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Hi all,

A friend just let me know about a 487-byte chess "engine". Don't expect FIDE compliance or search for this size! It will move into check for example; consider it a variant.

Release announcement: http://www.pouet.net/prod.php?which=64962
Direct link: http://olivier.poudade.free.fr/arc/BootChess.zip

Fabien.

some nice tricks to keep it small, including self-modifying code, relative addressing to save some bytes etc.
including instructions no optimizer will ever emit, I also like the idea of using segment register as a temporary and the use of BCD-adjustment instructions.
very nice.

Very impressive.

Incredible!

Xann wrote:Hi all,

A friend just let me know about a 487-byte chess "engine". Don't expect FIDE compliance or search for this size! It will move into check for example; consider it a variant.

Release announcement: http://www.pouet.net/prod.php?which=64962
Direct link: http://olivier.poudade.free.fr/arc/BootChess.zip

Fabien.

Truly astounding.

Your description of your program raises the question,
"How small can a chess engine be made which can correctly process every fide rule, including draw detection, underpromotion, e.p. capture, etc.?"
I guess that it cannot be done in under 1024 bytes.

Dann Corbit wrote:Your description of your program raises the question, ...

Just to be clear, it's not my program.

Fabien.

Dann Corbit wrote:

Xann wrote:Hi all,

A friend just let me know about a 487-byte chess "engine". Don't expect FIDE compliance or search for this size! It will move into check for example; consider it a variant.

Release announcement: http://www.pouet.net/prod.php?which=64962
Direct link: http://olivier.poudade.free.fr/arc/BootChess.zip

Fabien.

Truly astounding.

Your description of your program raises the question,
"How small can a chess engine be made which can correctly process every fide rule, including draw detection, underpromotion, e.p. capture, etc.?"
I guess that it cannot be done in under 1024 bytes.

Here is the smallest program that plays legal chess according to FIDE rules:

int main() {
printf("I offer a draw, accept? ");
scanf("%s", answer);
if (!strcmp(answer, "yes"))
exit 0;
printf("I resign\n");
}

Actually the program could always resign, making it even smaller (17 bytes):
But yours is clearly stronger.

mar wrote:Actually the program could always resign, making it even smaller (17 bytes):

Code: Select all

org 100h
mov ah, 9
mov dx, msg
int 21h
retn

msg db 'I resign$'

But yours is clearly stronger.

I didn't liked the fact it puts its own king in check and only considers half-ply (per author comments), so I made from scratch my own program.

And here it is Toledo Atomchess in only 481 bytes of x86 machine code, it searchs 3-ply depth and doesn't make illegal moves http://nanochess.org/chess6.html

Alas, it also makes only basic chess moves.