bcw (12/13/82)
From: Bruce C. Wright @ Duke University Re: Chess positions I don't remember the position which had the most legal moves, but it had lots of Pawns on the 7th rank each of which could capture a couple of enemy pieces on the 8th rank (thereby promoting into N's, R's, B's, or Q's), and other highly improbable things. As I recall en passant and castling were not legal anyway. The position had about 215 legal moves I think, each promotion to a different piece counting as a different legal move. Positions of this type were discussed about a couple of years ago in some publication I get, but I've forgotten which one (probably Chess Life and Review or Chess Life [the same publication, it's gone through several name changes]). You could also likely find something about this in problem books if you look hard enough. I don't know of any work done on maximizing the number of moves after 3 ply. It would probably depend on whether there was some "reasonable- ness" criterion placed on the moves (i. e., could come up in the course of some "reasonable" alpha-beta search or which could come up as the main line), or whether the position can be reached by the cooperation of both players. Probably the easiest way to get this position would be to work back from the above position ... it wouldn't be a unique solution. Bruce C. Wright @ Duke University