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Find the opening moves that cost you points

Read your games, compare every repeated opening decision against a Lichess-derived opening book and a Stockfish evaluation, and turn what it finds into drills.

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Engine & data

Bundled engine

Stockfish is GPLv3 and ships as a binary in chessopening/bin/; source at official-stockfish/Stockfish.

Opening book

Built from monthly dumps at database.lichess.org (CC0), with ECO names from lichess-org/chess-openings (CC0). Rebuild any month with tools/build_local_db.py.

How a finding is ranked

What each flag means

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    Where your games go