Solution Steps:

1. Row 9 / Column 9 → 9 (Naked Single)
2. Row 8 / Column 9 → 5 (Naked Single)
3. Row 7 / Column 8 → 6 (Full House)
4. Row 7 / Column 2 → 4 (Naked Single)
5. Row 7 / Column 1 → 9 (Naked Single)
6. Row 7 / Column 3 → 3 (Naked Single)
7. Row 7 / Column 4 → 5 (Naked Single)
8. Row 4 / Column 3 → 2 (Hidden Single)
9. Row 1 / Column 3 → 9 (Hidden Single)
10. Row 8 / Column 4 → 9 (Hidden Single)
11. Locked Pair: 7,8 in r6c23 => r46c1,r5c3,r6c58<>8
12. Row 6 / Column 1 → 5 (Naked Single)
13. Row 3 / Column 1 → 8 (Hidden Single)
14. Row 5 / Column 8 → 8 (Hidden Single)
15. Row 1 / Column 9 → 8 (Hidden Single)
16. Locked Candidates Type 1 (Pointing): 3 in b6 => r23c7<>3
17. Locked Candidates Type 1 (Pointing): 4 in b6 => r123c7<>4
18. Locked Candidates Type 2 (Claiming): 4 in r1 => r2c45,r3c45<>4
19. Hidden Pair: 2,7 in r17c6 => r1c6<>1, r1c6<>5, r1c6<>6
20. Locked Candidates Type 1 (Pointing): 5 in b2 => r4c5<>5
21. Empty Rectangle: 6 in b7 (r5c36) => r8c6<>6
22. XY-Wing: 4/5/6 in r35c7,r5c3 => r3c3<>6
23. Uniqueness Test 1: 2/7 in r1c56,r7c56 => r1c5<>2, r1c5<>7
24. Hidden Rectangle: 1/9 in r2c78,r6c78 => r2c7<>1
25. XY-Chain: 6 6- r1c2 -7- r3c3 -4- r3c9 -3- r3c4 -6 => r1c45<>6
26. Hidden Rectangle: 1/4 in r1c45,r9c45 => r9c5<>1
27. XY-Chain: 5 5- r3c7 -6- r3c4 -3- r3c9 -4- r3c3 -7- r1c2 -6- r2c1 -4- r4c1 -6- r5c3 -4- r5c7 -5 => r14c7<>5
28. XY-Chain: 9 9- r2c7 -6- r2c1 -4- r4c1 -6- r5c3 -4- r5c7 -5- r4c8 -1- r6c8 -9 => r2c8,r6c7<>9
29. Row 2 / Column 7 → 9 (Hidden Single)
30. Row 6 / Column 8 → 9 (Hidden Single)
31. XY-Wing: 1/6/7 in r1c27,r2c8 => r1c8<>7
32. Sue de Coq: r2c45 - {1367} (r2c8 - {17}, r3c4 - {36}) => r3c5<>3, r3c5<>6
33. Empty Rectangle: 6 in b2 (r24c1) => r4c4<>6
34. Discontinuous Nice Loop: 1/4 r1c5 =5= r1c8 =2= r1c6 =7= r1c2 =6= r1c7 -6- r3c7 -5- r3c5 =5= r1c5 => r1c5<>1, r1c5<>4
35. Row 1 / Column 5 → 5 (Naked Single)
36. Row 1 / Column 4 → 4 (Hidden Single)
37. Row 9 / Column 5 → 4 (Hidden Single)
38. Locked Candidates Type 1 (Pointing): 1 in b2 => r2c8<>1
39. Row 2 / Column 8 → 7 (Naked Single)
40. Discontinuous Nice Loop: 6 r2c4 -6- r2c1 =6= r1c2 -6- r1c7 -1- r6c7 =1= r6c5 -1- r2c5 =1= r2c4 => r2c4<>6
41. 2-String Kite: 6 in r2c5,r8c2 (connected by r1c2,r2c1) => r8c5<>6
42. Locked Candidates Type 1 (Pointing): 6 in b8 => r9c3<>6
43. X-Wing: 6 c15 r24 => r4c6<>6
44. XYZ-Wing: 1/3/5 in r4c68,r6c5 => r4c45<>1
45. XY-Chain: 4 4- r3c3 -7- r6c3 -8- r9c3 -1- r9c6 -6- r5c6 -5- r5c7 -4- r5c3 -6- r4c1 -4 => r2c1,r5c3<>4
46. Row 2 / Column 1 → 6 (Naked Single)
47. Row 4 / Column 1 → 4 (Full House)
48. Row 5 / Column 3 → 6 (Naked Single)
49. Row 1 / Column 2 → 7 (Naked Single)
50. Row 3 / Column 3 → 4 (Full House)
51. Row 5 / Column 6 → 5 (Naked Single)
52. Row 5 / Column 7 → 4 (Full House)
53. Row 1 / Column 6 → 2 (Naked Single)
54. Row 6 / Column 2 → 8 (Naked Single)
55. Row 6 / Column 3 → 7 (Full House)
56. Row 8 / Column 2 → 6 (Full House)
57. Row 3 / Column 9 → 3 (Naked Single)
58. Row 2 / Column 9 → 4 (Full House)
59. Row 1 / Column 8 → 1 (Naked Single)
60. Row 1 / Column 7 → 6 (Full House)
61. Row 3 / Column 5 → 7 (Naked Single)
62. Row 7 / Column 6 → 7 (Naked Single)
63. Row 7 / Column 5 → 2 (Full House)
64. Row 3 / Column 4 → 6 (Naked Single)
65. Row 4 / Column 8 → 5 (Naked Single)
66. Row 3 / Column 8 → 2 (Full House)
67. Row 3 / Column 7 → 5 (Full House)
68. Row 4 / Column 5 → 6 (Hidden Single)
69. Row 9 / Column 6 → 6 (Hidden Single)
70. Row 4 / Column 4 → 8 (Hidden Single)
71. Row 9 / Column 4 → 1 (Naked Single)
72. Row 2 / Column 4 → 3 (Full House)
73. Row 9 / Column 3 → 8 (Full House)
74. Row 2 / Column 5 → 1 (Full House)
75. Row 8 / Column 3 → 1 (Full House)
76. Row 8 / Column 6 → 3 (Naked Single)
77. Row 4 / Column 6 → 1 (Full House)
78. Row 6 / Column 5 → 3 (Full House)
79. Row 8 / Column 5 → 8 (Full House)
80. Row 4 / Column 7 → 3 (Full House)
81. Row 6 / Column 7 → 1 (Full House)