What are PGN files?

PGN stands for Portable Game Notation. It is the standard format used to record the moves played by the players in a chess game. By using the PGN format, we can record and store the game moves in a regular text file. 

Whenever we play chess online on popular websites like https://chess.com or https://lichess.org, these websites automatically generate the PGN files of our games. We can use these files to watch and analyze our games in the future. We will use these PGN files in order to extract data from our chess games using the chess library in Python.

Let us take a look at the contents of a PGN file in order to understand the contents of the file.

[Event "Live Chess"]
[Site "Chess.com"]  
[Date "2021.08.05"] 
[Round "-"]
[White "urvishmhjn"]
[Black "yannickhs"]
[Result "1-0"]
[CurrentPosition "r1b1q1r1/p2nbk2/4pp1Q/1p1p3B/2pP3N/1PP1P3/P4PPP/R4RK1 b - -"]
[Timezone "UTC"]
[ECO "A45"]
[UTCDate "2021.08.05"]
[UTCTime "09:25:32"]
[WhiteElo "1220"]
[BlackElo "1140"]
[TimeControl "900+10"]
[Termination "urvishmhjn won by resignation"]

1. d4 Nf6 2. Bf4 e6 3. e3 d5 4. Bd3 c5 5. c3 c4 6. Be2 Nc6 
7. Nf3 Be7 8. Nbd2 O-O 9. O-O Nh5 10. Be5 Nxe5 11. Nxe5 Nf6 
12. b3 b5 13. Qc2 Nd7 14. Ndf3 f6 15. Ng4 h5 16. Nh6+ gxh6 
17. Qg6+ Kh8 18. Qxh6+ Kg8 19. Qxh5 Qe8 20. Qg4+ Kf7 
21. Nh4 Rg8 22. Qh5+ Kf8 23. Qh6+ Kf7 24. Bh5+ 1-0 

In the above file, we can see that some of the text is written inside square brackets. These square brackets are called tag pairs. The content inside a tag pair gives us basic information about the game and the players playing it. For example, tag pairs tell us the username of each player, the date on which the game was played, the time format of the game, which player won the game, etc. 

We can also see the text without square brackets. This text represents the moves played by each player. The numbers 1., 2., 3., etc. denote the move numbers. The text d4, Nf6, Bh+, etc. is the standard way of denoting the movement of a piece on the chessboard. Text 1-0  written at the end of the file denotes that white has won the game. 0-1 means that black has won, and 1/2-1/2 means that the game was a draw. 

In this article, we are going to see how to extract data from PGN Files using the chess library in Python.

With the help of the chess library in python, we can perform several operations like validating a move, extracting data, and even making moves on the chessboard. In this article, we will extract data from a PGN file or a PGN string using the python-chess library.

Installing the library: Enter the following command in the command prompt.

pip install chess