This is a great question. Some context is important to answer this question.
At the beginning of the story, Meimei's (Waverly's) mother taught her the art of invisible strength. This was to win arguments and respect from others. Meimei's mother was teaching her life lessons.
As the story progresses, Meimei learned to play chess. She not only liked it, but also excelled at it. She easily beat her bothers and she began entering tournaments. She excelled there as well. At one point, she even gained national recognition, as a promising young chess player.
Meimei's mother was very proud of her, and as they went to the market, she would boast of her daughter's achievements. This made Meimei uncomfortable, until she confronted her mother and ran away for a few hours. When she returned home, she know that she would have to deal with her mother. Fear gripped her heart. She went into her room and realized that she was in a chess game with her mother and teacher. Her mother was her new adversary. The story ends with a chess analogy to show this point.
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. As her men drew closer to my edge, I felt myself growing light. I rose up into the air and flew out the window. Higher and higher, above the alley, over the tops of tiled roofs, where I was gathered up by the wind and pushed up toward the night sky until everything below me disappeared and I was alone. I closed my eyes and pondered my next move.