In chess, there are a multitude of strange words but German word "zugzwang" is one of the most famous. Zugzwang means "compulsion to move," and the diagrams below represent two famous examples. At the end of this article, IM-elect Stephen Muhammad provides some analysis on this concept. He credits Mark Dvoretsky as his inspiration for the article.

Zugzwang

Zugzwang example #1 is from Saemisch-Nimzovich, Copehagen 1923. White resigned here shortly after eating a sacrificed piece. Every move will result in material loss or mate and white position is ridiculously frozen. After a couple of pawn moves white is complete zugzwang. Try to find a move for white.

Zugzwang example #2 is from the Garry Kasparov-Deep Blue match which Kasparov won 4½-1½.  Although a pawn up, Black cannot make any moves that will improve his position. In fact, all four of his pieces are paralyzed while White enjoys an immense spatial advantage and will eventually infiltrate on the dark squares and checkmate the Black King.

Mutual Zugzwang

"Mutual Zugzwang," also known as "reciprocal zugzwang," is a term not known by many chess players, but is a key concept. Mutual zugzwang occurs when each side would be at a disadvantage if it were their turn to move. These positions are common in King and Pawn endings.

Mutual Zugzwang example #1 is from a famous ending. In this position, Black would lose if it had to move since 1… Kg7 would allow infiltration by the White King after 2.Ke7 followed by 2.f8(Q). On the other hand, if White were to move, the game would be a draw since either the pawn would be lost, or a stalemate draw would occur after 1.Kf6.

Mutual Zugzwang example #1 is a bit more complex and involves a concept called, "mutual zugzwang squares." The lesson below features analysis from Muhammad and the instructive play that results. As one can see, when one has a bishop locked in by it's own pawns,  gaining and losing tempos become a matter of life or death at the chess board. Note: The analysis done by Muhammad was the subject of an article appearing in the June/July 1999 issue of Georgia Chess magazine and was reprinted with permission.

Posted by The Chess Drum: 18 September 2003