Complete Chess Games Enable LLM Become A Chess Master

Yinqi Zhang, Xintian Han, Haolong Li, Kedi Chen, Shaohui Lin


Abstract
Large language models (LLM) have shown remarkable abilities in text generation, question answering, language translation, reasoning and many other tasks. It continues to advance rapidly and is becoming increasingly influential in various fields, from technology and business to education and entertainment. Despite LLM’s success in multiple areas, its ability to play abstract games, such as chess, is underexplored. Chess-playing requires the language models to output legal and reasonable moves from textual inputs. Here, we propose the Large language model ChessLLM to play full chess games. We transform the game into a textual format with the best move represented in the Forsyth-Edwards Notation. We show that by simply supervised fine-tuning, our model has achieved a professional-level Elo rating of 1788 in matches against the standard Elo-rated Stockfish when permitted to sample 10 times. We further show that data quality is important. Long-round data supervision enjoys a 350 Elo rating improvement over short-round data.
Anthology ID:
2025.naacl-short.1
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1–7
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-short.1/
DOI:
Bibkey:
Cite (ACL):
Yinqi Zhang, Xintian Han, Haolong Li, Kedi Chen, and Shaohui Lin. 2025. Complete Chess Games Enable LLM Become A Chess Master. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers), pages 1–7, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Complete Chess Games Enable LLM Become A Chess Master (Zhang et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-short.1.pdf