OpeningBook

OpeningBook is a clean, offline reference and trainer for chess openings. BROWSE EVERYTHING • Thousands of named openings and variations, organized by ECO volume (A–E), family, and line — sourced from the open Lichess openings database. • Step through any line move-by-move on a real, playable board. • Read key ideas and classic traps for the major openings. SEARCH & FILTER • Find any opening by name, ECO code, or move sequence. • Filter by line length with a simple move-count slider. TRAIN YOUR REPERTOIRE • Add lines to your training set as White or Black. • Drill them in a play-your-side-vs-app loop. • Spaced repetition brings each line back for review at the right time. 100% offline. No account, no ads, no tracking.