Prelims
a) R12C1 = {17/26/35}, no 4,8,9
b) R12C2 = {29/38/47/56}, no 1
c) R1C34 = {29/38/47/56}, no 1
d) R12C5 = {18/27/36/45}, no 9
e) R1C67 = {29/38/47/56}, no 1
f) R12C8 = {15/24}
g) R12C9 = {49/58/67}, no 1,2,3
h) R2C34 = {18/27/36/45}, no 9
i) R2C67 = {39/48/57}, no 1,2,6
j) R3C12 = {16/25/34}, no 7,8,9
k) R34C3 = {89}
l) R34C7 = {18/27/36/45}, no 9
m) R3C89 = {49/58/67}, no 1,2,3
n) R67C1 = {16/25/34}, no 7,8,9
o) R67C9 = {18/27/36/45}, no 9
p) R7C23 = {19/28/37/46}, no 5
r) R7C78 = {17/26/35}, no 4,8,9
s) R89C1 = {69/78}
t) R89C9 = {17/26/35}, no 4,8,9
u) 9(3) cage at R4C4 = {126/135/234}, no 7,8,9
v) 11(3) cage at R9C4 = {128/137/146/236/245}, no 9
w) 28(4) cage at R5C5 = {4789/5689}, no 1,2,3
x) 28(4) cage at R8C7 = {4789/5689}, no 1,2,3
1. Naked pair {89} in R34C3, locked for C3 and NR3C2, clean-up: no 2,3 in R1C4, no 1 in R2C4, no 1 in R34C7, no 4,5 in R3C9, no 1,2 in R7C2
2. 45 rule on R789 2 outies R6C19 = 3 = {12}, locked for R6, R7C1 = {56}, R7C9 = {78}
2a. R89C9 = {26/35} (cannot be {17} which clashes with R67C9), no 1,7
3. 9(3) cage at R4C4 = {126/135} (cannot be {234} which clashes with R34C7), no 4, 1 locked for R4 and NR3C2, clean-up: no 6 in R3C1
3a. R34C7 = {27/45} (cannot be {36} which clashes with 9(3) cage), no 3,6
3b. Killer pair 2,5 in R34C7 and 9(3) cage, locked for NR3C2, clean-up: no 2,5 in R3C1, no 8 in R3C9
3c. Killer pair 4,6 in R3C12 and R3C89, locked for R3, clean-up: no 5 in R4C7
4. Killer triple 5,6,7 in R12C1, R7C1 and R89C1, locked for C1
5. 45 rule on C1 3 innies R345C1 = 15 = {249/348}, no 1, clean-up: no 6 in R3C2
5a. Naked pair {34} in R3C12, locked for R3, clean-up: no 9 in R3C9
5b. Naked pair {67} in R3C89, locked for R3, clean-up: no 2 in R4C7
5c. R12C9 = {49/58} (cannot be {67} which clashes with R3C9), no 6,7
6. 15(3) cage at R3C4 = {159} (only remaining combination, cannot be {258} which clashes with R3C7), locked for R3 and NR1C5 -> R34C3 = [89], R3C7 = 2, R4C7 = 7, both placed for NR3C2 -> R3C8 = 6, placed for NR3C2, R3C9 = 7, placed for NR1C6, clean-up: no 4,8 in R12C5, no 4,9 in R1C6, no 4 in R1C7, no 4 in R2C3, no 4,8 in R2C4, no 3,7 in R2C6, no 3 in R2C7, no 1 in R7C8
[Alternatively 1 in R3 only in 15(3) cage = {159} …]
6a. Naked pair {48} in R2C67, locked for R2, clean-up: no 3,7 in R1C2, no 2 in R1C8, no 5,9 in R1C9
7. R7C9 = 8, R6C9 = 1, both placed for NR6C9, R6C1 = 2, R7C1 = 5, both placed for NR6C1, R1C9 = 4, R2C9 = 9, placed for NR1C6, clean-up: no 3,6 in R12C1, no 2 in R1C2, no 7 in R1C34, no 2 in R1C6, no 7 in R2C2, no 2 in R2C8, no 3 in R7C7, no 3,7 in R7C8
7a. Naked pair {15} in R12C8, locked for C8 and NR1C6, clean-up: no 6 in R1C67
7b. Naked pair {38} in R1C67, locked for R1 and NR1C6, clean-up: no 3 in R2C2, no 6 in R2C5
7c. Naked pair {26} in R45C9, locked for C9 and 21(4) cage at R4C8
8. R45C9 = {26} = 8 -> R45C8 = 13 = [49], both placed for NR4C8, R9C8 = 7, R8C8 = 8, placed for NR4C8, R67C8 = [32], both placed for NR4C8, R7C7 = 6, placed for NR6C9, R56C7 = [15], clean-up: no 4 in R7C23
8a. Naked pair {49} in R89C7, locked for C7 -> R2C67 = [48], R1C67 = [83]
8b. Naked pair {67} in R56C6, locked for C6
9. Naked triple {135} in 9(3) cage at R4C4, locked for R4 and NR3C2 -> R3C2 = 4, R3C1 = 3, R45C1 = [84] = 12 -> R45C2 = 9 = [27/63], clean-up: no 7 in R8C1
9a. Killer pair 2,6 in R12C2 and R4C2, locked for C2
9b. Naked pair {69} in R89C1, locked for NR6C1
10. 4 in R7 only in 14(3) cage at R7C4, locked for NR5C5
11. Naked pair {35} in R89C9, locked for NR6C9 -> R9C6 = 2
11a. 2 in R8 only in 13(3) cage at R8C4 = {256} (only remaining combination) -> R8C6 = 5, placed for NR5C5, R8C45 = {26}, locked for R8 and NR5C5 -> R89C1 = [96], R89C7 = [49], R89C9 = [35]
11b. R9C6 = 2 -> R9C45 = 9 = {18}, locked for R9 -> R9C2 = 3, placed for NR6C1, R9C3 = 4, R5C2 = 7, R4C2 = 2 (step 10), R45C9 = [62], R5C5 = 8, R56C6 = [67], R6C5 = 9, placed for NR5C5, R6C234 = [864], R9C5 = 1, placed for NR5C5, R7C6 = 3, clean-up: no 5 in R1C4, no 3 in R2C4
12. R3C5 = 5, R4C56 = [31], R4C4 = 5, R5C34 = [53], R1C3 = 2, R8C23 = [17], R2C3 = 3, R2C4 = 6
and the rest is naked singles, without using the nonets.