Chess is a major part of the story. Waverly admits this from the beginning. She says that she applied to chess what her mother taught her, namely, the art of invisible strength, a way to win arguments and respect from people.
As the story progresses, Waverly learns chess and more importantly she excels. At one point, she gains national recognition. Some critics even say that she might be the first female Grandmaster. In one of her matches, she describes her strategy in terms of the art of invisible strength. Here is an excerpt:
As I began to play, the boy disappeared, the color ran out of the room, and I saw only my white pieces and his black ones waiting on the other side. A light wind began blowing past my ears. It whispered secrets only I could hear. "Blow from the South," it murmured. "The wind leaves no trail." I saw a clear path, the traps to avoid.
By the end of the story, Waverly sees her life as a chess game, especially in her relationship with her mother. Waverly increasingly wants independence, but her mother is not ready to let her go. At the end, a conflict ensues. Waverly runs away and when see comes back, she knows that she will have to confront her mother. She lies in bed and contemplates her next move. The way she describes this is through a game of chess.
Her black men advanced across the plane, slowly marching to each successive level as a single unit. My white pieces screamed as they scurried and fell off the board one by one.
Hence, the game of chess frames the story. It is a metaphor about Waverly's life and relationships.