A chess library with move generation and validation, Polyglot opening book probing, PGN reading and writing, Gaviota tablebase probing, Syzygy tablebase probing, and XBoard/UCI engine communication.
.. image:: https://github.com/niklasf/python-chess/workflows/Test/badge.svg :target: https://github.com/niklasf/python-chess/actions :alt: Test status
.. image:: https://badge.fury.io/py/chess.svg :target: https://pypi.python.org/pypi/chess :alt: PyPI package
.. image:: https://readthedocs.org/projects/python-chess/badge/?version=v1.11.1 :target: https://python-chess.readthedocs.io/en/v1.11.1/ :alt: Docs
.. image:: https://badges.gitter.im/python-chess/community.svg :target: https://gitter.im/python-chess/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge :alt: Chat on Gitter
python-chess is a chess library for Python, with move generation, move validation, and support for common formats. This is the Scholar's mate in python-chess:
.. code:: python
>>> import chess
>>> board = chess.Board()
>>> board.legal_moves
<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')
Requires Python 3.8+. Download and install the latest release:
::
pip install chess
Documentation <https://python-chess.readthedocs.io/en/v1.11.1/>__Core <https://python-chess.readthedocs.io/en/v1.11.1/core.html>_PGN parsing and writing <https://python-chess.readthedocs.io/en/v1.11.1/pgn.html>_Polyglot opening book reading <https://python-chess.readthedocs.io/en/v1.11.1/polyglot.html>_Gaviota endgame tablebase probing <https://python-chess.readthedocs.io/en/v1.11.1/gaviota.html>_Syzygy endgame tablebase probing <https://python-chess.readthedocs.io/en/v1.11.1/syzygy.html>_UCI/XBoard engine communication <https://python-chess.readthedocs.io/en/v1.11.1/engine.html>_Variants <https://python-chess.readthedocs.io/en/v1.11.1/variant.html>_Changelog <https://python-chess.readthedocs.io/en/v1.11.1/changelog.html>_Includes mypy typings.
IPython/Jupyter Notebook integration.
SVG rendering docs <https://python-chess.readthedocs.io/en/v1.11.1/svg.html>_.
.. code:: python
>>> board
.. image:: https://backscattering.de/web-boardimage/board.png?fen=r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR&lastmove=h5f7&check=e8 :alt: r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR
Chess variants: Standard, Chess960, Suicide, Giveaway, Atomic,
King of the Hill, Racing Kings, Horde, Three-check, Crazyhouse.
Variant docs <https://python-chess.readthedocs.io/en/v1.11.1/variant.html>_.
Make and unmake moves.
.. code:: python
>>> 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.
.. code:: python
>>> 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.
.. code:: python
>>> 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.
.. code:: python
>>> 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 as a draw (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.
.. code:: python
>>> board.is_fivefold_repetition()
False
>>> board.is_seventyfive_moves()
False
Detects checks and attacks.
.. code:: python
>>> board.is_check()
True
>>> board.is_attacked_by(chess.WHITE, chess.E8)
True
>>> attackers = board.attackers(chess.WHITE, chess.F3)
>>> attackers
SquareSet(0x0000_0000_0000_4040)
>>> chess.G2 in attackers
True
>>> print(attackers)
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . 1 .
. . . . . . 1 .
Parses and creates SAN representation of moves.
.. code:: python
>>> 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.
.. code:: python
>>> 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.
.. code:: python
>>> 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 <https://python-chess.readthedocs.io/en/v1.11.1/core.html#chess.Board.pin>_.
Reads Polyglot opening books.
Docs <https://python-chess.readthedocs.io/en/v1.11.1/polyglot.html>__.
.. code:: python
>>> 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
>>> book.close()
Reads and writes PGNs. Supports headers, comments, NAGs and a tree of
variations.
Docs <https://python-chess.readthedocs.io/en/v1.11.1/pgn.html>__.
.. code:: python
>>> import chess.pgn
>>> with open("data/pgn/molinari-bordais-1979.pgn") as pgn:
... first_game = chess.pgn.read_game(pgn)
>>> first_game.headers["White"]
'Molinari'
>>> first_game.headers["Black"]
'Bordais'
>>> first_game.mainline()
<Mainline at ... (1. e4 c5 2. c4 Nc6 3. Ne2 Nf6 4. Nbc3 Nb4 5. g3 Nd3#)>
>>> first_game.headers["Result"]
'0-1'
Probe Gaviota endgame tablebases (DTM, WDL).
Docs <https://python-chess.readthedocs.io/en/v1.11.1/gaviota.html>__.
Probe Syzygy endgame tablebases (DTZ, WDL).
Docs <https://python-chess.readthedocs.io/en/v1.11.1/syzygy.html>__.
.. code:: python
>>> import chess.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 on asyncio.
Docs <https://python-chess.readthedocs.io/en/v1.11.1/engine.html>__.
.. code:: python
>>> import chess.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)
<PlayResult at ... (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:
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/syzygy.png?raw=true | https://syzygy-tables.info/ |
| :height: 64 | |
| :width: 64 | |
| :target: https://syzygy-tables.info/ | A website to probe Syzygy endgame tablebases |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/maia.png?raw=true | https://maiachess.com/ |
| :height: 64 | |
| :width: 64 | |
| :target: https://maiachess.com/ | A human-like neural network chess engine |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/clente-chess.png?raw=true | clente/chess <https://github.com/clente/chess>_ |
| :height: 64 | |
| :width: 64 | |
| :target: https://github.com/clente/chess | Oppinionated wrapper to use python-chess from the R programming language |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/crazyara.png?raw=true | https://crazyara.org/ |
| :height: 64 | |
| :width: 64 | |
| :target: https://crazyara.org/ | Deep learning for Crazyhouse |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/jcchess.png?raw=true | http://johncheetham.com <http://johncheetham.com/projects/jcchess/>_ |
| :height: 64 | |
| :width: 64 | |
| :target: http://johncheetham.com/projects/jcchess/ | A GUI to play against UCI chess engines |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/pettingzoo.png?raw=true | https://pettingzoo.farama.org <https://pettingzoo.farama.org/environments/classic/chess/>_ |
| :width: 64 | |
| :height: 64 | |
| :target: https://pettingzoo.farama.org/environments/classic/chess/ | A multi-agent reinforcement learning environment |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
| .. image:: https://github.com/niklasf/python-chess/blob/master/docs/images/cli-chess.png?raw=true | cli-chess <https://github.com/trevorbayless/cli-chess>_ |
| :width: 64 | |
| :height: 64 | |
| :target: https://github.com/trevorbayless/cli-chess | A highly customizable way to play chess in your terminal |
+------------------------------------------------------------------------------------------------------+----------------------------------------------------------------------------------------------+
https://jupyter.brynmawr.edu <https://jupyter.brynmawr.edu/services/public/dblank/CS371%20Cognitive%20Science/2016-Fall/Programming%20a%20Chess%20Player.ipynb>_Alexa skill to play blindfold chess <https://www.amazon.com/Laynr-blindfold-chess/dp/B0859QF8YL>_ – https://github.com/laynr/blindfold-chessbrowser based PGN viewer <https://about.nmstoker.com/chess2.html>_ written in PyScript – https://github.com/nmstoker/ChessMatchViewerThanks to the Stockfish authors and thanks to Sam Tannous for publishing his
approach to avoid rotated bitboards with direct lookup (PDF) <http://arxiv.org/pdf/0704.3773.pdf>_
alongside his GPL2+ engine Shatranj <https://github.com/stannous/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 Kristian Glass <https://github.com/doismellburning>_ for
transferring the namespace chess on PyPI.
python-chess is licensed under the GPL 3 (or any later version at your option).
Check out LICENSE.txt for the full text.
FAQs
A chess library with move generation and validation, Polyglot opening book probing, PGN reading and writing, Gaviota tablebase probing, Syzygy tablebase probing, and XBoard/UCI engine communication.
We found that chess demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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