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 he may 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, or Losums) is a chess variant in which 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. Losing chess is one of the most popular of all chess variants.^[1]

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.
• In addition to its normal promotion options, a pawn may 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 are the only pieces remaining).

Analysis

	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 d6?? White wins with: 2.Qg4! Bxg4 3.Kd1 Bxd1 4.a3 Bxc2 5.Ra2 Bxb1 6.a4 Bxa2 7.b3 Bxb3 8.g3 Bxa4 9.Bb5 Bxb5 10.Ne2 Bxe2 11.Rf1 Bxf1 12.h3 Bxh3 13.g4 Bxg4 14.f3 Bxf3 15.e4 Bxe4 16.d3 Bxd3 17.Bh6 Nxh6 1–0^[2]

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]}

Work to weakly solve the main variant of Losing chess is ongoing. As of February 2015 it has been found that, with perfect play, White is able to force a win after 19 of Black's 20 legal responses to 1.e3. Only the outcome of 1...b6 is currently unsolved.^[3]

In the example diagram, 1...d6?? is a blunder, since White can easily force victory. In this sequence, each move by Black from 2...Bxg4 through 16...Bxd3 is the only legal move available.

Variations

Several variants of the game exist.

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.^[3] 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:

• Pawns promote only to queens.
• Stalemate is a draw.

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.

Endings

P. H. Törngren
Tidskrift för Schack, 1929

	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 play and win 

Solution:
1.h3! a5 2.h4 a4 3.h5 a3 4.h6 a2 5.h7

• 5...a1=R! 6.h8=B! R moves (Black is in zugzwang) 7.Ba1 Rxa1 White wins
• 5...a1=K! 6.h8=R! and White will sacrifice the rook, e.g. 6...Kb2 7.Rd8 Kb3 8.Rd5 Kb2 9.Rd4 Ka1 10.Rc4 Ka2 11.Rc6 Ka3 12.Rc5 Ka2 13.Rc4 Ka1 14.Rc3 +−

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.^[2]

References

Notes

1. Solutions by David Bronstein were published in Popular Chess Variants (2000), pp. 33–34:
   • 1.d4?? e5 2.dxe5 Qg5 3.Qxd7 Bxd7 4.Bxg5 Kd8 5.Bxd8 a6 6.Bxc7 Ra7 7.Bxb8 b6 8.Bxa7 a5 9.Bxb6 g6 10.Bxa5 Bb4 11.Bxb4 Ne7 12.Bxe7 Rf8 13.Bxf8 h6 14.Bxh6 g5 15.Bxg5 f6 16.Bxf6 Bh3 17.Nxh3 0–1
   • 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 Rb8 14.Nxh7 Rb1 15.Qxb1 Bb7 16.Qxb7 a6 17.Qxa6 0–1
   • 1.e4?? b5 2.Bxb5 Nf6 3.Bxd7 Nxe4 and White loses no matter which capture he chooses:
     • 4.Bxe8 Qxd2 5.Qxd2 (if 5.Bxf7 Qxc1 6.Qxc1 Nxf2 7.Kxf2 Rg8 etc.) 5...Nxd2 6.Kxd2 Rg8 7.Bxf7 c5 8.Bxg8 g6 9.Bxh7 e5 10.Bxg6 e4 11.Bxe4 Nc6 12.Bxc6 Bb7 13.Bxb7 Rc8 14.Bxc8 a6 15.Bxa6 c4 16.Bxc4 Ba3 17.Nxa3 0–1
     • Or 4.Bxc8 Nxd2 5.Bxd2 Qxd2 6.Qxd2 Na6 7.Bxa6 Rc8 8.Bxc8 f5 9.Bxf5 Rg8 10.Bxh7 c5 11.Bxg8 e6 12.Bxe6 c4 13.Bxc4 a6 14.Bxa6 g5 15.Qxg5 Kd8 16.Qxd8 Be7 17.Qxe7 0–1

Citations

1. Pritchard (2007), p. 86
2. Pritchard (2000), p. 34
3. For all responses except 1...c5 and 1....b6, see: Watkins, Mark (10 September 2014). "Solved Openings in Losing Chess" (PDF). Retrieved 15 January 2015.
   For 1...c5 see Watkins' Losing Chess page
4. Bodlaender, Hans. "Losing Chess". The Chess Variant Pages. Retrieved 25 January 2016.
5. Pritchard (1994), p. 176

Bibliography

• 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 (French)
• Nilatac's opening book Suicide chess book browser
• Scidb a chess database supporting Losing chess
• Simple programs by Ed Friedlander:

• Losing Chess (Java)
• Losing Chess II (Java)
• Losing Chess III (Java)
• Losing Chess IV (Java)