Legal move trees
Every main line and variation must be readable from its starting position. If a token is rejected, cleaned output is withheld.
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.
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.