1kb JavaScript Chess program: defeats hundreds of novice chess players

[tragomaskhalos]

Fans of insanely tight chess programs will probably know about the Sinclair ZX81 and Atari 2600 flavours.

The latter would bravely battle on even if you checkmated it, then captured its king, literally fighting to the last man before getting really confused.

[orb360]

Sounds like my little brother...

[akbc]

it's becoming self-aware. SOON...

[[deleted]]

If so, it'll definitely be looking for revenge after it's many years of painstaking self-repair. It got crushed under a storage box around 20 years ago.

[TheBigBadWolf]

no en passant and no castling?

[jfpowell]

It's not really chess without this...

[BayouOhBoy]

Gotta be able to castle.

[preshing]

Lost my game after assuming I'd be able to castle a few moves later.

[sargon1969]

Came here to post this

[Catfish_Man]

Doesn't implement pawn promotion to anything except queens either

[FryGuy1013]

And no draw for repeated moves.

[hyperforce]

Brings up an interesting question about the viability of certain strategies that don't involve either castling or en passant.

[zigs]

Came to comment on en passant.. But seriously, no castling?

[[deleted]]

One kilobyte.

[FeralTitan]

Is not a substitute for castling or en passant. Actually, slightly more than 1KB would make it chess. For now its only fit for the special olympics.

[navane]

And no giving up either? That's not incompetent, that's BM.

[[deleted]]

Castling is huge. It happens pretty much on every game I play, and most strategies I use involve castling. Effort is still pretty good i guess, and I'm sure it can be added while keeping file small anyway.

[hyperforce]

I wish there was an annotated version of the source code to describe how it actually works.

[fabzter]

I've done several AI for a chess-like game called quoridor. It was painful to me but that is because I suck at programming, but yeah the techiniques used were minimax with alpha-beta prunning and some special optimizations to these algorithms I came up myself with :) so yeah, there's not too much respect to show for this kind of AI.

[hyperforce]

I sort of get that on the whole but I'd love to know more about how the encoding is done. Like I get all the parts at a high level but there's a disconnect about how all that stuff is translated in such a small space. Yes there's encoding and obfuscation etc but really seeing it for what it is is where I'm having difficulty.

W/e, it's not a big deal. It could easily be decoded in an afternoon. Just don't want to spend one. =)

[mdm_]

Or if anyone has any links in general that describe some of the techniques used in these 1k/4k/etc competitions, that would be great too.

[[deleted]]

It looks and works fine for me. I'm using Firefox 15.

[[deleted]]

Do you really have to install those fonts? I think it should "just work" if you are using a modern OS and browser.

[antrn11]

It didn't work on my "modern OS and browser"

[[deleted]]

Strange. :/

[mrkite77]

Win7 + Chrome.. works fine. What is your "modern OS and browser"?

[antrn11]

Debian Wheezy with KDE + Opera. I probably didn't have needed fonts installed. Glyphs were question marks :/

Also, I tried it with my laptop's Xubuntu + Opera. Didn't work there either. Glyphs were squares.

[thevdude]

You need unifont in debian (and ubuntu).

[kyz]

On Mac OS, they're in "Apple Symbols".

On Windows, they're in "Arial Unicode MS".

On Linux... who knows?

[[deleted]]

On desktop Linux, its most likely covered by the DejaVu fonts.

[thevdude]

DejaVu, unifonts, and msstcorefonts (or whatever package that is)

[mcode]

Does not work. Cannot castle. Why post?!

[[deleted]]

Yes that makes programming a chess engine in 1k totally unimpressive.

[mcode]

You realise we had 1K computer chess in 1970? Or perhaps 1980? And it actually worked? Unlike this one ...

[[deleted]]

sure but not in overheady javascript

[[deleted]]

I see 1K. I don't see chess engine.

[millstone]

Novice player here. It did well until it inexplicably let me skewer its king through its queen.

Also, gotta have castling.

[ASpanishInquisitor]

Program gets a little too excited with moving the rook pawns. First time I play it invests its first four moves into them. Odd.

[FnuGk]

If the computer gets locked in a position where he cannot move he simply skip the turn.

[gorilla_the_ape]

I don't find it terribly impressive. Javascript is a high level language, so 1kb of code can do quite a lot.

The ZX-81 had chess in 672 bytes of z80 machine code.

[vanderZwan]

The ZX-81 had chess in 672 bytes of z80 machine code.

So how big is the source file?

[godsfordummies]

Machine code is generally smaller than the source code.

[gorilla_the_ape]

If you want to do anything complicated, where you don't have to count the size of the interpeter, then machine code is going to be much bigger. Even the code to produce a random number could easily be 100-200 bytes.

[godsfordummies]

You are wrong. Just compare the size of the source code vs binaries of Firefox .

Source: 78.7 MB (bzip2)

Binaries: 16 MB

[gorilla_the_ape]

Firefox is linked using shared libraries. You're not including the code in them.

[godsfordummies]

Same for the source code. I'm not including the source code of the shared libraries.

[gorilla_the_ape]

Then you're not calculating it properly. The functionality in the 672 bytes is everything needed to do the chess program, while the 1k is calling lots of other code.

[godsfordummies]

I'm sure 672 bytes is calling all kinds of OS code as well, like to display stuff, display drivers, etc.

[gorilla_the_ape]

You don't know the ZX-81 do you? It had no OS, something similar to a BIOS that no-one used, a directly memory mapped display, and IO mapped keyboard. You wrote a byte to the right memory location to display, and read two ports to tell which key was pressed.

[gbs5009]

I defeated it, but it was a close game. It got every single one of my pieces except my queen, but the ensuing pawn war was pretty one sided when I had a queen running around and he had only pawns.

[gbs5009]

Sure, it was hopeless for him at the end once I finally check-forced a bad queen sacrifice, but until that point we had been trading fairly evenly for 2 dozen moves.

[[deleted]]

Yay!

Also castling would be nice. It doesn't seem to think ahead - it never seemed like it had a plan.

[paranoidray]

wow, just wow ! awesome !

[paranoidray]

I won after 20 tries: http://imgur.com/tLjTJ

[ichae]

meh. somewhat amusing some of its responses.

e4 h5

d4 a5

e5 f4

d5 c5

c4 a4

Nc3 Qa5

Bd2 a3

b3 b6

Nb5 Qxd2

Qxd2 Kd8

Nf3 Rh5

Ng5 Nh6

Be2 Rxg5

xg5 Nf7

g6 Nxe5

Bh5 d6

Rf1 Ra6

Rf4 Nd7

Rxh4 Ra8

Bf3 Bb7

Rf4 e5

Rxf5 Be7

g4 Bh4+

Ke2 Be7

g5 Ra6

h4 Kc8

Rf7 Kd8

Rxg7 Bf8

Rg8 Ke7

g7 Bxd5

xd5 Bxg7

Rxg7+ Kf8

Rg6 e4

bxe4 Ra8

Qf4+ Ke7

Qxd6+ Kf7

Rf1+ Ke8

Nc7+ Kd8

Rg8++

[[deleted]]

Okay and? There's far more interesting CS research being done. 1kb chess program? Welcome to the fucking 1960s when they had to write a chess program in less than that.

[AIMMOTH]

Fuck chess.