GoKawiilDisadvantage in a game due to obligation to move
This article uses algebraic notation to describe chess moves.
This article is about the disadvantageous requirement to move. For the move interposition tactic, see Zwischenzug . For other uses, see Zugzwang (disambiguation)
Zugzwang (from German 'compulsion to move'; pronounced [ˈtsuːktsvaŋ]) is a situation found in chess and other turn-based games wherein one player is put at a disadvantage because of their obligation to make a move; a player is said to be "in zugzwang" when any legal move will worsen their position.[1]
Although the term is used less precisely in games such as chess, it is used specifically in combinatorial game theory to denote a move that directly changes the outcome of the game from a win to a loss.[2][3] Putting the opponent in zugzwang is a common way to help the superior side win a game, and in some cases it is necessary in order to make the win possible.[4] More generally, the term can also be used to describe a situation where passing the turn, if this were allowed, would be the best move.[5][6][7]
The term zugzwang was used in German chess literature in 1858 or earlier,[8] and the first known use of the term in English was by World Champion Emanuel Lasker in 1905.[9] The concept of zugzwang was known to chess players many centuries before the term was coined, appearing in an endgame study published in 1604 by Alessandro Salvio, one of the first writers on the game, and in shatranj studies dating back to the early 9th century, over 1000 years before the first known use of the term. International chess notation uses the symbol " ⊙ " to indicate a zugzwang position.
Positions with zugzwang occur fairly often in chess endgames, especially in king and pawn endgames and elementary checkmates (such as a rook and king against a lone king). According to John Nunn, positions of reciprocal zugzwang are surprisingly important in the analysis of endgames.[10][11]
Etymology [ edit ]
The word comes from German Zug 'move' + Zwang 'compulsion', so that Zugzwang means 'being forced to make a move'. Originally the term was used interchangeably with the term Zugpflicht 'obligation to make a move' as a general game rule. Games like chess and checkers have "zugzwang" (or "zugpflicht"): a player must always make a move on their turn even if this is to their disadvantage. Over time, the term became especially associated with chess.
According to chess historian Edward Winter, the term had been in use in German chess circles in the 19th century.[8]
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