Re: [math-fun] Maximum number of queens simultaneously on a chessboard from a legal game

Dan Asimov:

There is an obvious upper bound of 18. Is this achievable?

Yes. A better question might be what is the minimum number of moves in which it is achievable. I see it done in 58 moves here: http://www.chess.com/forum/view/off-topic/18-queens?page=2