OpenBook
Free chess opening trainer
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What is OpenBook? ↓Build an opening repertoire. Practice until it sticks.
OpenBook is for chess players who want to improve their opening prep — a repertoire builder and trainer in one. Our goal is to be simple and intuitive. There are two modes:
Mode 1
Build your repertoire
Pick a side, walk through your lines, and let the Lichess opening database show you what real players (at both your rating and at the master level) actually play. Save the moves you want to learn. Then check your prep with one click: find popular opponent moves you haven't answered, and let Stockfish — running right in your browser — flag the moves in your repertoire that give up ground. Once you've played some games, Review Games fetches your recent Lichess or Chess.com games and shows you exactly where each one left your prep — all in your browser, without your games ever touching OpenBook's servers.
Build mode: every move shows real-game statistics at your rating, masters picks (★), and Stockfish's verdict (◆).
Mode 2
Practice your repertoire
Drill your saved lines with spaced repetition so they become second nature. Lines you get wrong come back sooner; lines you've mastered stay out of your way until you need a refresher. Preparing for something specific? Save any part of your repertoire — say, your anti-Sicilian lines — as a named set and focus a session on just those. A few minutes a day keeps your whole repertoire sharp.
Practice mode: your saved lines come back as spaced-repetition drills until they're automatic.
Your repertoire is yours
Already have prep? Import any PGN — a multi-chapter Lichess study, a course export, or a file from another trainer — and it merges into your repertoire, chapter by chapter, variations included. Everything comes back out just as easily: export your lines as a standard PGN that works in any chess app, or download a one-file JSON backup of everything, practice progress included. There's room for 20,000 positions per color. No lock-in is the point.
Pricing
Free, without paid tiers or ads. No account needed to try it — sign in with Lichess whenever you want your repertoire synced across devices.
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