''1K ZX Chess'' is a 1982 chess program for the unexpanded
Sinclair ZX81
The ZX81 is a home computer that was produced by Sinclair Research and manufactured in Dundee, Scotland, by Timex Corporation. It was launched in the United Kingdom in March 1981 as the successor to Sinclair's ZX80 and designed to be a low-cost ...
.
Description
''1K ZX Chesss code takes up only 672 bytes in memory,
but implements
chess
Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to dist ...
rules except for
castling
Castling is a move in chess. It consists of moving the king two squares toward a rook on the same and then moving the rook to the square that the king passed over. Castling is permitted only if neither the king nor the rook has previously mo ...
,
promotion
Promotion may refer to:
Marketing
* Promotion (marketing), one of the four marketing mix elements, comprising any type of marketing communication used to inform or persuade target audiences of the relative merits of a product, service, brand or i ...
, and
en passant
''En passant'' (, "in passing") is a method of capturing in chess that occurs when a pawn captures a horizontally adjacent enemy pawn that has just made an initial two-square advance. The capturing pawn moves to the square that the enemy pa ...
, including a computer opponent. It was the smallest implementation of chess on any computer, although today that title is held by ChesSkelet with 269 bytes (less than half the size of ''1K ZX Chess'').
Developer David Horne discussed ''1K ZX Chess'' and published the full
source code
In computing, source code, or simply code, is any collection of code, with or without comment (computer programming), comments, written using a human-readable programming language, usually as plain text. The source code of a Computer program, p ...
as a
type-in program
A type-in program or type-in listing was computer source code printed in a home computer magazine or book. It was meant to be entered via the Keyboard (computing), keyboard by the reader and then saved to Compact Cassette (data), cassette tape or ...
in a series of articles in ''
Your Computer'' in 1982 and 1983.
Reception
''
Popular Computing Weekly'' in 1982 called ''1K ZX Chess'' "one of the most interesting ZX tapes to pass through our office in recent weeks". It approved of the computer displaying moves while considering them and noted "the skills which went into writing a chess program in 1K of machine code. Is there anyone reading this who could even contemplate doing the same?" The magazine concluded, "Despite the limitations this is one cassette, at £3, which I would recommend."
''
Sinclair User
''Sinclair User'' was a magazine dedicated to the Sinclair Research range of home computers, most specifically the ZX Spectrum (while also occasionally covering arcade games). Initially published by ECC Publications, and later EMAP, it was pub ...
'' in 1983 stated that "it takes some technical wizardry to squeeze this kind of game into the unexpanded ZX81". The magazine praised the game's quick loading speed, and found that it "makes its moves very fast for the amount of memory available for it".
''Home Computing Weekly'' gave the game three out of five stars, criticizing the confusing user interface but stating that "it still produces play which needs some thought to beat".
wrote in a 1985 book on computer chess that "the man who did it must be some sort of genius". While describing ''1K ZX Chess'' quality of play as "so appalling that it would be hard to make it beat you" and criticizing the backward
algebraic notation, he concluded that "the program is nevertheless a fantastic technical achievement".
''1K ZX Chess'' came in second place for best software in a poll of ZX81 users. ''Retrogaming Times Monthly'' described it as "history's greatest game programming feat";
''BootChess'' author Olivier Poudade praised ''1K ZX Chess''s code, stating that at first writing a smaller chess program "seemed impossible ... Horne had nailed it so much already". Poudade acknowledged replicating some of Horne's methods as he could not improve them.
See also
*
Microchess
References
External links
Full ZX-81 Chess in 1K1K ZX Chess
at Chess Programming Wiki
''1K ZX Chess''
ZX81 Collection entry with the original inlay scan and program listing. An emulator is available on the site to play the game online.
{{chess, state=collapsed
1982 video games
Chess software
ZX81 games
Commercial video games with freely available source code
Video games developed in the United Kingdom