OpeningBook is a clean, offline reference and trainer for chess openings — browse thousands of named openings, search and filter them, step through lines on a real board, and drill your repertoire with spaced repetition.
Questions, bug reports, or feedback? Email zhenghongpengcs@gmail.com and we'll get back to you.
Is the app offline? Yes. All opening data is bundled; the app makes no network requests and requires no account.
How do I unlock Training? Open the Train tab and complete the one-time in-app purchase. It's yours forever.
I bought Training but it's locked. On the Train tab tap Restore Purchases, or email us above.
OpeningBook collects no personal data. See the full Privacy Policy.