spooky_chess 🎃👻

Rust and Python library for the game of Chess.

Features

• Drive external engines with Universal Chess Interface.
• Variable board sizes from 6x6 to 16x16.
• Relatively fast.
• Out-of-the-box support for DL/ML, including AlphaZero and MAIA2 action encoding.
• Consistent interface with spooky-connect4 and spooky-go.

Performance

Measured with a Threadripper 9980x, and 6400 MT/s CL36 DDR5. Python 3.14.

> cd tests/comparison && cargo run --release && cd -
50000 random game playouts
  spooky_chess (Rust Bindings):
    moves:   4936906
    time:    2.14s
    moves/s: 2311096.73

> uv run python -m pytest -k test_compare_random_game_playout -s --run-slow
50000 random game playouts
  spooky_chess (Python Bindings):
    moves:   4936141
    time:    6.66s
    moves/s: 740666.24
  python-chess:
    moves:   4935315
    time:    113.33s
    moves/s: 43548.00
  Speedup: 17.01x

Validity

Fuzz-tested against python-chess, with 5 million random playouts.

Install

Rust

cargo add spooky_chess

Python

uv add spooky-chess

Includes type hints.

Examples

Quick start:

Rust:

cargo run --example quick_start

Python:

uv run python examples/quick_start.py

More Rust examples:

• cargo run --example pgn_summary
• cargo run --example legal_moves
• cargo run --example action_encoding
• cargo run --example custom_board

More Python examples:

• uv run python examples/pgn_summary.py
• uv run python examples/legal_moves.py
• uv run python examples/action_encoding.py
• uv run python examples/custom_board.py

PGN + UCI analysis:

Rust:

cargo run --example analyse_pgn

Python:

uv run python examples/analyse_pgn.py

Develop

Tests

• fish run_tests.fish
  • fish run_python_tests.fish
  • fish run_rust_tests.fish

Lints

• fish run_lints.fish

Docs

• uv run --with sphinx==9.1.0 python -m sphinx -b html -E docs docs/_build/html

Performance

• fish run_benchmark.fish
• fish run_profile.fish

See Also

• spooky-chess
• spooky-connect4
• spooky-go