Naoko is Ran Yahiro's mother. Nao had an affair and divorced Ran's father when she was a young child. After that event, she ceased all communication with Ran. Ran resents her for this but in her shigofumi it is revealed that she actively followed Ran's tennis career throughout her life and cheered her on from the sidelines. Ran makes her peace with her mother post-humously after finding this out.