Extremely tangential, but how to chess engines do when playing from illegal board states? Could the LLM have a chance of competing with a real chess engine from there?

Understanding is a funny concept to try to apply to computer programs anyway. But playing from an illegal state seems (to me at least) to indicate something interesting about the ability to comprehend the general idea of chess.

I just checked the Lichess board editor tool and it won’t let you continue analyzing with an engine if you have an illegal board setup (like the two kings adjacent to each other).

I haven’t tried this yet, but I think you can set up and analyze board positions that are legal but that could never be reached in a real game (e.g, having nine pawns of one color).