Solution for Evil Sudoku #2151472396841

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

This Sudoku Puzzle has 71 steps and it is solved using Naked Single, Full House, Hidden Single, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), Naked Triple, Hidden Pair, undefined, AIC, Locked Pair, Continuous Nice Loop, Skyscraper, Sue de Coq techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Row 5 / Column 3 → 4 (Naked Single)
  2. Row 5 / Column 7 → 9 (Naked Single)
  3. Row 5 / Column 8 → 7 (Naked Single)
  4. Row 5 / Column 2 → 6 (Full House)
  5. Row 3 / Column 1 → 6 (Hidden Single)
  6. Row 6 / Column 4 → 6 (Hidden Single)
  7. Row 9 / Column 9 → 6 (Hidden Single)
  8. Row 9 / Column 8 → 5 (Hidden Single)
  9. Locked Candidates Type 1 (Pointing): 4 in b1 => r2c79<>4
  10. Locked Candidates Type 1 (Pointing): 5 in b6 => r6c6<>5
  11. Locked Candidates Type 1 (Pointing): 1 in b9 => r8c16<>1
  12. Locked Candidates Type 2 (Claiming): 8 in r9 => r7c12,r8c13<>8
  13. Naked Triple: 2,8,9 in r368c6 => r2c6<>2, r27c6<>8, r24c6<>9
  14. Hidden Pair: 1,7 in r1c5,r2c6 => r1c5<>2, r1c5<>3
  15. 2-String Kite: 8 in r3c6,r7c9 (connected by r7c4,r8c6) => r3c9<>8
  16. Locked Candidates Type 2 (Claiming): 8 in r3 => r2c4<>8
  17. XY-Wing: 3/9/8 in r4c3,r69c2 => r9c3<>8
  18. Row 9 / Column 3 → 2 (Naked Single)
  19. XY-Chain: 8 8- r2c7 -1- r2c6 -7- r1c5 -1- r9c5 -9- r9c2 -8 => r2c2<>8
  20. AIC: 8 8- r2c7 -1- r2c6 =1= r7c6 =5= r7c4 =8= r7c9 -8 => r12c9,r8c7<>8
  21. Locked Pair: 1,4 in r8c78 => r78c9,r8c1<>4
  22. Continuous Nice Loop: 2/3/8/9 4= r2c1 =2= r2c4 -2- r8c4 =2= r8c6 -2- r6c6 -9- r6c2 =9= r9c2 =8= r9c1 =1= r7c1 =4= r2c1 =2 => r3c46<>2, r27c1<>3, r2c1<>8, r6c5,r9c1<>9
  23. Skyscraper: 9 in r6c6,r9c5 (connected by r69c2) => r4c5,r8c6<>9
  24. X-Wing: 9 r48 c14 => r23c4<>9
  25. Row 2 / Column 9 → 9 (Hidden Single)
  26. Sue de Coq: r78c4 - {23589} (r23c4 - {238}, r7c6,r9c5 - {159}) => r7c5<>1
  27. Row 7 / Column 5 → 3 (Naked Single)
  28. XY-Chain: 7 7- r1c5 -1- r9c5 -9- r9c2 -8- r9c1 -1- r7c1 -4- r7c2 -7 => r1c2<>7
  29. Row 1 / Column 5 → 7 (Hidden Single)
  30. Row 2 / Column 6 → 1 (Naked Single)
  31. Row 4 / Column 5 → 4 (Naked Single)
  32. Row 2 / Column 7 → 8 (Naked Single)
  33. Row 7 / Column 6 → 5 (Naked Single)
  34. Row 4 / Column 8 → 3 (Naked Single)
  35. Row 6 / Column 5 → 2 (Naked Single)
  36. Row 4 / Column 6 → 7 (Naked Single)
  37. Row 7 / Column 4 → 8 (Naked Single)
  38. Row 4 / Column 3 → 8 (Naked Single)
  39. Row 3 / Column 5 → 9 (Naked Single)
  40. Row 9 / Column 5 → 1 (Full House)
  41. Row 6 / Column 6 → 9 (Naked Single)
  42. Row 4 / Column 4 → 5 (Full House)
  43. Row 4 / Column 1 → 9 (Full House)
  44. Row 6 / Column 2 → 3 (Full House)
  45. Row 3 / Column 4 → 3 (Naked Single)
  46. Row 7 / Column 9 → 7 (Naked Single)
  47. Row 8 / Column 6 → 2 (Naked Single)
  48. Row 3 / Column 6 → 8 (Full House)
  49. Row 2 / Column 4 → 2 (Full House)
  50. Row 8 / Column 4 → 9 (Full House)
  51. Row 9 / Column 1 → 8 (Naked Single)
  52. Row 9 / Column 2 → 9 (Full House)
  53. Row 8 / Column 1 → 3 (Naked Single)
  54. Row 1 / Column 2 → 8 (Naked Single)
  55. Row 3 / Column 9 → 4 (Naked Single)
  56. Row 3 / Column 8 → 2 (Full House)
  57. Row 7 / Column 2 → 4 (Naked Single)
  58. Row 2 / Column 2 → 7 (Full House)
  59. Row 7 / Column 1 → 1 (Full House)
  60. Row 8 / Column 3 → 7 (Full House)
  61. Row 2 / Column 3 → 3 (Full House)
  62. Row 2 / Column 1 → 4 (Full House)
  63. Row 1 / Column 1 → 2 (Full House)
  64. Row 8 / Column 9 → 8 (Naked Single)
  65. Row 6 / Column 9 → 5 (Naked Single)
  66. Row 1 / Column 9 → 3 (Full House)
  67. Row 6 / Column 7 → 4 (Full House)
  68. Row 1 / Column 8 → 1 (Naked Single)
  69. Row 1 / Column 7 → 5 (Full House)
  70. Row 8 / Column 7 → 1 (Full House)
  71. Row 8 / Column 8 → 4 (Full House)
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