For 32 years, David Horne’s 1K ZX Chess stood as the smallest chess program ever written at 672 bytes; just recently, however, that record was broken by Olivier Poudade, a French programmer who created BootChess, which fits in a mere 487 bytes. Poudade’s program, which he wrote in assembly over a three month period, creating more than 200 versions along the way, was meant to fit on the boot sector of a floppy disk (512 bytes). Like Horne’s 1K ZX Chess, BootChess lacks some of basic chess moves such as castling and en passant; unlike Horne’s program, however, it does support queening, though not under-promotion. When it comes to miniature chess programs, it remains to be seen whether Poudade’s work is a checkmate or simply check.
“As someone who has written a chess program which even after some code optimisation still came out at ~3000 lines of C, I can tell you this is damn impressive.” Viol8
“The fact that it has any AI at all in this file size is amazing to me.” Wickwick
“... a very cool accomplishment in micro-optimization techniques.” Dutch Gun
“The code is a work of art by an exceptionally skilled craftsman.” foxyshadis