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

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): 4 in b5 => r1c6<>4
  2. Skyscraper: 1 in r2c7,r9c8 (connected by r29c6) => r13c8,r8c7<>1
  3. Skyscraper: 7 in r1c6,r3c9 (connected by r4c69) => r1c8,r3c45<>7
  4. W-Wing: 6/8 in r6c7,r7c8 connected by 8 in r1c78 => r6c8,r8c7<>6
  5. XY-Wing: 8/9/6 in r29c9,r7c8 => r3c8,r8c9<>6
  6. Uniqueness Test 4: 4/9 in r1c14,r3c14 => r13c4<>9
  7. Sue de Coq: r3c789 - {13679} (r3c3 - {13}, r2c9 - {69}) => r1c78,r2c7<>9, r2c7<>6, r3c5<>1
  8. Empty Rectangle: 9 in b8 (r2c49) => r8c9<>9
  9. Row 8 / Column 9 → 3 (Naked Single)
  10. Row 5 / Column 7 → 3 (Hidden Single)
  11. Locked Candidates Type 1 (Pointing): 5 in b6 => r4c56<>5
  12. Discontinuous Nice Loop: 2/7 r1c4 =4= r1c1 =9= r1c5 =1= r8c5 -1- r9c6 -5- r5c6 =5= r5c5 -5- r3c5 =5= r3c4 =4= r1c4 => r1c4<>2, r1c4<>7
  13. Row 1 / Column 4 → 4 (Naked Single)
  14. Row 1 / Column 1 → 9 (Naked Single)
  15. Row 3 / Column 1 → 4 (Full House)
  16. AIC: 8 8- r1c8 -3- r1c3 -1- r1c5 =1= r8c5 =9= r3c5 -9- r2c4 =9= r2c9 -9- r9c9 -8 => r79c8<>8
  17. Row 7 / Column 8 → 6 (Naked Single)
  18. Row 9 / Column 9 → 8 (Hidden Single)
  19. Naked Pair: 7,8 in r47c5 => r16c5<>7, r6c5<>8
  20. Row 1 / Column 6 → 7 (Hidden Single)
  21. Row 4 / Column 6 → 4 (Naked Single)
  22. Row 5 / Column 9 → 4 (Hidden Single)
  23. Row 6 / Column 7 → 6 (Hidden Single)
  24. Row 6 / Column 5 → 2 (Naked Single)
  25. Row 1 / Column 5 → 1 (Naked Single)
  26. Row 1 / Column 3 → 3 (Naked Single)
  27. Row 3 / Column 3 → 1 (Full House)
  28. Row 1 / Column 8 → 8 (Naked Single)
  29. Row 1 / Column 7 → 2 (Full House)
  30. Row 3 / Column 7 → 9 (Naked Single)
  31. Row 6 / Column 8 → 7 (Naked Single)
  32. Row 6 / Column 4 → 8 (Full House)
  33. Row 2 / Column 7 → 1 (Naked Single)
  34. Row 2 / Column 9 → 6 (Naked Single)
  35. Row 8 / Column 7 → 5 (Naked Single)
  36. Row 4 / Column 7 → 8 (Full House)
  37. Row 3 / Column 8 → 3 (Naked Single)
  38. Row 3 / Column 9 → 7 (Full House)
  39. Row 4 / Column 9 → 9 (Full House)
  40. Row 4 / Column 8 → 5 (Full House)
  41. Row 4 / Column 5 → 7 (Full House)
  42. Row 7 / Column 4 → 7 (Naked Single)
  43. Row 7 / Column 5 → 8 (Full House)
  44. Row 2 / Column 6 → 2 (Naked Single)
  45. Row 2 / Column 4 → 9 (Full House)
  46. Row 9 / Column 4 → 5 (Naked Single)
  47. Row 3 / Column 4 → 6 (Naked Single)
  48. Row 3 / Column 5 → 5 (Full House)
  49. Row 8 / Column 4 → 2 (Full House)
  50. Row 9 / Column 6 → 1 (Naked Single)
  51. Row 9 / Column 8 → 9 (Full House)
  52. Row 8 / Column 8 → 1 (Full House)
  53. Row 5 / Column 5 → 6 (Naked Single)
  54. Row 5 / Column 6 → 5 (Full House)
  55. Row 8 / Column 6 → 6 (Full House)
  56. Row 8 / Column 5 → 9 (Full House)
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