7
4
1
9
3
5
7
5
6
2
8
4
6
4
5
2
7
3
8
1
9
8
9
4
6
7
3
6
5
8
2
4
9
1
9
6
3

This Sudoku Puzzle has 56 steps and it is solved using Locked Candidates Type 1 (Pointing), Skyscraper, undefined, Uniqueness Test 4, Sue de Coq, Empty Rectangle, Naked Single, Hidden Single, Discontinuous Nice Loop, Full House, AIC, Naked Pair techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Locked Candidates Type 1 (Pointing): 6 in b4 => r1c1<>6
  2. Skyscraper: 8 in r3c9,r9c8 (connected by r39c1) => r12c8,r7c9<>8
  3. Skyscraper: 3 in r1c1,r2c7 (connected by r6c17) => r1c8,r2c23<>3
  4. W-Wing: 1/7 in r4c9,r8c8 connected by 7 in r1c89 => r4c8,r7c9<>1
  5. XY-Wing: 2/7/1 in r39c7,r8c8 => r2c8,r7c7<>1
  6. Uniqueness Test 4: 2/6 in r1c25,r2c25 => r12c2<>2
  7. Sue de Coq: r2c789 - {12348} (r2c6 - {48}, r3c7 - {12}) => r1c89,r3c9<>2, r3c9<>1, r2c3<>8
  8. Empty Rectangle: 2 in b7 (r3c27) => r7c7<>2
  9. Row 7 / Column 7 → 4 (Naked Single)
  10. Row 5 / Column 9 → 4 (Hidden Single)
  11. Locked Candidates Type 1 (Pointing): 5 in b6 => r6c13<>5
  12. Discontinuous Nice Loop: 3/9 r1c2 =6= r1c5 =2= r1c3 =8= r7c3 -8- r9c1 -5- r5c1 =5= r5c3 -5- r2c3 =5= r2c2 =6= r1c2 => r1c2<>3, r1c2<>9
  13. Row 1 / Column 2 → 6 (Naked Single)
  14. Row 1 / Column 5 → 2 (Naked Single)
  15. Row 2 / Column 5 → 6 (Full House)
  16. AIC: 7 7- r1c8 -4- r1c6 -8- r1c3 =8= r7c3 =2= r2c3 -2- r3c2 =2= r3c7 -2- r9c7 -7 => r89c8<>7
  17. Row 8 / Column 8 → 1 (Naked Single)
  18. Row 9 / Column 7 → 7 (Hidden Single)
  19. Naked Pair: 3,7 in r68c3 => r14c3<>3, r4c3<>7
  20. Row 1 / Column 1 → 3 (Hidden Single)
  21. Row 6 / Column 1 → 6 (Naked Single)
  22. Row 5 / Column 7 → 6 (Hidden Single)
  23. Row 4 / Column 9 → 1 (Hidden Single)
  24. Row 4 / Column 3 → 9 (Naked Single)
  25. Row 1 / Column 3 → 8 (Naked Single)
  26. Row 1 / Column 6 → 4 (Naked Single)
  27. Row 2 / Column 6 → 8 (Full House)
  28. Row 1 / Column 8 → 7 (Naked Single)
  29. Row 1 / Column 9 → 9 (Full House)
  30. Row 2 / Column 9 → 2 (Naked Single)
  31. Row 4 / Column 8 → 3 (Naked Single)
  32. Row 4 / Column 2 → 7 (Full House)
  33. Row 3 / Column 9 → 8 (Naked Single)
  34. Row 3 / Column 7 → 1 (Naked Single)
  35. Row 7 / Column 9 → 5 (Naked Single)
  36. Row 6 / Column 9 → 7 (Full House)
  37. Row 2 / Column 8 → 4 (Naked Single)
  38. Row 2 / Column 7 → 3 (Full House)
  39. Row 6 / Column 7 → 2 (Full House)
  40. Row 6 / Column 8 → 5 (Full House)
  41. Row 6 / Column 3 → 3 (Full House)
  42. Row 8 / Column 2 → 3 (Naked Single)
  43. Row 8 / Column 3 → 7 (Full House)
  44. Row 3 / Column 1 → 9 (Naked Single)
  45. Row 3 / Column 2 → 2 (Full House)
  46. Row 9 / Column 2 → 5 (Naked Single)
  47. Row 2 / Column 2 → 1 (Naked Single)
  48. Row 2 / Column 3 → 5 (Full House)
  49. Row 7 / Column 2 → 9 (Full House)
  50. Row 9 / Column 1 → 8 (Naked Single)
  51. Row 9 / Column 8 → 2 (Full House)
  52. Row 7 / Column 8 → 8 (Full House)
  53. Row 5 / Column 3 → 1 (Naked Single)
  54. Row 5 / Column 1 → 5 (Full House)
  55. Row 7 / Column 1 → 1 (Full House)
  56. Row 7 / Column 3 → 2 (Full House)
Show More...