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

This Sudoku Puzzle has 71 steps and it is solved using Naked Single, Hidden Single, Full House, Locked Candidates Type 1 (Pointing), Skyscraper, undefined, Uniqueness Test 4, Sue de Coq, Empty Rectangle, AIC, Naked Pair techniques.

Naked Single Explanation
Hidden Single Explanation
Locked Candidates Explanation
Full House Explanation
Try To Solve This Puzzle

Solution Steps:

  1. Row 5 / Column 6 → 4 (Naked Single)
  2. Row 1 / Column 6 → 7 (Hidden Single)
  3. Row 3 / Column 8 → 2 (Hidden Single)
  4. Row 3 / Column 5 → 4 (Hidden Single)
  5. Row 5 / Column 4 → 2 (Hidden Single)
  6. Row 5 / Column 5 → 3 (Naked Single)
  7. Row 3 / Column 4 → 5 (Hidden Single)
  8. Row 6 / Column 4 → 6 (Hidden Single)
  9. Row 1 / Column 4 → 1 (Hidden Single)
  10. Row 7 / Column 4 → 9 (Naked Single)
  11. Row 2 / Column 4 → 8 (Full House)
  12. Row 1 / Column 5 → 9 (Full House)
  13. Row 4 / Column 5 → 8 (Naked Single)
  14. Row 4 / Column 6 → 9 (Full House)
  15. Row 6 / Column 1 → 8 (Hidden Single)
  16. Locked Candidates Type 1 (Pointing): 8 in b3 => r9c9<>8
  17. Skyscraper: 5 in r5c3,r7c1 (connected by r57c9) => r4c1,r89c3<>5
  18. Skyscraper: 9 in r8c2,r9c9 (connected by r3c29) => r8c78,r9c3<>9
  19. W-Wing: 3/7 in r2c1,r6c3 connected by 7 in r9c13 => r2c3,r4c1<>3
  20. XY-Wing: 1/7/3 in r57c2,r6c3 => r4c2,r8c3<>3
  21. Uniqueness Test 4: 1/8 in r8c68,r9c68 => r89c8<>1
  22. Sue de Coq: r8c123 - {12359} (r8c5 - {25}, r7c2 - {13}) => r79c1,r9c3<>1, r7c1<>3, r8c7<>5
  23. Empty Rectangle: 1 in b6 (r7c28) => r4c2<>1
  24. Row 4 / Column 2 → 2 (Naked Single)
  25. Row 1 / Column 1 → 2 (Hidden Single)
  26. Locked Candidates Type 1 (Pointing): 6 in b1 => r3c79<>6
  27. AIC: 1/8 8- r8c6 =8= r8c8 =6= r8c7 -6- r1c7 =6= r1c9 -6- r5c9 -5- r4c7 =5= r9c7 =1= r9c6 -1 => r8c6<>1, r9c6<>8
  28. Row 8 / Column 6 → 8 (Naked Single)
  29. Row 9 / Column 6 → 1 (Full House)
  30. Row 9 / Column 8 → 8 (Hidden Single)
  31. AIC: 7 7- r5c2 -1- r7c2 =1= r7c8 -1- r8c7 =1= r4c7 =5= r9c7 -5- r9c5 -2- r9c3 -7 => r56c3<>7
  32. Row 6 / Column 3 → 3 (Naked Single)
  33. Row 5 / Column 2 → 7 (Hidden Single)
  34. Naked Pair: 7,9 in r36c7 => r2c7<>7, r29c7<>9
  35. Row 9 / Column 9 → 9 (Hidden Single)
  36. Row 3 / Column 9 → 8 (Naked Single)
  37. Row 1 / Column 2 → 8 (Hidden Single)
  38. Row 2 / Column 1 → 3 (Hidden Single)
  39. Row 2 / Column 7 → 4 (Naked Single)
  40. Row 9 / Column 7 → 5 (Naked Single)
  41. Row 9 / Column 5 → 2 (Naked Single)
  42. Row 8 / Column 5 → 5 (Full House)
  43. Row 9 / Column 3 → 7 (Naked Single)
  44. Row 9 / Column 1 → 4 (Full House)
  45. Row 8 / Column 1 → 1 (Naked Single)
  46. Row 2 / Column 3 → 9 (Naked Single)
  47. Row 2 / Column 8 → 7 (Full House)
  48. Row 7 / Column 1 → 5 (Naked Single)
  49. Row 4 / Column 1 → 6 (Naked Single)
  50. Row 3 / Column 1 → 7 (Full House)
  51. Row 7 / Column 2 → 3 (Naked Single)
  52. Row 3 / Column 2 → 1 (Naked Single)
  53. Row 8 / Column 2 → 9 (Full House)
  54. Row 8 / Column 3 → 2 (Full House)
  55. Row 3 / Column 3 → 6 (Full House)
  56. Row 3 / Column 7 → 9 (Full House)
  57. Row 6 / Column 8 → 9 (Naked Single)
  58. Row 6 / Column 7 → 7 (Full House)
  59. Row 7 / Column 9 → 4 (Naked Single)
  60. Row 7 / Column 8 → 1 (Full House)
  61. Row 5 / Column 8 → 6 (Naked Single)
  62. Row 5 / Column 9 → 5 (Naked Single)
  63. Row 5 / Column 3 → 1 (Full House)
  64. Row 4 / Column 3 → 5 (Full House)
  65. Row 8 / Column 8 → 3 (Naked Single)
  66. Row 4 / Column 8 → 4 (Full House)
  67. Row 8 / Column 7 → 6 (Full House)
  68. Row 4 / Column 9 → 3 (Naked Single)
  69. Row 1 / Column 9 → 6 (Full House)
  70. Row 1 / Column 7 → 3 (Full House)
  71. Row 4 / Column 7 → 1 (Full House)
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