Zugzwang (German for “compulsion to move”) is a position in which any move worsens the player's position. If you could pass, everything would be fine, but the rules require you to move.
Zugzwang occurs most often in the endgame, when there are few pieces on the board and the players have few useful moves.
Mutual zugzwang
Especially interesting is mutual zugzwang: a position in which whoever is to move loses.
In this position the pawns are blocked; only the kings can move. But as soon as a king steps away, its pawn is left without protection and will be taken.
- If it is White to move, they lose the e4 pawn.
- If it is Black to move, they lose the e5 pawn.
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Zugzwang in pawn endgames
The theme of zugzwang is closely linked to the opposition and triangulation: with their help a player “passes the move” to the opponent and puts them in zugzwang.
Zugzwang in the middlegame
Occasionally zugzwang arises even with many pieces on the board: when all of one side's pieces are tied to defence and any move breaks the defensive setup. Such games are considered masterpieces of positional play.
How to use it
If your opponent has few useful moves, do not rush into action — sometimes the best move is a waiting move: make a neutral move and let your opponent worsen their own position.