"Zugzwang is one of my favourite words, and an extremely useful one. Essentially, it's a condition where it would be better not to move, in a game where you have to move, such as chess. Strictly speaking, it describes a situation where that move will end the game, with the mover as the loser, but the definition in chess is looser, and only demands the loss of a piece or the worsening of the player's position. The player has to take the least worst option. It's a kind of judo – using the ineluctable forward momentum of the rules of the game to force the opposing player to do your work for you." The momentum of rules! I like that a lot.