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.

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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