Learned of “Zugzwang” in Arthur & George by Julian Barnes, which I’ve just finished reading:
Zugzwang (German for “compulsion to move”, pronounced [ËˆtsuËktsvaÅ‹]) is a term usually used in chess which also applies to various other games. The term finds its formal definition in combinatorial game theory, and it describes a situation where one player is put at a disadvantage because he has to make a move when he would prefer to pass and make no move. The fact that the player must make a move means that his position will be significantly weaker than the hypothetical one in which it was his opponent’s turn to move.
In game theory, it specifically means that it directly changes the outcome of the game from a win to a loss. The term is used less precisely in games such as chess; i.e., the game theory definition is not necessarily used in chess. For instance, it may be defined loosely as “a player to move cannot do anything without making an important concession”. Putting the opponent in zugzwang is a common way to help the superior side win a game. In some cases it is necessary to make the win possible.