I assume you are referring to Waverly's first chess game that she plays in a tournament. It is clear that as she goes up to play the fifteen-year-old boy from Oakland who is her opponent, Waverly is nervous, however, when she starts playing, she very quickly loses all of her nerves:
As I began to play, the boy disappeared, the colour 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.
It is typical of Amy Tan's style that she occasionally inserts lyrical passages like this one that show the imagination of her main character. The next paragraph describes how this wind gives Waverly strategies which she uses to win the match. The wind could be said to represent quiet strength or strategy to the narrator, but it also follows Waverly's own earlier comments about how it is important to keep your opponent guessing, distracting them and avoiding their traps.