Chess engines do weird stuff
60 points
1 hour ago
| 4 comments
| girl.surgery
| HN
Related: https://cosmo.tardis.ac/files/2026-02-12-az-rl-and-spsa.html
mpolson64
27 minutes ago
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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.

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incognito124
50 minutes ago
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Please be careful when visiting the homepage
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pavel_lishin
28 minutes ago
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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.)
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incognito124
21 minutes ago
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or kittens on encyclopediabrittanica
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WesolyKubeczek
39 minutes ago
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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.

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uncivilized
31 minutes ago
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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 ^^

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pavel_lishin
25 minutes ago
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> What were you browsing where someone cutting off their own testicles is not as bizarre as other things?

One of my formative early internet experiences was loading up a video of a man being beheaded with a knife.

Luckily, I realized what was about to happen, and didn't subject myself to the whole thing.

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RivieraKid
48 minutes ago
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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.
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helloplanets
26 minutes ago
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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)

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RivieraKid
17 minutes ago
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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.

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MengerSponge
5 minutes ago
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That just means that Stockfish doesn't get stronger with more than 1 minute per move on a modern computer. It doesn't say anything about other engines.
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altruios
43 minutes ago
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Even by a stockfish running on a modern laptop with 2 minutes per move (provided they are going second)?!
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RivieraKid
14 minutes ago
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Yes, that's what "unbeatable from the starting position" means.
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GaggiX
1 hour ago
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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.

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dang
59 minutes ago
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Thanks! I've put that link in the toptext as well.
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