In "Rules of the Game," what is one way that Lau Po helps Waverly?

Shortly after falling in love with the game of chess, Waverly spots a group of old men playing chess in the park and runs home to grab her chess set in hopes of competing against one of them. When Waverly returns to the park, she befriends an old man named Lau Po, who ends up playing her in several games of chess. Despite losing numerous games to Lau Po, Waverly learns many secret tricks and moves by playing with him throughout the summer. As an experienced chess player, Lau Po teaches Waverly various moves like The Double Attack from the East and West Shores and The Surprise from the Sleeping Guard.
In addition to teaching Waverly a myriad of moves, Lau Po also teaches Waverly chess etiquette. Waverly learns to keep captured chess pieces in neat order, remain composed after a loss, and act humble while putting someone in check. By the end of the summer, Lau Po has taught Waverly everything he knew about chess, and she becomes a significantly better player.