---
license: apache-2.0
datasets:
- mlabonne/chessllm
library_name: transformers
tags:
- chess
pipeline_tag: text-generation
base_model:
- FlameF0X/ChessSLM
---
# ChessSLM
**ChessSLM-PM** is a small language model build on top of **ChessSLM**, designed to play chess using natural language move generation.
Despite having only **30M parameters**, it is capable of competing with and occasionally outperforming larger language models in chess-playing tasks.
The model is based on the **ChessSLM** and was *fine-tuned* on **441,000 chess games** rated over 2000 elo from the `mlabonne/chessllm` dataset using **SAN (Standard Algebraic Notation)**.
Play against ChessSLM [here](https://flamef0x.github.io/other/chess).
---
## Overview
- **Architecture:** GPT-2
- **Parameters:** ~30M
- **Training data:** 441k chess games rated over 2000 elo
- **Notation:** SAN (Standard Algebraic Notation)
- **Task:** Autoregressive chess move generation
ChessSLM demonstrates that **specialized small language models can perform competitively in narrow domains** such as chess.
---
## Capabilities
ChessSLM can play chess by generating moves sequentially in SAN notation.
It has been evaluated in matches against several language models, including:
- Claude [Won against it]
- Gemini [Lost again it]
- Qwen
- GPT-2
- GPT-Neo
- Pythia
- LLaMA
- Mistral
- other small chess-oriented models
The model achieves an averaging rating of **around {tba} Elo** against other language models despite its small size.
---
| Model | Elo Rating |
| ------------------------------ | ---------- |
| **FlameF0X/ChessSLM** | 1154 |
| DedeProGames/mini-chennus | 1114 |
| EleutherAI/pythia-70m-deduped | 1099 |
| nlpguy/smolchess-v2 | 1092 |
| DedeProGames/dialochess | 1078 |
| nlpguy/amdchess-v9 | 1073 |
| mlabonne/grandpythia-200k-70m | 1065 |
| **FlameF0X/ChessSLM-PM** | 1055 |
| DedeProGames/Chesser-248K-Mini | 1050 |
| bharathrajcl/chess_llama_68m | 1048 |
| **FlameF0X/ChessSLM-RL** | 1047 |
| distilbert/distilgpt2 | 1047 |
| Mattimax/EliaChess-70m | 1047 |
| HuggingFaceTB/SmolLM2-135M | 1042 |
| nlpguy/amdchess-v5 | 1041 |
| facebook/opt-125m | 1041 |
| EleutherAI/pythia-14m | 1037 |
| DedeProGames/chennus | 1034 |
| Smilyai-labs/Smily-ultra-1 | 1034 |
| huyvux3005/chessllm_FPT | 1034 |
---
## Limitations
Like many language-model-based chess systems, ChessSLM has several limitations:
- **Illegal move hallucinations:** The model may occasionally generate moves that violate chess rules.
- **No board-state verification:** Moves are generated purely from learned patterns rather than a validated game state.
- **Limited strategic depth:** While competitive at lower Elo levels, it cannot match dedicated chess engines.
These limitations are common for **pure language-model chess agents** that do not use external rule engines.
## Summary
ChessSLM shows that **very small language models can achieve meaningful chess performance** when trained on domain-specific data.
It serves as a lightweight baseline for exploring **LLM-based chess agents** and **specialized small language models (SLMs)**.