Losing Chess

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

After 1.e3 b5 2.Bxb5 Bb7 (diagram) White must play 3.Bxd7, the only legal capturing move. Then Black must also make a capture, but can choose among the four options Nxd7, Qxd7, Kxd7, or Bxg2.

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.^[1][2] 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.

Rules (main variant)

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

• Capturing is compulsory.
• When more than one capture is available, the player may choose.
• The king has no royal power and accordingly:
  • it may be captured as any other piece;
  • there is no check or checkmate;
  • there is no castling;
  • a pawn may also promote to a king.
• Stalemate is a win for the stalemated player.

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).

Analysis

1.d3?? is one of several openings that lose by force: 1.d3 g5 2.Bxg5 Bg7 3.Bxe7 Bxb2 4.Bxd8 Bxa1 5.Bxc7 Bc3 6.Bxb8 Rxb8 7.Nxc3 d5 8.Nxd5 Nf6 9.Nxf6 Rg8 10.Nxe8 Rxg2 11.Bxg2 f6 12.Bxb7 Rxb7 13.Nxf6 h5 14.Nxh5 Rb1 15.Qxb1 Bb7 16.Qxb7 a6 17.Qxa6 0–1

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.^{[lower-alpha 1]}

This main variant of Losing Chess was weakly solved in October 2016; White is able to force a win beginning with 1.e3.^{[lower-alpha 2]}

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.^[3]

Variations

Variations regarding stalemate

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

White to move, but there are no legal moves. The position is stalemate. The game result depends on the variant being played.

Implementations of the main variant can vary in regard to stalemate.^[4] "International" rules are as described above, with the stalemated player winning. FICS rules resolve stalemate as a win for the player with the fewer number of pieces remaining; if both have the same number, it is a draw (the piece types are irrelevant). "Joint" FICS/International rules resolves stalemate as a draw unless it is a victory for one player under both rulesets.^{[lower-alpha 2]} The stalemate in the diagram is a win for White under "International" rules, a win for Black under FICS rules, and a draw under "joint" rules.

Variants in The Encyclopedia of Chess Variants

Pritchard discusses the following variants of the game in The Encyclopedia of Chess Variants.^[5]

Variant 2

Rules are the same as the main rules, except:

Variant 3

Rules are the same as the main rules, except:

• The king has royal powers, and removing the king from check takes precedence over capturing another piece.
• A player wins by reducing his pieces to just a king, or by checkmating the opponent.
• Stalemate is a draw.

Variant 4

Rules are the same as variant 3, except:

• A player wins by reducing his pieces to just a king, or by getting checkmated.

Notes

References

Bibliography

• Parlett, David (1999). The Oxford History of Board Games. Oxford University Press Inc. ISBN 0-19-212998-8. 
• Pritchard, D. B. (1994). "Losing Chess". The Encyclopedia of Chess Variants. Games & Puzzles Publications. pp. 176–79. ISBN 0-9524142-0-1. 
• Pritchard, D. B. (2000). "§7 Losing Chess". Popular Chess Variants. B.T. Batsford Ltd. pp. 32–38. ISBN 0-7134-8578-7. 
• Pritchard, D. B. (2007). "§10.9 Playing to lose". In Beasley, John. The Classified Encyclopedia of Chess Variants. John Beasley. pp. 85–89. ISBN 978-0-9555168-0-1. 

External links

• Losing Chess by Hans Bodlaender, The Chess Variant Pages
• Suicide Chess Review by Vladica Andrejić
• Losing Chess by Fabrice Liardet (in French)
• Nilatac's opening book Suicide Chess book browser
• Scidb a chess database supporting Losing Chess
• Losing Chess Losing Chess II Losing Chess III Losing Chess IV simple programs by Ed Friedlander (Java)