''Colossus Chess'' is a series of chess-playing computer programs developed by

Martin Bryant Martin John Bryant (born 7 May 1967) is an Australian mass murderer who shot and killed 35 people and injured 23 others in the Port Arthur massacre on 28 and 29 April 1996. He is currently serving thirty-five life sentences, and 1035 ...

, commercially released for various

home computer Home computers were a class of microcomputers that entered the market in 1977 and became common during the 1980s. They were marketed to consumers as affordable and accessible computers that, for the first time, were intended for the use of a s ...

s in the 1980s.

History

Bryant started ''Colossus Chess'' in 1983, using his '' White Knight Mk 11'' program, winner of the 1983 European Microcomputer Chess Championship, as a basis. It was developed on an

Apple II Apple II ("apple Roman numerals, two", stylized as Apple ][) is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The Apple II (original), original Apple II model, which gave the series its name, was designed ...

, but was first commercially released for Commodore 64 as ''Colossus Chess 2.0'' (CDS Micro Systems, 1984). A number of releases for 8-bit microcomputers followed. Version 3.0 was released in 1984 for the Atari 8-bit computers (published by English Software), followed by 4.0 in 1985 which was released on most formats of the day (published by CDS). As other games of the time, the

Acorn Electron The Acorn Electron (nicknamed the Elk inside Acorn and beyond) was introduced as a lower-cost alternative to the BBC Micro educational/home computer, also developed by Acorn Computers, to provide many of the features of that more expensive mach ...

implementation required that part of the screen memory be used as working space. ''Colossus Chess'' featured time-controlled play with

game clock A chess clock is a device that comprises two adjacent clocks with buttons to stop one clock while starting the other, so that the two clocks never run simultaneously. The clocks are used in games where the time is allocated between two parties. T ...

s, an opening book with 3,000 positions, and

problem Problem solving is the process of achieving a goal by overcoming obstacles, a frequent part of most activities. Problems in need of solutions range from simple personal tasks (e.g. how to turn on an appliance) to complex issues in business an ...

-solving mode that could solve normal mates,

selfmate A selfmate is a chess problem in which White, moving first, must force Black to deliver checkmate within a specified number of moves. Selfmates were once known as sui-mates. Example The problem shown is a relatively simple example. It is a sel ...

s and

helpmate A helpmate is a type of chess problem in which both sides cooperate in order to achieve the goal of checkmating Black. In a helpmate in ''n'' moves, Black moves first, then White, each side moving ''n'' times, to culminate in White's ''nth'' m ...

s. (product manual) Pondering on opponent's time and a three-dimensional

chessboard A chessboard is a game board used to play chess. It consists of 64 squares, 8 rows by 8 columns, on which the chess pieces are placed. It is square in shape and uses two colours of squares, one light and one dark, in a chequered pattern. During p ...

were introduced in ''Colossus Chess 4.0''. All releases were written in the

assembly language In computing, assembly language (alternatively assembler language or symbolic machine code), often referred to simply as assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence bet ...

of the appropriate

CPU A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, log ...

; the

ZX Spectrum The ZX Spectrum () is an 8-bit computing, 8-bit home computer developed and marketed by Sinclair Research. One of the most influential computers ever made and one of the all-time bestselling British computers, over five million units were sold. ...

version could examine an average of 170 positions per second. Uncommon for microcomputer chess programs of the era, ''Colossus'' had a full implementation of the

rules of chess The rules of chess (also known as the laws of chess) govern the play of the game of chess. Chess is a two-player Abstract strategy game, abstract strategy board game. Each player controls sixteen chess piece, pieces of six types on a chessboar ...

, including

underpromotion In chess, promotion is the replacement of a pawn with a new piece when the pawn is moved to its . The player replaces the pawn immediately with a queen, rook, bishop, or knight of the same . The new piece does not have to be a previously captu ...

, the

fifty-move rule The fifty-move rule in chess states that a player can claim a draw if no has been made and no pawn has been moved in the last fifty moves (where a "move" consists of a player completing a turn followed by the opponent completing a turn). The pur ...

, draw by repetition, and

draw Draw, drawing, draws, or drawn most commonly refer to: * Draw (terrain), a terrain feature formed by two parallel ridges or spurs with low ground in between them * Draw (tie), in a competition, where competitors achieve equal outcomes * Draw ...

by insufficient material. ''Colossus'' was also able to execute all the basic

checkmate Checkmate (often shortened to mate) is any game position in chess and other chess-like games in which a player's king is in check (threatened with ) and there is no possible escape. Checkmating the opponent wins the game. In chess, the king is ...

s, including the difficult

bishop and knight checkmate In chess, the bishop and knight checkmate is the checkmate of a lone king by an opposing king, bishop, and knight. With the stronger side to move, checkmate can be in at most thirty-three moves from almost any starting position. Although it is c ...

''Colossus Chess X''

The program was subsequently ported to

Atari ST Atari ST is a line of personal computers from Atari Corporation and the successor to the company's Atari 8-bit computers, 8-bit computers. The initial model, the Atari 520ST, had limited release in April–June 1985, and was widely available i ...

(1988),

Amiga Amiga is a family of personal computers produced by Commodore International, Commodore from 1985 until the company's bankruptcy in 1994, with production by others afterward. The original model is one of a number of mid-1980s computers with 16-b ...

(1989) and

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the List of IBM Personal Computer models, IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on ...

(1990) under the title ''Colossus Chess X''. The new releases featured four chess sets and enhanced graphics developed with the assistance of Gary Thomlinson and Carl Cropley. The opening book was extended to 11,000 positions, and the program had the ability to learn from past playing experiences.

UCI version

No work was done on ''Colossus Chess'' from 1991 to 2005, when Martin Bryant created a completely new and freely available Windows version conforming to the

Universal Chess Interface The Universal Chess Interface (UCI) is an open communication protocol that enables chess engines to communicate with user interfaces. History In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the ...

. It was written in C#, then converted to C for speed, and was finally publicly released in 2006. , the latest version is 2025a.

Reception

Info Info is shorthand for "information Information is an Abstraction, abstract concept that refers to something which has the power Communication, to inform. At the most fundamental level, it pertains to the Interpretation (philosophy), interpr ...

'' gave ''Colossus Chess IV'' for the Commodore 64 three stars out of five, stating that it was less attractive but "a darn sight more playable" than ''

Chessmaster 2000 ''The Chessmaster 2000'' is a computer chess game by The Software Toolworks. It was the first in the ''Chessmaster'' series and published in 1986. It was released for Amiga, Apple II, Atari 8-bit computers, Atari ST, ZX Spectrum, Commodore 64, ...

'' with both keyboard and joystick controls. The magazine warned of the difficulty of remembering the "shifted keyboard control sequences" and said it was "badly in need of a quick-reference card".

References

External links

Colossus home page
* * * * *
''Colossus Chess 4.0 product manual'' (C64)
{{BBC Computer Literacy Project 1984 video games 1985 video games 1986 video games 1987 video games 1988 video games 1989 video games 1990 video games Chess software Amiga games Amstrad CPC games Amstrad PCW games Apple II games Atari 8-bit computer games Atari ST games BBC Micro and Acorn Electron games Commodore 16 and Plus/4 games Commodore 64 games DOS games MSX games ZX Spectrum games Video games developed in the United Kingdom