What zugzwang means
Chess has no pass move. In almost every position that is no problem, because having the move is an advantage: you can improve a piece, make a threat or take something. Zugzwang is the exception. The position is fine as it stands, but whoever has to move must spoil it.
Nothing needs to be attacked for zugzwang to bite. The damage comes from the move itself: a king has to step off a key square, a defending piece has to leave the square it guards, or a pawn has to advance and give up control of a square behind it.
Mutual zugzwang
When the position would be bad for whichever side has to move, it is a mutual, or reciprocal, zugzwang. The result then depends on nothing but the turn.
The example below is a standard case. With White king d6, pawn e7 and Black king e8, Black to move must play Kf7, and after Kd7 the pawn promotes. With White to move it is a draw: the only king move that keeps the pawn protected is Ke6, and that is stalemate. Positions like this sit at the heart of the opposition and of triangulation, which are both ways of reaching a zugzwang with the opponent to move.
Where zugzwang appears
It is most common in endgames, where there are few pieces and few useful moves. King and pawn endings are full of it, and so are endings such as queen against rook, where the defender's pieces must hold one exact arrangement.
It is rare in the middlegame, because there are usually plenty of harmless moves, but it does happen in blocked positions where every piece move loosens the defence. In these fights a spare pawn move, called a reserve tempo, is valuable: it lets you hand the move back without changing anything else.
How to use it
In a pawn ending, ask what the position would look like with the opponent to move. If that would win, look for a way to lose a move: a waiting pawn move, a king triangle or an outflanking manoeuvre. Count the spare pawn moves on both sides before you start pushing pawns, because each one is a tempo you can use later.
Common mistakes
- Confusing zugzwang with a merely bad position. Zugzwang means the position would be fine if you could pass, and only the obligation to move hurts.
- Using up spare pawn moves early in a pawn ending, so that none are left when a waiting move is needed.
- Forgetting stalemate. In many zugzwang positions the natural move for the stronger side stalemates the opponent.
Questions about zugzwang
What does zugzwang mean?
It is German for "compulsion to move". In chess it describes a position where the side to move would be better off passing, because every legal move worsens their position.
What is the difference between zugzwang and stalemate?
In stalemate the side to move has no legal moves and is not in check, and the game is drawn at once. In zugzwang there are legal moves, but all of them are harmful.
Can zugzwang happen in the middlegame?
Yes, but rarely. It needs a position where every available move weakens something, which is far more common once most pieces have been exchanged.
Practise it
- Pawn endgame puzzles from real games, with solutions