What is implied in the short story is that Waverly learned a lot from her mother, but she has not learned enough to beat her. In other words, the student has not exceeded the master.
In the opening words of the story, Waverly says that her mother taught her the art of invisible strength. It was an art to win in life.
I was six when my mother taught me the art of invisible strength. It was a strategy for winning arguments, respect from others, and eventually, though neither of us knew it at the time, chess games.
Waverly learned this lesson well. In fact, she learned this lesson so well that she became nearly a master in chess. She certainly gained national recognition. With this new confidence, Waverly challenged her mother. When he mother bragged about her success in chess, she resented it and ran away. When Waverly finally came home, she knew that she was in trouble. A chess game with her mother had started. More importantly, Waverly was losing.
This is how the story ends:
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.