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

This Sudoku Puzzle has 77 steps and it is solved using Hidden Single, Naked Single, Locked Candidates Type 2 (Claiming), Naked Pair, Naked Triple, Locked Candidates Type 1 (Pointing), undefined, Uniqueness Test 1, Uniqueness Test 4, Sue de Coq, Skyscraper, Full House, AIC, Bivalue Universal Grave + 1 techniques.

Try To Solve This Puzzle

## Solution Steps:

1. Row 4 / Column 6 → 6 (Hidden Single)
2. Row 2 / Column 1 → 7 (Hidden Single)
3. Row 2 / Column 9 → 3 (Naked Single)
4. Row 2 / Column 7 → 5 (Naked Single)
5. Row 1 / Column 8 → 7 (Naked Single)
6. Row 2 / Column 3 → 8 (Naked Single)
7. Row 5 / Column 6 → 9 (Hidden Single)
8. Row 3 / Column 2 → 2 (Hidden Single)
9. Row 1 / Column 6 → 8 (Hidden Single)
10. Locked Candidates Type 2 (Claiming): 4 in r9 => r7c78,r8c789<>4
11. Locked Candidates Type 2 (Claiming): 1 in c6 => r8c5,r9c4<>1
12. Locked Candidates Type 2 (Claiming): 2 in c6 => r8c5,r9c4<>2
13. Naked Pair: 3,7 in r37c6 => r89c6<>3, r8c6<>7
14. Naked Triple: 3,6,7 in r7c46,r9c4 => r78c5<>3, r78c5<>7
15. Locked Candidates Type 1 (Pointing): 7 in b8 => r7c7<>7
16. Locked Candidates Type 2 (Claiming): 3 in c5 => r5c4<>3
17. Locked Candidates Type 2 (Claiming): 7 in c5 => r5c4<>7
18. 2-String Kite: 3 in r1c2,r7c6 (connected by r1c4,r3c6) => r7c2<>3
19. Uniqueness Test 1: 1/2 in r2c45,r5c45 => r5c5<>1, r5c5<>2
20. Uniqueness Test 4: 3/7 in r3c46,r7c46 => r37c4<>3
21. Uniqueness Test 4: 4/8 in r7c15,r8c15 => r78c1<>8
22. Locked Candidates Type 1 (Pointing): 8 in b7 => r5c2<>8
23. Sue de Coq: r5c12 - {1238} (r5c4 - {12}, r6c1 - {38}) => r4c13,r6c3<>3, r5c8<>1
24. Row 4 / Column 8 → 1 (Hidden Single)
25. Skyscraper: 3 in r7c6,r8c3 (connected by r3c36) => r7c1<>3
26. XY-Chain: 5 5- r1c2 -3- r5c2 -1- r6c3 -9- r4c3 -5- r3c3 -3- r3c6 -7- r3c4 -5 => r1c4,r3c3<>5
27. Row 1 / Column 4 → 3 (Naked Single)
28. Row 1 / Column 2 → 5 (Full House)
29. Row 3 / Column 3 → 3 (Full House)
30. Row 3 / Column 6 → 7 (Naked Single)
31. Row 9 / Column 4 → 6 (Naked Single)
32. Row 3 / Column 4 → 5 (Naked Single)
33. Row 7 / Column 6 → 3 (Naked Single)
34. Row 7 / Column 4 → 7 (Naked Single)
35. XY-Chain: 9 9- r6c3 -1- r8c3 -5- r7c1 -4- r7c5 -8- r7c2 -6- r7c7 -9 => r6c7<>9
36. AIC: 8 8- r5c8 =8= r6c9 =6= r6c7 -6- r7c7 -9- r7c8 =9= r3c8 =4= r3c9 -4- r9c9 -8 => r6c9,r789c8<>8
37. Row 6 / Column 1 → 8 (Hidden Single)
38. Row 5 / Column 8 → 8 (Hidden Single)
39. Row 5 / Column 7 → 4 (Hidden Single)
40. Row 5 / Column 5 → 7 (Hidden Single)
41. Locked Candidates Type 1 (Pointing): 3 in b6 => r89c7<>3
42. Row 9 / Column 7 → 2 (Naked Single)
43. Row 9 / Column 6 → 1 (Naked Single)
44. Row 8 / Column 6 → 2 (Full House)
45. XYZ-Wing: 3/4/5 in r78c1,r8c8 => r8c3<>5
46. Row 8 / Column 3 → 1 (Naked Single)
47. Row 6 / Column 3 → 9 (Naked Single)
48. Row 4 / Column 3 → 5 (Full House)
49. Row 6 / Column 9 → 6 (Naked Single)
50. Row 4 / Column 1 → 2 (Naked Single)
51. Row 6 / Column 7 → 3 (Naked Single)
52. Row 6 / Column 5 → 1 (Full House)
53. Row 4 / Column 5 → 3 (Naked Single)
54. Row 5 / Column 4 → 2 (Full House)
55. Row 2 / Column 4 → 1 (Full House)
56. Row 2 / Column 5 → 2 (Full House)
57. Row 5 / Column 1 → 3 (Naked Single)
58. Row 5 / Column 2 → 1 (Full House)
59. Bivalue Universal Grave + 1 => r8c2<>3, r8c2<>6
60. Row 8 / Column 2 → 8 (Naked Single)
61. Row 7 / Column 2 → 6 (Naked Single)
62. Row 9 / Column 2 → 3 (Full House)
63. Row 8 / Column 5 → 4 (Naked Single)
64. Row 7 / Column 5 → 8 (Full House)
65. Row 8 / Column 9 → 7 (Naked Single)
66. Row 7 / Column 7 → 9 (Naked Single)
67. Row 9 / Column 8 → 4 (Naked Single)
68. Row 9 / Column 9 → 8 (Full House)
69. Row 8 / Column 1 → 5 (Naked Single)
70. Row 7 / Column 1 → 4 (Full House)
71. Row 7 / Column 8 → 5 (Full House)
72. Row 4 / Column 9 → 9 (Naked Single)
73. Row 4 / Column 7 → 7 (Full House)
74. Row 8 / Column 7 → 6 (Full House)
75. Row 8 / Column 8 → 3 (Full House)
76. Row 3 / Column 8 → 9 (Full House)
77. Row 3 / Column 9 → 4 (Full House)