Los Alamos chess is a chess variant

Chess variant

A chess variant is a game related to, derived from or inspired by chess. The difference from chess might include one or more of the following:...

 played on a 6×6 board

Minichess

Minichess is a family of chess variants played with regular chess pieces and standard rules, but on a smaller board.The motivation for these variants is to make the game simpler and shorter than the standard chess. Martin Gardner recommended 5x5 chess variant to fill short breaks during the work...

 without bishops

Bishop (chess)

A bishop is a piece in the board game of chess. Each player begins the game with two bishops. One starts between the king's knight and the king, the other between the queen's knight and the queen...

. This was the first chess-like game played by a computer program. This program was written in Los Alamos laboratory

Los Alamos National Laboratory

Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...

 by Paul Stein and Mark Wells for the MANIAC I

MANIAC I

The MANIAC was an early computer built under the direction of Nicholas Metropolis at the Los Alamos Scientific Laboratory...

 computer in 1956. The reduction of the board size and the number of pieces from standard chess

Chess

Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...

 was due to the very limited capacity of computers at the time.

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

Chess handicap

A handicap in chess is a way to enable a weaker player to have a chance of winning against a stronger one. There are many kinds of such handicaps, such as material odds, extra moves A handicap (or "odds") in chess is a way to enable a weaker player to have a chance of winning against a stronger...

. The human player won. In the third game, MANIAC I played against a novice chess player who had been taught the rules just before the game. The computer won, marking the first time that a computer had beaten a human player in a chess-like game.

Rules

The starting position is shown on the right. All rules are as in chess except:

• There is no pawn double-move, nor is there en passant
  En passant
  En passant is a move in the board game of chess . It is a special pawn capture which can occur immediately after a player moves a pawn two squares forward from its starting position, and an enemy pawn could have captured it had it moved only one square forward...
  
  capture;
• Pawns
  Pawn (chess)
  The pawn is the most numerous and weakest piece in the game of chess, historically representing infantry, or more particularly armed peasants or pikemen. Each player begins the game with eight pawns, one on each square of the rank immediately in front of the other pieces...
  
   may not promote to bishops;
• There is no castling
  Castling
  Castling is a special move in the game of chess involving the king and either of the original rooks of the same color. It is the only move in chess in which a player moves two pieces at the same time. Castling consists of moving the king two squares towards a rook on the player's first rank, then...
  
  .

External links

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