Los Alamos chess

Los Alamos chess (or anti-clerical chess[1]) is a chess variant played on a 6×6 board without bishops. This was the first chess-like game played by a computer program. This program was written at Los Alamos Scientific Laboratory by Paul Stein and Mark Wells for the MANIAC I computer[2] in 1956. The reduction of the board size and the number of pieces from standard chess was due to the very limited capacity of computers at the time.

	a	b	c	d	e	f
6							6
5							5
4							4
3							3
2							2
1							1
	a	b	c	d	e	f

Los Alamos chess setup

Game rules

The starting position is illustrated. All rules are as in chess except:

• there is no pawn double-step move, nor is there en passant capture;
• pawns may not promote to bishops;
• there is no castling.

Los Alamos trials

The computer played three games. The first it played against itself. The second one was against a strong human player, who played without a queen. The human player won. In the third game, MANIAC I played against a laboratory assistant who had been taught the rules of chess in the preceding week specifically for the game. The computer won, marking the first time that a computer had beaten a human player in a chess-like game.[2][3]

The third game

	a	b	c	d	e	f
6							6
5							5
4							4
3							3
2							2
1							1
	a	b	c	d	e	f

Final position after 23.Ne5#

White: MANIAC I   Black: Beginner
1.d3 b4 2.Nf3 d4 3.b3 e4 4.Ne1 a4 5.bxa4 Nxa4 6.Kd2 Nc3 7.Nxc3 bxc3+ 8.Kd1 f4 9.a3 Rb6 10.a4 Ra6 11.a5 Kd5 12.Qa3 Qb5 13.Qa2+ Ke5 14.Rb1 Rxa5 15.Rxb5 Rxa2 16.Rb1 Ra5 17.f3 Ra4 18.fxe4 c4 19.Nf3+ Kd6 20.e5+ Kd5 21.exf6=Q Nc5 22.Qxd4+ Kc6 23.Ne5# 1–0[4]

See also

• Minichess

References

1. Anderson (1986), p. 105
2. Pritchard (1994), p. 175
3. Pritchard (2007), p. 112
4. Pritchard (1994), p. 176

Bibliography

• Anderson, Herbert L. (Fall 1986). "Metropolis, Monte Carlo, and the MANIAC" (PDF). Los Alamos Science: 104–105. Issue #14
• Pritchard, D. B. (1994). "Los Alamos Chess". The Encyclopedia of Chess Variants. Games & Puzzles Publications. ISBN 0-9524142-0-1.
• Pritchard, D. B. (2007). "Los Alamos Chess". In Beasley, John (ed.). The Classified Encyclopedia of Chess Variants. John Beasley. ISBN 978-0-9555168-0-1.

Further reading

• Chess Review, January 1957

External links

• Los Alamos Chess by Hans L. Bodlaender, The Chess Variant Pages
• A short history of computer chess by Frederic Friedel
• BrainKing.com - internet server to play Los Alamos chess.