Legal move trees
Every main line and variation must be readable from its starting position. If a token is rejected, cleaned output is withheld.
Free browser tool
Validate and clean a chess PGN
Paste one game or a multi-game file. ChessDesk checks its move trees, structure and standard headers, then produces normalized PGN only when it can do so without guessing.
Validation runs in this browser. The selected file is read locally and is not uploaded.
Checks and limits
A validator, not an automatic game rewriter
Headers and structure
Malformed tag pairs, unbalanced comments or variations, invalid result values and missing standard headers are surfaced separately.
Conservative normalization
Spacing and SAN are standardized. Unsupported embedded commands block output instead of disappearing without notice.
Four synthetic PGN files
Why won't this PGN import?
Download a broken file and its corrected version, then open each in the validator above. These examples contain fictional games and one deliberate problem each. When the source location is certain, the validator reports line and column. Correct the source, then validate again. The tool never guesses a replacement for a move.
Result disagrees
The Result header says 1-0 but the final token says 0-1. The author must choose which result is true; this sample aligns the final token with the header.
Comment does not close
A missing } hides the rest of the move text. The corrected file closes the comment before Black's move.
Illegal bishop move
After 1. e4 e5, 2. Bh6 is not legal. The corrected file uses the legal 2. Nf3 as an illustrative human choice, not an automatic repair.
Coordinate notation in a PGN
e2e4 is a coordinate move, not SAN. The corrected PGN uses e4. Use the notation converter when the source uses another move format.
Spacing, standard headers and parsed comments can be normalized. Illegal moves, unsupported commands and ambiguous results need a human decision. Once validation succeeds, use “Review the validated game” in the tool to carry this exact PGN into Game Review.
Next step
Use the validated game
A clean PGN can move directly into analysis, a private Study or your notation workflow.
FAQ
PGN validation questions
What does the PGN validator check?
It parses every game, checks whether the move tree can be read legally, flags malformed structure and reviews the standard PGN headers. It also warns when an embedded command cannot be preserved safely.
Does the cleaner repair illegal chess moves?
No. An illegal or unreadable move is reported and normalized output is withheld. Guessing a replacement could change the game, so ChessDesk does not make that ambiguous repair.
What does PGN normalization change?
It standardizes line endings, spacing, header layout and SAN formatting. Missing Seven Tag Roster fields receive PGN placeholder values. Parsed variations, comments, NAG symbols and supported board shapes are retained.
Is my PGN file uploaded?
No. Pasted text and selected PGN files are processed in your browser. The tool does not need a ChessDesk account.