I’ve used my starting steps for A379 up to step 8a, with a few detail omissions.
Prelims
a) R12C1 = {16/25/34}, no 7,8,9
b) R12C7 = {18/27/36/45}, no 1
c) R56C1 = {89}
d) R56C3 = {49/58/67}, no 1,2,3
e) Not applicable for V1.60
f) 11(3) cage at R4C2 = {128/137/146/236/245}, no 9
g) 20(3) cage at R7C9 = {389/479/569/578}, no 1,2
h) 21(3) cage at R8C1 = {489/579/678}, no 1,2,3
i) 17(5) cage at R9C5 = {12347/12356}, no 8,9
Steps resulting from Prelims
1a. Naked pair {89} in R56C1, locked for C1 and N4, clean-up: no 4,5 in R56C3
1b. Naked pair {67} in R56C3, locked for C3 and N4
1c. 11(3) cage at R4C2 = {245} (only remaining combination), locked for C2 and N4
1d. Naked pair {13} in R4C13, locked for R4 and 21(5) cage at R2C2
1e. 17(5) cage at R9C5 = {12347/12356}, 1,2,3 locked for R9
1f. 8,9 in R9 only in R9C234 -> no 8,9 in R8C2 (CPE)
2a. 21(3) cage at R8C1 = {579/678} (cannot be {489} because 8,9 only in R9C2), no 4
2b. 8,9 only in R9C2 -> R9C2 = {89}
2c. R89C1 = {57/67}, 7 locked for C1 and N7
3a. R4C13 = {13} = 4 -> R2C2 + R3C12 = 17 = {269/278/467} (cannot be {458} because 4,5 only in R3C1)
3b. 2,4 only in R3C1 -> R3C1 = {24}
[At this stage I saw combined cage R12C1 + R2C2 + R3C12 must contain 2 in R123C1 but decided to leave that for later if necessary, which it wasn’t.]
4. 45 rule on N7 4 outies R6789C4 = 29 = {5789}, locked for C4
5. 45 rule on C9 1 outie R8C8 = 2 innies R19C9 + 6
5a. Min R19C9 = 3 -> R8C8 = 9, R19C9 = {12}, 9 placed for D\
5b. Naked pair {12} in R19C9, locked for C9
5c. Naked pair {12} in R19C9, CPE no 1,2 in R1C1 + R5C5 using D\, clean-up: no 5,6 in R2C1
6a and 6b. Not applicable for V1.60
7. Hidden killer pair 8,9 in R9C2 and R9C34 for R9, R9C2 = {89} -> R9C34 must contain one of 8,9
7a. 22(4) cage at R8C2 = {1489/1579/3478} (cannot be {4567} which doesn’t contain 8 or 9, cannot be {1678/3469/3568} because 1,3,6 only in R8C2), no 6
7b. 4 of {1489/3478} must be in R9C3 -> no 8 in R9C3
7c. 45 rule on R9 4 innies R9C1234 = 28 = {4789/5689}
7d. Consider placement for 7 in N7
R8C1 = 7 => R9C12 = 14 = [59] (cannot be [68] because R9C34 cannot be {59} without 7 in R8C4)
or R9C1 = 7
-> R9C1 = {57}
7e. R9C1234 = {4789} (only remaining combination), no 5 -> R9C1 = 7, placed for D/, R9C3 = 4, R9C24 = {89}
7f. 22(4) cage contains 4 = {1489/3478}, no 5
7g. 5 in C4 only in R67C4, locked for 31(6) cage at R6C6
7h. R8C1 = 5 (hidden single in N7) -> R9C2 = 9 (cage sum), R89C4 = [78] -> R8C2 = 3 (cage sum), placed for D/, clean-up: no 2 in R2C1
7i. Killer pair 1,3 in R12C1 and R4C1, locked for C1
7j. R2C2 + R3C12 (step 3a) = {278} (only remaining combination, cannot be {467} which clashes with R12C1) -> R3C1 = 2, R23C2 = {78}, locked for N1, 8 locked for C2 -> R7C12 = [61], clean-up: no 1 in R2C1
7k. Naked pair {34} in R12C1, 3 locked for C1 and N1
7l. R1C2 = 6 -> R1C345 = 19 = {289/379} (cannot be {478} because no 4,7,8 in R1C3) -> R1C3 = 9, R1C45 = [28/37], clean-up: no 3 in R2C7
7m. Naked pair {15} in R23C3, locked for C3 and 24(5) cage at R2C3
7n. R23C3 = {15} = 6 -> R3C456 = 18 = {369/468} (cannot be {378} which clashes with R3C2), no 7, 6 locked for R3 and N2
8. 1 on D/ only in R1C9 + R2C8 + R3C7, locked for N3, clean-up: no 8 in R12C7
8a. 35(7) cage at R1C8 contains 1 = {1235789/1245689/1345679}, 9 locked for C7
8b. 9 in C7 only in R34C7, CPE no 9 in R4C6
[That was also available for A379 but I didn’t spot it then.]
9. 6 on D\ only in R4C4 + R5C5 + R6C6, locked for N5
9a. 6 on D/ only in R2C8 + R5C5, CPE no 6 in R5C8
10. Killer pair 3,8 in R1C45 and R3C456, locked for N2
10a. 17(4) cage at R1C6 = {1259/1457}
10b. R2C456 cannot contain both of 1,5, which would clash with R2C3 -> R1C6 = {15}
10c. Killer pair 1,5 in R2C3 and R2C456, locked for R2, clean-up: no 4 in R1C7
11. 19(4) cage at R4C4 = {1468/1567/2368/2458/2467/3457} (cannot be {1279} because 7,9 only in R4C5, cannot be {1369/1378} because 1,3 only in R5C4, cannot be {1459/2359} which clash with R6C4), no 9
11a. 9 in R4 only in R4C79, locked for N6
12. 45 rule on N3689 3 innies R7C45 + R8C5 = 1 outie R5C6 + 12
12a. Max R7C45 + R6C5 = 20 -> max R5C6 = 8
12b. R5C1 = 9 (hidden single in R5) -> R6C1 = 8
13. 2 in N3 only in R1C789 + R2C78, CPE no 2 in R4C7
[Another one that I didn’t spot for A379; it was available after step 5.]
14. 17(4) cage at R1C6 (step 10a) = {1259/1457}
14a. Consider permutations for R1C45 (step 7l) = [28/37]
R1C45 = [28] => 17(4) cage = {1457}, 4 locked for R2 => R2C1 = 3
or R1C45 = [35] => R1C1 = 4
-> R12C1 = [43], 4 placed for D\
15. 19(4) cage at R4C4 (step 11) = {1468/1567/2368/2458/2467} (cannot be {3457} because R4C4 only contains 2,6)
15a. Consider placements for R1C9
R1C9 = 1 => R9C9 = 2, placed for D\ => R4C4 = 6 => 19(4) cage = {1468/1567/2368/2467}
or R1C9 = 2 => R1C6 = 1 (hidden single in R1) => R5C4 = 1 (hidden single in C4) => 19(4) cage = {1468/1567}
-> 19(4) cage = {1468/1567/2368/2467} -> R4C4 = 6
15b. R2C8 = 6 (hidden single on D/), clean-up: no 3 in R1C7
15c. 4 on D/ only in R3C7 + R4C6, CPE no 4 in R3C6 + R4C78
15d. 35(7) cage at R1C8 contains 1 and 6 = {1245689/1345679}, 4 locked for N3, clean-up: no 5 in R1C7
[Ed pointed out that 4 is also locked for R3. This would immediately place R3C4 = 3, R1C45 = [28], R5C5 = 5 etc. which would simplify some of my later steps.]
15e. Naked pair {27} in R12C7, locked for C7 and N3
15f. 35(7) cage at R1C8 = {1245689/1345679} contains one of 2,7 -> R4C8 = {27}
16a. R1C9 = 1, R9C9 = 2, placed for D\, R1C6 = 5
16b. R3C3 = 1 (hidden single in R3), placed for D\
16c. 5 on D\ only in R5C5 + R7C7, CPE no 5 in R35C7 + R7C5
16d. 5 on D/ only in R5C5 + R6C4, locked for N5
16e. Consider placement for 5 on D\
R5C5 = 5 => R67C4 = [95]
or R7C7 = 5
-> 5 in R7C47, locked for R7
16f. R8C8 = 9 -> R78C9 = 11 = [38/74]
16g. 6 in N9 only in R89C7, locked for C7
17. Caged X-Wing for 5 in 35(7) cage at R1C8 and 31(5) cage at R1C8, no other 5 in N36
18. 19(4) cage at R4C4 (step 15a) = {1468/2368/2467}
18a. Consider permutations for R1C45 (step 7l) = [28/37]
R1C45 = [28] => 19(4) cage = {1468/2368} (cannot be {2467} = [6724] which clashes with R4C8)
or R1C45 = [37] => 19(4) cage = {1468/2368}
-> 19(4) cage = {1468/2368}, no 7, 8 locked for R4 and N5
18b. 1,3 of 19(4) cage only in R5C4 -> R5C4 = {13}
[Now I’m back where I would have been if I hadn’t overlooked 4 locked for R3 in step 15d.]
18c. R5C5 = 5 -> R67C4 = [95], 9 placed for D/
18d. R4C7 = 9 (hidden single in C7)
18e. 7 in R4 only in R4C89, locked for N6
18f. 3 on D\ only in R6C6 + R7C7, CPE no 3 in R6C78 + R7C56
19. 13(3) cage at R5C6 = {148/238} (cannot be {247} = [742] which clashes with R6C78, ALS block, but simpler is {247} clashes with R5C2), no 7, 8 locked for N6
19a. R5C3 = 7 (hidden single in R5) -> R6C3 = 6
19b. R5C9 = 6 (hidden single in R5)
20a. Naked quad {3478} in R7C789 + R8C9, locked for N9
20b. Deleted after an earlier correction
20c. R789C9 + R8C9 = {3478} = 22, R78C9 (step 16f) = 11 -> R7C78 = 11 = {38}, locked for N9, 8 also locked for R7 -> R78C9 = [74], R46C9 = [53], R7C3 = 2, placed for D/, R6C6 = 7, placed for D\, R2C2 = 8, placed for D\
20d. R7C78 = 11 -> R6C78 = 5 = {14}, locked for R6 and N6
20e. R5C78 = [82] -> R5C6 = 3 (cage sum)
20f. R36C7 = [41], R8C7 = 6 -> R78C6 = 6 = [42]
and the rest is naked singles.
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