open-chess/Caissa-Chess-M1

TEXT GENERATIONConcurrency Cost:1Model Size:7.6BQuant:FP8Ctx Length:32kTool Calling:SupportedPublished:Jun 16, 2026License:apache-2.0Architecture:Transformer Open Weights Cold

Caissa-Chess-M1 is a 7.6 billion parameter chess reasoning model developed by Open Chess, based on the Qwen 2.5 architecture. It is fine-tuned with LoRA on 20,000 complex chess positions, providing grandmaster-level analysis and Chain-of-Thought explanations. This model specializes in structured reasoning for chess, utilizing tags for evaluation, calculation, and reasoning to explain moves.

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Caissa-Chess-M1: Grandmaster Chess Reasoning

Caissa-Chess-M1 is a specialized 7.6 billion parameter model from Open Chess, built upon the Qwen 2.5 architecture. It is uniquely fine-tuned using LoRA on a dataset of 20,000 complex chess positions, each accompanied by detailed Chain-of-Thought explanations. This training methodology enables the model to perform grandmaster-level analysis, focusing on positions with balanced centipawn values (-400 to +400).

Key Capabilities

  • Structured Reasoning: Provides analysis using distinct <evaluation>, <calculation>, and <reasoning> tags.
  • High-Level Analysis: Trained on positions analyzed to Stockfish depth 28+, ensuring sophisticated chess insights.
  • Transparent Explanations: Offers Chain-of-Thought explanations for every suggested move, detailing the rationale.

Good For

  • Chess Analysis Tools: Integrating advanced chess reasoning and explanation capabilities.
  • Educational Platforms: Demonstrating complex chess strategies and thought processes.
  • AI Chess Research: Exploring structured reasoning and Chain-of-Thought in domain-specific applications.