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python-chess is a chess library for Python, with move generation,move validation, and support for common formats. This is the Scholar's mate inpython-chess:

>>>importchess>>>board=chess.Board()>>>board.legal_moves# doctest: +ELLIPSIS<LegalMoveGeneratorat ... (Nh3,Nf3,Nc3,Na3,h3,g3,f3,e3,d3,c3, ...)>>>>chess.Move.from_uci("a8a1")inboard.legal_movesFalse>>>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>>>boardBoard('r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4')

Requires Python 3.8+. Download and install the latest release:

pip install chess

• Core
• PGN parsing and writing
• Polyglot opening book reading
• Gaviota endgame tablebase probing
• Syzygy endgame tablebase probing
• UCI/XBoard engine communication
• Variants
• Changelog

• Includes mypy typings.

• IPython/Jupyter 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 moveMove.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 .bqkb .rpppp .Qpp. .n . .n . .. . . .p . . .. .B .P . . .. . . . . . . .PPPP .PPPRNB .K .NR

• Detects checkmates, stalemates and draws by insufficient material.

  >>>board.is_stalemate()False>>>board.is_insufficient_material()False>>>board.outcome()Outcome(termination=<Termination.CHECKMATE:1>,winner=True)

• Detects repetitions. Has a half-move clock.

  >>>board.can_claim_threefold_repetition()False>>>board.halfmove_clock0>>>board.can_claim_fifty_moves()False>>>board.can_claim_draw()False

  With the new rules from July 2014, a game ends as a draw (even without aclaim) once a fivefold repetition occurs or if there are 75 moves withouta 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)>>>attackersSquareSet(0x0000_0000_0000_4040)>>>chess.G2inattackersTrue>>>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)formin ["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

• Detectsabsolute pins and their directions.

• Reads Polyglot opening books.Docs.

  >>>importchess.polyglot>>>book=chess.polyglot.open_reader("data/polyglot/performance.bin")>>>board=chess.Board()>>>main_entry=book.find(board)>>>main_entry.moveMove.from_uci('e2e4')>>>main_entry.weight1>>>book.close()

• Reads and writes PGNs. Supports headers, comments, NAGs and a tree ofvariations.Docs.

  >>>importchess.pgn>>>withopen("data/pgn/molinari-bordais-1979.pgn")aspgn:...first_game=chess.pgn.read_game(pgn)>>>first_game.headers["White"]'Molinari'>>>first_game.headers["Black"]'Bordais'>>>first_game.mainline()# doctest: +ELLIPSIS<Mainlineat ... (1.e4c52.c4Nc63.Ne2Nf64.Nbc3Nb45.g3Nd3#)>>>>first_game.headers["Result"]'0-1'

• Probe Gaviota endgame tablebases (DTM, WDL).Docs.

• Probe Syzygy endgame tablebases (DTZ, WDL).Docs.

  >>>importchess.syzygy>>>tablebase=chess.syzygy.open_tablebase("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")>>>tablebase.probe_dtz(board)-53>>>tablebase.close()

• Communicate with UCI/XBoard engines. Based onasyncio.Docs.

  >>>importchess.engine>>>engine=chess.engine.SimpleEngine.popen_uci("stockfish")>>>board=chess.Board("1k1r4/pp1b1R2/3q2pp/4p3/2B5/4Q3/PPP2B2/2K5 b - - 0 1")>>>limit=chess.engine.Limit(time=2.0)>>>engine.play(board,limit)# doctest: +ELLIPSIS<PlayResultat ... (move=d6d1,ponder=c1d1,info={...},draw_offered=False,resigned=False)>>>>engine.quit()

If you like, share interesting things you are using python-chess for, for example:

	https://syzygy-tables.info/ A website to probe Syzygy endgame tablebases
	https://maiachess.com/ A human-like neural network chess engine
	clente/chess Oppinionated wrapper to use python-chess from the R programming language
	https://crazyara.org/ Deep learning for Crazyhouse
	http://johncheetham.com A GUI to play against UCI chess engines
	https://pettingzoo.farama.org A multi-agent reinforcement learning environment
	cli-chess A highly customizable way to play chess in your terminal

• extensions to build engines (search and evaluation) –https://github.com/Mk-Chan/python-chess-engine-extensions
• a stand-alone chess computer based on DGT board –https://picochess.com/
• a bridge between Lichess API and chess engines –https://github.com/lichess-bot-devs/lichess-bot
• a command-line PGN annotator –https://github.com/rpdelaney/python-chess-annotator
• an HTTP microservice to render board images –https://github.com/niklasf/web-boardimage
• building a toy chess engine with alpha-beta pruning, piece-square tables, and move ordering –https://healeycodes.com/building-my-own-chess-engine/
• a JIT compiled chess engine –https://github.com/SamRagusa/Batch-First
• teaching Cognitive Science –https://jupyter.brynmawr.edu
• anAlexa skill to play blindfold chess –https://github.com/laynr/blindfold-chess
• a chessboard widget for PySide2 –https://github.com/H-a-y-k/hichesslib
• Django Rest Framework API for multiplayer chess –https://github.com/WorkShoft/capablanca-api
• abrowser based PGN viewer written in PyScript –https://github.com/nmstoker/ChessMatchViewer
• an accessible chessboard that allows blind and visually impaired players to play chess against Stockfish –https://github.com/blindpandas/chessmart
• a web-based chess vision exercise –https://github.com/3d12/rookognition

Thanks to the Stockfish authors and thanks to Sam Tannous for publishing hisapproach toavoid rotated bitboards with direct lookup (PDF)alongside his GPL2+ engineShatranj.Some move generation ideas are taken from these sources.

Thanks to Ronald de Man for hisSyzygy endgame tablebases.The probing code in python-chess is very directly ported from his C probing code.

Thanks toKristian Glass fortransferring the namespacechess on PyPI.

python-chess is licensed under the GPL 3 (or any later version at your option).Check outLICENSE.txt for the full text.