🎓 A1Learner
🔍
0 of 43 lessons completed

Zugzwang

Zugzwang is a position where any move makes things worse. The player to move would rather pass, but passing is not allowed.

Zugzwang before a promotion

Black to move must move the king, because there are no other pieces. The king moves to h8. The pawn then promotes to a queen with check. Any king move loses the same way.

FEN: 6k1/4P3/6K1/8/8/8/8/8 b - - 0 1

a b c d e f g h
8 . . . . . . k . 8
7 . . . . P . . . 7
6 . . . . . . K . 6
5 . . . . . . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . . . . . 1
  a b c d e f g h

Zugzwang in a king and pawn race

Black to move must move the king. The king moves to d8. The pawn moves to e7 and gives check. The king must move again, and the pawn will promote.

FEN: 4k3/8/4P3/4K3/8/8/8/8 b - - 0 1

a b c d e f g h
8 . . . . k . . . 8
7 . . . . . . . . 7
6 . . . . P . . . 6
5 . . . . K . . . 5
4 . . . . . . . . 4
3 . . . . . . . . 3
2 . . . . . . . . 2
1 . . . . . . . . 1
  a b c d e f g h

Key points

  • Zugzwang means being forced to move when every move loses.
  • Zugzwang is common in king and pawn endgames.
  • The player in zugzwang must weaken a square or lose a pawn.
  • The player who is not in zugzwang can wait with a safe move.
  • A triangulation can put the opponent in zugzwang.
  • A zugzwang often decides a pawn promotion race.
  • Recognise zugzwang by checking every legal move for a loss.

Try it Yourself

Edit the code, then press Run.

Running is simulated · Rust Playground

Exercise

Black to move. Which move shows Black is in zugzwang?