Zugzwang: the obligation to move as a weapon
Chess has no passing move. Almost everything interesting about the endgame follows from that one rule.
- 120 positions in the course
- Difficulty 421–2282
- Section: Sacrifices and Quiet Moves
- 5 levels
What zugzwang is
Zugzwang is a position in which a player is not currently losing anything, but is compelled to move, and every legal move makes their position worse. If they were allowed to pass, they would hold. They are not allowed to pass.
It is overwhelmingly an endgame phenomenon, because zugzwang requires a shortage of useful moves, and a middlegame position with sixteen pieces on the board almost always has a harmless one available. In king and pawn endings it is not an occasional trick but the main mechanism by which games are won.
How to spot it
- Count the opponent's available moves. Two or three is where the idea starts to exist.
- Look for a waiting move of your own -- a king step or a spare pawn tempo -- that hands the obligation back to them.
- In pawn endings, think in terms of opposition: whoever must move first in a symmetrical king standoff is usually the one who loses ground.
- Ask what each of their legal moves gives up. If the answer is 'a square' for all of them, you have zugzwang.
Three zugzwang positions
Three positions from the 120 in this skill, easiest first. The highlighted squares are the move your opponent has just played. Work it out before you open the answer.
Position 1
Black to move. Find the best move.
Show the answer
39.Kd2 39...Kd4 40.Kc2 40...Ke3
The line comes out level on material and ahead on position. The side to move has no move that does not concede something, and the winning method is to hand the obligation back rather than to attack.
The position comes from an endgame of a real game, rated 421 for difficulty. The answer reaches a clear advantage.
Position 2
Black to move. Find the best move.
Show the answer
41.Kh5 41...g5 42.Kh6 42...Kxg4
The line comes out 1 pawn ahead. The side to move has no move that does not concede something, and the winning method is to hand the obligation back rather than to attack.
The position comes from an endgame of a real game, rated 1350 for difficulty. The answer reaches a winning advantage.
Position 3
Black to move. Find the best move.
Show the answer
38.Ke2 38...h5 39.Ke1 39...Ke3
The line comes out level on material and ahead on position. The side to move has no move that does not concede something, and the winning method is to hand the obligation back rather than to attack.
The position comes from an endgame of a real game, rated 1916 for difficulty. The answer reaches a winning advantage.
Triangulation and spare tempi
The standard technique for creating zugzwang is to lose a move on purpose. A king that can reach the same square in three moves instead of one -- triangulation -- returns the position to the opponent with the turn changed, and that is frequently the entire winning plan in a king and pawn ending.
The related resource is the spare pawn tempo. Keeping one unmoved pawn that can advance one or two squares is often worth more in an endgame than a better placed king, purely because it lets you pass when you need to.
Questions people ask
What does zugzwang mean in chess?
A position where a player is obliged to move and every legal move worsens their position. The German means roughly 'move compulsion'. If passing were legal, the position would be held.
What is mutual zugzwang?
A position where whichever side is to move loses or is worse. Also called reciprocal zugzwang. These positions are the theoretical core of king and pawn endings, where the entire result turns on whose move it is.
What is triangulation?
A technique for creating zugzwang: the king takes a three-move route to a square it could reach in one, so the same position arises with the opponent to move instead. It is the standard way of losing a tempo on purpose.
Nearby patterns
Running Out of Moves sits in Sacrifices and Quiet Moves. The rest of that section:
- SacrificesGive material, get more back
- Quiet MovesThe winning move that threatens nothing
- In-Between MovesInsert a move before recapturing
- DefendingFinding the only move that holds
Tell it apart from its neighbour
Running Out of Moves is confused with these more often than anything else, and the difference is usually one sentence long.