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This Sudoku Puzzle has 90 steps and it is solved using Locked Candidates Type 1 (Pointing), Hidden Rectangle, AIC, Locked Candidates Type 2 (Claiming), Discontinuous Nice Loop, Hidden Single, Skyscraper, Grouped AIC, Empty Rectangle, Naked Single, undefined, Naked Pair, Naked Triple, Jellyfish, Locked Pair, Full House techniques.

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

Solution Steps:

  1. Locked Candidates Type 1 (Pointing): 7 in b1 => r3c79<>7
  2. Locked Candidates Type 1 (Pointing): 7 in b4 => r4c46<>7
  3. Locked Candidates Type 1 (Pointing): 9 in b6 => r4c46<>9
  4. Hidden Rectangle: 7/8 in r3c12,r4c12 => r4c2<>8
  5. AIC: 8 8- r2c1 -4- r1c3 =4= r1c9 =7= r7c9 =9= r9c8 -9- r9c2 -8 => r23c2,r7c1<>8
  6. Locked Candidates Type 2 (Claiming): 8 in c2 => r7c3<>8
  7. Discontinuous Nice Loop: 1 r4c2 -1- r6c2 -4- r8c2 =4= r8c1 -4- r2c1 -8- r3c1 -7- r3c2 =7= r4c2 => r4c2<>1
  8. Row 6 / Column 2 → 1 (Hidden Single)
  9. Row 6 / Column 5 → 4 (Hidden Single)
  10. Skyscraper: 4 in r1c9,r5c8 (connected by r15c3) => r2c8,r4c9<>4
  11. AIC: 7 7- r3c1 -8- r2c1 -4- r8c1 =4= r8c2 -4- r4c2 -7 => r3c2,r4c1<>7
  12. Row 3 / Column 1 → 7 (Hidden Single)
  13. Row 4 / Column 2 → 7 (Hidden Single)
  14. Discontinuous Nice Loop: 6 r3c9 -6- r3c2 =6= r2c2 =4= r8c2 =2= r8c8 =6= r8c9 -6- r3c9 => r3c9<>6
  15. Discontinuous Nice Loop: 5 r4c5 -5- r5c5 -8- r7c5 =8= r7c2 -8- r9c2 -9- r9c8 =9= r7c9 =7= r1c9 =4= r2c9 =1= r3c9 -1- r3c5 =1= r4c5 => r4c5<>5
  16. Discontinuous Nice Loop: 8 r4c5 -8- r7c5 =8= r7c2 -8- r9c2 -9- r9c8 =9= r7c9 =7= r1c9 =4= r2c9 =1= r3c9 -1- r3c5 =1= r4c5 => r4c5<>8
  17. Discontinuous Nice Loop: 6 r4c9 -6- r8c9 -5- r9c8 -9- r4c8 =9= r4c9 => r4c9<>6
  18. AIC: 5 5- r4c9 -9- r4c8 =9= r9c8 -9- r9c2 -8- r7c2 =8= r7c5 -8- r5c5 -5 => r4c46,r5c8<>5
  19. Discontinuous Nice Loop: 5 r5c4 -5- r5c5 -8- r7c5 =8= r7c2 -8- r9c2 -9- r9c8 =9= r4c8 =4= r5c8 =6= r5c6 =7= r5c4 => r5c4<>5
  20. Hidden Rectangle: 7/8 in r5c46,r9c46 => r9c6<>8
  21. Discontinuous Nice Loop: 5 r5c6 -5- r5c5 -8- r7c5 =8= r7c2 -8- r9c2 -9- r9c8 =9= r4c8 =4= r5c8 =6= r5c6 => r5c6<>5
  22. Grouped AIC: 5 5- r4c9 -9- r4c8 =9= r9c8 -9- r9c2 -8- r9c4 =8= r7c5 -8- r5c5 -5- r6c46 =5= r6c7 -5 => r4c78<>5
  23. Discontinuous Nice Loop: 5 r7c7 -5- r6c7 =5= r4c9 =9= r7c9 =7= r7c7 => r7c7<>5
  24. Empty Rectangle: 5 in b5 (r36c7) => r3c5<>5
  25. Discontinuous Nice Loop: 7/8 r5c6 =6= r5c8 =4= r5c3 -4- r1c3 =4= r1c9 =7= r1c7 -7- r7c7 -2- r8c8 =2= r8c2 =4= r2c2 =6= r3c2 -6- r3c7 =6= r4c7 -6- r4c6 =6= r5c6 => r5c6<>7, r5c6<>8
  26. Row 5 / Column 6 → 6 (Naked Single)
  27. Row 5 / Column 8 → 4 (Naked Single)
  28. Row 5 / Column 4 → 7 (Hidden Single)
  29. Row 9 / Column 6 → 7 (Hidden Single)
  30. Finned X-Wing: 8 c16 r24 fr3c6 => r2c4<>8
  31. AIC: 4/8 8- r2c1 -4- r2c2 =4= r8c2 =2= r8c8 -2- r7c7 -7- r7c9 =7= r1c9 =4= r1c3 -4- r4c3 =4= r4c1 -4 => r2c1<>4, r4c1<>8
  32. Row 2 / Column 1 → 8 (Naked Single)
  33. Discontinuous Nice Loop: 1 r3c6 -1- r3c9 -5- r4c9 -9- r4c8 =9= r9c8 =5= r9c4 =8= r4c4 -8- r4c6 =8= r3c6 => r3c6<>1
  34. Discontinuous Nice Loop: 3 r3c6 -3- r3c8 =3= r4c8 =9= r9c8 =5= r9c4 =8= r4c4 -8- r4c6 =8= r3c6 => r3c6<>3
  35. Discontinuous Nice Loop: 5 r3c6 -5- r3c7 =5= r6c7 -5- r4c9 -9- r4c8 =9= r9c8 =5= r9c4 =8= r4c4 -8- r4c6 =8= r3c6 => r3c6<>5
  36. Locked Candidates Type 1 (Pointing): 5 in b2 => r2c89<>5
  37. AIC: 6 6- r2c8 -2- r8c8 =2= r8c2 =4= r2c2 =6= r3c2 -6 => r2c2,r3c78<>6
  38. Row 3 / Column 2 → 6 (Hidden Single)
  39. Row 4 / Column 7 → 6 (Hidden Single)
  40. Locked Candidates Type 1 (Pointing): 9 in b1 => r7c3<>9
  41. Naked Pair: 2,4 in r28c2 => r7c2<>2
  42. XY-Chain: 1 1- r3c9 -5- r4c9 -9- r4c8 -3- r4c5 -1 => r3c5<>1
  43. Row 3 / Column 9 → 1 (Hidden Single)
  44. Row 4 / Column 5 → 1 (Hidden Single)
  45. Naked Triple: 2,4,6 in r2c289 => r2c46<>2
  46. X-Wing: 2 r28 c28 => r3c8<>2
  47. Naked Triple: 3,5,9 in r349c8 => r8c8<>5
  48. Jellyfish: 5 r2369 c4678 => r8c46<>5
  49. Locked Pair: 1,3 in r8c46 => r7c5,r8c1<>3
  50. Row 7 / Column 1 → 3 (Hidden Single)
  51. Row 3 / Column 5 → 3 (Hidden Single)
  52. Row 3 / Column 8 → 5 (Naked Single)
  53. Row 3 / Column 7 → 2 (Naked Single)
  54. Row 9 / Column 8 → 9 (Naked Single)
  55. Row 2 / Column 8 → 6 (Naked Single)
  56. Row 3 / Column 3 → 9 (Naked Single)
  57. Row 3 / Column 6 → 8 (Full House)
  58. Row 7 / Column 7 → 7 (Naked Single)
  59. Row 4 / Column 8 → 3 (Naked Single)
  60. Row 8 / Column 8 → 2 (Full House)
  61. Row 9 / Column 2 → 8 (Naked Single)
  62. Row 9 / Column 4 → 5 (Full House)
  63. Row 2 / Column 9 → 4 (Naked Single)
  64. Row 1 / Column 7 → 3 (Naked Single)
  65. Row 6 / Column 7 → 5 (Full House)
  66. Row 1 / Column 9 → 7 (Full House)
  67. Row 4 / Column 9 → 9 (Full House)
  68. Row 7 / Column 9 → 5 (Naked Single)
  69. Row 8 / Column 9 → 6 (Full House)
  70. Row 4 / Column 6 → 2 (Naked Single)
  71. Row 8 / Column 2 → 4 (Naked Single)
  72. Row 7 / Column 2 → 9 (Naked Single)
  73. Row 2 / Column 2 → 2 (Full House)
  74. Row 1 / Column 3 → 4 (Full House)
  75. Row 2 / Column 4 → 1 (Naked Single)
  76. Row 2 / Column 6 → 5 (Full House)
  77. Row 7 / Column 5 → 8 (Naked Single)
  78. Row 7 / Column 3 → 2 (Full House)
  79. Row 8 / Column 1 → 5 (Full House)
  80. Row 5 / Column 5 → 5 (Full House)
  81. Row 4 / Column 1 → 4 (Full House)
  82. Row 5 / Column 3 → 8 (Full House)
  83. Row 4 / Column 3 → 5 (Full House)
  84. Row 4 / Column 4 → 8 (Full House)
  85. Row 1 / Column 6 → 9 (Naked Single)
  86. Row 1 / Column 4 → 2 (Full House)
  87. Row 8 / Column 4 → 3 (Naked Single)
  88. Row 6 / Column 4 → 9 (Full House)
  89. Row 6 / Column 6 → 3 (Full House)
  90. Row 8 / Column 6 → 1 (Full House)
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