py-draughts 1.8.1

Fastest Python draughts / checkers library (import: draughts). Bitboard move generation ~200x faster than pydraughts. PDN/FEN, alpha-beta engine, HUB protocol, web UI. 8 variants: International, American, Frisian, Russian, Brazilian, Antidraughts, Breakthrough, Frysk!

py-draughts — fastest Python draughts & checkers library

py-draughts (import name: draughts) is a fast, modern Python library for draughts (also known as checkers). Bitboard-backed move generation, PDN/FEN parsing, a built-in alpha-beta engine, HUB protocol bridge for external engines like Scan and Kingsrow, an interactive web UI, and tensor exports for RL / ML — all in one package.

[!IMPORTANT] The fastest pure-Python draughts library: ~200x faster legal-move generation than pydraughts, with 8 supported variants and 260+ tests.

py-draughts vs pydraughts

	py-draughts	pydraughts
Legal moves generation	21.4 µs	5.18 ms (243x slower)
Make move	1.2 µs	552.50 µs (460x slower)
Board init	3.3 µs	579.45 µs (176x slower)
FEN parse	27.4 µs	295.10 µs (11x slower)
Variants	8 (Standard, American, Frisian, Russian, Brazilian, Antidraughts, Breakthrough, Frysk!)	6
Built-in AI engine	✅ Alpha-beta + transposition tables	❌ External only
Engine benchmarking suite	✅	❌
Web UI	✅ FastAPI + interactive board	❌
SVG rendering	✅	❌
ML/RL helpers (tensors, masks)	✅	❌
Test suite	260+ tests, real Lidraughts PDN replays	Limited
HUB protocol (Scan, Kingsrow)	✅	✅
Implementation	Bitboards (NumPy uint64)	Object lists

Full comparison →

Features: 8 variants • Built-in AI engine • External engines via HUB protocol (Scan, Kingsrow) • RL/ML ready (tensors, masks) • SVG rendering • Web UI

Installation

pip install py-draughts

Core

>>> import draughts
>>> board = draughts.Board()

>>> board.legal_moves
[Move: 31->27, Move: 31->26, Move: 32->28, ...]

>>> board.push_uci("31-27")
>>> board.push_uci("18-22")
>>> board.push_uci("27x18")
>>> board.push_uci("12x23")

>>> board
 . b . b . b . b . b
 b . b . b . b . b .
 . b . b . . . b . b
 . . . . b . b . b .
 . . . b . . . . . .
 . . . . . . . . . .
 . w . w . w . w . w
 w . w . w . w . w .
 . w . w . w . w . w
 w . w . w . w . w .

>>> board.pop()  # Unmake the last move
Move: 12->23

>>> board.turn
Color.WHITE

Make and unmake moves

>>> board.push_uci("32-28")  # Make a move
>>> board.pop()              # Unmake the last move
Move: 32->28

Show ASCII board

>>> board = draughts.Board()
>>> print(board)
 . b . b . b . b . b     .  1 .  2 .  3 .  4 .  5
 b . b . b . b . b .      6 .  7 .  8 .  9 . 10 .
 . b . b . b . b . b     . 11 . 12 . 13 . 14 . 15
 b . b . b . b . b .     16 . 17 . 18 . 19 . 20 .
 . . . . . . . . . .     . 21 . 22 . 23 . 24 . 25
 . . . . . . . . . .     26 . 27 . 28 . 29 . 30 .
 . w . w . w . w . w     . 31 . 32 . 33 . 34 . 35
 w . w . w . w . w .     36 . 37 . 38 . 39 . 40 .
 . w . w . w . w . w     . 41 . 42 . 43 . 44 . 45
 w . w . w . w . w .     46 . 47 . 48 . 49 . 50 .

Detects draws and game end

>>> board.is_draw
False
>>> board.is_threefold_repetition
False
>>> board.game_over
False
>>> board.result
'-'

FEN parsing and writing

>>> board.fen
'[FEN "W:W:W31,32,33,...:B1,2,3,..."]'

>>> board = draughts.Board.from_fen("W:WK10,K20:BK35,K45")
>>> board
 . . . . . . . B . .
 . . . . . . . . . .
 . . . . . . . . . .
 . . . . . . . . . .
 . . . . . . . . . .
 . . . . . . . . . .
 . . . . W . . . . .
 . . . . . . . . . .
 . . . . W . . . . .
 B . . . . . . . . .

PDN parsing and writing

>>> board = draughts.Board()
>>> board.push_uci("32-28")
>>> board.push_uci("18-23")
>>> board.pdn
'[GameType "20"]
[Variant "Standard (international) checkers"]
[Result "-"]
1. 32-28 18-23'

>>> board = draughts.Board.from_pdn('[GameType "20"]\n1. 32-28 19-23 2. 28x19 14x23')

Variants

Variant	Class	Board	Flying Kings	Max Capture	Notes
Standard	StandardBoard	10×10	Yes	Required	International / FMJD rules
American	AmericanBoard	8×8	No	Not required	Men capture forward only
Frisian	FrisianBoard	10×10	Yes	Required (by value)	Diagonal + orthogonal captures
Russian	RussianBoard	8×8	Yes	Not required	Mid-capture promotion
Brazilian	BrazilianBoard	8×8	Yes	Required	International rules on 8×8
Antidraughts	AntidraughtsBoard	10×10	Yes	Required	Lose all pieces (or get blocked) to win
Breakthrough	BreakthroughBoard	10×10	Yes	Required	First player to make a king wins
Frysk!	FryskBoard	10×10	Yes	Required (by value)	Frisian rules with 5 men per side

>>> from draughts import (
...     StandardBoard,
...     AmericanBoard,
...     FrisianBoard,
...     RussianBoard,
...     BrazilianBoard,
...     AntidraughtsBoard,
...     BreakthroughBoard,
...     FryskBoard,
... )

>>> board = AmericanBoard()
>>> board
 . b . b . b . b
 b . b . b . b .
 . b . b . b . b
 . . . . . . . .
 . . . . . . . .
 w . w . w . w .
 . w . w . w . w
 w . w . w . w .

SVG Rendering

>>> import draughts
>>> board = draughts.Board()
>>> draughts.svg.board(board, size=400)  # Returns SVG string

>>> board = draughts.Board.from_fen("W:WK10,K20:BK35,K45")
>>> draughts.svg.board(board, size=400)

Engine

Built-in alpha-beta engine with transposition tables and iterative deepening:

>>> from draughts import Board, AlphaBetaEngine

>>> board = Board()
>>> engine = AlphaBetaEngine(depth_limit=5)

>>> move = engine.get_best_move(board)
>>> move
Move: 32->28

>>> move, score = engine.get_best_move(board, with_evaluation=True)
>>> score
0.15

External Engines (Hub Protocol)

Use external engines like Scan via the Hub protocol:

>>> from draughts import Board, HubEngine

>>> with HubEngine("path/to/scan.exe", time_limit=1.0) as engine:
...     board = Board()
...     move, score = engine.get_best_move(board, with_evaluation=True)
...     print(f"Best: {move}, Score: {score}")
Best: 32-28, Score: 0.15

Compatible engines:

• Scan - World champion level, supports 10x10
• Kingsrow - Multiple variants, endgame databases
• Any engine implementing the Hub protocol

Engine Benchmarking

Compare engines against each other with comprehensive statistics:

>>> from draughts import Benchmark, AlphaBetaEngine

>>> stats = Benchmark(
...     AlphaBetaEngine(depth_limit=4),
...     AlphaBetaEngine(depth_limit=6),
...     games=20
... ).run()

>>> print(stats)
============================================================
  BENCHMARK: AlphaBetaEngine (d=4) vs AlphaBetaEngine (d=6)
============================================================
  RESULTS: 2-12-6 (W-L-D)
  AlphaBetaEngine (d=4) win rate: 25.0%
  Elo difference: -191
  ...

Writing Your Own AI

Build custom agents with neural networks, MCTS, or any algorithm:

>>> from draughts import Board, BaseAgent, AgentEngine, Benchmark

>>> class GreedyAgent(BaseAgent):
...     def select_move(self, board):
...         return max(board.legal_moves, key=lambda m: len(m.captured_list))

>>> board = Board()
>>> agent = GreedyAgent()
>>> move = agent.select_move(board)

# Use with Benchmark
>>> stats = Benchmark(agent.as_engine(), AlphaBetaEngine(depth_limit=4), games=10).run()

ML-ready features:

>>> board.to_tensor()        # (4, 50) tensor for neural networks
>>> board.legal_moves_mask() # Boolean mask for policy outputs
>>> board.features()         # Material, mobility, game phase
>>> clone = board.copy()     # Fast cloning for tree search

Server

Interactive web interface for playing and engine testing:

from draughts import Board, Server, AlphaBetaEngine, HubEngine

server = Server(
    board=Board(),
    white_engine=AlphaBetaEngine(depth_limit=6),
    black_engine=HubEngine("path/to/scan.exe", time_limit=1.0)
)
server.run() # Open http://localhost:8000

Performance

Legal moves generation in ~10-30 microseconds:

Operation	py-draughts	pydraughts	Speedup
Board init	3.30 µs	579.45 µs	176x faster
FEN parse	27.40 µs	295.10 µs	11x faster
Legal moves	21.35 µs	5.18 ms	243x faster
Make move	1.20 µs	552.50 µs	460x faster

Engine search at various depths:

Depth	Time	Nodes
5	274 ms	3,263
6	619 ms	7,330
7	2.20 s	21,642
8	6.55 s	98,987

Testing

Comprehensive test suite with 260+ tests covering all variants and edge cases:

pytest test/ -v

Tests include:

• Move generation - Push/pop roundtrips, legal move validation
• Real game replays - PDN games from Lidraughts for all variants
• Edge cases - Complex king captures, promotion mid-capture, draw rules
• Engine correctness - Hash stability, transposition tables, board immutability
• All 8 variants - Standard, American, Frisian, Russian, Brazilian, Antidraughts, Breakthrough, Frysk!

Contributing

Contributions welcome! Please open an issue or submit a pull request.

License

py-draughts is licensed under the GPL 3.