This is a fully working chess program with graphics. In 1024 bytes of JS. o_0

by archon810 • 16 years ago

189 68 16 years ago

adamtj2• 16 years ago

It's not quite fully working. Either that, or I just can't figure out how to castle. Even so, it's very impressive.

StavrosK3• 16 years ago

It says in the description that it doesn't support castling or en passant. Also, wtf, the guy wrote a chess program with AI in 1 kb and you're complaining about castling?

CGamesPlay• 16 years ago

The title here on HN is "fully working", which isn't true.

kiiski• 16 years ago

Castling is pretty important move in chess. You can hardly claim an implementation to be fully working without it (although it wasn't the author claiming that).

StavrosK3• 16 years ago

Looks like someone just won the contest...

phoboslab• 16 years ago

Chess is damn impressive, but so is Tetris ( http://js1k.com/demo/663 ) or a Jump'n'Run ( http://js1k.com/demo/635 ). There are also a lot of very beautiful graphic demos like http://js1k.com/demo/171 or http://js1k.com/demo/49

Shameless plug: My syntax highlighting Quine: http://js1k.com/demo/223

StavrosK3• 16 years ago

Jesus, those are all amazing. It was very nice of the Jump'n'Run guy to include the commented source.

cakeface• 16 years ago

I really like this one too http://js1k.com/demo/12

AndyKelley2• 16 years ago

Syntax highlighting Quine is great! Although quine part was pretty easy :P

julian37• 16 years ago

He won the IOCCC a number of times before.

http://nanochess.110mb.com/

dsplittgerber• 16 years ago

Brilliant. Reminds of the old 4k demo competitions - craft at its best.

mechanical_fish• 16 years ago

It reminds me of Atari 2600 chess, which used to be able to beat me [1] using 4k of ROM and 128 bytes of RAM [2].

---

[1] This is not a particularly remarkable achievement even today, of course.

[2] Note to people younger than twenty: this is not a typo.

SageRaven• 16 years ago

I used to get repeatedly trounced by "Video Chess" on the TI-99/4A. Don't know how large that game was, but being from '79 it couldn't have been that large. Not that I was (or am) any good at chess -- if I fired up that game under MESS today it would probably still trounce me.

halo• 16 years ago

Reminded me of 1k ZX Chess (http://en.wikipedia.org/wiki/1K_ZX_Chess), an implementation of chess with AI for the ZX-81, a home computer which had a whopping 1k of RAM.

caf• 16 years ago

That's actually a more impressive achievement, since Z80 assembler is far less expressive than Javascript. And all the display output had to be in that, too!

pella2• 16 years ago

...only 672 bytes. source code:

http://users.ox.ac.uk/~uzdm0006/scans/1kchess/

and ZX-81 emulator to play the game:

http://www.zx81stuff.org.uk/zx81/emulate.php?tzx=0/1KZXChess...

wensing4• 16 years ago

In case you don't take the time to have your mind blown, here's the source (1014 characters):

for(B=i=y=u=b=i=5-5,x=10,I=[],l=[];l[B]="ECDFBDCEAAAAAAAAIIIIIIIIMKLNJLKM@G@TSb~?A6J57IKJT576,+-48HLSUmgukgg OJNMLK IDHGFE".charCodeAt(B)-64,B++<120;I[B-1]=B%x?B/x%x<2|B%x<2?7:B/x&4?0:l[i++]:7);function X(c,h,e,s){e^=8;for(var o,S,C,A,R,T,G,n,N=-1e8,O=20;++O<99;)if((o=I[T=O])&&(G=o^e)<7){A=G--&2?8:4;C=o-9?l[61+G]:49;do if(!(R=I[T+=l[C]])&&!!G|A<3||(R+1^e)>9&&G|A>2){if(!(R-2&7))return 78-h<<x;n=G|(e?T>29:T<91)?o:6^e;S=(R&&l[R&7|32]-h-G)+(G?0:n-o?55:(A<2)+1);if(c>h||1<c&c==h&&S>2){I[T]=n;I[O]=0;S-=X(c,h+1,e,S-N);if(!(h||c-1|B-O|T-b|S<-1e4))return W(B=0),e&&setTimeout("X(2,0,8),X(1,0,8)",50);I[O]=o;I[T]=R}if(S>N||!h&S==N&&Math.random()<.5)if(N=S,c>1)if(h?s-S<0:(B=O,b=T,0))return S}while(!R&G>2||(T=O,(G||A>2|(e?O>78:O<41)&!R)&&++C--A))}return N}function W(){i="<table>";for(u=18;u<98;i+=++u%x-9?"<th width=60 height=60 onclick='I[b="+u+"]>8?W(B=b):X(1,0,0)'style='font-size:50px'bgcolor=#"+(u-B?u.9&1||9:"d")+"0f0e0>&#"+(I[u]?9808+l[67+I[u]]:160)+";":u++&&"<tr>");document.body.innerHTML=i+"</table>"}W();

Beautified:

   for (B = i = y = u = b = i = 5 - 5, x = 10, I = [], l = []; l[B] = "ECDFBDCEAAAAAAAAIIIIIIIIMKLNJLKM@G@TSb~?A6J57IKJT576,+-48HLSUmgukgg OJNMLK IDHGFE".charCodeAt(B) - 64, B++ < 120; I[B - 1] = B % x ? B / x % x < 2 | B % x < 2 ? 7 : B / x & 4 ? 0 : l[i++] : 7);
   
   function X(c, h, e, s) {
       e ^= 8;
       for (var o, S, C, A, R, T, G, n, N = -1e8, O = 20; ++O < 99;) if ((o = I[T = O]) && (G = o ^ e) < 7) {
           A = G-- & 2 ? 8 : 4;
           C = o - 9 ? l[61 + G] : 49;
           do
           if (!(R = I[T += l[C]]) && !! G | A < 3 || (R + 1 ^ e) > 9 && G | A > 2) {
               if (!(R - 2 & 7)) return 78 - h << x;
               n = G | (e ? T > 29 : T < 91) ? o : 6 ^ e;
               S = (R && l[R & 7 | 32] - h - G) + (G ? 0 : n - o ? 55 : (A < 2) + 1);
               if (c > h || 1 < c & c == h && S > 2) {
                   I[T] = n;
                   I[O] = 0;
                   S -= X(c, h + 1, e, S - N);
                   if (!(h || c - 1 | B - O | T - b | S < -1e4)) return W(B = 0), e && setTimeout("X(2,0,8),X(1,0,8)", 50);
                   I[O] = o;
                   I[T] = R
               }
               if (S > N || !h & S == N && Math.random() < .5) if (N = S, c > 1) if (h ? s - S < 0 : (B = O, b = T, 0)) return S
           }
           while (!R & G > 2 || (T = O, (G || A > 2 | (e ? O > 78 : O < 41) & !R) && ++C--A))
       }
       return N
   }
   function W() {
       i = "<table>";
       for (u = 18; u < 98; i += ++u % x - 9 ? "<th width=60 height=60 onclick='I[b=" + u + "]>8?W(B=b):X(1,0,0)'style='font-size:50px'bgcolor=#" + (u - B ? u.9 & 1 || 9 : "d") + "0f0e0>&#" + (I[u] ? 9808 + l[67 + I[u]] : 160) + ";" : u++ && "<tr>");
       document.body.innerHTML = i + "</table>"
   }
   W();

baby2• 16 years ago

if someone's wondering how he displays chess symbols that's how :

http://en.wikipedia.org/wiki/Chess_symbols_in_Unicode

ps : also it's better to beautifier the code to (try to) understand it :

http://jsbeautifier.org/

Torn• 16 years ago

I'm getting empty character boxes instead of chess symbols, even if I force UTF-8 in Chrome or IE. Any ideas?

euccastro4• 16 years ago

for(B=i=y=u=b=i=5-5, [...]

Is there a point in saying 5-5 instead of 0, other than wasting two characters for the fun of it?

palish2• 16 years ago

Probably because he wanted to keep 1-letter variable names, and 1024 is more interesting than 1022.

DougBTX• 16 years ago

Also setting i twice, I'm not sure why.

superk• 16 years ago

Extra points for the function call:

X(c, h, e, s)

jpwagner3• 16 years ago

would you mind re-pasting the beautified code from the locally saved source? there are characters missing in the pasted blob (notice the italics.)

pfreet• 16 years ago

Not a very good one :-) I just got to checkmate in 6 moves!

sandipagr• 16 years ago

If only I could understand what is going on in the code...the variable names make my head explode :(

seles• 16 years ago

Nice, but it isn't very good, lost to Fools Mate (it took a knight then got mated) (1 look ahead would see it, queen and bishop just attack pawn near king)

wensing4• 16 years ago

Feel free to improve on it.

wensing4• 16 years ago

Title is wrong: it's 1014 bytes.

dansingerman• 16 years ago

Can castling and/or en passant be squeezed into 10 bytes?

ilitirit• 16 years ago

Anyone wanna have a stab at explaining how it works?

dabeeeenster• 16 years ago

It's recursive. Probably easier to get your head around the recursive solution to the towers of hanoi (http://en.wikipedia.org/wiki/Tower_of_Hanoi) and then start on the Chess code!

kenjackson• 16 years ago

I really don't think the recursion is the hard part to understand. It's what each variable and magic number means. A while ago someone had a post of the exponentiation function written with single letter variables. It was difficult to know what it was doing. With proper variable names it would be apparent.

I think what people are asking is basically, could someone convert this to a program that is actually meant to be read, while still maintaining its exact control flow and logic.

michael_dorfman• 16 years ago

My favorite is still Peter Jennings' Micro-Chess, from 1976, which ran on a KIM-1 (6502) machine and used 1.1K of RAM.

http://users.telenet.be/kim1-6502/microchess/microchess.html

I had the PET 2001 version (which ran in 7K) and played pretty competent chess, all things considered-- disassembling that, back in the day, was a major boost to my software development education.

eliben• 16 years ago

Well done, but no castling support and the the AI seems pseudo-random :-)

Not to take credit from this achievement though, it's a commendable hack!

pavs• 16 years ago

As someone who have been involved with chess engine community for the last 15 years or so (not anymore) I can tell you that, until recently, almost every single new engine, that has been written from scratch instead of copying an OS implementation, almost always left out en passant and castling in its first few releases. Even when they did implement those rules in to the engine, they did so grudgingly or as an after thought. I wonder why.

Now, everyone just copies the few dozens of OS options available out there and use their move generator which support all the rules, they just tweak with the piece values and algorithm to give a "personal touch" to the engine.

Twisol• 16 years ago

Apparently, I play chess worse than a pseudo-random 1012-byte JS chess bot. Burn...

joey_bananas• 16 years ago

1024 bytes... and a 60 meg browser.

iamwil2• 16 years ago

Yes, and you can play anywhere in the world, on all different operating systems and platforms.

philjackson• 16 years ago

Plus all of that libc. Not to mention the megabytes of kernel. How big is a bootloader these days?

antirez• 16 years ago

it's easy to defeat but definitely not random, it will win most of the times against people that just know the rules but rarely played.

iamwil2• 16 years ago

I lost. :(

daralthus2• 16 years ago

well I don't want to be in his place debugging this: http://tinypic.com/r/24zknc9/7 :D

euccastro4• 16 years ago

How is that position illegal? A black pawn could have eaten some piece at h3, then advanced two squares to be promoted to queen.

daralthus2• 16 years ago

oops my bad.. seems like you are right. I'm really ashamed now.. I go and play more as a punishment:D

pella2• 16 years ago

elblanco• 16 years ago

Perhaps someone should look at modifying this for a 4k competition with good AI and all of the movement rules.

fizx• 16 years ago

http://nanochess.110mb.com/chess4.html

Much older than this article, but same idea.

SeanLuke• 16 years ago

Castling is broken.

Jach• 16 years ago

It's trivial to defeat with the four-move checkmate, but still an interesting piece of code.

clueinfool• 16 years ago

Here is a very small program, well-known in chess circles because it plays at nearly 1800 elo, which is good enough to beat strong club players.

http://home.hccnet.nl/h.g.muller/max-src2.html

jacquesm• 16 years ago

The 'best' page is really useful sometimes, I completely missed this one. What a gem!

AndyKelley2• 16 years ago

Nothing like something like this to come along every now and then and completely destroy my hubris.

This is a fully working chess program with graphics. In 1024 bytes of JS. o_0

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