12:21 am
irv

Done. very easy for expert

8:29 am
spellacked

Since this one ended up with a small number of unknowns at the point where I wanted to guess, I went to check how https://www.sudokuwiki.org/sudoku.htm would solve it. And I can see the logic of the XY-Chains it suggests, the problem is that without exhaustive searches that computers find easy to do, how would I locate those XY-Chains. Is there a trick to finding those Once you find enough of those, the remaining dozen numbers are all forced and easy.

10:56 am
gman

Spellacked: let me know if you find a clue cause I dont think theres enough time in the day to find one X/Y chain much less the several that might be required to solve the nasty expert puzzles. No tricks, I believe, just brute computing. Thats why I end up guessing on most Experts and some hard puzzles. Happy Friday

11:02 am
KnightTime

there are 2 x-wings in this puzzle one of which has an obvious non-value on one of the corners, i.e. it leads to duplicate numbers if the value is chosen, therefore choosing the other value solves the puzzle.

11:04 am
gman

Thanx KT. I have15 numbers solved and slowing down. Might have to go green when I get back to it.