---
pretty_name: Chess Games Dataset
license: cc-by-nc-sa-4.0
size_categories:
- 10M<n<100M
tags:
- chess
- chess-games
- uci
- parquet
- lumbras-giga-base
- machine-learning
- datasets
configs:
- config_name: default
  default: true
  data_files:
  - split: train
    path: "part-*.parquet"
---

# Chess Games Dataset

This dataset is a compact, ML-oriented chess game dataset generated from
[`angeluriot/chess_games`](https://huggingface.co/datasets/angeluriot/chess_games)
plus additional 2025 games extracted from
[Lumbras Giga Base](https://lumbrasgigabase.com/en/).

It keeps only the move sequence in UCI notation, a derived minimum Elo field,
and a source label. This makes the dataset smaller and simpler to consume than
the base dataset when the downstream task only needs legal move sequences and a
coarse player-strength signal.

## Dataset Summary

- Games: 15,272,234
- Files: 8 Parquet shards
- Compressed size: 2.48 GiB
- Split: `train`
- Format: Parquet

## Data Sources

| Source | Games | Share |
| --- | ---: | ---: |
| `LichessEliteDatabase` | 5,525,245 | 36.18% |
| `LumbrasGigaBase` | 4,785,121 | 31.33% |
| `PGNMentor` | 3,431,537 | 22.47% |
| `TWIC` | 858,163 | 5.62% |
| `Masters` | 322,166 | 2.11% |
| `LichessBroadcast` | 105,329 | 0.69% |
| `ChessOK` | 62,895 | 0.41% |
| `Britbase` | 60,148 | 0.39% |
| `Kingbase` | 59,317 | 0.39% |
| `Convekta` | 37,536 | 0.25% |
| `ChessNostalgia` | 24,592 | 0.16% |
| `Chessopolis` | 123 | 0.00% |
| `GamesOfGMs` | 62 | 0.00% |
| Total | 15,272,234 | 100.00% |

The base dataset is
[`angeluriot/chess_games`](https://huggingface.co/datasets/angeluriot/chess_games),
which already includes games from multiple public chess sources.

The added 2025 games come from
[Lumbras Giga Base](https://lumbrasgigabase.com/en/), using the 2025 OTB and
Online PGN files. Special thanks to Lumbras Giga Base for collecting and
curating the chess game sources used by the base dataset and this extension.

## Dataset Structure

Each row represents one chess game.

| Field | Type | Description |
| --- | --- | --- |
| `moves_uci` | `list[string]` | Mainline game moves in Universal Chess Interface notation, for example `e2e4`. |
| `min_elo` | `int64` or `null` | Minimum of White Elo and Black Elo when both ratings are available; otherwise `null`. |
| `source` | `string` | Source label preserved from the base dataset when available; added 2025 Lumbras games use `LumbrasGigaBase`. |

Rows with `null` `min_elo`: 2,053,362.

## Differences From `angeluriot/chess_games`

This dataset is not a full mirror of the base dataset. It intentionally removes
metadata that is not needed for the target training workflows.

Removed fields:

- `date`
- `white_elo`
- `black_elo`
- `end_type`
- `winner`
- `moves_san`
- `moves_custom`

Added or changed fields:

- `min_elo` is derived from `white_elo` and `black_elo`.
- `source` preserves the original base-dataset source label when available.
- 2025 Lumbras Giga Base OTB and Online PGN games are appended.
- Rows are sorted by descending `min_elo`, with null values last.

## Usage

### Hugging Face Datasets

```python
from datasets import load_dataset

dataset = load_dataset("mrmlengineer/chess_games")

game = dataset["train"][0]
print(game["moves_uci"])
print(game["min_elo"])
print(game["source"])
```

### Streaming

```python
from datasets import load_dataset

dataset = load_dataset(
    "mrmlengineer/chess_games",
    streaming=True,
)

for game in dataset["train"]:
    print(game["moves_uci"])
    break
```

## License

This combined dataset is released under
[Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-nc-sa/4.0/)
because Lumbras Giga Base states that its work is licensed under CC BY-NC-SA
4.0. The base dataset `angeluriot/chess_games` is distributed on Hugging Face
with an MIT license.

Users should respect the terms of both upstream sources.

## Limitations

- The dataset has a single `train` split; no validation or test split is
  provided.
- `min_elo` is null when either player Elo is unavailable.
- Only the mainline UCI move sequence is included.
- Commercial use is restricted by the CC BY-NC-SA 4.0 license.