1K ZX Chess

1982 video game 1K ZX Chess 1K ZX Chess - Sinclair - ZX81.jpg Box cover David Horne 1982Stokel-Walker Chris 2015-09-20 The bitter rivalry behind the world's smallest chess program http://kernelmag.dailydot.com/issue-sections/headline-story/14353/small-chess-program-bootchess-nanochess/ https://web.archive.org/web/20150923133713/http://kernelmag.dailydot.com/issue-sections/headline-story/14353/small-chess-program-bootchess-nanochess/ 2015-09-23 2021-03-07 The Kernel The Daily Dot In mid-1982, a small quarter-page advert appeared in a computer hobbyist magazine. For just £5 (about US$26.50 today), the ad’s pixelated block text promised a computer chess program with “absolutely flicker-free display” and an opponent who would make its move on average just six seconds after yours. “Sensational 1K ZX 81 Chess,” claimed the copy, and ignoring that today-inexplicable numerical assemblage, the important points are “sensational” and “chess.” dead Abstract strategy Single-player Sinclair ZX81 1K ZX Chess is a 1982 chess program for the unexpanded Sinclair ZX81. Description 1K ZX Chess'''s code takes up only 672 bytes in memory,https://archive.org/stream/YourComputer_198302/YourComputer8302#page/n99/mode/2up Full ZX-81 Chess in 1K Horne David February 1983 Your Computer 5 March 2018 100–102 but implements chess rules except for castling, promotion, and en passant, including a computer opponent.gilbert198303 It was the smallest implementation of chess on any computer at the time. Developer David Horne discussed 1K ZX Chess and published the full source code as a type-in program in a series of articles in Your Computer in 1982 and 1983.https://archive.org/stream/your-computer-magazine-1982-12/YourComputer_1982_12#page/n67/mode/2up Chess in 1K Your Computer December 1982 21 January 2015 Horne, David 68–69https://archive.org/stream/your-computer-magazine-1983-01/YourComputer_1983_01#page/n79/mode/2up 1K Chess Your Computer January 1983 21 January 2015 Horne, David 81, 83horne198302 ReceptionPopular 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."https://archive.org/stream/popular-computing-weekly-1982-07-15/PopularComputing_Weekly_Issue_1982-07-15#page/n11/mode/2up 1K ZX Chess Popular Computing Weekly 1982-07-15 1 February 2015 Scot, Duncan 12 Sinclair User 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".https://archive.org/stream/sinclair-user-magazine-012/SinclairUser_012_Mar_1983#page/n61/mode/2up Sinclair acts to improve the standard of its named software Sinclair User March 1983 28 January 2015 Gilbert, John 62–63 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".https://archive.org/stream/home-computing-weekly-001/Home_Computing_Weekly_001#page/n21/mode/2up Which ZX81 programs are best? Home Computing Weekly 1983-03-08 1 February 2015 Elder, Ray 21–22 Tim Harding 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".Tim Harding (chess player) https://books.google.com/books?id=pECeBQAAQBAJ&pg=PA161 The New Chess Computer Book Pergamon Press Harding, T. D. 1985 2nd 161 9781483140322 Price, Jill Levy, David N. L. Pergamon Chess Series A breakdown of all the optimizations was provided in a rebuild of the original source.https://hackaday.com/2026/04/03/for-such-a-small-program-zx81-1k-chess-sure-packs-a-lot-in/ For Such A Small Program, ZX81 1K Chess Sure Packs A Lot In Hackaday April 2026 List, Jenny1K 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";http://my.stratos.net/~hewston95/RTM56/RTM56.html#ZX81 The Thrill of Defeat: Catching the 1k Bug Retrogames Times Monthly January 2009 21 January 2015 Sabbatini, Mark Kuro5hin agreed, calling 1K ZX Chess "the greatest program ever written". 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.stokelwalker20150920 See also Microchess References 30em External links Full ZX-81 Chess in 1K 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. collapsed Category:1982 video games Category:Video games about chess Category:Commercial video games with freely available source code Category:Single-player video games Category:Video games developed in the United Kingdom Category:ZX81 games