A pure Python chess library with move generation and validation, Polyglot opening book probing, PGN reading and writing, Gaviota tablebase probing, Syzygy tablebase probing and UCI engine communication.
Project description
Introduction
python-chess is a pure Python chess library with move generation and validation and handling of common formats. This is the scholars mate in python-chess:
>>> import chess
>>> board = chess.Board()
>>> board.legal_moves # doctest: +ELLIPSIS
<LegalMoveGenerator at ... (Nh3, Nf3, Nc3, Na3, h3, g3, f3, e3, d3, c3, ...)>
>>> chess.Move.from_uci("a8a1") in board.legal_moves
False
>>> board.push_san("e4")
Move.from_uci('e2e4')
>>> board.push_san("e5")
Move.from_uci('e7e5')
>>> board.push_san("Qh5")
Move.from_uci('d1h5')
>>> board.push_san("Nc6")
Move.from_uci('b8c6')
>>> board.push_san("Bc4")
Move.from_uci('f1c4')
>>> board.push_san("Nf6")
Move.from_uci('g8f6')
>>> board.push_san("Qxf7")
Move.from_uci('h5f7')
>>> board.is_checkmate()
True
>>> board
Board('r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4')
Documentation
Features
Supports Python 2.6+, Python 3.3+ and PyPy.
IPython notebook integration. SVG rendering docs.
>>> board # doctest: +SKIP
Chess variants: Standard, Chess960, Suicide, Giveaway, Atomic, King of the Hill, Racing Kings, Horde, Three-check, Crazyhouse. Variant docs.
Make and unmake moves.
>>> Nf3 = chess.Move.from_uci("g1f3") >>> board.push(Nf3) # Make the move >>> board.pop() # Unmake the last move Move.from_uci('g1f3')
Show a simple ASCII board.
>>> board = chess.Board("r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4") >>> print(board) r . b q k b . r p p p p . Q p p . . n . . n . . . . . . p . . . . . B . P . . . . . . . . . . . P P P P . P P P R N B . K . N R
Detects checkmates, stalemates and draws by insufficient material.
>>> board.is_stalemate() False >>> board.is_insufficient_material() False >>> board.is_game_over() True
Detects repetitions. Has a half move clock.
>>> board.can_claim_threefold_repetition() False >>> board.halfmove_clock 0 >>> board.can_claim_fifty_moves() False >>> board.can_claim_draw() False
With the new rules from July 2014 a game ends drawn (even without a claim) once a fivefold repetition occurs or if there are 75 moves without a pawn push or capture. Other ways of ending a game take precedence.
>>> board.is_fivefold_repetition() False >>> board.is_seventyfive_moves() False
Detects checks and attacks.
>>> board.is_check() True >>> board.is_attacked_by(chess.WHITE, chess.E8) True >>> attackers = board.attackers(chess.WHITE, chess.F3) >>> attackers SquareSet(0b0000000000000000000000000000000000000000000000000100000001000000) >>> chess.G2 in attackers True >>> print(attackers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . 1 .
Parses and creates SAN representation of moves.
>>> board = chess.Board() >>> board.san(chess.Move(chess.E2, chess.E4)) 'e4' >>> board.parse_san('Nf3') Move.from_uci('g1f3') >>> board.variation_san([chess.Move.from_uci(m) for m in ["e2e4", "e7e5", "g1f3"]]) '1. e4 e5 2. Nf3'
Parses and creates FENs, extended FENs and Shredder FENs.
>>> board.fen() 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1' >>> board.shredder_fen() 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w HAha - 0 1' >>> board = chess.Board("8/8/8/2k5/4K3/8/8/8 w - - 4 45") >>> board.piece_at(chess.C5) Piece.from_symbol('k')
Parses and creates EPDs.
>>> board = chess.Board() >>> board.epd(bm=board.parse_uci("d2d4")) 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - bm d4;' >>> ops = board.set_epd("1k1r4/pp1b1R2/3q2pp/4p3/2B5/4Q3/PPP2B2/2K5 b - - bm Qd1+; id \"BK.01\";") >>> ops == {'bm': [chess.Move.from_uci('d6d1')], 'id': 'BK.01'} True
Detects absolute pins and their directions.
Read Polyglot opening books. Docs.
>>> import chess.polyglot >>> book = chess.polyglot.open_reader("data/polyglot/performance.bin") >>> board = chess.Board() >>> main_entry = book.find(board) >>> main_entry.move() Move.from_uci('e2e4') >>> main_entry.weight 1 >>> main_entry.learn 0 >>> book.close()
Read and write PGNs. Supports headers, comments, NAGs and a tree of variations. Docs.
>>> import chess.pgn >>> pgn = open("data/pgn/molinari-bordais-1979.pgn") >>> first_game = chess.pgn.read_game(pgn) >>> pgn.close() >>> first_game.headers["White"] 'Molinari' >>> first_game.headers["Black"] 'Bordais' >>> # Get the mainline as a list of moves. >>> moves = first_game.main_line() >>> first_game.board().variation_san(moves) '1. e4 c5 2. c4 Nc6 3. Ne2 Nf6 4. Nbc3 Nb4 5. g3 Nd3#' >>> # Iterate through the mainline of this embarrasingly short game. >>> node = first_game >>> while not node.is_end(): ... next_node = node.variation(0) ... print(node.board().san(next_node.move)) ... node = next_node e4 c5 c4 Nc6 Ne2 Nf6 Nbc3 Nb4 g3 Nd3# >>> first_game.headers["Result"] '0-1'
Probe Gaviota endgame tablebases (DTM, WDL). Docs.
Probe Syzygy endgame tablebases (DTZ, WDL). Docs.
>>> import chess.syzygy >>> tablebases = chess.syzygy.open_tablebases("data/syzygy/regular") >>> # Black to move is losing in 53 half moves (distance to zero) in this >>> # KNBvK endgame. >>> board = chess.Board("8/2K5/4B3/3N4/8/8/4k3/8 b - - 0 1") >>> tablebases.probe_dtz(board) -53 >>> tablebases.close()
Communicate with an UCI engine. Docs.
>>> import chess.uci >>> engine = chess.uci.popen_engine("stockfish") >>> engine.uci() >>> engine.author # doctest: +SKIP 'Tord Romstad, Marco Costalba and Joona Kiiski' >>> # Synchronous mode. >>> board = chess.Board("1k1r4/pp1b1R2/3q2pp/4p3/2B5/4Q3/PPP2B2/2K5 b - - 0 1") >>> engine.position(board) >>> engine.go(movetime=2000) # Gets tuple of bestmove and ponder move. BestMove(bestmove=Move.from_uci('d6d1'), ponder=Move.from_uci('c1d1')) >>> # Asynchronous mode. >>> def callback(command): ... bestmove, ponder = command.result() ... assert bestmove == chess.Move.from_uci('d6d1') ... >>> command = engine.go(movetime=2000, async_callback=callback) >>> command.done() False >>> command.result() BestMove(bestmove=Move.from_uci('d6d1'), ponder=Move.from_uci('c1d1')) >>> command.done() True >>> # Quit. >>> engine.quit() 0
Installing
Download and install the latest release:
pip install python-chess[uci,gaviota]
Selected use cases
If you like, let me know if you are creating something intresting with python-chess, for example:
a stand alone chess computer based on DGT board - http://www.picochess.org/
a website to probe Syzygy endgame tablebases - https://syzygy-tables.info/
a GUI to play against UCI chess engines - http://johncheetham.com/projects/jcchess/
an HTTP microservice to render board images - https://github.com/niklasf/web-boardimage
a bot to play chess on Telegram - https://github.com/cxjdavin/tgchessbot
connecting Stockfish to the Novag Citrine - http://empiricalrabbit.blogspot.de/2016/05/integrating-with-python-chess-module.html
a tool to build Anki decks from a PGN opening repertoire - https://github.com/asdfjkl/pgn2anki
Acknowledgements
Thanks to the Stockfish authors and thanks to Sam Tannous for publishing his approach to avoid rotated bitboards with direct lookup (pdf) alongside his GPL2+ engine Shatranj. Some move generation ideas are taken from these sources.
Thanks to Ronald de Man for his Syzygy endgame tablebases (https://github.com/syzygy1/tb). The probing code in python-chess is very directly ported from his C probing code.
Thanks to Miguel A. Ballicora for his Gaviota tablebases (https://github.com/michiguel/Gaviota-Tablebases). (I wish the generating code was free software).
License
python-chess is licensed under the GPL 3 (or any later version at your option). See the LICENSE file for the full license text.
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