Chessbook is a dedicated opening repertoire app that helps players build and memorize a complete opening system. You choose an Elo range and Chessbook selects the lines most likely to be played against you at that level, focusing your study time on what actually matters for your rating band rather than rare grandmaster sidelines.

The spaced repetition engine tracks which lines you know well and which you forget, automatically scheduling reviews at the right intervals. As you improve, Chessbook updates recommendations to reflect the openings played at your new level. A built-in game analyzer can also compare your games against your repertoire to identify where you deviated.

Chessbook is free for a limited number of moves per day; a subscription unlocks unlimited training. It is available on iOS, Android, and web. The focus on practical relevance by Elo band makes it particularly useful for club players who want an efficient opening system without getting lost in deep theoretical lines.