Zugzwang

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Zugzwang is a chess term. It means a situation where any move by a player will weaken the player's position.[1] The fact that the player is compelled to move means that their position will become significantly weaker.

For example...

Example of zugzwang
Start of chess board.
a8 __ b8 __ c8 black king d8 __ e8 __ f8 __ g8 __ h8 __
a7 __ b7 __ c7 __ d7 __ e7 __ f7 __ g7 __ h7 __
a6 __ b6 __ c6 __ d6 __ e6 __ f6 __ g6 __ h6 __
a5 __ b5 __ c5 white pawn d5 white king e5 __ f5 __ g5 __ h5 __
a4 __ b4 __ c4 __ d4 __ e4 __ f4 __ g4 __ h4 __
a3 __ b3 __ c3 __ d3 __ e3 __ f3 __ g3 __ h3 __
a2 __ b2 __ c2 __ d2 __ e2 __ f2 __ g2 __ h2 __
a1 __ b1 __ c1 __ d1 __ e1 __ f1 __ g1 __ h1 __
End of chess board.
Black to play

1. ... Kd7 and White cannot win:

2. c6+ Kc7

3. Kc5 Kc8

4. Kd6 Kd8 (opposing the king)

5. c7+ Kc8

6. Kc6 is stalemate


White to play

But if it is White to play in the original position, he can win by zugzwang:

1. Kc6! and now Black must move his king, for example

1..... Kd8

3. Kb7 and queens the pawn.

Mutual zugzwang[change | change source]

Either player to move loses
Start of chess board.
a8 black king b8 black king c8 black king d8 black king e8 black king f8 black king g8 black king h8 black king
a7 black king b7 black king c7 black king d7 black king e7 black king f7 black king g7 black king h7 black king
a6 black king b6 black king c6 black king d6 black king e6 black king f6 black king g6 black king h6 black king
a5 black king b5 black king c5 black king d5 black pawn e5 white king f5 black king g5 black king h5 black king
a4 black king b4 black king c4 black king d4 white pawn e4 black king f4 black king g4 black king h4 black king
a3 black king b3 black king c3 black king d3 black king e3 black king f3 black king g3 black king h3 black king
a2 black king b2 black king c2 black king d2 black king e2 black king f2 black king g2 black king h2 black king
a1 black king b1 black king c1 black king d1 black king e1 black king f1 black king g1 black king h1 black king
End of chess board.

There are positions where either player to move will lose.

On the following diagram, Whichever king moves, he loses his pawn and the opponent will win the game.

History[change | change source]

The concept of zugzwang was known in the old forms of chess, like shatranj. We know this because there are some Arabic chess problems which use the idea.

The term itself comes from the 19th century in a German chess magazine. Its first use in English was in the early 20th century.[2]

References[change | change source]

  1. Hoope D. & Whyld K. 1992. The Oxford companion to chess. Oxford University Press. ISBN 978-0-19-280049-7
  2. Winter, Edward 1997. Zugzwang. www.chesshistory.com [1]