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· 4 min read
How to Replay a Chess Game From PGN
Heshan Fernando
Co-founder & COO
Someone sends you a game as a block of text: tag headers in square brackets, then a list of moves in algebraic notation with numbers and occasional exclamation marks.
That’s PGN, it’s the universal chess interchange format, and reading it on a board rather than on the page is the difference between a list of moves and a game.
What’s in a PGN
Tag pairs at the top: event, site, date, players, result, and often the players’ ratings and the opening’s ECO code. Seven of these are standard; software adds more.
Movetext: the moves in standard algebraic notation, with move numbers.
Annotations, where present:
!good move,!!excellent,?mistake,??blunder,!?interesting,?!dubious- Text comments in braces
- Variations in parentheses — alternative lines showing what could have been played
Result at the end: 1-0, 0-1, or 1/2-1/2.
The variations are the most valuable part of a well-annotated game and the part a plain text reading loses entirely. Nested parentheses several levels deep are unreadable as text and perfectly clear on a board you can step through.
Read before you engine
The temptation with any game is to run an engine over it immediately and get a numeric evaluation of every move.
There’s a good argument for not doing that first.
Stepping through a game and forming your own view — where did the position turn, what was the plan, why did that piece end up badly placed — is the part that builds understanding. An engine gives you the answer and skips the thinking, and the thinking is what transfers to your own games.
Read it, form a view, then check with an engine. The moments where you disagree are where the learning is.
An annotated game from a strong player is better still, because the annotations explain why in words rather than in centipawns. An engine says −1.4; an annotator says “the knight has no squares and Black’s plan of doubling on the c-file is unstoppable”. Only one of those helps you next time.
| Element | Value |
|---|---|
| Moves | The game |
| Variations | What was considered and rejected |
| Text comments | The reasoning |
| Engine evaluation | The verdict — read it last |
Flip the board
Small feature, disproportionate value. Viewing a game from the side you were playing makes your own mistakes far more legible, because the position looks the way it looked at the time.
Reviewing your own loss from White’s perspective when you played Black is a genuinely different experience from reviewing it the right way round.
Common mistakes to avoid
- Reading PGN as text and skipping the variations.
- Running an engine before forming a view.
- Reviewing only losses. Wins contain mistakes that happened to go unpunished, and those are the ones that will cost you later.
- Ignoring the tag headers, which include the time control — a blitz blunder and a classical blunder mean different things.
- Studying master games without annotations, where the moves are correct and the reasons are invisible.
How to do it with Chess PGN Viewer
The Chess PGN Viewer steps through the game with variations and comments.
- Paste the PGN, including the tag headers.
- Step through move by move rather than jumping to the end.
- Follow the variations where the annotator marked alternatives.
- Flip the board to view from the side you played.
Other games are in the tools directory.
Frequently asked questions
What is PGN?
Portable Game Notation — a plain-text standard for recording chess games, with tag headers followed by moves in algebraic notation. Almost every chess program reads and writes it.
Can it analyse the game?
No. It replays what the notation records. Analysis needs an engine, and reading a game without one first is arguably better practice — you form your own view before the engine gives you its.
What are variations in a PGN?
Alternative lines recorded in brackets, showing what could have been played instead. Annotators use them to explain why a move was chosen, and they’re the most useful part of a well-annotated game.
Final thought
Step through it once with the engine closed. Your own view of where the game turned is worth more than an evaluation bar, and you only get it by looking first.