u/masterchiefcodes

▲ 7 r/chessprogramming+1 crossposts

I built a system that lets anyone generate a playable chess bot from their Chess.com/Lichess games using my new fine-tuning algorithm

Hey all — a few weeks ago I posted about my paper being accepted to the IEEE Conference on Games 2026 on using preference learning to improve fine-tuning for Maia-style chess models.

Since then I’ve been building out the ideas further in a website called garrychess.ai.

Last night I released a feature that lets anyone:

  • import their Chess.com or Lichess games
  • train a personalized chess bot from their own games
  • play against it in-browser
  • share the bot with friends via a public link

The system tries to preserve stylistic tendencies rather than simply maximize engine strength.

I’ve also been experimenting with style embeddings trained on a few million games to estimate similarity between players and various grandmasters. The same embeddings are currently being used to cluster puzzles by style/archetype (e.g. positional/Karpov-like middlegames vs sharper tactical positions).

Some observations so far:

  • openings are surprisingly reproducible from relatively small datasets
  • it picks up a mixed style if multiple people play on the account. My girlfriend's style clusters were nakamura (counter attacker) for middle game (when I sometimes start playing) and fischer endgame.
  • My bot seemed to capture my stronger intensity in the lategame and blunder propensity midgame.

Training currently costs $1 per bot to roughly cover GPU/training costs. Playing against generated bots and the style-based puzzle features are free.

If anyone here tries it, I’d love feedback on:

  • realism of the generated bots
  • evaluation ideas for stylistic fidelity
  • better approaches for human-like search/sampling
  • whether the style clustering actually feels meaningful
u/masterchiefcodes — 6 days ago

The paper the models are based on was accepted recently to IEEE Conference on Games (oral / speaker presentation).

You can play against models trained on:

  1. Garry Kasparov
  2. Anatoly Karpov
  3. Bobby Fischer
  4. Magnus Carlsen
  5. Judit Polgar
  6. More soon

The models can be tuned to be anywhere from 2100-2800 approximate ELO and are much more realistic than the Stockfish +hardcoded chess.com bots (hopefully!)

For more info check out:

Demo - https://garrychess.ai

PDF (first draft submission, not camera ready) - https://drive.google.com/file/d/1qiqwGH57pe-lHIzwa79Qaww6M-WVUvy2/view

Discord community for project updates - https://discord.gg/ANNZ78c7

The training process uses preference optimization to get data about a given player using not just what move they picked, but also moves they rejected that were strong candidates. This makes it learn more quickly and effectively than the usual fine-tuning process.

u/masterchiefcodes — 16 days ago

I’ve written a paper on preference-optimized chess policies for modeling grandmaster playing style. After submitting for acceptance to the IEEE Conference on Games, I just learned I was chosen to present on my research (conference speaker). I wanted to share it because I would love any feedback and I also think some of you might find the work interesting.

The basic question was: can a chess model learn to play more like a specific grandmaster rather than just choosing engine-best moves?

The outcome of my research was playable opponent chess bots that, as far as I can tell, accurately mimic specific gm player styles to a high degree. I’ve set up a website ( https://garrychess.ai ) for anyone to play a few premade gm based bots I generated, with the option to tweak ELO levels and styles, so if you choose to play please let me know what you think! I also am testing out some features that demonstrate how it could be used in training like puzzles and style courses.

So far, for demonstration purposes, I have modeled & made playable:

  1. Carlsen
  2. Kasparov
  3. Fischer
  4. Karpov
  5. Polgar
  6. Pragg

Here is the gist of my research setup:
- start from Maia-2, a neural policy calibrated to human chess play
- collect historical games from a target GM
- treat the GM’s actual move as the preferred action
- compare it against plausible Stockfish candidate moves
- fine-tune using NLL, pairwise ranking, DPO, and hybrid objectives

I put up a free demo of the models here:

https://garrychess.ai (https://garrychess.ai/)

Paper PDF:

https://drive.google.com/file/d/1qiqwGH57pe-lHIzwa79Qaww6M-WVUvy2/view

Like I said, most curious what people think of the bots and using some of the models I trained to find similar positions one should train against i.e. one of the top 3 stockfish moves was positional inspired by Anatoly Karpov, so link to some similar scenarios tagged with a Karpov inspired top 3 move and practice puzzles or brief play against a bot at your target ELO.

tl;dr I found a way to recreate style and model faithful Magnus/Kasparov/Fischer/Karpov/whomever bots that actually think and learn like them, hopefully way better then whatever inconsistent hardcoded “gm” bots chess.com puts out

reddit.com
u/masterchiefcodes — 17 days ago