Passaggi della soluzione:

1. Riga 4 / Colonna 4 → 1 (Hidden Single)
2. Riga 2 / Colonna 9 → 6 (Hidden Single)
3. Riga 8 / Colonna 5 → 8 (Hidden Single)
4. Riga 6 / Colonna 4 → 7 (Hidden Single)
5. Riga 3 / Colonna 9 → 4 (Hidden Single)
6. Locked Candidates Type 1 (Pointing): 5 in b3 => r4c8<>5
7. Locked Candidates Type 1 (Pointing): 5 in b4 => r78c3<>5
8. Locked Candidates Type 1 (Pointing): 6 in b4 => r79c3<>6
9. Locked Candidates Type 1 (Pointing): 6 in b5 => r1c5<>6
10. Locked Candidates Type 1 (Pointing): 9 in b8 => r13c4<>9
11. Naked Pair: 2,8 in r4c17 => r4c358<>2, r4c89<>8
12. Riga 4 / Colonna 8 → 7 (Naked Single)
13. Riga 4 / Colonna 9 → 5 (Naked Single)
14. Riga 6 / Colonna 3 → 5 (Hidden Single)
15. Riga 6 / Colonna 5 → 6 (Hidden Single)
16. Riga 4 / Colonna 5 → 4 (Naked Single)
17. Riga 4 / Colonna 3 → 6 (Naked Single)
18. Riga 3 / Colonna 5 → 2 (Hidden Single)
19. Locked Candidates Type 1 (Pointing): 2 in b5 => r5c38<>2
20. Locked Candidates Type 1 (Pointing): 2 in b4 => r78c1<>2
21. Locked Candidates Type 1 (Pointing): 3 in b5 => r5c8<>3
22. Locked Candidates Type 1 (Pointing): 2 in b6 => r8c7<>2
23. Locked Candidates Type 2 (Claiming): 3 in c5 => r1c46,r23c6,r3c4<>3
24. Riga 1 / Colonna 4 → 6 (Naked Single)
25. Riga 3 / Colonna 4 → 5 (Naked Single)
26. Riga 2 / Colonna 8 → 5 (Hidden Single)
27. Locked Candidates Type 2 (Claiming): 8 in c9 => r79c8<>8
28. Naked Triple: 1,3,9 in r2c157 => r2c36<>1, r2c3<>3, r2c3<>9
29. Naked Triple: 4,7,9 in r13c2,r2c3 => r2c1,r3c3<>9, r3c3<>7
30. Locked Candidates Type 1 (Pointing): 9 in b1 => r5789c2<>9
31. Hidden Pair: 5,6 in r7c26 => r7c2<>7, r7c2<>8, r7c6<>2, r7c6<>3
32. XY-Wing: 4/8/9 in r15c2,r5c8 => r1c8<>9
33. W-Wing: 1/3 in r1c8,r2c1 connected by 3 in r12c5 => r2c7<>1
34. Riga 2 / Colonna 1 → 1 (Hidden Single)
35. Riga 3 / Colonna 3 → 3 (Naked Single)
36. Sue de Coq: r7c123 - {2356789} (r7c48 - {239}, r89c2 - {5678}) => r8c3<>7, r7c9<>3, r7c9<>9
37. XY-Chain: 3 3- r2c7 -9- r2c5 -3- r1c5 -9- r1c2 -4- r5c2 -8- r5c8 -9- r6c9 -3 => r6c7<>3
38. Riga 6 / Colonna 9 → 3 (Hidden Single)
39. Locked Candidates Type 2 (Claiming): 9 in c9 => r79c8,r8c7<>9
40. Naked Triple: 1,2,3 in r179c8 => r3c8<>1
41. W-Wing: 3/9 in r2c7,r8c1 connected by 9 in r6c17 => r8c7<>3
42. Riga 8 / Colonna 7 → 1 (Naked Single)
43. Riga 2 / Colonna 7 → 3 (Hidden Single)
44. Riga 1 / Colonna 8 → 1 (Naked Single)
45. Riga 2 / Colonna 5 → 9 (Naked Single)
46. Riga 1 / Colonna 5 → 3 (Full House)
47. Riga 1 / Colonna 6 → 4 (Naked Single)
48. Riga 1 / Colonna 2 → 9 (Full House)
49. Riga 2 / Colonna 6 → 7 (Naked Single)
50. Riga 2 / Colonna 3 → 4 (Full House)
51. Riga 3 / Colonna 2 → 7 (Full House)
52. Riga 3 / Colonna 6 → 1 (Full House)
53. Riga 5 / Colonna 3 → 9 (Naked Single)
54. Riga 8 / Colonna 2 → 5 (Naked Single)
55. Riga 5 / Colonna 8 → 8 (Naked Single)
56. Riga 6 / Colonna 1 → 2 (Naked Single)
57. Riga 6 / Colonna 7 → 9 (Full House)
58. Riga 4 / Colonna 7 → 2 (Full House)
59. Riga 4 / Colonna 1 → 8 (Full House)
60. Riga 5 / Colonna 2 → 4 (Full House)
61. Riga 3 / Colonna 7 → 8 (Full House)
62. Riga 3 / Colonna 8 → 9 (Full House)
63. Riga 8 / Colonna 3 → 2 (Naked Single)
64. Riga 7 / Colonna 2 → 6 (Naked Single)
65. Riga 9 / Colonna 2 → 8 (Full House)
66. Riga 7 / Colonna 3 → 7 (Naked Single)
67. Riga 9 / Colonna 3 → 1 (Full House)
68. Riga 8 / Colonna 6 → 3 (Naked Single)
69. Riga 7 / Colonna 6 → 5 (Naked Single)
70. Riga 9 / Colonna 9 → 9 (Naked Single)
71. Riga 7 / Colonna 9 → 8 (Naked Single)
72. Riga 8 / Colonna 9 → 7 (Full House)
73. Riga 8 / Colonna 1 → 9 (Full House)
74. Riga 7 / Colonna 1 → 3 (Full House)
75. Riga 5 / Colonna 6 → 2 (Naked Single)
76. Riga 5 / Colonna 4 → 3 (Full House)
77. Riga 9 / Colonna 6 → 6 (Full House)
78. Riga 9 / Colonna 4 → 2 (Naked Single)
79. Riga 7 / Colonna 4 → 9 (Full House)
80. Riga 7 / Colonna 8 → 2 (Full House)
81. Riga 9 / Colonna 8 → 3 (Full House)