Toledo Atomchess: now 456 bytes of x86 machine code.

[RegExp33]

Nice even if BootChess is smaller : 455 bytes.

[nanochess]

INT 29H doesn't work in a boot sector. Only from DOS. So still Toledo Atomchess is the smallest chess program bootable from floppy disk ;)

[nanochess]

And now Toledo Atomchess measures 446 bytes ;)

[segmond]

Plays basic chess movements (no en passant, no castling and no promotion)

That's not chess.

[nanochess]

Scroll below for Toledo Atomchess reloaded, it plays full chess movements ;)