mahjong

Japanese riichi mahjong hand calculator library.

Compute hand cost (han, fu, yaku, and scores), validate winning hands, and calculate shanten (minimum tiles to tenpai).

The code was validated on tenhou.net phoenix replays in total on 26,148,038 hands.

So, we can say that our hand calculator works the same way that tenhou.net hand calculation.

Documentation

• API reference
• Wiki — Supported rules and usage examples

How to install

pip install mahjong

Local development setup

To set up the project locally for development:

1. Clone the repository:

   bash git clone https://github.com/MahjongRepository/mahjong.git cd mahjong

2. Setup env using uv:

   bash uv sync

3. Run tests to verify setup:

   ```bash make tests

   Or directly:

   uv run pytest ```

4. Run full checks before committing:

   bash make check # Runs format, lint, and tests

License

This library is licensed under the MIT license.