With an iPhone or iPad, there are a chess tutor and six sparring partners stay with you in the PVChess APP. Based on Stockfish Artificial Intelligence Engine, the tutor is a world-champion level mentor. Beginners can follow his hint to learn how to play as an expert step by step. Intermediate players may switch hint off firstly, think your move, then switch hint on to compare. Please challenge the highest level sparring partner without tutor hints when you are ready, he is almost world-champion level too. Any game you played could be saved for later review and analysis. Here you can read classical chess tutor books with animated chess board, and practice with AI tutor about ending-game, middle-game and opening-game. Let's take a picture to setup your king face and start learning now! Notes: - If you shake phone after a tutor's hint step showed, the step will move automatically. - To make Castling happen, please move the king two squares towards a rook, then the APP will move the rook to the square over which the king crossed automatically.