Zugzwang
Zugzwang is a position where having to move is a disadvantage. The side to move would rather pass, but the rules do not allow a pass, and every legal move makes the position worse.
It is most common in pawn endings, where a king step abandons a key square. It also appears in some piece endings, when any piece move drops material or allows mate.
Mutual zugzwang means both sides would be worse off if it were their turn. Whose move it is decides the result.
A check is not zugzwang. Zugzwang is about quiet positions, where the move itself is the problem. The tactic page collects puzzles tagged with this idea.
On the board
Kings only, White to move. Step the king and watch Black take the opposition by moving straight back. Nothing is captured. The point is whose turn it is.
Common mistakes
- Using the word for any bad position. Zugzwang means the obligation to move is the cause.
- Assuming you may skip a move. Passing is not legal.