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This Sudoku Puzzle has 78 steps and it is solved using Hidden Single, Locked Candidates Type 1 (Pointing), undefined, AIC, Discontinuous Nice Loop, Locked Candidates Type 2 (Claiming), Naked Single, Turbot Fish, Full House techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Row 5 / Column 8 → 5 (Hidden Single)
  2. Row 7 / Column 7 → 4 (Hidden Single)
  3. Row 7 / Column 8 → 7 (Hidden Single)
  4. Row 1 / Column 7 → 7 (Hidden Single)
  5. Row 9 / Column 8 → 3 (Hidden Single)
  6. Row 1 / Column 3 → 5 (Hidden Single)
  7. Row 7 / Column 1 → 5 (Hidden Single)
  8. Locked Candidates Type 1 (Pointing): 9 in b6 => r4c123<>9
  9. Locked Candidates Type 1 (Pointing): 2 in b8 => r9c2<>2
  10. Locked Candidates Type 1 (Pointing): 8 in b9 => r23c7<>8
  11. 2-String Kite: 9 in r1c2,r9c5 (connected by r1c4,r2c5) => r9c2<>9
  12. Locked Candidates Type 1 (Pointing): 9 in b7 => r7c4<>9
  13. AIC: 3 3- r4c5 -1- r8c5 -5- r8c9 -6- r6c9 -7- r4c9 =7= r4c1 =3= r6c1 -3 => r4c1,r6c45<>3
  14. Row 6 / Column 1 → 3 (Hidden Single)
  15. AIC: 4/9 9- r2c5 =9= r9c5 =5= r9c7 -5- r3c7 =5= r3c9 =4= r2c9 -4 => r2c5<>4, r2c9<>9
  16. Row 6 / Column 5 → 4 (Hidden Single)
  17. Discontinuous Nice Loop: 8 r1c2 -8- r9c2 =8= r9c7 =5= r9c5 =9= r9c4 -9- r1c4 =9= r1c2 => r1c2<>8
  18. Discontinuous Nice Loop: 8 r2c4 -8- r6c4 =8= r4c6 =3= r4c5 -3- r2c5 =3= r2c4 => r2c4<>8
  19. Locked Candidates Type 2 (Claiming): 8 in r2 => r3c12<>8
  20. Discontinuous Nice Loop: 9 r3c2 -9- r1c2 =9= r1c4 -9- r9c4 =9= r9c5 =5= r8c5 =1= r8c3 =2= r8c1 -2- r3c1 =2= r3c2 => r3c2<>9
  21. Discontinuous Nice Loop: 8 r4c1 -8- r4c6 =8= r6c4 =7= r6c9 -7- r4c9 =7= r4c1 => r4c1<>8
  22. Discontinuous Nice Loop: 9 r2c1 -9- r2c5 =9= r9c5 =5= r9c7 =8= r9c2 -8- r8c1 =8= r2c1 => r2c1<>9
  23. Discontinuous Nice Loop: 2/6 r4c1 =7= r4c9 =9= r3c9 -9- r3c1 =9= r5c1 =7= r4c1 => r4c1<>2, r4c1<>6
  24. Row 4 / Column 1 → 7 (Naked Single)
  25. Row 6 / Column 9 → 7 (Hidden Single)
  26. Row 5 / Column 4 → 7 (Hidden Single)
  27. AIC: 8 8- r8c7 =8= r9c7 =5= r9c5 =9= r9c4 =2= r6c4 =8= r6c3 -8- r4c2 =8= r9c2 -8 => r8c13,r9c7<>8
  28. Row 2 / Column 1 → 8 (Hidden Single)
  29. Row 8 / Column 7 → 8 (Hidden Single)
  30. Row 9 / Column 2 → 8 (Hidden Single)
  31. Turbot Fish: 6 r3c1 =6= r8c1 -6- r8c9 =6= r9c7 => r3c7<>6
  32. AIC: 6/9 9- r1c2 =9= r1c4 -9- r9c4 =9= r9c5 =5= r9c7 =6= r8c9 -6- r8c1 =6= r3c1 -6 => r1c2<>6, r3c1<>9
  33. Row 5 / Column 1 → 9 (Hidden Single)
  34. Discontinuous Nice Loop: 2 r4c2 -2- r4c7 =2= r6c7 -2- r6c4 =2= r9c4 -2- r9c6 -6- r9c7 =6= r8c9 -6- r8c1 -2- r3c1 =2= r3c2 -2- r4c2 => r4c2<>2
  35. Discontinuous Nice Loop: 9 r3c9 -9- r4c9 =9= r4c7 =2= r6c7 -2- r6c4 =2= r9c4 =9= r9c5 =5= r9c7 -5- r3c7 =5= r3c9 => r3c9<>9
  36. Row 4 / Column 9 → 9 (Hidden Single)
  37. Finned X-Wing: 6 c19 r38 fr2c9 => r3c8<>6
  38. AIC: 5/6 5- r3c9 =5= r3c7 =9= r3c4 -9- r9c4 =9= r9c5 =5= r9c7 =6= r8c9 -6 => r8c9<>5, r3c9<>6
  39. Row 8 / Column 9 → 6 (Naked Single)
  40. Row 9 / Column 7 → 5 (Full House)
  41. Row 2 / Column 9 → 4 (Naked Single)
  42. Row 3 / Column 9 → 5 (Full House)
  43. Row 8 / Column 1 → 2 (Naked Single)
  44. Row 3 / Column 1 → 6 (Full House)
  45. Row 9 / Column 5 → 9 (Naked Single)
  46. Row 8 / Column 3 → 1 (Naked Single)
  47. Row 8 / Column 5 → 5 (Full House)
  48. Row 2 / Column 3 → 9 (Naked Single)
  49. Row 1 / Column 2 → 4 (Naked Single)
  50. Row 3 / Column 2 → 2 (Full House)
  51. Row 7 / Column 3 → 6 (Naked Single)
  52. Row 7 / Column 2 → 9 (Full House)
  53. Row 5 / Column 2 → 1 (Naked Single)
  54. Row 4 / Column 2 → 6 (Full House)
  55. Row 5 / Column 6 → 2 (Naked Single)
  56. Row 5 / Column 3 → 4 (Full House)
  57. Row 9 / Column 6 → 6 (Naked Single)
  58. Row 9 / Column 4 → 2 (Full House)
  59. Row 1 / Column 6 → 8 (Naked Single)
  60. Row 1 / Column 8 → 6 (Naked Single)
  61. Row 1 / Column 4 → 9 (Full House)
  62. Row 2 / Column 7 → 1 (Naked Single)
  63. Row 6 / Column 8 → 1 (Naked Single)
  64. Row 3 / Column 8 → 8 (Full House)
  65. Row 3 / Column 7 → 9 (Full House)
  66. Row 3 / Column 4 → 1 (Naked Single)
  67. Row 3 / Column 6 → 4 (Full House)
  68. Row 2 / Column 5 → 3 (Naked Single)
  69. Row 2 / Column 4 → 6 (Full House)
  70. Row 4 / Column 5 → 1 (Full House)
  71. Row 4 / Column 7 → 2 (Naked Single)
  72. Row 6 / Column 7 → 6 (Full House)
  73. Row 6 / Column 4 → 8 (Naked Single)
  74. Row 7 / Column 4 → 3 (Full House)
  75. Row 4 / Column 6 → 3 (Full House)
  76. Row 4 / Column 3 → 8 (Full House)
  77. Row 6 / Column 3 → 2 (Full House)
  78. Row 7 / Column 6 → 1 (Full House)
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