---
tags:
- trl
license: cc0-1.0
---

# Chess Puzzles Dataset

## Summary

The Chess Puzzles dataset is a processed version of the [Lichess puzzle database](https://huggingface.co/datasets/Lichess/chess-puzzles): 6 million positions from real games, each with a single winning move, rated by how hard Lichess players found them. Each puzzle is a prompt showing the board, its FEN and the legal moves, and a completion with the first move of the solution in UCI notation.

## Data Structure

- **Format**: [Conversational](https://huggingface.co/docs/trl/main/dataset_formats#conversational)
- **Type**: [Prompt-completion](https://huggingface.co/docs/trl/main/dataset_formats#prompt-completion)

Columns:
- `"prompt"`: The puzzle: the side to move, the board, its FEN and the legal moves.
- `"completion"`: The first move of the solution, in UCI notation (for example `e2e4`).
- `"PuzzleId"`, `"Rating"`, `"Themes"`: The Lichess puzzle ID, its rating, and its themes (`mateIn2`, `fork`, ...).

The test split holds 1,000 puzzles. Lichess also accepts any move that mates, so a model that answers with another mating move solves the puzzle too.

## Generation script

The script used to generate this dataset can be found [here](https://github.com/huggingface/trl/blob/main/examples/datasets/chess_puzzles.py).