Chess engines do weird stuff (girl.surgery)

124 points by admiringly 5 hours ago

mpolson64 4 hours ago

I'm no expert on chess engine development, but it's surprising to me that both lc0 and stockfish use SPSA for "tuning" the miscellaneous magic numbers which appear in the system rather than different black box optimization algorithms like Bayesian optimization or evolutionary algorithms. As far as I am aware both of these approaches are used more often for similar tasks in non-chess applications (ex. hyperparameter optimization in ML training) and have much more active research communities compared to SPSA.

Is there something special about these chess engines that makes SPSA more desirable for these use cases specifically? My intuition is that something like Bayesian optimization could yield stronger optimization results, and that the computational overhead of doing BO would be minimal compared to the time it takes to train and evaluate the models.

LPisGood 2 hours ago

One thing I wonder is why design of experiments (DOE) methodology is so seldom used for these things.

Statisticians and operations researchers have spent a hundred years deciding how to do as few experiments as possible to tweak parameters in the ways that give the highest impact with statistical basis that the selections are good.

In the language of information and decision trees, these experiments are trying to in some sense “branch” on the entropy minimizing variables.

agalunar 2 hours ago

SPRT is used religiously in engine development today. There is enormous incentive to test efficiently.

https://github.com/official-stockfish/fishtest/wiki/Fishtest...

mpolson64 2 hours ago

DOE is still very useful in many contexts, but when it's possible do use a sequential design these adaptive techniques really start to pull away in terms of optimization quality.

There's simply a lot of sample efficiency to gain by adapting the experiment to incoming data in a regime where one can repeatedly design n candidates, observe their effects, and repeat m times compared to a setting where one must design a fixed experiment with n*m samples.

sscg13 3 hours ago

Engines like Stockfish might have over 100 "search parameters" that need to be tuned, to my best knowledge SPSA is preferred because the computational cost typically does not depend on the number of parameters.

Or, if attempting to use SPSA to say, perform a final post-training tune to the last layers of a neural network, this could be thousands of parameters or more.

mpolson64 2 hours ago

The concern about the dimensionality of the search space is real, especially once things cross over into the 100s -- BO would certainly not be useful post-training the way the blog post talks about using SPSA.

That being said, it still seems possible to be that using a different black box optimization technique for a fairly constrained set of related magic numbers (say, fewer than 50) might lead to some real performance improvements in these systems, could be worth reaching out to the lc0 or stockfish development communities.

incognito124 4 hours ago

Please be careful when visiting the homepage

andix 10 minutes ago

If you paid for MS FrontPage, you better get some value out of it!

NooneAtAll3 3 hours ago

as always, genius and insanity are only 1 step apart

pavel_lishin 4 hours ago

This really reminds me of the web as I remember it from the mid-to-late 90's; I feel like I'm just a click away from the old deoxy.org, if anyone remembers that. (Don't go there now; the domain appears to have been long-ago hijacked.)

fsiefken 9 minutes ago

I loved the deoxy site, it was one of my favorites :-) Next to the site and writings of the esoteric Brother Blue, who was he? It eventually caused me to go in a reality tunnel for a few years. It was a fascinating and puzzling experience similar as to what was described in Cosmic Trigger III by R.A. Wilson.

incognito124 4 hours ago

or kittens on encyclopediabrittanica

WesolyKubeczek 4 hours ago

It gave me serious vibes of the old internet homepages of highly eccentric people that became a part of the internet folklore, whether in a good way or a bad way.

The video is probably the least bizarre thing there, if that's what you are warning about.

uncivilized 4 hours ago

What were you browsing where someone cutting off their own testicles is not as bizarre as other things? I didn't watch the video but atleast there was a warning.

Feds this guy right here ^^

mghackerlady 2 hours ago

ASalazarMX 3 hours ago

pavel_lishin 4 hours ago

WesolyKubeczek 3 hours ago

t1234s 3 hours ago

The homepage for this site is defiantly NSFW.

voxl an hour ago

You probably meant definitely, but defiantly amusingly works too

thinkingtoilet an hour ago

"definitely" or "defiantly"?

The idea of something being "defiantly" NSFW gave me a chuckle.

GaggiX 5 hours ago

https://cosmo.tardis.ac/files/2026-02-12-az-rl-and-spsa.html

Response from the author of Viridithas, there is a link to this engine in her webpage.

dang 4 hours ago

Thanks! I've put that link in the toptext as well.

twiclo 2 hours ago

Her?

GaggiX an hour ago

I read "girl.surgery" and guessed.

RivieraKid 4 hours ago

AFAIK chess is has been "solved" for a few years in the sense that Stockfish running on modern laptop with 1 minute per move is unbeatable from the starting position.

helloplanets 4 hours ago

This is not true. Stockfish is not unbeatable by another engine, or another copy of Stockfish.

Chess engines have been impossible for humans to beat for well over a decade.

But a position in chess being solved is a specific thing, which is still very far from having happened for the starting position. Chess has been solved up to 7 pieces. Solving basically amounts to some absolutely massive tables that have every variation accounted for, so that you know whether a given position will end in a draw, black win or white win. (https://syzygy-tables.info)

LeifCarrotson 3 hours ago

The parent is using a different definition, so they put "solved" in quotes. What word would you suggest to describe the situation where the starting position with 32 pieces always ends in either a draw or win for white, regardless of the compute and creativity available to black?

I haven't verified OP's claim attributed to 'someone on the Stockfish discord', but if true, that's fascinating. There would be nothing left for the engine developers to do but improve efficiency and perhaps increase the win-to-draw ratio.

helloplanets 3 hours ago

gowld 3 hours ago

RivieraKid 4 hours ago

Do you have a source? I remember asking on the Stockfish Discord and being told that Stockfish on a modern laptop with 1 min per move will never lose against Stockfish with 1000 min per move from the starting position.

But I'm not sure whether that guy was guessing or confident about that claim.

helloplanets 3 hours ago

LogicalRisk 3 hours ago

MengerSponge 4 hours ago

sscg13 3 hours ago

Hypothetically, what reward would be worth the cost for you to attempt to beat Stockfish 18, 100 million nodes/move, from the starting position?

sscg13 3 hours ago

You can run Stockfish single threaded in a deterministic manner by specifying nodes searched instead of time, so in principle it is possible to set some kind of bounty for beating Stockfish X at Y nodes per move from the start position, but I haven't seen anyone willing to actually do so.

altruios 4 hours ago

Even by a stockfish running on a modern laptop with 2 minutes per move (provided they are going second)?!

RivieraKid 4 hours ago

Yes, that's what "unbeatable from the starting position" means.

bee_rider 3 hours ago

“Solved” is a term of art. Defining it in some other way is not really wrong (since it is a definition) but it seems… unnecessary.

TZubiri 2 hours ago

I know a fair deal about the subject of chess AI, but when I was reading this and I didn't understand. I was polarized, was I reading a mastermind that was way above my level? Or someone way too confident that learned enough buzzwords through an LLM to briefly delude someone else other than themselves?

A quick visit at the homepage suggests that it's probably the latter. I don't want to be rude, not posting out of malice, but if someone else was reading this and was trying to parse it, I think it might be helpful to compare notes and evaluate whether it's better to discard the article altogether.

Paracompact 2 hours ago

Curious, what has you believe that? As someone who doesn't know much about chess AI, I was mostly able to follow along, and figured there were simply some prereqs the author wasn't explaining (e.g. distillation, test-time search, RLVR). If the article is deeply confused in some way I would indeed like to calibrate my BS detectors.

potsandpans 2 hours ago

This comment is another example of an "llm psychosis" that is currently occuring in common discourse.

The mass delusion of, "I don't understand what I'm reading, therefore it must be produced by an llm."

I think it's a pretty serious problem. Not that llm text exists on the internet, but that reasonable people are reflexively closed off to creativity because the mere existence of the possibility that something is created by an llm is in their minds grounds for disqualification.

TZubiri 28 minutes ago

Nono, the claim is not that it is produced by an llm, rather that author researches the subject with llms and generally is a high frequency user.

A common property of llm psychosis is the development of an internal vocabulary that the llm learns, often reusing words but adopting specific meanings, for some reason quantum and quantic are very popular for this.