"It's a chess term referring to a state in which, similar to a `perpetual check', any further progress in a game becomes impossible. This would be the opposite of an endless repetition of moves, because all moves would disappear, and it would bring about a kind of deadlock. In chess, this would lead to a draw, just as a perpetual check would. ...However, there can be no draws in the game between you and Milady. Therefore, I am unable to answer a question that would bring about a stalemate."