Losing chess

Losing Chess (also known as Antichess, the Losing Game, Giveaway Chess, Suicide Chess, Killer Chess, Must-Kill, Take-All Chess, Capture Chess or Losums) is one of the most popular of all chess variants. The objective of each player is to lose all of his pieces or be stalemated, that is, a misère version. In some variations, a player may also win by checkmating or by being checkmated.

The origin of the game is unknown, but believed to significantly predate an early version, named Take Me, played in the 1870s. Because of the popularity of Losing Chess, several variations have spawned. The most widely played (main variant) is described in Popular Chess Variants by D. B. Pritchard.

The rules are the same as those for standard chess, except for the following special rules:

A player wins by losing all his pieces, or being stalemated. Apart from move repetition, draw by agreement, and the fifty-move rule, the game is also drawn when a win is impossible (such as if a dark-squared bishop and a light-squared bishop of opposite colours are the only pieces remaining).

Because of the forced capture rule, Losing Chess games often involve long sequences of forced captures by one player. This means that a minor mistake can doom a game. Such mistakes can be made from the very first move—losing openings for White include 1.e4, 1.d4, 1.d3, 1.Nf3, 1.Nc3, 1.f4, 1.h4, 1.b4, 1.h3, 1.a3, 1.c3 and 1.f3. Some of these openings took months of computer time to solve, but wins against 1.e4, 1.d4, and 1.d3 consist of simple series of forced captures and can be played from memory by most experienced players.

This main variant of Losing Chess was weakly solved in October 2016; White is able to force a win beginning with 1.e3.

David Pritchard, the author of The Encyclopedia of Chess Variants, wrote that the "complexity and beauty" of Losing Chess is found in its endgame. He noted that, in contrast with regular chess, Losing Chess endgames with just two pieces require considerable skill to play correctly, whilst three or four pieces endgames can exceed human capacity to solve precisely.

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Wikipedia