Check the PGN tree
Start with represented replies that have no answer. These are deterministic holes in the material you pasted.
Variations in parentheses are audited as branches. For multi-game PGN files, this first version checks the first game only.
How to use the result
Audit, fill the gaps, then keep the work
Review common replies
Use the explorer-backed list when available. Frequencies come from the selected Lichess rating band, not an engine guess.
Build and save
Add branches in the repertoire builder, inspect positions in Explorer, or keep annotated lesson material in a Study.
FAQ
Repertoire coverage questions
What does the repertoire coverage checker analyze?
It reads the first game in your PGN, including its variations. It counts the opponent reply points represented in the tree and shows any included opponent reply that has no following repertoire move.
How does Chessdesk find common missing replies?
When opening explorer data is available, Chessdesk compares the moves in your PGN with real Lichess player data for the selected rating band. It flags an absent reply only when that move appears in at least 5% of games at the exact position.
What happens if opening frequency data is unavailable?
The deterministic branch audit still runs for the complete PGN tree. Chessdesk does not call any unlisted move common without explorer evidence, so the frequency section clearly reports that live data was unavailable.
Can the checker read PGN variations?
Yes. Standard PGN variations in parentheses are preserved by the parser and audited as separate branches. If the file contains several games, this version checks the first game only.
Is the opening repertoire coverage checker free?
Yes. You can paste and audit a PGN without creating an account. Use the free Opening Repertoire Builder to add branches, then create an account if you want to save and train a repertoire.