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

This Sudoku Puzzle has 77 steps and it is solved using Hidden Single, Locked Candidates Type 1 (Pointing), Naked Triple, undefined, Discontinuous Nice Loop, Naked Single, Sashimi Swordfish, Locked Candidates Type 2 (Claiming), Naked Pair, AIC, Empty Rectangle, Hidden Rectangle, Full House, Bivalue Universal Grave + 1 techniques.

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

Solution Steps:

  1. Row 2 / Column 8 → 3 (Hidden Single)
  2. Locked Candidates Type 1 (Pointing): 7 in b9 => r45c9<>7
  3. Naked Triple: 5,7,9 in r9c139 => r9c2567<>5, r9c256<>9
  4. Sashimi X-Wing: 9 c36 r28 fr7c3 fr9c3 => r8c2<>9
  5. Discontinuous Nice Loop: 1/5/8 r5c7 =2= r5c8 =6= r4c8 =7= r4c4 =3= r7c4 -3- r7c7 =3= r9c7 =2= r5c7 => r5c7<>1, r5c7<>5, r5c7<>8
  6. Row 5 / Column 7 → 2 (Naked Single)
  7. Row 9 / Column 7 → 3 (Naked Single)
  8. Row 8 / Column 8 → 2 (Hidden Single)
  9. Row 9 / Column 2 → 2 (Hidden Single)
  10. Row 7 / Column 2 → 6 (Hidden Single)
  11. Sashimi Swordfish: 1 r268 c269 fr6c7 fr6c8 => r5c9<>1
  12. Discontinuous Nice Loop: 1/4/5 r1c5 =9= r7c5 -9- r8c6 =9= r8c9 =1= r8c2 -1- r2c2 =1= r2c6 =9= r1c5 => r1c5<>1, r1c5<>4, r1c5<>5
  13. Row 1 / Column 5 → 9 (Naked Single)
  14. Row 8 / Column 6 → 9 (Hidden Single)
  15. Locked Candidates Type 1 (Pointing): 8 in b8 => r46c4<>8
  16. Locked Candidates Type 2 (Claiming): 4 in r1 => r3c7<>4
  17. Naked Pair: 1,5 in r7c7,r8c9 => r7c9<>1, r79c9<>5
  18. Locked Candidates Type 2 (Claiming): 5 in r9 => r7c13,r8c2<>5
  19. 2-String Kite: 1 in r1c9,r7c1 (connected by r7c7,r8c9) => r1c1<>1
  20. Locked Candidates Type 2 (Claiming): 1 in r1 => r3c7<>1
  21. W-Wing: 5/1 in r1c8,r7c7 connected by 1 in r18c9 => r13c7<>5
  22. Row 3 / Column 7 → 8 (Naked Single)
  23. Row 1 / Column 1 → 8 (Hidden Single)
  24. 2-String Kite: 5 in r6c7,r8c4 (connected by r7c7,r8c9) => r6c4<>5
  25. AIC: 5 5- r1c8 -1- r1c9 =1= r8c9 -1- r8c2 -8- r7c3 =8= r5c3 -8- r5c9 -5 => r1c9,r456c8<>5
  26. Row 1 / Column 8 → 5 (Hidden Single)
  27. Locked Candidates Type 2 (Claiming): 1 in c8 => r6c7<>1
  28. AIC: 1/3 1- r3c1 =1= r7c1 -1- r7c7 -5- r7c5 -3- r7c4 =3= r4c4 -3- r4c2 =3= r3c2 -3 => r3c2<>1, r3c1<>3
  29. Row 3 / Column 2 → 3 (Hidden Single)
  30. Row 5 / Column 1 → 3 (Hidden Single)
  31. XY-Wing: 1/8/5 in r48c2,r8c9 => r4c9<>5
  32. XY-Wing: 4/8/5 in r4c29,r6c7 => r6c12<>5
  33. Empty Rectangle: 5 in b2 (r24c2) => r4c5<>5
  34. Hidden Rectangle: 3/5 in r4c45,r7c45 => r4c4<>5
  35. XY-Chain: 4 4- r4c9 -8- r5c9 -5- r8c9 -1- r8c2 -8- r6c2 -9- r6c1 -7- r6c4 -4 => r4c456,r6c7<>4
  36. Row 6 / Column 7 → 5 (Naked Single)
  37. Row 5 / Column 9 → 8 (Naked Single)
  38. Row 7 / Column 7 → 1 (Naked Single)
  39. Row 1 / Column 7 → 4 (Full House)
  40. Row 1 / Column 9 → 1 (Full House)
  41. Row 4 / Column 9 → 4 (Naked Single)
  42. Row 8 / Column 9 → 5 (Naked Single)
  43. Row 8 / Column 4 → 8 (Naked Single)
  44. Row 8 / Column 2 → 1 (Full House)
  45. Row 7 / Column 3 → 8 (Hidden Single)
  46. Row 3 / Column 1 → 1 (Hidden Single)
  47. Row 2 / Column 6 → 1 (Hidden Single)
  48. Row 5 / Column 5 → 1 (Hidden Single)
  49. Row 9 / Column 1 → 5 (Hidden Single)
  50. Row 6 / Column 8 → 1 (Hidden Single)
  51. Naked Triple: 3,6,7 in r4c458 => r4c6<>6
  52. Bivalue Universal Grave + 1 => r2c3<>4, r2c3<>9
  53. Row 2 / Column 3 → 5 (Naked Single)
  54. Row 2 / Column 2 → 9 (Naked Single)
  55. Row 2 / Column 4 → 4 (Full House)
  56. Row 3 / Column 3 → 4 (Full House)
  57. Row 3 / Column 5 → 5 (Full House)
  58. Row 5 / Column 3 → 7 (Naked Single)
  59. Row 9 / Column 3 → 9 (Full House)
  60. Row 7 / Column 1 → 7 (Full House)
  61. Row 6 / Column 1 → 9 (Full House)
  62. Row 6 / Column 2 → 8 (Naked Single)
  63. Row 4 / Column 2 → 5 (Full House)
  64. Row 6 / Column 4 → 7 (Naked Single)
  65. Row 6 / Column 6 → 4 (Full House)
  66. Row 7 / Column 5 → 3 (Naked Single)
  67. Row 5 / Column 8 → 6 (Naked Single)
  68. Row 4 / Column 8 → 7 (Full House)
  69. Row 5 / Column 6 → 5 (Full House)
  70. Row 9 / Column 9 → 7 (Naked Single)
  71. Row 7 / Column 9 → 9 (Full House)
  72. Row 7 / Column 4 → 5 (Full House)
  73. Row 4 / Column 4 → 3 (Full House)
  74. Row 4 / Column 6 → 8 (Naked Single)
  75. Row 9 / Column 6 → 6 (Full House)
  76. Row 4 / Column 5 → 6 (Full House)
  77. Row 9 / Column 5 → 4 (Full House)
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