OpeningTree is a chess openings book that allows users to explore the tree of openings and analyze them using the Crafty engine. With the ability to load chess games for comparison or viewing purposes, users can also make their own side line moves and easily return to the main line. The opening book is compiled from 345,000 high-rated games from recent years, with both players rated 2300 and above. By simply touching moves in the list or making moves on the board, users can see the response and the numbers next to the moves indicate the win-draw-loss statistics. OpeningTree aims to provide users with a comprehensive understanding of opening positions, starting with the full tree rather than selecting a specific opening to study. The app also offers Crafty engine analysis, allowing users to view the openings move table or analyze the position. Additionally, the app is accessible to the blind and visually impaired using Voice Over, making it inclusive for all users. With its various features and user-friendly interface, OpeningTree is a valuable tool for chess enthusiasts of all skill levels.