => r89c6<>6
Skyscraper: 3 in r6c7,r7c9 (connected by r67c6) => r5c9,r8c7<>3
Naked Single: r5c9=5
Full House: r6c7=3
Naked Single: r8c7=1
Naked Single: r3c9=2
Naked Single: r2c7=6
Full House: r1c7=5
Full House: r2c9=1
Naked Single: r3c2=7
Full House: r3c4=5
Naked Single: r2c2=2
Full House: r1c2=1
Full House: r2c6=7
Hidden Single: r6c5=5
Full House: r6c6=6
Naked Single: r1c6=2
Full House: r1c5=6
Hidden Single: r8c6=5
W-Wing: 3/9 in r5c6,r7c9 connected by 9 in r57c5 => r7c6<>3
Hidden Single: r7c9=3
Full House: r8c9=9
Naked Single: r8c1=7
Naked Single: r4c1=1
Naked Single: r8c3=6
Full House: r8c4=3
Naked Single: r9c3=1
Naked Single: r4c4=7
Full House: r4c3=3
Full House: r5c3=7
Naked Single: r9c6=9
Naked Single: r5c4=2
Full House: r9c4=6
Full House: r9c1=2
Full House: r7c1=9
Naked Single: r5c6=3
Full House: r7c6=1
Full House: r7c5=2
Full House: r5c5=9
|
normal_sudoku_1440
|
.5..9.7....7....8.2..6..4.......3..46..12.....9.5........4...13..1..854.5...1...8
|
354891726167245389289637451815973264673124895492586137728459613931768542546312978
|
Basic 9x9 Sudoku 1440
|
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 . 7 . .
. . 7 . . . . 8 .
2 . . 6 . . 4 . .
. . . . . 3 . . 4
6 . . 1 2 . . . .
. 9 . 5 . . . . .
. . . 4 . . . 1 3
. . 1 . . 8 5 4 .
5 . . . 1 . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
354891726167245389289637451815973264673124895492586137728459613931768542546312978 #1 Extreme (24822) bf
Finned X-Wing: 4 c15 r26 fr1c1 => r2c2<>4
Brute Force: r5c4=1
Brute Force: r5c6=4
Hidden Single: r2c5=4
Hidden Single: r9c2=4
Hidden Single: r4c4=9
Hidden Single: r1c4=8
Locked Candidates Type 2 (Claiming): 7 in c4 => r7c56,r8c5,r9c6<>7
Locked Candidates Type 2 (Claiming): 7 in r7 => r8c12<>7
2-String Kite: 3 in r3c5,r9c3 (connected by r8c5,r9c4) => r3c3<>3
Turbot Fish: 9 r3c3 =9= r2c1 -9- r8c1 =9= r8c9 => r3c9<>9
Discontinuous Nice Loop: 3 r3c2 -3- r3c5 =3= r8c5 -3- r8c1 -9- r2c1 =9= r3c3 =8= r3c2 => r3c2<>3
Almost Locked Set XZ-Rule: A=r2c12,r3c23 {13689}, B=r1c6,r2c4 {123}, X=3, Z=1 => r1c1<>1
Hidden Rectangle: 3/4 in r1c13,r6c13 => r6c3<>3
Discontinuous Nice Loop: 1 r2c6 -1- r1c6 =1= r1c9 -1- r3c9 -5- r2c9 =5= r2c6 => r2c6<>1
Almost Locked Set XY-Wing: A=r2c12,r3c23 {13689}, B=r8c45,r9c4 {2367}, C=r2c4 {23}, X,Y=2,3, Z=6 => r8c2<>6
Empty Rectangle: 6 in b5 (r8c59) => r6c9<>6
W-Wing: 2/3 in r2c4,r8c2 connected by 3 in r9c34 => r8c4<>2
Grouped AIC: 5 5- r2c6 -2- r2c4 -3- r9c4 =3= r9c3 =6= r7c23 -6- r7c5 -5 => r3c5,r7c6<>5
Hidden Single: r7c5=5
Grouped Discontinuous Nice Loop: 6 r7c6 -6- r8c5 -3- r9c4 =3= r9c3 =6= r7c23 -6- r7c6 => r7c6<>6
Uniqueness Test 5: 2/9 in r7c67,r9c67 => r9c8<>6
Forcing Chain Contradiction in r7c7 => r2c7<>2
r2c7=2 r7c7<>2
r2c7=2 r2c4<>2 r2c4=3 r9c4<>3 r9c3=3 r9c3<>6 r7c23=6 r7c7<>6
r2c7=2 r2c4<>2 r9c4=2 r7c6<>2 r7c6=9 r7c7<>9
Forcing Chain Contradiction in r6c9 => r1c6=1
r1c6<>1 r1c9=1 r6c9<>1
r1c6<>1 r1c6=2 r1c8<>2 r12c9=2 r6c9<>2
r1c6<>1 r3c6=1 r3c6<>7 r6c6=7 r6c9<>7
Locked Candidates Type 1 (Pointing): 2 in b2 => r2c9<>2
Forcing Chain Contradiction in r6c9 => r2c4=2
r2c4<>2 r2c6=2 r2c6<>5 r2c9=5 r3c9<>5 r3c9=1 r6c9<>1
r2c4<>2 r2c4=3 r3c5<>3 r8c5=3 r8c5<>6 r8c9=6 r1c9<>6 r1c9=2 r6c9<>2
r2c4<>2 r2c4=3 r3c5<>3 r3c5=7 r3c6<>7 r6c6=7 r6c9<>7
Naked Single: r2c6=5
Naked Single: r3c6=7
Full House: r3c5=3
Naked Single: r6c6=6
Naked Single: r8c5=6
Locked Candidates Type 1 (Pointing): 6 in b9 => r24c7<>6
Hidden Single: r4c8=6
Hidden Single: r4c3=5
Skyscraper: 2 in r4c7,r8c9 (connected by r48c2) => r6c9,r79c7<>2
Locked Pair: 6,9 in r79c7 => r25c7,r8c9,r9c8<>9
Hidden Single: r8c1=9
Hidden Single: r2c9=9
Naked Single: r3c8=5
Naked Single: r3c9=1
Naked Single: r2c7=3
Naked Single: r3c2=8
Full House: r3c3=9
Naked Single: r6c9=7
Naked Single: r1c8=2
Full House: r1c9=6
Naked Single: r2c1=1
Full House: r2c2=6
Naked Single: r5c7=8
Naked Single: r5c9=5
Full House: r8c9=2
Naked Single: r6c5=8
Full House: r4c5=7
Naked Single: r6c8=3
Naked Single: r9c8=7
Full House: r5c8=9
Naked Single: r5c3=3
Full House: r5c2=7
Naked Single: r8c2=3
Full House: r8c4=7
Full House: r9c4=3
Naked Single: r4c1=8
Naked Single: r6c1=4
Naked Single: r1c3=4
Full House: r1c1=3
Full House: r7c1=7
Naked Single: r7c2=2
Full House: r4c2=1
Full House: r6c3=2
Full House: r4c7=2
Full House: r6c7=1
Naked Single: r7c6=9
Full House: r9c6=2
Naked Single: r9c3=6
Full House: r7c3=8
Full House: r7c7=6
Full House: r9c7=9
|
normal_sudoku_6488
|
96.....275....6....3..4....14.6....93..1.9..5..9.3.....9.4.1.......659..6..3...5.
|
964583127587216394231947568148652739326179845759834216895421673413765982672398451
|
Basic 9x9 Sudoku 6488
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 6 . . . . . 2 7
5 . . . . 6 . . .
. 3 . . 4 . . . .
1 4 . 6 . . . . 9
3 . . 1 . 9 . . 5
. . 9 . 3 . . . .
. 9 . 4 . 1 . . .
. . . . 6 5 9 . .
6 . . 3 . . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
964583127587216394231947568148652739326179845759834216895421673413765982672398451 #1 Extreme (13852) bf
Hidden Single: r6c3=9
Hidden Single: r6c6=4
Hidden Single: r8c1=4
Hidden Single: r1c6=3
Hidden Single: r9c5=9
Hidden Single: r7c3=5
Hidden Single: r6c2=5
Hidden Single: r5c3=6
Hidden Single: r4c5=5
Hidden Single: r8c3=3
Hidden Rectangle: 5/8 in r1c47,r3c47 => r3c7<>8
Brute Force: r5c2=2
Skyscraper: 2 in r2c5,r3c1 (connected by r7c15) => r2c3,r3c46<>2
Forcing Chain Contradiction in r3c1 => r4c6<>7
r4c6=7 r4c6<>2 r9c6=2 r9c3<>2 r3c3=2 r3c1<>2
r4c6=7 r4c3<>7 r6c1=7 r3c1<>7
r4c6=7 r3c6<>7 r3c6=8 r3c1<>8
Grouped Discontinuous Nice Loop: 8 r6c7 -8- r6c1 -7- r6c4 =7= r5c5 =8= r5c78 -8- r6c7 => r6c7<>8
Grouped Discontinuous Nice Loop: 8 r6c8 -8- r6c1 -7- r6c4 =7= r5c5 =8= r5c78 -8- r6c8 => r6c8<>8
Grouped Discontinuous Nice Loop: 8 r6c9 -8- r6c1 -7- r6c4 =7= r5c5 =8= r5c78 -8- r6c9 => r6c9<>8
Finned Franken Swordfish: 7 c16b5 r367 fr5c5 fr9c6 => r7c5<>7
Discontinuous Nice Loop: 7 r5c8 -7- r5c5 =7= r2c5 =2= r2c4 =9= r2c8 =4= r5c8 => r5c8<>7
Forcing Chain Contradiction in r3c1 => r4c6=2
r4c6<>2 r9c6=2 r9c3<>2 r3c3=2 r3c1<>2
r4c6<>2 r4c6=8 r3c6<>8 r3c6=7 r3c1<>7
r4c6<>2 r4c6=8 r4c3<>8 r6c1=8 r3c1<>8
Naked Pair: 7,8 in r6c14 => r6c78<>7
W-Wing: 8/7 in r3c6,r6c4 connected by 7 in r25c5 => r123c4<>8
Naked Single: r1c4=5
Hidden Single: r3c7=5
Sashimi Swordfish: 8 c146 r367 fr8c4 fr9c6 => r7c5<>8
Naked Single: r7c5=2
Hidden Single: r2c4=2
Hidden Single: r3c1=2
Hidden Single: r9c3=2
Hidden Single: r8c9=2
Hidden Single: r2c8=9
Hidden Single: r3c4=9
Hidden Single: r6c7=2
Hidden Single: r5c8=4
Hidden Single: r7c7=6
Locked Candidates Type 1 (Pointing): 1 in b7 => r2c2<>1
Remote Pair: 7/8 r3c6 -8- r9c6 -7- r8c4 -8- r6c4 -7- r6c1 -8- r4c3 => r3c3<>7, r3c3<>8
Naked Single: r3c3=1
Hidden Single: r3c6=7
Full House: r9c6=8
Full House: r8c4=7
Full House: r6c4=8
Full House: r5c5=7
Full House: r5c7=8
Naked Single: r6c1=7
Full House: r4c3=8
Full House: r7c1=8
Naked Single: r1c3=4
Full House: r2c3=7
Full House: r2c2=8
Naked Single: r7c9=3
Full House: r7c8=7
Naked Single: r8c2=1
Full House: r8c8=8
Full House: r9c2=7
Naked Single: r1c7=1
Full House: r1c5=8
Full House: r2c5=1
Naked Single: r4c8=3
Full House: r4c7=7
Naked Single: r3c8=6
Full House: r3c9=8
Full House: r6c8=1
Full House: r6c9=6
Naked Single: r2c9=4
Full House: r2c7=3
Full House: r9c7=4
Full House: r9c9=1
|
normal_sudoku_945
|
..6.5..4......18....4936.5.7........9....4.....5.6..3....6.5.2.....2.3.4..2..3...
|
196258743253471896874936251768392415931584672425167938389645127517829364642713589
|
Basic 9x9 Sudoku 945
|
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 . 5 . . 4 .
. . . . . 1 8 . .
. . 4 9 3 6 . 5 .
7 . . . . . . . .
9 . . . . 4 . . .
. . 5 . 6 . . 3 .
. . . 6 . 5 . 2 .
. . . . 2 . 3 . 4
. . 2 . . 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
196258743253471896874936251768392415931584672425167938389645127517829364642713589 #1 Extreme (37456) bf
Hidden Single: r3c6=6
Locked Candidates Type 1 (Pointing): 8 in b2 => r1c12<>8
Locked Candidates Type 1 (Pointing): 6 in b4 => r89c2<>6
Locked Candidates Type 1 (Pointing): 5 in b9 => r9c12<>5
Hidden Pair: 3,5 in r45c4 => r45c4<>1, r45c4<>2, r45c4<>8, r5c4<>7
Grouped Discontinuous Nice Loop: 2 r4c7 -2- r5c79 =2= r5c2 =6= r4c2 =4= r4c7 => r4c7<>2
Brute Force: r5c5=8
Locked Candidates Type 1 (Pointing): 7 in b5 => r6c79<>7
Finned Swordfish: 8 r367 c129 fr7c3 => r8c12,r9c12<>8
Forcing Net Contradiction in c7 => r4c2<>1
r4c2=1 r4c2<>4 r4c7=4 r4c7<>5
r4c2=1 r5c3<>1 r5c3=3 r5c4<>3 r5c4=5 r5c7<>5
r4c2=1 (r4c2<>4 r4c7=4 r4c7<>6) r4c2<>6 r5c2=6 r5c7<>6 r9c7=6 r9c7<>5
Forcing Net Contradiction in r7 => r7c2<>7
r7c2=7 (r7c2<>4) (r7c3<>7) r8c3<>7 r2c3=7 r2c5<>7 r2c5=4 r7c5<>4 r7c1=4 r7c1<>8
r7c2=7 r7c2<>8
r7c2=7 (r7c2<>3) (r7c2<>4) (r7c3<>7) r8c3<>7 r2c3=7 r2c5<>7 r2c5=4 r7c5<>4 r7c1=4 r7c1<>3 r7c3=3 r7c3<>8
r7c2=7 (r7c3<>7) r8c3<>7 r2c3=7 r2c5<>7 r2c5=4 r2c4<>4 r9c4=4 r9c4<>8 r9c89=8 r7c9<>8
Brute Force: r5c7=6
Hidden Single: r4c2=6
Hidden Single: r4c7=4
Hidden Single: r9c7=5
Forcing Net Contradiction in r7c7 => r1c6<>2
r1c6=2 (r2c4<>2) r4c6<>2 r4c9=2 (r2c9<>2) r5c9<>2 r5c2=2 r2c2<>2 r2c1=2 (r2c1<>3) r2c1<>5 r2c2=5 (r2c2<>3) r8c2<>5 r8c1=5 r8c1<>6 r8c8=6 r2c8<>6 r2c9=6 r2c9<>3 r2c3=3 r4c3<>3 r4c4=3 r4c4<>5 r4c9=5 r4c9<>2 r4c6=2 r1c6<>2
Locked Candidates Type 1 (Pointing): 2 in b2 => r6c4<>2
Forcing Net Contradiction in r9c2 => r8c2<>9
r8c2=9 r8c2<>5 r8c1=5 r8c1<>6 r8c8=6 r2c8<>6 (r2c9=6 r2c9<>3 r2c1=3 r1c2<>3) r2c8=7 (r3c9<>7 r3c2=7 r1c2<>7) r5c8<>7 (r5c9=7 r5c9<>2 r5c2=2 r1c2<>2) r5c8=1 r5c3<>1 r5c3=3 r2c3<>3 r2c3=9 (r2c3<>7) (r2c8<>9) r1c2<>9 r1c2=1 r9c2<>1
r8c2=9 (r8c3<>9 r2c3=9 r2c8<>9) r8c2<>5 r8c1=5 r8c1<>6 r8c8=6 r2c8<>6 r2c8=7 r2c5<>7 r2c5=4 r2c4<>4 r9c4=4 r9c2<>4
r8c2=9 (r8c3<>9 r2c3=9 r2c8<>9) r8c2<>5 r8c1=5 r8c1<>6 r8c8=6 r2c8<>6 r2c8=7 (r3c7<>7) r3c9<>7 r3c2=7 r9c2<>7
r8c2=9 r9c2<>9
Brute Force: r5c8=7
Grouped Discontinuous Nice Loop: 7 r9c2 -7- r8c23 =7= r8c46 -7- r79c5 =7= r2c5 -7- r2c3 =7= r123c2 -7- r9c2 => r9c2<>7
Forcing Chain Contradiction in c3 => r8c4<>7
r8c4=7 r9c45<>7 r9c9=7 r9c9<>6 r2c9=6 r2c8<>6 r2c8=9 r2c3<>9
r8c4=7 r8c23<>7 r7c3=7 r7c3<>9
r8c4=7 r6c4<>7 r6c4=1 r4c5<>1 r4c5=9 r79c5<>9 r8c6=9 r8c3<>9
Forcing Chain Contradiction in r9 => r9c9<>1
r9c9=1 r9c9<>6 r2c9=6 r2c8<>6 r2c8=9 r2c3<>9 r12c2=9 r9c2<>9
r9c9=1 r89c8<>1 r4c8=1 r4c5<>1 r4c5=9 r9c5<>9
r9c9=1 r9c9<>6 r2c9=6 r2c8<>6 r2c8=9 r9c8<>9
r9c9=1 r9c9<>9
Forcing Net Contradiction in r9c9 => r1c6=8
r1c6<>8 (r1c6=7 r2c5<>7 r2c5=4 r2c4<>4 r9c4=4 r9c2<>4) r1c4=8 r8c4<>8 r8c4=1 (r8c8<>1) (r7c5<>1) r9c5<>1 r4c5=1 r4c8<>1 r9c8=1 r9c2<>1 r9c2=9 (r7c3<>9) r8c3<>9 r2c3=9 r2c8<>9 r2c8=6 r2c9<>6 r9c9=6
r1c6<>8 r1c4=8 (r9c4<>8) r8c4<>8 r8c4=1 (r8c8<>1) (r7c5<>1) r9c5<>1 r4c5=1 r4c8<>1 r9c8=1 r9c8<>8 r9c9=8
Grouped Discontinuous Nice Loop: 9 r4c8 -9- r4c5 =9= r79c5 -9- r8c6 -7- r9c45 =7= r9c9 =6= r2c9 -6- r2c8 -9- r4c8 => r4c8<>9
W-Wing: 8/1 in r4c8,r8c4 connected by 1 in r4c5,r6c4 => r8c8<>8
Grouped Discontinuous Nice Loop: 9 r8c8 -9- r8c6 -7- r9c45 =7= r9c9 =6= r2c9 -6- r2c8 -9- r8c8 => r8c8<>9
Empty Rectangle: 9 in b1 (r29c8) => r9c2<>9
Discontinuous Nice Loop: 1 r8c4 -1- r6c4 -7- r6c6 =7= r8c6 =9= r8c3 =8= r8c4 => r8c4<>1
Naked Single: r8c4=8
Locked Candidates Type 1 (Pointing): 8 in b7 => r7c9<>8
Sue de Coq: r8c123 - {15679} (r8c6 - {79}, r9c12 - {146}) => r7c123<>1, r7c12<>4
Hidden Single: r7c5=4
Naked Single: r2c5=7
Naked Single: r1c4=2
Full House: r2c4=4
Locked Candidates Type 1 (Pointing): 7 in b1 => r8c2<>7
Locked Candidates Type 1 (Pointing): 1 in b8 => r9c128<>1
Naked Single: r9c2=4
Naked Single: r9c1=6
Hidden Single: r6c1=4
Hidden Single: r8c8=6
Naked Single: r2c8=9
Naked Single: r2c3=3
Naked Single: r9c8=8
Full House: r4c8=1
Naked Single: r1c1=1
Naked Single: r5c3=1
Naked Single: r4c3=8
Naked Single: r4c5=9
Full House: r9c5=1
Naked Single: r1c7=7
Naked Single: r8c1=5
Naked Single: r6c2=2
Full House: r5c2=3
Naked Single: r4c6=2
Naked Single: r9c4=7
Full House: r8c6=9
Full House: r6c6=7
Full House: r9c9=9
Naked Single: r1c2=9
Full House: r1c9=3
Naked Single: r2c1=2
Naked Single: r8c2=1
Full House: r8c3=7
Full House: r7c3=9
Naked Single: r2c2=5
Full House: r2c9=6
Naked Single: r6c7=9
Naked Single: r5c4=5
Full House: r5c9=2
Naked Single: r4c9=5
Full House: r6c9=8
Full House: r6c4=1
Full House: r4c4=3
Naked Single: r7c7=1
Full House: r3c7=2
Full House: r3c9=1
Full House: r7c9=7
Naked Single: r7c2=8
Full House: r3c2=7
Full House: r3c1=8
Full House: r7c1=3
|
normal_sudoku_2479
|
...2...9.....4.62.6249.7.........7...3.75...27..19....8...6..7.9....1..6.....8..4
|
587216493391845627624937158452683719139754862768192345845369271973421586216578934
|
Basic 9x9 Sudoku 2479
|
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 . . . 9 .
. . . . 4 . 6 2 .
6 2 4 9 . 7 . . .
. . . . . . 7 . .
. 3 . 7 5 . . . 2
7 . . 1 9 . . . .
8 . . . 6 . . 7 .
9 . . . . 1 . . 6
. . . . . 8 . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
587216493391845627624937158452683719139754862768192345845369271973421586216578934 #1 Easy (384)
Hidden Single: r2c8=2
Hidden Single: r1c6=6
Naked Single: r5c6=4
Naked Single: r5c1=1
Hidden Single: r4c4=6
Hidden Single: r7c6=9
Hidden Single: r1c7=4
Hidden Single: r9c7=9
Naked Single: r5c7=8
Naked Single: r5c8=6
Full House: r5c3=9
Hidden Single: r4c1=4
Hidden Single: r2c4=8
Hidden Single: r4c5=8
Naked Single: r4c2=5
Naked Single: r4c3=2
Naked Single: r4c6=3
Full House: r6c6=2
Full House: r2c6=5
Naked Single: r4c8=1
Full House: r4c9=9
Naked Single: r2c1=3
Naked Single: r1c1=5
Full House: r9c1=2
Hidden Single: r8c8=8
Hidden Single: r2c2=9
Hidden Single: r6c8=4
Hidden Single: r7c7=2
Hidden Single: r8c5=2
Hidden Single: r3c9=8
Hidden Single: r3c7=1
Naked Single: r2c9=7
Full House: r2c3=1
Naked Single: r3c5=3
Full House: r1c5=1
Full House: r3c8=5
Full House: r1c9=3
Full House: r9c5=7
Full House: r9c8=3
Naked Single: r6c9=5
Full House: r6c7=3
Full House: r8c7=5
Full House: r7c9=1
Naked Single: r9c4=5
Naked Single: r7c2=4
Naked Single: r9c3=6
Full House: r9c2=1
Naked Single: r7c4=3
Full House: r7c3=5
Full House: r8c4=4
Naked Single: r8c2=7
Full House: r8c3=3
Naked Single: r6c3=8
Full House: r1c3=7
Full House: r1c2=8
Full House: r6c2=6
|
normal_sudoku_3234
|
..6.385..43..1...8.8.9...3...3...6..1...5.....2.8...7..9.3..8..3....4.....7....23
|
716438592439512768582967134943721685178653249625849371294375816361284957857196423
|
Basic 9x9 Sudoku 3234
|
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 8 5 . .
4 3 . . 1 . . . 8
. 8 . 9 . . . 3 .
. . 3 . . . 6 . .
1 . . . 5 . . . .
. 2 . 8 . . . 7 .
. 9 . 3 . . 8 . .
3 . . . . 4 . . .
. . 7 . . . . 2 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
716438592439512768582967134943721685178653249625849371294375816361284957857196423 #1 Extreme (16836) bf
Hidden Single: r2c2=3
Forcing Net Contradiction in r8c7 => r8c9<>5
r8c9=5 (r8c2<>5) (r7c8<>5) r8c8<>5 r4c8=5 (r4c2<>5 r9c2=5 r9c1<>5) r4c8<>8 r4c1=8 r9c1<>8 r9c1=6 r8c2<>6 r8c2=1 r1c2<>1 r1c2=7 (r1c1<>7) r3c1<>7 r4c1=7 r4c1<>8 r4c8=8 r4c8<>5 r78c8=5 r8c9<>5
Brute Force: r5c7=2
Hidden Single: r5c6=3
Hidden Single: r6c7=3
Naked Triple: 4,8,9 in r5c389 => r5c24<>4
Finned Swordfish: 4 c257 r349 fr6c5 => r4c4<>4
Hidden Single: r1c4=4
XY-Wing: 1/9/7 in r1c28,r2c7 => r1c9<>7
Locked Candidates Type 2 (Claiming): 7 in r1 => r3c1<>7
XY-Chain: 7 7- r2c7 -9- r1c8 -1- r1c2 -7- r5c2 -6- r5c4 -7 => r2c4<>7
Discontinuous Nice Loop: 9 r4c8 -9- r1c8 -1- r1c2 -7- r1c1 =7= r4c1 =8= r4c8 => r4c8<>9
Discontinuous Nice Loop: 9 r5c3 -9- r2c3 =9= r1c1 =7= r4c1 =8= r5c3 => r5c3<>9
Locked Candidates Type 2 (Claiming): 9 in r5 => r46c9<>9
Grouped Discontinuous Nice Loop: 1 r1c9 -1- r46c9 =1= r4c8 =8= r4c1 =7= r1c1 =2= r1c9 => r1c9<>1
Forcing Chain Contradiction in c3 => r2c8=6
r2c8<>6 r2c8=9 r2c3<>9 r1c1=9 r1c1<>7 r4c1=7 r4c1<>8 r5c3=8 r5c3<>4
r2c8<>6 r2c8=9 r2c3<>9 r6c3=9 r6c3<>4
r2c8<>6 r3c9=6 r3c9<>4 r3c7=4 r9c7<>4 r9c2=4 r7c3<>4
Almost Locked Set XY-Wing: A=r289c7 {1479}, B=r13456c9 {124579}, C=r3c13567 {124567}, X,Y=4,7, Z=1 => r78c9<>1
Forcing Chain Contradiction in r6c1 => r2c3<>2
r2c3=2 r3c1<>2 r3c1=5 r6c1<>5
r2c3=2 r2c3<>9 r1c1=9 r1c1<>7 r1c2=7 r5c2<>7 r5c2=6 r6c1<>6
r2c3=2 r2c3<>9 r6c3=9 r6c1<>9
Locked Candidates Type 2 (Claiming): 2 in r2 => r3c56<>2
Almost Locked Set XZ-Rule: A=r8c24789 {125679}, B=r37c5 {267}, X=2, Z=6,7 => r8c5<>6, r8c5<>7
Almost Locked Set XY-Wing: A=r8c24789 {125679}, B=r26c3 {459}, C=r36789c5 {246789}, X,Y=2,4, Z=5 => r8c3<>5
Forcing Chain Contradiction in c3 => r3c9<>7
r3c9=7 r2c7<>7 r2c7=9 r2c3<>9 r1c1=9 r1c1<>7 r4c1=7 r4c1<>8 r5c3=8 r5c3<>4
r3c9=7 r2c7<>7 r2c7=9 r2c3<>9 r6c3=9 r6c3<>4
r3c9=7 r3c9<>4 r3c7=4 r9c7<>4 r9c2=4 r7c3<>4
Locked Candidates Type 1 (Pointing): 7 in b3 => r8c7<>7
Hidden Pair: 6,7 in r78c9 => r7c9<>4, r7c9<>5, r8c9<>9
Locked Candidates Type 1 (Pointing): 5 in b9 => r4c8<>5
2-String Kite: 4 in r4c2,r7c8 (connected by r7c3,r9c2) => r4c8<>4
Discontinuous Nice Loop: 6 r7c1 -6- r7c9 -7- r8c9 =7= r8c4 -7- r5c4 -6- r5c2 =6= r6c1 -6- r7c1 => r7c1<>6
Naked Pair: 2,5 in r37c1 => r1c1<>2, r469c1<>5
Hidden Single: r1c9=2
Hidden Single: r5c9=9
X-Wing: 4 r57 c38 => r6c3<>4
Naked Pair: 5,9 in r26c3 => r37c3<>5
2-String Kite: 6 in r5c4,r9c1 (connected by r5c2,r6c1) => r9c4<>6
XY-Wing: 6/9/7 in r16c1,r5c2 => r1c2,r4c1<>7
Naked Single: r1c2=1
Naked Single: r1c8=9
Full House: r1c1=7
Naked Single: r3c3=2
Naked Single: r2c7=7
Naked Single: r3c1=5
Full House: r2c3=9
Naked Single: r7c1=2
Naked Single: r6c3=5
Hidden Single: r4c9=5
Naked Pair: 6,7 in r7c59 => r7c6<>6, r7c6<>7
Naked Pair: 1,5 in r7c6,r9c4 => r8c4,r9c6<>1, r8c4,r9c6<>5
Naked Pair: 6,7 in r37c5 => r4c5<>7, r69c5<>6
Naked Triple: 6,8,9 in r9c156 => r9c2<>6, r9c7<>9
Hidden Single: r8c7=9
X-Wing: 6 r69 c16 => r3c6<>6
Naked Single: r3c6=7
Naked Single: r3c5=6
Naked Single: r7c5=7
Naked Single: r7c9=6
Naked Single: r8c9=7
Empty Rectangle: 1 in b9 (r49c4) => r4c8<>1
Naked Single: r4c8=8
Naked Single: r4c1=9
Naked Single: r5c8=4
Full House: r6c9=1
Full House: r3c9=4
Full House: r3c7=1
Full House: r9c7=4
Naked Single: r6c1=6
Full House: r9c1=8
Naked Single: r5c3=8
Naked Single: r9c2=5
Naked Single: r5c2=7
Full House: r4c2=4
Full House: r8c2=6
Full House: r5c4=6
Naked Single: r6c6=9
Full House: r6c5=4
Naked Single: r8c3=1
Full House: r7c3=4
Naked Single: r9c5=9
Naked Single: r9c4=1
Full House: r9c6=6
Naked Single: r4c5=2
Full House: r8c5=8
Naked Single: r8c4=2
Full House: r8c8=5
Full House: r7c6=5
Full House: r7c8=1
Naked Single: r4c4=7
Full House: r4c6=1
Full House: r2c4=5
Full House: r2c6=2
|
normal_sudoku_4757
|
3.67...2.5.7...4...42.3.6..63...1...25..7.9.......8..3...5.3.727..86254.........6
|
386749125517286439942135687638921754251374968479658213164593872793862541825417396
|
Basic 9x9 Sudoku 4757
|
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 . 6 7 . . . 2 .
5 . 7 . . . 4 . .
. 4 2 . 3 . 6 . .
6 3 . . . 1 . . .
2 5 . . 7 . 9 . .
. . . . . 8 . . 3
. . . 5 . 3 . 7 2
7 . . 8 6 2 5 4 .
. . . . . . . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
386749125517286439942135687638921754251374968479658213164593872793862541825417396 #1 Medium (494)
Hidden Single: r1c1=3
Hidden Single: r2c8=3
Hidden Single: r5c4=3
Hidden Single: r3c9=7
Hidden Single: r6c2=7
Hidden Single: r9c6=7
Hidden Single: r7c2=6
Hidden Single: r9c2=2
Hidden Single: r9c3=5
Hidden Single: r8c3=3
Hidden Single: r9c7=3
Hidden Single: r4c7=7
Hidden Single: r6c7=2
Locked Candidates Type 1 (Pointing): 8 in b4 => r7c3<>8
Locked Candidates Type 1 (Pointing): 5 in b5 => r1c5<>5
Locked Candidates Type 1 (Pointing): 8 in b7 => r3c1<>8
Hidden Single: r3c8=8
Naked Single: r1c7=1
Full House: r7c7=8
Naked Single: r4c8=5
Naked Single: r2c9=9
Full House: r1c9=5
Naked Single: r2c6=6
Naked Single: r8c9=1
Full House: r8c2=9
Full House: r9c8=9
Naked Single: r5c6=4
Naked Single: r1c2=8
Full House: r2c2=1
Full House: r3c1=9
Naked Single: r1c6=9
Full House: r3c6=5
Full House: r3c4=1
Full House: r1c5=4
Naked Single: r5c9=8
Full House: r4c9=4
Naked Single: r2c4=2
Full House: r2c5=8
Naked Single: r9c4=4
Naked Single: r9c5=1
Full House: r7c5=9
Full House: r9c1=8
Naked Single: r5c3=1
Full House: r5c8=6
Full House: r6c8=1
Naked Single: r4c4=9
Full House: r6c4=6
Naked Single: r4c5=2
Full House: r6c5=5
Full House: r4c3=8
Naked Single: r6c1=4
Full House: r6c3=9
Full House: r7c3=4
Full House: r7c1=1
|
normal_sudoku_2051
|
8...56..9.3............36.8.72...8.69467.85..31......2...9...2.1...4.7.....1.....
|
827456319635891247491273658572314896946728531318569472763985124159642783284137965
|
Basic 9x9 Sudoku 2051
|
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 6 . . 9
. 3 . . . . . . .
. . . . . 3 6 . 8
. 7 2 . . . 8 . 6
9 4 6 7 . 8 5 . .
3 1 . . . . . . 2
. . . 9 . . . 2 .
1 . . . 4 . 7 . .
. . . 1 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
827456319635891247491273658572314896946728531318569472763985124159642783284137965 #1 Easy (370)
Naked Single: r5c2=4
Naked Single: r1c2=2
Naked Single: r4c1=5
Full House: r6c3=8
Naked Single: r1c4=4
Naked Single: r3c4=2
Naked Single: r4c4=3
Naked Single: r2c4=8
Hidden Single: r2c1=6
Hidden Single: r5c5=2
Hidden Single: r6c8=7
Hidden Single: r2c9=7
Hidden Single: r2c7=2
Hidden Single: r9c1=2
Hidden Single: r8c6=2
Hidden Single: r1c3=7
Naked Single: r3c1=4
Full House: r7c1=7
Naked Single: r7c6=5
Naked Single: r8c4=6
Full House: r6c4=5
Naked Single: r9c6=7
Hidden Single: r3c5=7
Hidden Single: r2c8=4
Hidden Single: r6c5=6
Hidden Single: r7c2=6
Hidden Single: r9c8=6
Hidden Single: r4c6=4
Naked Single: r6c6=9
Full House: r2c6=1
Full House: r4c5=1
Full House: r6c7=4
Full House: r2c5=9
Full House: r4c8=9
Full House: r2c3=5
Naked Single: r3c2=9
Full House: r3c3=1
Full House: r3c8=5
Hidden Single: r7c5=8
Full House: r9c5=3
Naked Single: r9c7=9
Naked Single: r9c3=4
Naked Single: r7c3=3
Full House: r8c3=9
Naked Single: r9c9=5
Full House: r9c2=8
Full House: r8c2=5
Naked Single: r7c7=1
Full House: r1c7=3
Full House: r7c9=4
Full House: r1c8=1
Naked Single: r8c9=3
Full House: r5c9=1
Full House: r5c8=3
Full House: r8c8=8
|
normal_sudoku_641
|
..3...7.2...326...4.2....6.....7..23.2.8.4...5.4.9.18..4.7.......7..9..56.5...9..
|
163548792978326541452917368896175423721834659534692187249751836387469215615283974
|
Basic 9x9 Sudoku 641
|
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 . . . 7 . 2
. . . 3 2 6 . . .
4 . 2 . . . . 6 .
. . . . 7 . . 2 3
. 2 . 8 . 4 . . .
5 . 4 . 9 . 1 8 .
. 4 . 7 . . . . .
. . 7 . . 9 . . 5
6 . 5 . . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
163548792978326541452917368896175423721834659534692187249751836387469215615283974 #1 Extreme (5712)
Hidden Single: r1c9=2
Hidden Single: r3c7=3
Hidden Single: r4c7=4
Hidden Single: r3c6=7
Hidden Single: r1c2=6
Locked Candidates Type 1 (Pointing): 4 in b2 => r1c8<>4
Locked Candidates Type 1 (Pointing): 5 in b6 => r5c5<>5
Locked Candidates Type 1 (Pointing): 9 in b6 => r5c13<>9
Locked Candidates Type 2 (Claiming): 2 in r9 => r7c6,r8c4<>2
Hidden Pair: 3,7 in r5c1,r6c2 => r5c1<>1
Discontinuous Nice Loop: 8 r2c2 -8- r2c7 -5- r5c7 -6- r6c9 -7- r6c2 =7= r2c2 => r2c2<>8
Forcing Chain Contradiction in r7 => r4c3<>9
r4c3=9 r4c3<>6 r4c4=6 r4c4<>5 r4c6=5 r7c6<>5 r7c5=5 r7c5<>6
r4c3=9 r7c3<>9 r7c1=9 r7c1<>2 r7c7=2 r7c7<>6
r4c3=9 r4c3<>6 r4c4=6 r6c4<>6 r6c9=6 r7c9<>6
Forcing Chain Contradiction in r7 => r7c3<>1
r7c3=1 r5c3<>1 r5c5=1 r4c6<>1 r4c6=5 r7c6<>5 r7c5=5 r7c5<>6
r7c3=1 r7c3<>9 r7c1=9 r7c1<>2 r7c7=2 r7c7<>6
r7c3=1 r5c3<>1 r5c3=6 r5c7<>6 r78c7=6 r7c9<>6
Forcing Chain Contradiction in r9 => r7c6<>3
r7c6=3 r6c6<>3 r6c2=3 r9c2<>3
r7c6=3 r9c5<>3
r7c6=3 r9c6<>3
r7c6=3 r6c6<>3 r6c2=3 r6c2<>7 r6c9=7 r9c9<>7 r9c8=7 r9c8<>3
Naked Triple: 1,5,8 in r147c6 => r9c6<>1, r9c6<>8
Forcing Net Contradiction in r8 => r4c3=6
r4c3<>6 r5c3=6 r5c3<>1 r5c5=1 (r3c5<>1) r4c6<>1 r4c6=5 r7c6<>5 r7c5=5 r3c5<>5 r3c5=8 (r1c5<>8) r1c6<>8 r1c1=8 r8c1<>8
r4c3<>6 (r4c4=6 r5c5<>6) r5c3=6 r5c3<>1 r5c5=1 (r5c5<>3 r5c1=3 r8c1<>3) (r5c5<>3 r5c1=3 r7c1<>3 r7c8=3 r8c8<>3) r4c6<>1 r4c6=5 r7c6<>5 r7c5=5 r7c5<>6 r8c5=6 r8c5<>3 r8c2=3 r8c2<>8
r4c3<>6 (r5c3=6 r5c3<>1 r5c5=1 r3c5<>1) r4c4=6 r4c4<>5 r4c6=5 r7c6<>5 r7c5=5 r3c5<>5 r3c5=8 r8c5<>8
r4c3<>6 r5c3=6 r5c7<>6 r5c7=5 r2c7<>5 r2c7=8 r8c7<>8
Naked Single: r5c3=1
Skyscraper: 8 in r1c6,r2c3 (connected by r7c36) => r1c1<>8
Locked Candidates Type 2 (Claiming): 8 in r1 => r3c5<>8
2-String Kite: 8 in r3c9,r7c3 (connected by r2c3,r3c2) => r7c9<>8
W-Wing: 8/9 in r2c3,r4c1 connected by 9 in r7c13 => r2c1<>8
W-Wing: 1/5 in r3c5,r4c6 connected by 5 in r7c56 => r1c6<>1
Sue de Coq: r2c123 - {15789} (r2c7 - {58}, r1c1 - {19}) => r3c2<>1, r3c2<>9, r2c8<>5, r2c9<>8
XY-Chain: 1 1- r1c1 -9- r2c3 -8- r3c2 -5- r3c5 -1 => r1c45<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r3c9<>1
Sue de Coq: r12c8 - {1459} (r78c8 - {134}, r2c7,r3c9 - {589}) => r2c9<>9, r9c8<>1, r9c8<>3, r9c8<>4
Naked Single: r9c8=7
XY-Chain: 3 3- r7c8 -1- r7c9 -6- r6c9 -7- r6c2 -3- r6c6 -2- r9c6 -3 => r7c5<>3
Continuous Nice Loop: 1/6/9 7= r2c2 =5= r2c7 -5- r5c7 -6- r6c9 -7- r6c2 =7= r2c2 =5 => r2c2<>1, r5c9<>6, r2c2<>9
Hidden Single: r4c2=9
Naked Single: r4c1=8
Locked Candidates Type 1 (Pointing): 1 in b1 => r78c1<>1
Skyscraper: 6 in r7c9,r8c4 (connected by r6c49) => r7c5,r8c7<>6
XY-Chain: 3 3- r6c2 -7- r2c2 -5- r2c7 -8- r8c7 -2- r8c1 -3 => r5c1,r89c2<>3
Naked Single: r5c1=7
Full House: r6c2=3
Naked Single: r5c9=9
Naked Single: r6c6=2
Naked Single: r3c9=8
Naked Single: r5c8=5
Naked Single: r6c4=6
Full House: r6c9=7
Full House: r5c7=6
Full House: r5c5=3
Naked Single: r9c6=3
Naked Single: r2c7=5
Naked Single: r3c2=5
Naked Single: r2c2=7
Naked Single: r3c5=1
Full House: r3c4=9
Hidden Single: r9c4=2
Hidden Single: r2c3=8
Full House: r7c3=9
Hidden Single: r8c5=6
Hidden Single: r7c9=6
W-Wing: 4/1 in r8c4,r9c9 connected by 1 in r7c68 => r8c8,r9c5<>4
Naked Single: r9c5=8
Naked Single: r7c5=5
Full House: r1c5=4
Naked Single: r9c2=1
Full House: r8c2=8
Full House: r9c9=4
Full House: r2c9=1
Naked Single: r7c6=1
Full House: r8c4=4
Naked Single: r1c4=5
Full House: r1c6=8
Full House: r4c6=5
Full House: r4c4=1
Naked Single: r8c7=2
Full House: r7c7=8
Naked Single: r1c8=9
Full House: r1c1=1
Full House: r2c1=9
Full House: r2c8=4
Naked Single: r7c8=3
Full House: r7c1=2
Full House: r8c1=3
Full House: r8c8=1
|
normal_sudoku_2655
|
43...2.5.26.1.9.78..9.5.....5.9.....1.....8343.......9.......8.....7.4.3..13..7.5
|
438762951265149378719853642654938217197625834382417569573294186826571493941386725
|
Basic 9x9 Sudoku 2655
|
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 . 5 .
2 6 . 1 . 9 . 7 8
. . 9 . 5 . . . .
. 5 . 9 . . . . .
1 . . . . . 8 3 4
3 . . . . . . . 9
. . . . . . . 8 .
. . . . 7 . 4 . 3
. . 1 3 . . 7 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
438762951265149378719853642654938217197625834382417569573294186826571493941386725 #1 Extreme (3256)
Naked Single: r2c2=6
Naked Single: r2c3=5
Naked Single: r2c7=3
Full House: r2c5=4
Hidden Single: r5c2=9
Hidden Single: r1c7=9
Hidden Single: r6c7=5
Hidden Single: r3c8=4
Hidden Single: r3c2=1
Hidden Single: r7c3=3
Hidden Single: r4c9=7
Hidden Single: r4c5=3
Hidden Single: r3c6=3
Hidden Single: r1c9=1
Locked Candidates Type 1 (Pointing): 7 in b2 => r56c4<>7
Locked Candidates Type 1 (Pointing): 6 in b3 => r3c4<>6
Locked Candidates Type 1 (Pointing): 4 in b7 => r6c2<>4
Skyscraper: 1 in r4c7,r6c5 (connected by r7c57) => r4c6,r6c8<>1
Uniqueness Test 1: 2/6 in r3c79,r7c79 => r7c7<>2, r7c7<>6
Naked Single: r7c7=1
Hidden Single: r4c8=1
Hidden Single: r6c5=1
Hidden Single: r8c6=1
2-String Kite: 8 in r3c1,r9c5 (connected by r1c5,r3c4) => r9c1<>8
Hidden Rectangle: 6/9 in r7c15,r9c15 => r7c5<>6
Hidden Rectangle: 6/9 in r8c18,r9c18 => r8c8<>6
XY-Chain: 9 9- r7c5 -2- r5c5 -6- r1c5 -8- r1c3 -7- r3c1 -8- r4c1 -6- r9c1 -9 => r7c1,r9c5<>9
Hidden Single: r7c5=9
Discontinuous Nice Loop: 2 r5c4 -2- r5c5 -6- r1c5 -8- r1c3 -7- r5c3 =7= r5c6 =5= r5c4 => r5c4<>2
Discontinuous Nice Loop: 6 r6c3 -6- r6c8 -2- r4c7 =2= r4c3 =4= r6c3 => r6c3<>6
Discontinuous Nice Loop: 6 r7c4 -6- r7c9 -2- r3c9 =2= r3c7 -2- r4c7 =2= r4c3 =4= r4c6 -4- r6c4 =4= r7c4 => r7c4<>6
Grouped Discontinuous Nice Loop: 6 r7c6 -6- r7c9 =6= r9c8 -6- r6c8 =6= r6c46 -6- r5c4 -5- r5c6 =5= r7c6 => r7c6<>6
Empty Rectangle: 6 in b8 (r69c8) => r6c4<>6
Grouped Discontinuous Nice Loop: 9 r8c1 -9- r9c1 -6- r8c13 =6= r8c4 =5= r8c1 => r8c1<>9
Hidden Single: r8c8=9
Hidden Single: r9c1=9
Skyscraper: 2 in r5c5,r6c8 (connected by r9c58) => r6c4<>2
Hidden Single: r5c5=2
XY-Wing: 6/7/8 in r15c3,r4c1 => r3c1,r46c3<>8
Naked Single: r3c1=7
Full House: r1c3=8
Naked Single: r3c4=8
Naked Single: r1c5=6
Full House: r1c4=7
Full House: r9c5=8
Naked Single: r6c4=4
Hidden Single: r7c2=7
Hidden Single: r4c3=4
Hidden Single: r7c6=4
Naked Single: r9c6=6
Naked Single: r4c6=8
Naked Single: r9c8=2
Full House: r6c8=6
Full House: r7c9=6
Full House: r9c2=4
Full House: r4c7=2
Full House: r4c1=6
Full House: r3c9=2
Full House: r3c7=6
Naked Single: r6c6=7
Full House: r5c6=5
Full House: r5c4=6
Full House: r5c3=7
Naked Single: r7c1=5
Full House: r7c4=2
Full House: r8c1=8
Full House: r8c4=5
Naked Single: r6c3=2
Full House: r6c2=8
Full House: r8c2=2
Full House: r8c3=6
|
normal_sudoku_5561
|
1.96..53...45..2...7..3...4....8....41....3....62..9.....7...52..7..5..9....6.7..
|
189624537634571298572839164923186475418957326756243981341798652267315849895462713
|
Basic 9x9 Sudoku 5561
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . 9 6 . . 5 3 .
. . 4 5 . . 2 . .
. 7 . . 3 . . . 4
. . . . 8 . . . .
4 1 . . . . 3 . .
. . 6 2 . . 9 . .
. . . 7 . . . 5 2
. . 7 . . 5 . . 9
. . . . 6 . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
189624537634571298572839164923186475418957326756243981341798652267315849895462713 #1 Extreme (10790) bf
Locked Candidates Type 1 (Pointing): 9 in b4 => r4c46<>9
Brute Force: r5c7=3
Naked Single: r5c4=9
Hidden Single: r9c9=3
Skyscraper: 3 in r7c3,r8c4 (connected by r4c34) => r7c6,r8c12<>3
Hidden Single: r8c4=3
Empty Rectangle: 4 in b6 (r49c4) => r9c8<>4
Sashimi X-Wing: 8 c47 r39 fr7c7 fr8c7 => r9c8<>8
Naked Single: r9c8=1
Hidden Single: r8c5=1
Hidden Single: r7c3=1
Hidden Single: r1c5=2
Naked Single: r1c2=8
Naked Single: r1c9=7
Full House: r1c6=4
Hidden Single: r9c6=2
Hidden Single: r4c3=3
Naked Single: r6c2=5
Hidden Single: r6c6=3
Hidden Single: r4c9=5
Hidden Single: r5c5=5
Hidden Single: r6c9=1
Hidden Single: r2c6=1
Naked Single: r3c4=8
Naked Single: r3c6=9
Full House: r2c5=7
Naked Single: r9c4=4
Full House: r4c4=1
Naked Single: r3c8=6
Naked Single: r7c6=8
Full House: r7c5=9
Full House: r6c5=4
Naked Single: r9c2=9
Naked Single: r2c9=8
Full House: r5c9=6
Naked Single: r3c7=1
Full House: r2c8=9
Naked Single: r4c2=2
Naked Single: r4c7=4
Naked Single: r5c6=7
Full House: r4c6=6
Naked Single: r5c3=8
Full House: r5c8=2
Naked Single: r4c8=7
Full House: r4c1=9
Full House: r6c1=7
Full House: r6c8=8
Full House: r8c8=4
Naked Single: r7c7=6
Full House: r8c7=8
Naked Single: r9c3=5
Full House: r3c3=2
Full House: r9c1=8
Full House: r3c1=5
Naked Single: r8c2=6
Full House: r8c1=2
Naked Single: r7c1=3
Full House: r2c1=6
Full House: r2c2=3
Full House: r7c2=4
|
normal_sudoku_6930
|
.4.5..9.........63..9.6...7..82......5.6.8.2.9...4.7....5.....17...5.3...1.9.6...
|
643572918572189463189463257468217539357698124921345786835724691796851342214936875
|
Basic 9x9 Sudoku 6930
|
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 . . 9 . .
. . . . . . . 6 3
. . 9 . 6 . . . 7
. . 8 2 . . . . .
. 5 . 6 . 8 . 2 .
9 . . . 4 . 7 . .
. . 5 . . . . . 1
7 . . . 5 . 3 . .
. 1 . 9 . 6 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
643572918572189463189463257468217539357698124921345786835724691796851342214936875 #1 Extreme (22292) bf
Brute Force: r5c4=6
2-String Kite: 7 in r2c2,r5c5 (connected by r4c2,r5c3) => r2c5<>7
Multi Colors 1: 7 (r2c2,r5c3) / (r4c2,r5c5), (r2c4) / (r7c4) => r79c5<>7
Hidden Single: r9c8=7
Forcing Chain Contradiction in r4c2 => r4c1<>3
r4c1=3 r4c2<>3
r4c1=3 r4c8<>3 r6c8=3 r6c8<>8 r6c9=8 r6c9<>6 r4c79=6 r4c2<>6
r4c1=3 r5c13<>3 r5c5=3 r5c5<>7 r5c3=7 r4c2<>7
Forcing Chain Contradiction in c8 => r4c8<>1
r4c8=1 r5c7<>1 r5c7=4 r23c7<>4 r3c8=4 r3c8<>5
r4c8=1 r4c8<>5
r4c8=1 r4c8<>3 r6c8=3 r6c8<>5
Forcing Chain Contradiction in c8 => r2c7<>1
r2c7=1 r5c7<>1 r5c7=4 r23c7<>4 r3c8=4 r3c8<>5
r2c7=1 r45c7<>1 r6c8=1 r6c8<>3 r4c8=3 r4c8<>5
r2c7=1 r45c7<>1 r6c8=1 r6c8<>5
Forcing Chain Contradiction in c8 => r3c7<>1
r3c7=1 r5c7<>1 r5c7=4 r23c7<>4 r3c8=4 r3c8<>5
r3c7=1 r45c7<>1 r6c8=1 r6c8<>3 r4c8=3 r4c8<>5
r3c7=1 r45c7<>1 r6c8=1 r6c8<>5
Locked Candidates Type 1 (Pointing): 1 in b3 => r6c8<>1
Forcing Chain Contradiction in r6 => r1c6<>1
r1c6=1 r12c5<>1 r45c5=1 r6c46<>1 r6c3=1 r6c3<>2 r6c2=2 r6c2<>6
r1c6=1 r12c5<>1 r45c5=1 r6c46<>1 r6c3=1 r6c3<>6
r1c6=1 r1c8<>1 r1c8=8 r6c8<>8 r6c9=8 r6c9<>6
Forcing Chain Contradiction in r4c2 => r4c8<>9
r4c8=9 r5c9<>9 r5c5=9 r5c5<>3 r5c13=3 r4c2<>3
r4c8=9 r4c8<>3 r6c8=3 r6c8<>8 r6c9=8 r6c9<>6 r4c79=6 r4c2<>6
r4c8=9 r5c9<>9 r5c5=9 r5c5<>7 r5c3=7 r4c2<>7
Locked Candidates Type 1 (Pointing): 9 in b6 => r8c9<>9
Forcing Chain Verity => r5c1<>1
r3c1=1 r5c1<>1
r3c4=1 r12c5<>1 r45c5=1 r6c46<>1 r6c3=1 r5c1<>1
r3c6=1 r12c5<>1 r45c5=1 r6c46<>1 r6c3=1 r5c1<>1
r3c8=1 r3c8<>4 r23c7=4 r5c7<>4 r5c7=1 r5c1<>1
Forcing Net Verity => r1c1<>1
r4c1=1 r1c1<>1
r5c3=1 r5c7<>1 r5c7=4 (r2c7<>4) r3c7<>4 r3c8=4 r3c8<>1 r1c8=1 r1c1<>1
r6c3=1 (r6c6<>1) r6c4<>1 r6c4=3 (r6c8<>3) r6c6<>3 r6c6=5 r6c8<>5 r6c8=8 r1c8<>8 r1c8=1 r1c1<>1
Forcing Net Verity => r2c1<>1
r4c1=1 r2c1<>1
r5c3=1 (r5c5<>1) r5c7<>1 (r4c7=1 r4c5<>1) r5c7=4 (r2c7<>4) r3c7<>4 r3c8=4 r3c8<>1 r1c8=1 r1c5<>1 r2c5=1 r2c1<>1
r6c3=1 r6c4<>1 r6c4=3 (r6c6<>3 r6c6=5 r6c8<>5) r6c8<>3 r4c8=3 r4c8<>5 r3c8=5 r2c7<>5 r2c1=5 r2c1<>1
Finned Swordfish: 1 r268 c346 fr2c5 => r3c46<>1
Forcing Net Contradiction in r5c3 => r1c3<>2
r1c3=2 r1c9<>2 r1c9=8 r6c9<>8 r6c8=8 (r6c8<>5) r6c8<>3 r4c8=3 r4c8<>5 r3c8=5 r3c8<>4 r23c7=4 r5c7<>4 r5c7=1 r5c3<>1
r1c3=2 (r1c3<>6 r1c1=6 r4c1<>6) r1c9<>2 r1c9=8 r1c8<>8 r1c8=1 r3c8<>1 r3c1=1 r4c1<>1 r4c1=4 r5c1<>4 r5c1=3 r5c3<>3
r1c3=2 (r1c3<>6 r1c1=6 r4c1<>6) r1c9<>2 r1c9=8 r1c8<>8 r1c8=1 r3c8<>1 r3c1=1 r4c1<>1 r4c1=4 r5c3<>4
r1c3=2 (r2c3<>2) r1c9<>2 r1c9=8 r1c8<>8 r1c8=1 r3c8<>1 r3c1=1 r2c3<>1 r2c3=7 r5c3<>7
Forcing Net Verity => r3c8<>8
r4c1=1 r3c1<>1 r3c8=1 r3c8<>8
r5c3=1 r5c7<>1 r5c7=4 (r2c7<>4) r3c7<>4 r3c8=4 r3c8<>8
r6c3=1 (r6c6<>1) r6c4<>1 r6c4=3 (r6c8<>3) r6c6<>3 r6c6=5 r6c8<>5 r6c8=8 r3c8<>8
Forcing Net Verity => r4c7<>4
r4c1=1 r3c1<>1 r3c8=1 r3c8<>4 r23c7=4 r4c7<>4
r5c3=1 r5c7<>1 r5c7=4 r4c7<>4
r6c3=1 r6c4<>1 r6c4=3 (r6c6<>3 r6c6=5 r6c8<>5) r6c8<>3 r4c8=3 r4c8<>5 r3c8=5 r3c8<>4 r23c7=4 r4c7<>4
Forcing Net Verity => r9c9=5
r4c1=1 r3c1<>1 r3c8=1 r3c8<>5 r23c7=5 r9c7<>5 r9c9=5
r4c5=1 (r4c7<>1) (r6c4<>1) r6c6<>1 r6c3=1 (r6c3<>6) r6c3<>2 r6c2=2 r6c2<>6 r6c9=6 r4c7<>6 r4c7=5 r9c7<>5 r9c9=5
r4c6=1 (r4c7<>1) (r6c4<>1 r6c4=3 r6c8<>3) r4c6<>5 r6c6=5 (r6c9<>5) r6c8<>5 r6c8=8 r6c9<>8 r6c9=6 r4c7<>6 r4c7=5 r9c7<>5 r9c9=5
r4c7=1 (r4c1<>1 r3c1=1 r3c1<>5) r5c7<>1 r5c7=4 (r2c7<>4) r3c7<>4 r3c8=4 r3c8<>5 r3c7=5 r9c7<>5 r9c9=5
Almost Locked Set XZ-Rule: A=r6c468 {1358}, B=r456c9,r5c7 {14689}, X=8, Z=1 => r5c5<>1
Forcing Net Contradiction in c5 => r5c7=1
r5c7<>1 r5c7=4 (r4c9<>4) r5c9<>4 r8c9=4 r8c9<>2 r1c9=2 r1c5<>2
r5c7<>1 (r4c7=1 r4c5<>1) r5c7=4 (r2c7<>4) r3c7<>4 r3c8=4 r3c8<>1 r1c8=1 r1c5<>1 r2c5=1 r2c5<>2
r5c7<>1 (r4c7=1 r4c7<>6 r7c7=6 r7c7<>2) r5c7=4 (r3c7<>4 r3c8=4 r3c8<>1 r3c1=1 r3c1<>2) (r3c7<>4 r3c8=4 r3c8<>1 r3c1=1 r3c1<>5 r3c7=5 r2c7<>5 r2c1=5 r2c1<>2) (r4c9<>4) r5c9<>4 r8c9=4 r8c9<>2 r1c9=2 (r1c1<>2) (r2c7<>2) r3c7<>2 r9c7=2 r9c1<>2 r7c1=2 r7c5<>2
r5c7<>1 (r4c7=1 r4c7<>6 r7c7=6 r7c7<>2) r5c7=4 (r4c9<>4) r5c9<>4 r8c9=4 r8c9<>2 r1c9=2 (r2c7<>2) r3c7<>2 r9c7=2 r9c5<>2
Grouped Discontinuous Nice Loop: 4 r4c8 -4- r45c9 =4= r8c9 =6= r7c7 -6- r4c7 -5- r23c7 =5= r3c8 =1= r3c1 -1- r4c1 =1= r6c3 -1- r6c4 -3- r6c8 =3= r4c8 => r4c8<>4
Locked Candidates Type 1 (Pointing): 4 in b6 => r8c9<>4
Naked Triple: 2,6,8 in r168c9 => r4c9<>6
Hidden Rectangle: 3/5 in r4c68,r6c68 => r6c6<>3
Forcing Chain Contradiction in r8c3 => r6c2=2
r6c2<>2 r6c3=2 r8c3<>2
r6c2<>2 r6c3=2 r6c3<>1 r4c1=1 r3c1<>1 r3c8=1 r3c8<>4 r23c7=4 r9c7<>4 r9c13=4 r8c3<>4
r6c2<>2 r6c3=2 r6c3<>1 r4c1=1 r3c1<>1 r3c8=1 r3c8<>5 r23c7=5 r4c7<>5 r4c7=6 r7c7<>6 r8c9=6 r8c3<>6
Finned X-Wing: 6 c27 r47 fr8c2 => r7c1<>6
Continuous Nice Loop: 3/8 6= r6c3 =1= r4c1 -1- r3c1 =1= r3c8 -1- r1c8 -8- r6c8 =8= r6c9 =6= r6c3 =1 => r6c3<>3, r78c8<>8
Locked Pair: 4,9 in r78c8 => r3c8,r79c7<>4
Locked Candidates Type 2 (Claiming): 4 in r9 => r7c1,r8c3<>4
Hidden Rectangle: 3/4 in r5c13,r9c13 => r9c3<>3
Sue de Coq: r12c3 - {12367} (r68c3 - {126}, r23c2 - {378}) => r13c1<>3, r123c1<>8, r9c3<>2
Naked Single: r9c3=4
Locked Candidates Type 1 (Pointing): 8 in b1 => r78c2<>8
Skyscraper: 2 in r1c9,r2c3 (connected by r8c39) => r1c1,r2c7<>2
Naked Single: r1c1=6
X-Wing: 6 r47 c27 => r8c2<>6
Naked Single: r8c2=9
Naked Single: r8c8=4
Naked Single: r7c8=9
Hidden Pair: 4,7 in r7c46 => r7c46<>3, r7c4<>8, r7c6<>2
Locked Candidates Type 1 (Pointing): 3 in b8 => r145c5<>3
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c2<>3
Empty Rectangle: 2 in b8 (r28c3) => r2c5<>2
Empty Rectangle: 2 in b2 (r18c9) => r8c6<>2
Naked Single: r8c6=1
Naked Single: r6c6=5
Naked Single: r8c4=8
Locked Candidates Type 1 (Pointing): 2 in b8 => r1c5<>2
Locked Candidates Type 1 (Pointing): 8 in b9 => r23c7<>8
Hidden Single: r3c2=8
Naked Single: r2c2=7
Naked Single: r4c2=6
Full House: r7c2=3
Naked Single: r4c7=5
Naked Single: r6c3=1
Naked Single: r7c5=2
Naked Single: r2c7=4
Naked Single: r4c8=3
Naked Single: r1c3=3
Naked Single: r2c3=2
Naked Single: r4c1=4
Naked Single: r6c4=3
Naked Single: r7c1=8
Naked Single: r9c5=3
Naked Single: r2c4=1
Naked Single: r3c7=2
Naked Single: r6c8=8
Full House: r6c9=6
Naked Single: r5c3=7
Full House: r8c3=6
Full House: r5c1=3
Full House: r9c1=2
Full House: r9c7=8
Full House: r7c7=6
Full House: r8c9=2
Naked Single: r2c1=5
Full House: r3c1=1
Naked Single: r2c6=9
Full House: r2c5=8
Naked Single: r4c9=9
Full House: r5c9=4
Full House: r1c9=8
Full House: r5c5=9
Naked Single: r3c4=4
Full House: r7c4=7
Full House: r7c6=4
Naked Single: r1c8=1
Full House: r3c8=5
Full House: r3c6=3
Naked Single: r4c6=7
Full House: r1c6=2
Full House: r1c5=7
Full House: r4c5=1
|
normal_sudoku_1557
|
5.91.246..83647..1...9.........7.......2..6..7.2...893.1.....8...431.......8...19
|
579132468283647951461985732396478125158293647742561893915726384824319576637854219
|
Basic 9x9 Sudoku 1557
|
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 . 9 1 . 2 4 6 .
. 8 3 6 4 7 . . 1
. . . 9 . . . . .
. . . . 7 . . . .
. . . 2 . . 6 . .
7 . 2 . . . 8 9 3
. 1 . . . . . 8 .
. . 4 3 1 . . . .
. . . 8 . . . 1 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
579132468283647951461985732396478125158293647742561893915726384824319576637854219 #1 Hard (812)
Naked Single: r1c1=5
Naked Single: r1c2=7
Naked Single: r2c1=2
Naked Single: r1c9=8
Full House: r1c5=3
Naked Single: r2c8=5
Full House: r2c7=9
Hidden Single: r6c6=1
Hidden Single: r8c1=8
Hidden Single: r7c4=7
Hidden Single: r4c7=1
Hidden Single: r3c8=3
Hidden Single: r9c6=4
Hidden Single: r7c9=4
Hidden Single: r9c3=7
Hidden Single: r8c9=6
Locked Candidates Type 2 (Claiming): 5 in c4 => r45c6,r56c5<>5
Naked Single: r6c5=6
Hidden Single: r7c6=6
Naked Single: r7c3=5
Naked Triple: 2,4,5 in r4c489 => r4c12<>4, r4c2<>5
Naked Triple: 3,6,9 in r479c1 => r3c1<>6, r5c1<>3, r5c1<>9
Skyscraper: 9 in r4c1,r5c5 (connected by r7c15) => r4c6,r5c2<>9
XY-Wing: 3/9/2 in r7c17,r8c2 => r8c78<>2
Naked Single: r8c8=7
Naked Single: r5c8=4
Full House: r4c8=2
Naked Single: r8c7=5
Naked Single: r5c1=1
Naked Single: r4c9=5
Full House: r5c9=7
Full House: r3c9=2
Full House: r3c7=7
Naked Single: r8c6=9
Full House: r8c2=2
Naked Single: r3c1=4
Naked Single: r5c3=8
Naked Single: r4c4=4
Full House: r6c4=5
Full House: r6c2=4
Naked Single: r7c5=2
Full House: r9c5=5
Naked Single: r3c2=6
Full House: r3c3=1
Full House: r4c3=6
Naked Single: r5c5=9
Full House: r3c5=8
Full House: r3c6=5
Naked Single: r5c6=3
Full House: r4c6=8
Full House: r5c2=5
Naked Single: r7c7=3
Full House: r7c1=9
Full House: r9c7=2
Naked Single: r9c2=3
Full House: r4c2=9
Full House: r4c1=3
Full House: r9c1=6
|
normal_sudoku_3274
|
..715..26.4..3...5......3...5.4..1..1....3...9...715...3..17.....594...77.9......
|
387154926641239785592786341856492173174563892923871564438617259215948637769325418
|
Basic 9x9 Sudoku 3274
|
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 5 . . 2 6
. 4 . . 3 . . . 5
. . . . . . 3 . .
. 5 . 4 . . 1 . .
1 . . . . 3 . . .
9 . . . 7 1 5 . .
. 3 . . 1 7 . . .
. . 5 9 4 . . . 7
7 . 9 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
387154926641239785592786341856492173174563892923871564438617259215948637769325418 #1 Extreme (12402) bf
Hidden Single: r6c6=1
Hidden Single: r5c4=5
Hidden Single: r1c1=3
Hidden Single: r3c1=5
Hidden Single: r9c6=5
Hidden Single: r9c4=3
Hidden Single: r8c8=3
Hidden Single: r4c8=7
Hidden Single: r5c2=7
Hidden Single: r7c1=4
Hidden Single: r7c8=5
Hidden Single: r8c2=1
Hidden Single: r3c4=7
Hidden Single: r2c7=7
Brute Force: r5c5=6
Hidden Single: r6c8=6
Locked Candidates Type 1 (Pointing): 9 in b5 => r4c9<>9
Naked Pair: 2,8 in r6c24 => r6c39<>2, r6c39<>8
Forcing Net Verity => r9c2=6
r9c2=2 (r6c2<>2 r6c4=2 r7c4<>2 r7c4=6 r8c6<>6) r9c5<>2 r9c5=8 r7c4<>8 r2c4=8 (r2c1<>8) r6c4<>8 r6c2=8 (r6c4<>8) r4c1<>8 r8c1=8 r8c1<>6 r8c7=6 r9c7<>6 r9c2=6
r9c2=6 r9c2=6
r9c2=8 (r6c2<>8 r6c4=8 r7c4<>8 r7c4=6 r8c6<>6) r9c5<>8 r9c5=2 r7c4<>2 r2c4=2 (r2c1<>2) r6c4<>2 r6c2=2 (r6c4<>2) r4c1<>2 r8c1=2 r8c1<>6 r8c7=6 r9c7<>6 r9c2=6
Finned Franken Swordfish: 2 c24b7 r267 fr3c2 fr8c1 => r2c1<>2
W-Wing: 8/2 in r6c2,r7c3 connected by 2 in r48c1 => r45c3<>8
Locked Candidates Type 2 (Claiming): 8 in r5 => r4c9<>8
Sashimi Swordfish: 8 c234 r267 fr1c2 fr3c2 fr3c3 => r2c1<>8
Naked Single: r2c1=6
Hidden Single: r7c4=6
Hidden Single: r3c6=6
Hidden Single: r4c3=6
Hidden Single: r8c7=6
Hidden Single: r1c6=4
Hidden Single: r4c9=3
Naked Single: r6c9=4
Naked Single: r6c3=3
Hidden Single: r3c8=4
Hidden Single: r9c7=4
Hidden Single: r5c3=4
Remote Pair: 2/8 r2c4 -8- r6c4 -2- r6c2 -8- r4c1 -2- r8c1 -8- r7c3 => r2c3<>2, r2c3<>8
Naked Single: r2c3=1
Hidden Single: r9c8=1
Hidden Single: r3c9=1
Locked Candidates Type 1 (Pointing): 2 in b1 => r3c5<>2
Remote Pair: 2/8 r2c4 -8- r6c4 -2- r6c2 -8- r4c1 -2- r8c1 -8- r8c6 => r2c6<>2, r2c6<>8
Naked Single: r2c6=9
Naked Single: r2c8=8
Full House: r1c7=9
Full House: r2c4=2
Full House: r3c5=8
Full House: r5c8=9
Full House: r1c2=8
Full House: r6c4=8
Full House: r6c2=2
Full House: r3c2=9
Full House: r3c3=2
Full House: r4c1=8
Full House: r7c3=8
Full House: r8c1=2
Full House: r8c6=8
Full House: r9c5=2
Full House: r4c6=2
Full House: r4c5=9
Full House: r9c9=8
Naked Single: r7c7=2
Full House: r5c7=8
Full House: r5c9=2
Full House: r7c9=9
|
normal_sudoku_423
|
....8435...823.7.63....6.......5.....1..2......78..2.5.8.9....7..9.72....6...89.2
|
926784351458231796371596824842159673513627489697843215284965137139472568765318942
|
Basic 9x9 Sudoku 423
|
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 4 3 5 .
. . 8 2 3 . 7 . 6
3 . . . . 6 . . .
. . . . 5 . . . .
. 1 . . 2 . . . .
. . 7 8 . . 2 . 5
. 8 . 9 . . . . 7
. . 9 . 7 2 . . .
. 6 . . . 8 9 . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
926784351458231796371596824842159673513627489697843215284965137139472568765318942 #1 Extreme (31576) bf
Hidden Single: r5c5=2
Hidden Single: r9c1=7
Hidden Single: r3c8=2
Locked Candidates Type 1 (Pointing): 7 in b2 => r45c4<>7
Finned Swordfish: 5 r359 c134 fr3c2 => r2c1<>5
Discontinuous Nice Loop: 9 r3c2 -9- r3c5 -1- r1c4 -7- r1c2 =7= r3c2 => r3c2<>9
Forcing Chain Contradiction in r3 => r4c1<>2
r4c1=2 r4c2<>2 r1c2=2 r1c2<>7 r3c2=7 r3c2<>5
r4c1=2 r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 r3c3<>5
r4c1=2 r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 r9c3<>5 r9c4=5 r3c4<>5
Forcing Net Contradiction in r8 => r3c5=9
r3c5<>9 (r3c9=9 r5c9<>9) r6c5=9 (r5c6<>9) (r4c6<>9) (r5c6<>9) r6c6<>9 r2c6=9 r2c6<>5 r7c6=5 r9c4<>5 r9c3=5 r5c3<>5 r5c1=5 r5c1<>9 r5c8=9 (r5c8<>8) r5c8<>7 r5c6=7 r4c6<>7 r4c8=7 r4c8<>8 r8c8=8
r3c5<>9 (r3c9=9 r3c9<>8 r3c7=8 r8c7<>8) (r3c5=1 r9c5<>1 r9c5=4 r7c5<>4 r7c5=6 r8c4<>6) r6c5=9 (r4c6<>9) (r5c6<>9) r6c6<>9 r2c6=9 r2c6<>5 r7c6=5 r7c7<>5 r8c7=5 r8c7<>6 r8c8=6 r8c8<>8 r8c9=8
Forcing Net Contradiction in b9 => r3c2<>4
r3c2=4 (r3c2<>5) (r3c2<>5) r3c2<>7 r3c4=7 r3c4<>5 r3c3=5 (r7c3<>5) r2c2<>5 (r2c6=5 r7c6<>5) r8c2=5 r7c1<>5 r7c7=5 r7c7<>4
r3c2=4 (r2c1<>4) r2c2<>4 r2c8=4 r7c8<>4
r3c2=4 (r3c2<>5) (r3c2<>5) r3c2<>7 r3c4=7 (r1c4<>7 r1c4=1 r2c6<>1 r2c1=1 r8c1<>1) r3c4<>5 r3c3=5 r2c2<>5 r8c2=5 r8c1<>5 r8c1=4 r8c7<>4
r3c2=4 (r2c1<>4) r2c2<>4 r2c8=4 r8c8<>4
r3c2=4 (r3c2<>5) (r3c2<>5) r3c2<>7 r3c4=7 (r1c4<>7 r1c4=1 r2c6<>1 r2c1=1 r8c1<>1) r3c4<>5 r3c3=5 r2c2<>5 r8c2=5 r8c1<>5 r8c1=4 r8c9<>4
r3c2=4 (r2c1<>4) r2c2<>4 r2c8=4 r9c8<>4
Forcing Net Contradiction in b7 => r9c3<>4
r9c3=4 (r9c5<>4 r9c5=1 r7c6<>1) r9c3<>5 r9c4=5 r7c6<>5 r7c6=3 r7c3<>3
r9c3=4 (r9c5<>4 r9c5=1 r9c8<>1 r9c8=3 r6c8<>3) (r9c5<>4 r9c5=1 r7c6<>1) r9c3<>5 r9c4=5 r7c6<>5 r7c6=3 r6c6<>3 r6c2=3 r8c2<>3
r9c3=4 r9c3<>3
Brute Force: r5c6=7
Hidden Single: r4c8=7
Forcing Chain Contradiction in r3 => r4c9<>9
r4c9=9 r1c9<>9 r1c9=1 r1c4<>1 r1c4=7 r1c2<>7 r3c2=7 r3c2<>5
r4c9=9 r5c89<>9 r5c1=9 r5c1<>5 r5c3=5 r3c3<>5
r4c9=9 r5c89<>9 r5c1=9 r5c1<>5 r5c3=5 r9c3<>5 r9c4=5 r3c4<>5
Forcing Net Contradiction in r5 => r9c4<>1
r9c4=1 r9c4<>5 r9c3=5 r5c3<>5 r5c1=5 r5c1<>9
r9c4=1 (r9c5<>1 r9c5=4 r7c5<>4 r7c5=6 r8c4<>6) (r9c4<>5 r9c3=5 r8c1<>5) (r9c4<>5 r9c3=5 r8c2<>5) (r3c4<>1) r1c4<>1 r1c4=7 r3c4<>7 r3c4=5 r8c4<>5 r8c7=5 r8c7<>6 r8c8=6 r8c8<>8 r5c8=8 r5c8<>9
r9c4=1 (r9c5<>1 r9c5=4 r7c5<>4 r7c5=6 r8c4<>6 r8c4=3 r5c4<>3) (r9c5<>1 r9c5=4 r9c8<>4 r9c8=3 r5c8<>3) (r9c5<>1 r9c5=4 r9c8<>4 r9c8=3 r7c8<>3) (r1c4<>1) r3c4<>1 r2c6=1 r2c6<>5 r7c6=5 r7c6<>3 r7c3=3 r5c3<>3 r5c9=3 r5c9<>9
Brute Force: r5c7=4
Forcing Chain Verity => r7c5<>4
r3c3=4 r3c9<>4 r8c9=4 r9c8<>4 r9c45=4 r7c5<>4
r4c3=4 r4c4<>4 r6c5=4 r7c5<>4
r7c3=4 r7c5<>4
Forcing Net Verity => r1c1<>1
r8c1=1 r1c1<>1
r8c1=4 (r6c1<>4) (r2c1<>4) (r7c1<>4) r7c3<>4 r7c8=4 (r9c8<>4) r2c8<>4 r2c2=4 (r2c2<>5 r2c6=5 r3c4<>5) (r2c2<>5 r2c6=5 r3c4<>5) r6c2<>4 r6c5=4 r9c5<>4 r9c4=4 r9c4<>5 r8c4=5 r9c4<>5 r9c3=5 r3c3<>5 r3c2=5 r3c2<>7 r3c4=7 r1c4<>7 r1c4=1 r1c1<>1
r8c1=5 (r5c1<>5 r5c3=5 r3c3<>5) r9c3<>5 r9c4=5 r3c4<>5 r3c2=5 r3c2<>7 r3c4=7 r1c4<>7 r1c4=1 r1c1<>1
Forcing Net Contradiction in r8c2 => r4c1<>4
r4c1=4 (r6c2<>4 r6c5=4 r9c5<>4 r9c5=1 r9c3<>1) r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 r9c3<>5 r9c3=3 r8c2<>3
r4c1=4 (r4c4<>4) r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 r9c3<>5 r9c4=5 r9c4<>4 r8c4=4 r8c2<>4
r4c1=4 r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 (r3c3<>5) r9c3<>5 r9c4=5 r3c4<>5 r3c2=5 r8c2<>5
Forcing Net Contradiction in r4c2 => r4c3<>3
r4c3=3 (r4c4<>3) (r4c9<>3) (r4c2<>3) r6c2<>3 r8c2=3 (r8c4<>3) r8c9<>3 r5c9=3 r5c4<>3 (r5c4=6 r5c3<>6) r9c4=3 r9c4<>5 r9c3=5 r5c3<>5 r5c3=3 r4c3<>3
Forcing Chain Contradiction in r8c2 => r4c7<>8
r4c7=8 r4c1<>8 r5c1=8 r5c1<>5 r5c3=5 r5c3<>3 r46c2=3 r8c2<>3
r4c7=8 r3c7<>8 r3c9=8 r3c9<>4 r8c9=4 r8c2<>4
r4c7=8 r4c1<>8 r5c1=8 r5c1<>5 r78c1=5 r8c2<>5
Forcing Net Contradiction in r4 => r3c7=8
r3c7<>8 r3c9=8 r3c9<>4 (r3c3=4 r4c3<>4) (r3c3=4 r7c3<>4) r8c9=4 r7c8<>4 r7c1=4 r7c1<>2 r7c3=2 r4c3<>2 r4c3=6
r3c7<>8 r3c7=1 r4c7<>1 r4c7=6
Forcing Net Contradiction in c3 => r3c9=4
r3c9<>4 r3c3=4
r3c9<>4 (r3c3=4 r7c3<>4) r8c9=4 r7c8<>4 r7c1=4 r7c1<>2 (r7c3=2 r4c3<>2) r1c1=2 r1c1<>6 r1c3=6 r4c3<>6 r4c3=4
Almost Locked Set XY-Wing: A=r359c3 {1356}, B=r27c6 {135}, C=r46c6,r5c4 {1369}, X,Y=1,6, Z=3 => r7c3<>3
Grouped Discontinuous Nice Loop: 1 r9c3 -1- r3c3 -5- r23c2 =5= r8c2 =3= r9c3 => r9c3<>1
Almost Locked Set XY-Wing: A=r79c5 {146}, B=r78c7 {156}, C=r9c348 {1345}, X,Y=1,4, Z=6 => r7c8<>6
Finned Franken Swordfish: 1 r29b7 c168 fr7c3 fr9c5 => r7c6<>1
Discontinuous Nice Loop: 3 r8c4 -3- r8c2 =3= r9c3 =5= r9c4 -5- r7c6 -3- r8c4 => r8c4<>3
Finned Swordfish: 3 r678 c268 fr8c9 => r9c8<>3
Naked Pair: 1,4 in r9c58 => r9c4<>4
Naked Pair: 3,5 in r7c6,r9c4 => r8c4<>5
Skyscraper: 4 in r7c3,r8c4 (connected by r4c34) => r8c12<>4
Locked Candidates Type 1 (Pointing): 4 in b7 => r7c8<>4
Naked Pair: 3,5 in r8c2,r9c3 => r7c13,r8c1<>5
Naked Single: r8c1=1
Hidden Single: r5c1=5
Hidden Single: r4c1=8
Locked Candidates Type 1 (Pointing): 1 in b8 => r6c5<>1
Locked Candidates Type 2 (Claiming): 9 in r5 => r6c8<>9
Naked Pair: 3,6 in r5c34 => r5c89<>3, r5c8<>6
X-Wing: 1 r26 c68 => r4c6,r79c8<>1
Naked Single: r7c8=3
Naked Single: r9c8=4
Naked Single: r7c6=5
Naked Single: r8c9=8
Naked Single: r9c5=1
Naked Single: r2c6=1
Naked Single: r9c4=3
Full House: r9c3=5
Naked Single: r5c9=9
Naked Single: r8c8=6
Naked Single: r7c5=6
Full House: r8c4=4
Full House: r6c5=4
Naked Single: r1c4=7
Full House: r3c4=5
Naked Single: r2c8=9
Full House: r1c9=1
Full House: r4c9=3
Naked Single: r5c4=6
Full House: r4c4=1
Naked Single: r3c3=1
Full House: r3c2=7
Naked Single: r8c2=3
Full House: r8c7=5
Full House: r7c7=1
Full House: r4c7=6
Naked Single: r5c8=8
Full House: r6c8=1
Full House: r5c3=3
Naked Single: r2c1=4
Full House: r2c2=5
Naked Single: r4c6=9
Full House: r6c6=3
Naked Single: r6c2=9
Full House: r6c1=6
Naked Single: r7c1=2
Full House: r1c1=9
Full House: r7c3=4
Naked Single: r1c2=2
Full House: r1c3=6
Full House: r4c3=2
Full House: r4c2=4
|
normal_sudoku_2071
|
...125..38.1...57.3.9......936..4................1..67..2.73.9.64.............62.
|
467125983821936574359847216936784152175362849284519367512673498648291735793458621
|
Basic 9x9 Sudoku 2071
|
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 . . 3
8 . 1 . . . 5 7 .
3 . 9 . . . . . .
9 3 6 . . 4 . . .
. . . . . . . . .
. . . . 1 . . 6 7
. . 2 . 7 3 . 9 .
6 4 . . . . . . .
. . . . . . 6 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
467125983821936574359847216936784152175362849284519367512673498648291735793458621 #1 Easy (318)
Hidden Single: r3c1=3
Hidden Single: r4c4=7
Hidden Single: r1c7=9
Hidden Single: r9c2=9
Hidden Single: r1c2=6
Naked Single: r2c2=2
Hidden Single: r7c4=6
Hidden Single: r8c7=7
Hidden Single: r9c3=3
Hidden Single: r3c2=5
Naked Single: r6c2=8
Naked Single: r7c2=1
Full House: r5c2=7
Naked Single: r7c1=5
Naked Single: r8c3=8
Full House: r9c1=7
Naked Single: r1c1=4
Full House: r1c3=7
Full House: r1c8=8
Naked Single: r6c1=2
Full House: r5c1=1
Naked Single: r6c6=9
Naked Single: r2c6=6
Naked Single: r2c9=4
Naked Single: r3c8=1
Naked Single: r7c9=8
Full House: r7c7=4
Naked Single: r3c7=2
Full House: r3c9=6
Naked Single: r4c8=5
Naked Single: r6c7=3
Naked Single: r4c5=8
Naked Single: r8c8=3
Full House: r5c8=4
Naked Single: r5c7=8
Full House: r4c7=1
Full House: r4c9=2
Full House: r5c9=9
Naked Single: r6c4=5
Full House: r6c3=4
Full House: r5c3=5
Naked Single: r3c5=4
Naked Single: r5c6=2
Naked Single: r3c4=8
Full House: r3c6=7
Naked Single: r9c5=5
Naked Single: r5c4=3
Full House: r5c5=6
Naked Single: r8c6=1
Full House: r9c6=8
Naked Single: r9c4=4
Full House: r9c9=1
Full House: r8c9=5
Naked Single: r8c5=9
Full House: r2c5=3
Full House: r2c4=9
Full House: r8c4=2
|
normal_sudoku_2718
|
...3.68...3.4.75...8.5.16..6....829.8..9...7.3......6..972..............5...1...2
|
715396824236487519984521637641738295852964173379152468197245386428673951563819742
|
Basic 9x9 Sudoku 2718
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 3 . 6 8 . .
. 3 . 4 . 7 5 . .
. 8 . 5 . 1 6 . .
6 . . . . 8 2 9 .
8 . . 9 . . . 7 .
3 . . . . . . 6 .
. 9 7 2 . . . . .
. . . . . . . . .
5 . . . 1 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
715396824236487519984521637641738295852964173379152468197245386428673951563819742 #1 Hard (1074)
Naked Single: r1c4=3
Hidden Single: r2c5=8
Hidden Single: r2c3=6
Hidden Single: r5c5=6
Hidden Single: r6c9=8
Hidden Single: r6c3=9
Hidden Single: r7c9=6
Hidden Single: r7c8=8
Hidden Single: r8c8=5
Locked Pair: 1,7 in r46c4 => r46c5,r89c4<>7
Hidden Single: r9c7=7
Hidden Single: r8c5=7
Hidden Single: r9c6=9
Hidden Single: r8c7=9
Locked Candidates Type 1 (Pointing): 2 in b2 => r6c5<>2
Locked Candidates Type 1 (Pointing): 7 in b4 => r1c2<>7
Locked Candidates Type 2 (Claiming): 1 in c8 => r12c9<>1
Naked Single: r2c9=9
Naked Triple: 1,2,4 in r278c1 => r1c1<>1, r13c1<>2, r13c1<>4
Locked Candidates Type 2 (Claiming): 4 in c1 => r8c23,r9c23<>4
Naked Single: r9c2=6
Naked Single: r9c4=8
Naked Single: r8c4=6
Naked Single: r9c3=3
Full House: r9c8=4
Hidden Single: r8c3=8
Hidden Single: r3c8=3
Locked Candidates Type 1 (Pointing): 4 in b3 => r45c9<>4
Skyscraper: 3 in r4c5,r8c6 (connected by r48c9) => r5c6,r7c5<>3
Hidden Single: r4c5=3
Locked Candidates Type 2 (Claiming): 4 in r4 => r5c23,r6c2<>4
W-Wing: 1/4 in r6c7,r7c1 connected by 4 in r67c5 => r7c7<>1
Naked Single: r7c7=3
Full House: r8c9=1
Naked Single: r4c9=5
Naked Single: r8c2=2
Naked Single: r5c9=3
Naked Single: r8c1=4
Full House: r7c1=1
Full House: r8c6=3
Naked Single: r2c1=2
Full House: r2c8=1
Full House: r1c8=2
Naked Single: r3c3=4
Naked Single: r1c5=9
Full House: r3c5=2
Naked Single: r3c9=7
Full House: r1c9=4
Full House: r3c1=9
Full House: r1c1=7
Naked Single: r4c3=1
Naked Single: r1c3=5
Full House: r1c2=1
Full House: r5c3=2
Naked Single: r4c4=7
Full House: r4c2=4
Full House: r6c4=1
Naked Single: r5c2=5
Full House: r6c2=7
Naked Single: r6c7=4
Full House: r5c7=1
Full House: r5c6=4
Naked Single: r6c5=5
Full House: r6c6=2
Full House: r7c6=5
Full House: r7c5=4
|
normal_sudoku_2285
|
...8..276...7.2..1.2.......28..9.........5.4.4.5..78.985.9.....9.4....2..725.4...
|
341859276598762431627341985286493157719685342435217869853926714964178523172534698
|
Basic 9x9 Sudoku 2285
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 8 . . 2 7 6
. . . 7 . 2 . . 1
. 2 . . . . . . .
2 8 . . 9 . . . .
. . . . . 5 . 4 .
4 . 5 . . 7 8 . 9
8 5 . 9 . . . . .
9 . 4 . . . . 2 .
. 7 2 5 . 4 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
341859276598762431627341985286493157719685342435217869853926714964178523172534698 #1 Extreme (21768) bf
Hidden Single: r1c7=2
Hidden Single: r5c5=8
Hidden Single: r5c9=2
Hidden Single: r7c5=2
Hidden Single: r4c4=4
Hidden Single: r8c6=8
Hidden Single: r6c4=2
Hidden Single: r8c5=7
Naked Triple: 1,3,6 in r7c368 => r7c7<>1, r7c79<>3, r7c7<>6
Brute Force: r4c9=7
Naked Single: r7c9=4
Naked Single: r7c7=7
Brute Force: r4c7=1
Hidden Single: r4c8=5
Skyscraper: 1 in r6c5,r8c4 (connected by r68c2) => r5c4,r9c5<>1
Hidden Single: r6c5=1
Naked Pair: 3,6 in r4c3,r6c2 => r5c123<>3, r5c123<>6
XYZ-Wing: 3/5/6 in r58c7,r8c9 => r9c7<>3
Hidden Rectangle: 1/7 in r3c13,r5c13 => r3c3<>1
Almost Locked Set Chain: 3- r6c2 {36} -6- r6c8 {36} -3- r2379c8 {13689} -6- r8c79,r9c7 {3569} -3 => r8c2<>3
Discontinuous Nice Loop: 6 r3c4 -6- r5c4 =6= r5c7 -6- r6c8 =6= r6c2 -6- r8c2 -1- r8c4 =1= r3c4 => r3c4<>6
W-Wing: 3/6 in r4c6,r9c5 connected by 6 in r58c4 => r7c6<>3
Skyscraper: 3 in r6c2,r7c3 (connected by r67c8) => r4c3<>3
Naked Single: r4c3=6
Full House: r4c6=3
Full House: r5c4=6
Naked Single: r6c2=3
Full House: r6c8=6
Full House: r5c7=3
Hidden Single: r7c6=6
Naked Single: r9c5=3
Full House: r8c4=1
Full House: r3c4=3
Naked Single: r9c9=8
Naked Single: r8c2=6
Naked Single: r3c9=5
Full House: r8c9=3
Full House: r8c7=5
Naked Single: r9c1=1
Full House: r7c3=3
Full House: r7c8=1
Naked Single: r5c1=7
Naked Single: r9c8=9
Full House: r9c7=6
Naked Single: r3c1=6
Naked Single: r3c8=8
Full House: r2c8=3
Naked Single: r3c5=4
Naked Single: r2c1=5
Full House: r1c1=3
Naked Single: r1c5=5
Full House: r2c5=6
Naked Single: r3c7=9
Full House: r2c7=4
Naked Single: r3c3=7
Full House: r3c6=1
Full House: r1c6=9
Naked Single: r2c2=9
Full House: r2c3=8
Naked Single: r1c3=1
Full House: r1c2=4
Full House: r5c2=1
Full House: r5c3=9
|
normal_sudoku_5033
|
1.39...6..9..6.8...86.53.1.3..8....685....19..6..95......5.1..........7...56..92.
|
143987562597162843286453719379814256852736194461295387924571638618329475735648921
|
Basic 9x9 Sudoku 5033
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . 3 9 . . . 6 .
. 9 . . 6 . 8 . .
. 8 6 . 5 3 . 1 .
3 . . 8 . . . . 6
8 5 . . . . 1 9 .
. 6 . . 9 5 . . .
. . . 5 . 1 . . .
. . . . . . . 7 .
. . 5 6 . . 9 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
143987562597162843286453719379814256852736194461295387924571638618329475735648921 #1 Extreme (13998) bf
Hidden Single: r3c2=8
Hidden Single: r4c3=9
Hidden Single: r2c4=1
Hidden Single: r4c5=1
Hidden Single: r2c1=5
Hidden Single: r5c6=6
Hidden Single: r3c9=9
Hidden Single: r8c6=9
Hidden Single: r7c1=9
Hidden Single: r6c3=1
Hidden Single: r4c8=5
Hidden Single: r7c7=6
Hidden Single: r8c1=6
Forcing Net Verity => r1c2<>2
r3c1=2 r1c2<>2
r3c4=2 (r3c7<>2) (r2c6<>2 r4c6=2 r4c7<>2) r3c1<>2 r6c1=2 r6c7<>2 r1c7=2 r1c2<>2
r3c7=2 (r2c9<>2) (r4c7<>2) r3c1<>2 r6c1=2 r4c2<>2 r4c6=2 r2c6<>2 r2c3=2 r1c2<>2
Forcing Net Contradiction in c8 => r7c2<>4
r7c2=4 (r7c3<>4) (r8c3<>4) (r1c2<>4 r1c2=7 r2c3<>7) r9c1<>4 r9c1=7 r7c3<>7 r5c3=7 r5c3<>4 r2c3=4 r2c8<>4
r7c2=4 (r9c1<>4 r9c1=7 r6c1<>7) (r4c2<>4) r1c2<>4 r1c2=7 r4c2<>7 r4c2=2 r6c1<>2 r6c1=4 r6c8<>4
r7c2=4 r7c8<>4
Brute Force: r6c4=2
Hidden Single: r3c1=2
Locked Candidates Type 1 (Pointing): 3 in b5 => r5c9<>3
Locked Candidates Type 1 (Pointing): 2 in b8 => r1c5<>2
W-Wing: 4/7 in r3c7,r4c6 connected by 7 in r35c4 => r4c7<>4
2-String Kite: 4 in r4c6,r9c1 (connected by r4c2,r6c1) => r9c6<>4
Turbot Fish: 4 r2c3 =4= r1c2 -4- r4c2 =4= r4c6 => r2c6<>4
Empty Rectangle: 4 in b6 (r69c1) => r9c9<>4
Discontinuous Nice Loop: 4 r6c7 -4- r3c7 =4= r3c4 -4- r8c4 -3- r8c7 =3= r6c7 => r6c7<>4
XY-Wing: 4/7/3 in r2c8,r36c7 => r6c8<>3
Grouped AIC: 7 7- r1c2 -4- r2c3 =4= r2c89 -4- r3c7 -7 => r1c79<>7
Turbot Fish: 7 r2c9 =7= r3c7 -7- r3c4 =7= r5c4 => r5c9<>7
W-Wing: 4/7 in r2c3,r6c1 connected by 7 in r26c9 => r5c3<>4
W-Wing: 7/4 in r1c2,r9c1 connected by 4 in r4c2,r6c1 => r79c2<>7
Turbot Fish: 7 r1c2 =7= r2c3 -7- r7c3 =7= r7c5 => r1c5<>7
W-Wing: 7/4 in r4c6,r9c1 connected by 4 in r4c2,r6c1 => r9c6<>7
Naked Single: r9c6=8
Hidden Single: r1c5=8
Locked Candidates Type 1 (Pointing): 7 in b8 => r5c5<>7
Turbot Fish: 7 r3c7 =7= r3c4 -7- r5c4 =7= r4c6 => r4c7<>7
Naked Single: r4c7=2
Naked Single: r5c9=4
Naked Single: r5c5=3
Naked Single: r6c8=8
Naked Single: r5c4=7
Full House: r4c6=4
Full House: r5c3=2
Full House: r4c2=7
Full House: r6c1=4
Full House: r9c1=7
Naked Single: r3c4=4
Full House: r3c7=7
Full House: r8c4=3
Naked Single: r1c2=4
Full House: r2c3=7
Naked Single: r9c5=4
Naked Single: r6c7=3
Full House: r6c9=7
Naked Single: r1c7=5
Full House: r8c7=4
Naked Single: r2c6=2
Full House: r1c6=7
Full House: r1c9=2
Naked Single: r8c5=2
Full House: r7c5=7
Naked Single: r7c8=3
Full House: r2c8=4
Full House: r2c9=3
Naked Single: r8c3=8
Full House: r7c3=4
Naked Single: r8c2=1
Full House: r8c9=5
Naked Single: r7c2=2
Full House: r7c9=8
Full House: r9c9=1
Full House: r9c2=3
|
normal_sudoku_3832
|
4.69....1....4..........2....451.92..7.692...5.9..4..6.3.4.......5....8.9.1.6...2
|
456923871217845369398176245684517923173692458529384716832451697765239184941768532
|
Basic 9x9 Sudoku 3832
|
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.
|
4 . 6 9 . . . . 1
. . . . 4 . . . .
. . . . . . 2 . .
. . 4 5 1 . 9 2 .
. 7 . 6 9 2 . . .
5 . 9 . . 4 . . 6
. 3 . 4 . . . . .
. . 5 . . . . 8 .
9 . 1 . 6 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
456923871217845369398176245684517923173692458529384716832451697765239184941768532 #1 Extreme (11656) bf
Brute Force: r5c6=2
Hidden Single: r6c2=2
Hidden Single: r1c5=2
Hidden Single: r5c1=1
Hidden Single: r8c4=2
Locked Candidates Type 1 (Pointing): 1 in b8 => r23c6<>1
Naked Triple: 4,6,8 in r489c2 => r123c2<>8
Naked Single: r1c2=5
Hidden Pair: 1,9 in r78c6 => r7c6<>5, r78c6<>7, r7c6<>8, r8c6<>3
Empty Rectangle: 8 in b5 (r1c67) => r6c7<>8
Locked Candidates Type 2 (Claiming): 8 in r6 => r4c6<>8
Sashimi X-Wing: 7 r14 c69 fr1c7 fr1c8 => r23c9<>7
Grouped AIC: 3 3- r4c6 -7- r4c9 =7= r78c9 -7- r9c78 =7= r9c46 -7- r8c5 -3 => r6c5,r9c6<>3
Finned Swordfish: 3 r169 c478 fr1c6 => r23c4<>3
W-Wing: 7/3 in r4c6,r8c5 connected by 3 in r69c4 => r6c5,r9c6<>7
Naked Single: r6c5=8
Locked Candidates Type 1 (Pointing): 8 in b8 => r9c2<>8
Naked Single: r9c2=4
Naked Single: r8c2=6
Naked Single: r4c2=8
Naked Single: r8c1=7
Naked Single: r5c3=3
Full House: r4c1=6
Naked Single: r8c5=3
Hidden Single: r6c4=3
Full House: r4c6=7
Full House: r4c9=3
Hidden Single: r7c9=7
Naked Single: r7c5=5
Full House: r3c5=7
Naked Single: r9c6=8
Naked Single: r3c3=8
Naked Single: r1c6=3
Naked Single: r9c4=7
Naked Single: r3c1=3
Naked Single: r3c4=1
Full House: r2c4=8
Naked Single: r7c3=2
Full House: r2c3=7
Full House: r7c1=8
Full House: r2c1=2
Naked Single: r1c8=7
Full House: r1c7=8
Naked Single: r3c2=9
Full House: r2c2=1
Naked Single: r6c8=1
Full House: r6c7=7
Hidden Single: r5c9=8
Locked Candidates Type 2 (Claiming): 5 in c9 => r2c78,r3c8<>5
Bivalue Universal Grave + 1 => r2c8<>3, r2c8<>9
Naked Single: r2c8=6
Naked Single: r2c6=5
Full House: r3c6=6
Naked Single: r2c7=3
Full House: r2c9=9
Naked Single: r3c8=4
Full House: r3c9=5
Full House: r8c9=4
Naked Single: r7c8=9
Naked Single: r9c7=5
Full House: r9c8=3
Full House: r5c8=5
Full House: r5c7=4
Naked Single: r8c7=1
Full House: r7c7=6
Full House: r7c6=1
Full House: r8c6=9
|
normal_sudoku_4298
|
...........82..9.......5.78.6..1..933198..4....29..8......4.6....6.2...99..6...8.
|
295487136178263945643195278864512793319876452752934861581349627436728519927651384
|
Basic 9x9 Sudoku 4298
|
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 . . 9 . .
. . . . . 5 . 7 8
. 6 . . 1 . . 9 3
3 1 9 8 . . 4 . .
. . 2 9 . . 8 . .
. . . . 4 . 6 . .
. . 6 . 2 . . . 9
9 . . 6 . . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
295487136178263945643195278864512793319876452752934861581349627436728519927651384 #1 Extreme (32442) bf
Hidden Single: r5c3=9
Hidden Single: r4c1=8
Hidden Single: r7c6=9
Hidden Single: r1c5=8
Hidden Single: r7c2=8
Hidden Single: r8c6=8
Hidden Single: r1c2=9
Hidden Single: r3c5=9
Hidden Single: r3c1=6
Brute Force: r5c8=5
X-Wing: 2 c18 r17 => r1c79,r7c9<>2
2-String Kite: 5 in r4c3,r9c5 (connected by r4c4,r6c5) => r9c3<>5
Forcing Chain Contradiction in r1 => r6c6<>6
r6c6=6 r1c6<>6
r6c6=6 r5c56<>6 r5c9=6 r5c9<>2 r9c9=2 r7c8<>2 r1c8=2 r1c8<>6
r6c6=6 r6c8<>6 r12c8=6 r1c9<>6
Brute Force: r5c9=2
Naked Single: r4c7=7
Hidden Single: r4c6=2
Locked Candidates Type 1 (Pointing): 7 in b4 => r6c56<>7
Locked Candidates Type 1 (Pointing): 6 in b6 => r6c5<>6
Finned X-Wing: 4 r34 c34 fr3c2 => r1c3<>4
Finned Swordfish: 7 r268 c124 fr2c5 fr2c6 => r1c4<>7
Locked Candidates Type 2 (Claiming): 7 in c4 => r9c56<>7
Naked Pair: 3,5 in r69c5 => r2c5<>3
Uniqueness Test 1: 6/7 in r2c56,r5c56 => r2c6<>6, r2c6<>7
Naked Triple: 1,3,4 in r13c4,r2c6 => r1c6<>1, r1c6<>3, r1c6<>4
Forcing Net Contradiction in c9 => r7c1<>7
r7c1=7 r7c9<>7
r7c1=7 (r9c3<>7 r1c3=7 r1c3<>5) (r9c3<>7 r9c9=7 r9c9<>4) r7c1<>2 r7c8=2 r9c7<>2 r9c2=2 r9c2<>4 r9c3=4 (r3c3<>4) r4c3<>4 r4c4=4 (r1c4<>4 r1c9=4 r2c9<>4) (r6c6<>4 r6c1=4 r6c6<>4 r6c6=3 r9c6<>3 r9c6=1 r9c7<>1) (r6c6<>4 r6c1=4 r6c6<>4 r6c6=3 r6c5<>3 r9c5=3 r9c7<>3) r3c4<>4 r3c2=4 r3c2<>2 r3c7=2 r9c7<>2 r9c7=5 (r1c7<>5) r9c7<>2 r9c2=2 r3c2<>2 r3c7=2 r1c8<>2 r1c1=2 r1c1<>5 r1c9=5 r1c9<>4 r9c9=4 r9c9<>7
Forcing Net Contradiction in r9c9 => r7c9<>5
r7c9=5 (r9c7<>5) (r9c9<>5) (r7c4<>5) (r7c3<>5) (r8c7<>5) r9c7<>5 r1c7=5 r1c3<>5 r4c3=5 r4c4<>5 r8c4=5 r9c5<>5 r9c2=5 (r9c2<>4) (r9c2<>2 r9c7=2 r3c7<>2 r3c2=2 r3c2<>4) r9c5<>5 r6c5=5 r4c4<>5 r4c4=4 r3c4<>4 r3c3=4 r9c3<>4 r9c9=4 r9c9<>7 r7c9=7 r7c9<>5
Forcing Net Contradiction in r2 => r7c3<>7
r7c3=7 (r7c9<>7 r7c9=1 r8c7<>1) (r7c9<>7 r7c9=1 r8c8<>1) (r8c1<>7) r8c2<>7 r8c4=7 r8c4<>1 r8c1=1 r2c1<>1
r7c3=7 (r7c9<>7 r7c9=1 r9c7<>1) (r7c9<>7 r7c9=1 r9c9<>1) (r7c9<>7 r7c9=1 r8c7<>1) (r7c9<>7 r7c9=1 r8c8<>1) (r8c1<>7) r8c2<>7 r8c4=7 r8c4<>1 r8c1=1 r9c3<>1 r9c6=1 r2c6<>1
r7c3=7 r7c9<>7 r7c9=1 r6c9<>1 r6c8=1 r2c8<>1
r7c3=7 r7c9<>7 r7c9=1 r2c9<>1
Forcing Net Contradiction in r8 => r1c8<>6
r1c8=6 (r1c8<>4) (r1c6<>6 r1c6=7 r1c3<>7 r9c3=7 r9c3<>4) r1c8<>2 r1c1=2 (r1c1<>4) (r1c1<>4) r7c1<>2 r7c8=2 r9c7<>2 r9c2=2 r9c2<>4 r9c9=4 (r8c8<>4 r2c8=4 r2c6<>4 r6c6=4 r6c1<>4) r1c9<>4 r1c4=4 (r3c4<>4) r4c4<>4 r4c3=4 r3c3<>4 r3c2=4 r2c1<>4 r8c1=4 r8c1<>1
r1c8=6 r1c6<>6 r1c6=7 r1c3<>7 r9c3=7 (r8c1<>7) r8c2<>7 r8c4=7 r8c4<>1
r1c8=6 (r1c8<>4) (r1c6<>6 r1c6=7 r1c3<>7 r9c3=7 r9c3<>4) r1c8<>2 r1c1=2 (r1c1<>4) r7c1<>2 r7c8=2 r9c7<>2 r9c2=2 r9c2<>4 r9c9=4 r1c9<>4 r1c4=4 r4c4<>4 r4c4=5 r6c5<>5 r9c5=5 (r9c7<>5) r9c9<>5 r8c7=5 r8c7<>1
r1c8=6 r6c8<>6 r6c8=1 r8c8<>1
Forcing Net Verity => r1c9<>1
r1c8=4 (r2c9<>4 r9c9=4 r9c9<>7) r1c8<>2 r1c1=2 (r1c1<>7) r7c1<>2 r7c8=2 r9c7<>2 r9c2=2 r9c2<>7 r9c3=7 r1c3<>7 r1c6=7 r1c6<>6 r1c9=6 r1c9<>1
r1c9=4 r1c9<>1
r2c8=4 r2c8<>6 r6c8=6 r6c9<>6 r6c9=1 r1c9<>1
r2c9=4 (r2c9<>5) r2c6<>4 r6c6=4 r6c6<>3 r6c5=3 r9c5<>3 r9c5=5 r9c9<>5 r1c9=5 r1c9<>1
Forcing Net Contradiction in r1 => r6c2<>4
r6c2=4 (r9c2<>4) (r3c2<>4) r4c3<>4 r4c4=4 (r1c4<>4) r3c4<>4 r3c3=4 (r1c1<>4) r9c3<>4 r9c9=4 r1c9<>4 r1c8=4 r1c8<>2 r1c1=2 r1c1<>5
r6c2=4 r4c3<>4 r4c3=5 r1c3<>5
r6c2=4 (r9c2<>4) (r3c2<>4) r4c3<>4 r4c4=4 r3c4<>4 r3c3=4 r9c3<>4 r9c9=4 r9c9<>5 r89c7=5 r1c7<>5
r6c2=4 (r6c2<>7 r6c1=7 r1c1<>7) (r6c6<>4 r6c6=3 r9c6<>3 r9c6=1 r9c3<>1) (r6c6<>4 r6c6=3 r6c5<>3 r9c5=3 r9c3<>3) (r3c2<>4) r4c3<>4 r4c4=4 r3c4<>4 r3c3=4 r9c3<>4 r9c3=7 r1c3<>7 r1c6=7 r1c6<>6 r1c9=6 r1c9<>5
Forcing Net Contradiction in r2 => r7c8<>1
r7c8=1 (r8c7<>1) (r8c8<>1) r7c9<>1 r7c9=7 r7c4<>7 r8c4=7 r8c4<>1 r8c1=1 r2c1<>1
r7c8=1 (r9c7<>1) (r9c9<>1) (r8c7<>1) (r8c8<>1) r7c9<>1 r7c9=7 r7c4<>7 r8c4=7 r8c4<>1 r8c1=1 r9c3<>1 r9c6=1 r2c6<>1
r7c8=1 r2c8<>1
r7c8=1 r6c8<>1 r6c9=1 r2c9<>1
Forcing Net Contradiction in c4 => r1c1<>7
r1c1=7 (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r2c8<>3) (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r8c7<>3) (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r8c8<>3) (r8c1<>7) r1c3<>7 r9c3=7 r8c2<>7 r8c4=7 r8c4<>3 r8c2=3 r2c2<>3 r2c6=3 r1c4<>3
r1c1=7 (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r2c8<>3) (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r8c7<>3) (r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r8c8<>3) (r8c1<>7) r1c3<>7 r9c3=7 r8c2<>7 r8c4=7 r8c4<>3 r8c2=3 r2c2<>3 r2c6=3 r3c4<>3
r1c1=7 r1c1<>2 r1c8=2 r7c8<>2 r7c8=3 r7c4<>3
r1c1=7 (r8c1<>7) r1c3<>7 r9c3=7 r8c2<>7 r8c4=7 r8c4<>3
Forcing Chain Contradiction in r9c3 => r9c9<>1
r9c9=1 r9c3<>1
r9c9=1 r9c6<>1 r9c6=3 r9c3<>3
r9c9=1 r9c6<>1 r9c6=3 r6c6<>3 r6c6=4 r6c1<>4 r4c3=4 r9c3<>4
r9c9=1 r6c9<>1 r6c9=6 r1c9<>6 r1c6=6 r1c6<>7 r1c3=7 r9c3<>7
Forcing Net Contradiction in r1c9 => r1c7<>5
r1c7=5 (r1c9<>5) r2c9<>5 r9c9=5 (r9c9<>4 r8c8=4 r1c8<>4) r9c5<>5 r6c5=5 (r4c4<>5 r4c4=4 r1c4<>4) (r6c1<>5) r6c2<>5 r6c2=7 r6c1<>7 r6c1=4 r1c1<>4 r1c9=4
r1c7=5 (r1c9<>5) r2c9<>5 r9c9=5 (r9c9<>7) r9c5<>5 r6c5=5 r6c2<>5 r6c2=7 r9c2<>7 r9c3=7 r1c3<>7 r1c6=7 r1c6<>6 r1c9=6
Locked Candidates Type 1 (Pointing): 5 in b3 => r9c9<>5
Forcing Chain Contradiction in r8 => r8c2<>5
r8c2=5 r7c13<>5 r7c4=5 r4c4<>5 r4c4=4 r4c3<>4 r6c1=4 r8c1<>4
r8c2=5 r8c2<>4
r8c2=5 r7c13<>5 r7c4=5 r7c4<>7 r7c9=7 r9c9<>7 r9c9=4 r8c8<>4
Forcing Chain Contradiction in c8 => r9c2<>5
r9c2=5 r9c2<>2 r9c7=2 r3c7<>2 r1c8=2 r1c8<>4
r9c2=5 r9c5<>5 r9c5=3 r6c5<>3 r6c6=3 r6c6<>4 r2c6=4 r2c8<>4
r9c2=5 r7c13<>5 r7c4=5 r7c4<>7 r7c9=7 r9c9<>7 r9c9=4 r8c8<>4
Discontinuous Nice Loop: 7 r2c1 -7- r2c5 -6- r1c6 =6= r1c9 =5= r2c9 -5- r2c2 =5= r6c2 =7= r6c1 -7- r2c1 => r2c1<>7
Discontinuous Nice Loop: 5 r7c4 -5- r4c4 -4- r4c3 =4= r6c1 =7= r8c1 -7- r8c4 =7= r7c4 => r7c4<>5
Locked Candidates Type 2 (Claiming): 5 in r7 => r8c1<>5
Discontinuous Nice Loop: 1 r8c7 -1- r7c9 -7- r7c4 =7= r8c4 =5= r8c7 => r8c7<>1
Sashimi X-Wing: 1 c67 r29 fr1c7 fr3c7 => r2c89<>1
Finned Franken Swordfish: 1 r29b3 c367 fr1c8 fr2c1 => r1c3<>1
Forcing Chain Contradiction in c9 => r4c3=4
r4c3<>4 r4c3=5 r6c2<>5 r2c2=5 r2c9<>5 r1c9=5 r1c9<>4
r4c3<>4 r4c4=4 r6c6<>4 r2c6=4 r2c9<>4
r4c3<>4 r6c1=4 r6c1<>7 r8c1=7 r9c23<>7 r9c9=7 r9c9<>4
Full House: r4c4=5
Naked Single: r6c5=3
Naked Single: r6c6=4
Naked Single: r9c5=5
Hidden Single: r8c7=5
Empty Rectangle: 3 in b9 (r29c6) => r2c8<>3
Naked Triple: 4,5,6 in r12c9,r2c8 => r1c8<>4
2-String Kite: 4 in r2c8,r9c2 (connected by r8c8,r9c9) => r2c2<>4
W-Wing: 1/3 in r3c3,r9c6 connected by 3 in r2c26 => r9c3<>1
W-Wing: 3/1 in r1c7,r2c6 connected by 1 in r9c67 => r1c4<>3
W-Wing: 3/1 in r3c3,r9c6 connected by 1 in r2c16 => r9c3<>3
Naked Single: r9c3=7
Naked Single: r9c9=4
Hidden Single: r1c6=7
Naked Single: r2c5=6
Full House: r5c5=7
Full House: r5c6=6
Naked Single: r2c8=4
Naked Single: r2c9=5
Naked Single: r1c9=6
Naked Single: r2c1=1
Naked Single: r6c9=1
Full House: r6c8=6
Full House: r7c9=7
Naked Single: r2c6=3
Full House: r2c2=7
Full House: r9c6=1
Naked Single: r3c3=3
Naked Single: r8c1=4
Naked Single: r6c2=5
Full House: r6c1=7
Naked Single: r7c4=3
Full House: r8c4=7
Naked Single: r1c3=5
Full House: r7c3=1
Naked Single: r8c2=3
Full House: r8c8=1
Naked Single: r7c8=2
Full House: r1c8=3
Full House: r7c1=5
Full House: r1c1=2
Full House: r9c2=2
Full House: r9c7=3
Full House: r3c2=4
Naked Single: r1c7=1
Full House: r1c4=4
Full House: r3c4=1
Full House: r3c7=2
|
normal_sudoku_3766
|
....9......78..6.58....6.2.9...6.48.......7.9.1.9..........2..4.3..49...4..6..29.
|
563297148297814635841356927925761483386425719714938562679182354132549876458673291
|
Basic 9x9 Sudoku 3766
|
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 8 . . 6 . 5
8 . . . . 6 . 2 .
9 . . . 6 . 4 8 .
. . . . . . 7 . 9
. 1 . 9 . . . . .
. . . . . 2 . . 4
. 3 . . 4 9 . . .
4 . . 6 . . 2 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
563297148297814635841356927925761483386425719714938562679182354132549876458673291 #1 Extreme (14154) bf
Hidden Single: r6c4=9
Hidden Single: r2c2=9
Hidden Single: r3c7=9
Hidden Single: r7c3=9
Brute Force: r5c5=2
Hidden Single: r2c1=2
Hidden Single: r1c4=2
Hidden Single: r4c2=2
Hidden Single: r8c3=2
Hidden Single: r6c9=2
Hidden Single: r6c1=7
Hidden Single: r8c9=6
Hidden Single: r8c7=8
Hidden Single: r1c9=8
Swordfish: 7 r148 c468 => r37c4,r7c8,r9c6<>7
Naked Triple: 1,3,5 in r7c478 => r7c15<>1, r7c125<>5, r7c5<>3
Naked Single: r7c1=6
Naked Pair: 3,5 in r4c3,r5c1 => r5c23,r6c3<>5, r56c3<>3
Skyscraper: 1 in r7c7,r8c1 (connected by r1c17) => r8c8<>1
2-String Kite: 4 in r3c4,r6c3 (connected by r5c4,r6c6) => r3c3<>4
Finned Jellyfish: 5 r5678 c1478 fr5c6 fr6c5 fr6c6 => r4c4<>5
Empty Rectangle: 5 in b2 (r4c36) => r3c3<>5
Sue de Coq: r1c123 - {13456} (r1c7 - {13}, r3c2 - {45}) => r1c68<>1, r1c68<>3
Discontinuous Nice Loop: 3 r5c4 -3- r5c1 -5- r4c3 =5= r4c6 =7= r1c6 -7- r1c8 -4- r2c8 =4= r2c6 -4- r3c4 =4= r5c4 => r5c4<>3
Discontinuous Nice Loop: 5 r6c8 -5- r8c8 -7- r1c8 -4- r2c8 =4= r2c6 -4- r6c6 =4= r6c3 =6= r6c8 => r6c8<>5
Grouped Discontinuous Nice Loop: 5 r5c4 -5- r7c4 =5= r7c78 -5- r8c8 -7- r1c8 -4- r2c8 =4= r2c6 -4- r3c4 =4= r5c4 => r5c4<>5
Grouped AIC: 4 4- r6c3 =4= r6c6 -4- r2c6 =4= r2c8 -4- r1c8 -7- r8c8 -5- r5c8 =5= r6c7 -5- r6c5 =5= r456c6 -5- r1c6 =5= r1c123 -5- r3c2 -4- r3c4 =4= r5c4 -4 => r5c23,r6c6<>4
Hidden Single: r6c3=4
Hidden Single: r6c8=6
Locked Candidates Type 1 (Pointing): 8 in b4 => r5c6<>8
Grouped AIC: 4 4- r2c6 =4= r2c8 -4- r1c8 -7- r8c8 -5- r5c8 =5= r6c7 -5- r6c5 =5= r456c6 -5- r1c6 =5= r1c123 -5- r3c2 -4- r3c4 =4= r5c4 -4 => r3c4,r5c6<>4
Hidden Single: r3c2=4
Hidden Single: r5c4=4
Locked Candidates Type 1 (Pointing): 5 in b1 => r1c6<>5
Discontinuous Nice Loop: 3 r5c6 -3- r5c1 =3= r4c3 -3- r4c9 -1- r5c8 =1= r5c6 => r5c6<>3
Grouped AIC: 4/7 7- r1c6 =7= r3c5 =5= r3c4 -5- r7c4 =5= r7c78 -5- r8c8 -7- r1c8 -4 => r1c6<>4, r1c8<>7
Naked Single: r1c6=7
Naked Single: r1c8=4
Hidden Single: r2c6=4
Hidden Single: r8c8=7
Hidden Single: r3c9=7
Hidden Single: r4c4=7
Locked Candidates Type 1 (Pointing): 1 in b5 => r9c6<>1
Locked Candidates Type 1 (Pointing): 5 in b9 => r7c4<>5
2-String Kite: 3 in r2c8,r7c4 (connected by r2c5,r3c4) => r7c8<>3
Skyscraper: 3 in r1c1,r2c8 (connected by r5c18) => r1c7<>3
Naked Single: r1c7=1
Full House: r2c8=3
Full House: r2c5=1
Hidden Single: r8c1=1
Full House: r8c4=5
Naked Single: r3c4=3
Full House: r3c5=5
Full House: r3c3=1
Full House: r7c4=1
Naked Single: r7c8=5
Full House: r5c8=1
Naked Single: r7c7=3
Full House: r6c7=5
Full House: r4c9=3
Full House: r9c9=1
Naked Single: r5c6=5
Naked Single: r4c3=5
Full House: r4c6=1
Naked Single: r5c1=3
Full House: r1c1=5
Naked Single: r9c3=8
Naked Single: r1c2=6
Full House: r1c3=3
Full House: r5c3=6
Full House: r5c2=8
Naked Single: r7c2=7
Full House: r7c5=8
Full House: r9c2=5
Naked Single: r9c6=3
Full House: r6c6=8
Full House: r6c5=3
Full House: r9c5=7
|
normal_sudoku_200
|
.8..29...4.58..92...2.5....52..84...8....6.4....2..813.479..18.9.1.4...7....3....
|
786429351435817926192653478523184769819376542674295813347962185961548237258731694
|
Basic 9x9 Sudoku 200
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 . . 2 9 . . .
4 . 5 8 . . 9 2 .
. . 2 . 5 . . . .
5 2 . . 8 4 . . .
8 . . . . 6 . 4 .
. . . 2 . . 8 1 3
. 4 7 9 . . 1 8 .
9 . 1 . 4 . . . 7
. . . . 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
786429351435817926192653478523184769819376542674295813347962185961548237258731694 #1 Easy (264)
Hidden Single: r1c5=2
Naked Single: r7c5=6
Naked Single: r8c4=5
Naked Single: r7c6=2
Naked Single: r7c1=3
Full House: r7c9=5
Naked Single: r8c6=8
Naked Single: r8c2=6
Naked Single: r8c8=3
Full House: r8c7=2
Naked Single: r9c1=2
Naked Single: r9c2=5
Full House: r9c3=8
Hidden Single: r6c6=5
Hidden Single: r6c3=4
Hidden Single: r3c9=8
Hidden Single: r3c2=9
Naked Single: r6c2=7
Naked Single: r6c1=6
Full House: r6c5=9
Hidden Single: r4c4=1
Naked Single: r5c5=7
Full House: r2c5=1
Full House: r5c4=3
Naked Single: r9c4=7
Full House: r9c6=1
Naked Single: r5c7=5
Naked Single: r2c2=3
Full House: r5c2=1
Naked Single: r2c9=6
Full House: r2c6=7
Full House: r3c6=3
Naked Single: r5c3=9
Full House: r4c3=3
Full House: r1c3=6
Full House: r5c9=2
Naked Single: r3c8=7
Naked Single: r4c9=9
Naked Single: r1c4=4
Full House: r3c4=6
Naked Single: r1c8=5
Naked Single: r3c1=1
Full House: r3c7=4
Full House: r1c1=7
Naked Single: r4c8=6
Full House: r4c7=7
Full House: r9c8=9
Naked Single: r9c9=4
Full House: r1c9=1
Full House: r1c7=3
Full House: r9c7=6
|
normal_sudoku_2611
|
..1.7..62.9.4.23................47..9.25.7.3..7.23..45.2.9.358.5...2....8.9......
|
481375962795462318263891457358614729942587136176239845627943581514728693839156274
|
Basic 9x9 Sudoku 2611
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puzzles4_forum_hardest_1905
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Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
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. . 1 . 7 . . 6 2
. 9 . 4 . 2 3 . .
. . . . . . . . .
. . . . . 4 7 . .
9 . 2 5 . 7 . 3 .
. 7 . 2 3 . . 4 5
. 2 . 9 . 3 5 8 .
5 . . . 2 . . . .
8 . 9 . . . . . .
| 9
| 9
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None
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Complete the sudoku board based on the rules and visual elements.
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sudoku
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sudoku_annotation
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hard
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481375962795462318263891457358614729942587136176239845627943581514728693839156274 #1 Extreme (18084) bf
X-Wing: 9 r16 c67 => r3c67,r8c7<>9
Grouped Discontinuous Nice Loop: 4 r1c2 -4- r13c1 =4= r7c1 -4- r7c5 =4= r9c5 =5= r9c6 -5- r1c6 =5= r1c2 => r1c2<>4
Forcing Net Contradiction in b3 => r1c1=4
r1c1<>4 (r1c1=3 r1c4<>3 r1c4=8 r2c5<>8) (r1c1=3 r1c4<>3 r1c4=8 r8c4<>8 r8c6=8 r6c6<>8) r1c7=4 r1c7<>9 r1c6=9 r6c6<>9 r6c7=9 r6c7<>8 r6c3=8 r2c3<>8 r2c9=8
r1c1<>4 (r1c1=3 r1c4<>3 r1c4=8 r1c7<>8) (r1c1=3 r1c4<>3 r1c4=8 r2c5<>8) (r1c1=3 r1c4<>3 r1c4=8 r3c5<>8) r1c7=4 r1c7<>9 r1c6=9 r6c6<>9 r6c7=9 (r6c7<>8) (r4c8<>9) r4c9<>9 r4c5=9 r4c5<>8 r5c5=8 r5c7<>8 r3c7=8
Naked Triple: 1,6,7 in r267c1 => r34c1<>6, r3c1<>7, r4c1<>1
Forcing Net Contradiction in r4 => r3c3<>6
r3c3=6 (r6c3<>6 r6c3=8 r2c3<>8 r2c3=5 r4c3<>5) (r4c3<>6) (r6c3<>6 r6c3=8 r4c3<>8) r3c3<>2 r3c1=2 r4c1<>2 r4c1=3 r4c3<>3 r4c3=2
r3c3=6 r9c7=2 r9c8<>2 r4c8=2
Brute Force: r5c3=2
Naked Single: r4c1=3
Naked Single: r3c1=2
Hidden Single: r4c8=2
Hidden Single: r9c7=2
Hidden Single: r5c2=4
AIC: 3/5 5- r1c2 =5= r1c6 -5- r9c6 =5= r9c5 =4= r9c9 =3= r9c2 -3- r8c3 =3= r3c3 -3 => r1c2<>3, r3c3<>5
Hidden Single: r1c4=3
Finned Franken Swordfish: 1 r57b4 c159 fr4c2 fr5c7 => r4c9<>1
Finned Franken Swordfish: 8 r25b4 c359 fr4c2 fr5c7 => r4c9<>8
Grouped Discontinuous Nice Loop: 6 r3c5 -6- r5c5 =6= r5c79 -6- r4c9 -9- r4c5 =9= r3c5 => r3c5<>6
Grouped Discontinuous Nice Loop: 6 r6c6 -6- r5c5 =6= r5c79 -6- r4c9 -9- r4c5 =9= r6c6 => r6c6<>6
Finned Jellyfish: 6 r2567 c1359 fr5c7 fr6c7 => r4c9<>6
Naked Single: r4c9=9
Hidden Single: r3c5=9
Hidden Single: r6c6=9
Hidden Single: r1c7=9
Hidden Single: r8c8=9
Finned Jellyfish: 1 r2567 c1579 fr2c8 => r3c79<>1
Discontinuous Nice Loop: 1 r8c9 -1- r9c8 -7- r9c4 =7= r8c4 =8= r8c6 -8- r1c6 -5- r9c6 =5= r9c5 =4= r9c9 =3= r8c9 => r8c9<>1
Discontinuous Nice Loop: 1 r9c2 -1- r9c8 -7- r9c4 =7= r8c4 =8= r8c6 -8- r1c6 -5- r9c6 =5= r9c5 =4= r9c9 =3= r9c2 => r9c2<>1
2-String Kite: 1 in r6c7,r8c2 (connected by r4c2,r6c1) => r8c7<>1
Locked Candidates Type 2 (Claiming): 1 in c7 => r5c9<>1
Discontinuous Nice Loop: 6 r8c4 -6- r8c7 -4- r9c9 =4= r9c5 =5= r9c6 -5- r1c6 -8- r8c6 =8= r8c4 => r8c4<>6
Discontinuous Nice Loop: 1 r9c5 -1- r9c8 -7- r9c4 =7= r8c4 =8= r8c6 -8- r1c6 -5- r9c6 =5= r9c5 => r9c5<>1
Discontinuous Nice Loop: 1 r9c9 -1- r9c8 -7- r9c4 =7= r8c4 =8= r8c6 -8- r1c6 -5- r9c6 =5= r9c5 =4= r9c9 => r9c9<>1
Discontinuous Nice Loop: 7 r9c9 -7- r9c4 =7= r8c4 =8= r8c6 -8- r1c6 -5- r9c6 =5= r9c5 =4= r9c9 => r9c9<>7
Grouped Discontinuous Nice Loop: 7 r2c9 -7- r2c13 =7= r3c3 =3= r3c2 -3- r9c2 =3= r9c9 =4= r9c5 =5= r9c6 -5- r1c6 -8- r8c6 =8= r8c4 =7= r9c4 -7- r9c8 =7= r23c8 -7- r2c9 => r2c9<>7
Grouped Discontinuous Nice Loop: 8 r3c2 -8- r1c2 =8= r1c6 -8- r8c6 =8= r8c4 =7= r9c4 -7- r9c8 -1- r7c9 =1= r2c9 =8= r3c79 -8- r3c2 => r3c2<>8
AIC: 6 6- r5c9 -8- r6c7 =8= r6c3 -8- r4c2 =8= r1c2 =5= r1c6 -5- r9c6 =5= r9c5 =4= r9c9 -4- r8c7 -6 => r56c7,r789c9<>6
Hidden Single: r8c7=6
Hidden Single: r5c9=6
Hidden Single: r3c7=4
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c23<>6
X-Wing: 6 c26 r39 => r39c4,r9c5<>6
Hidden Single: r4c4=6
Locked Candidates Type 1 (Pointing): 1 in b5 => r27c5<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r3c8<>1
Locked Candidates Type 1 (Pointing): 8 in b5 => r2c5<>8
Naked Pair: 1,7 in r9c48 => r9c6<>1
XY-Chain: 3 3- r8c2 -1- r8c6 -8- r1c6 -5- r9c6 -6- r9c2 -3 => r3c2,r8c3<>3
Hidden Single: r3c3=3
Locked Candidates Type 1 (Pointing): 7 in b1 => r2c8<>7
W-Wing: 6/5 in r2c5,r3c2 connected by 5 in r1c26 => r2c13,r3c6<>6
Naked Single: r2c1=7
Hidden Single: r2c5=6
Naked Single: r7c5=4
Naked Single: r9c5=5
Naked Single: r9c6=6
Naked Single: r9c2=3
Naked Single: r8c2=1
Naked Single: r9c9=4
Naked Single: r7c1=6
Full House: r6c1=1
Naked Single: r8c6=8
Naked Single: r7c3=7
Full House: r7c9=1
Full House: r8c3=4
Naked Single: r6c7=8
Full House: r5c7=1
Full House: r6c3=6
Full House: r5c5=8
Full House: r4c5=1
Naked Single: r1c6=5
Full House: r1c2=8
Full House: r3c6=1
Full House: r3c4=8
Naked Single: r8c4=7
Full House: r8c9=3
Full House: r9c8=7
Full House: r9c4=1
Naked Single: r2c9=8
Full House: r3c9=7
Naked Single: r2c3=5
Full House: r2c8=1
Full House: r3c8=5
Full House: r3c2=6
Full House: r4c2=5
Full House: r4c3=8
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