gwish - 2026-02-04 8:35 PM
It's from sudoku.coach, so maybe it's because it has to follow strict techniques but humans don't have to?
btw the grid that it says chains are necessary at 012547080035180742487000050059008060008060500006305810061800405803654090594000608, and it gets r5c2=4 after those three steps
Made a video on this sudoku.
https://youtu.be/usuWNe_wONI