Rumi told her daughter that she met Youji for the first time in Hawaii, but this was a lie to keep Miki unaware of her past. Rumi dated Youji during college, but had a falling out and married Jin, one of her best friends, on the rebound.


Koishikawa Rumi is Miki's mother. She is originally married to Jin, but divorces him and marries Matsuura Youji, Yuu's father. Rumi is a working mom who always has an immaculately groomed, professonial appearance. She loves her daughter, but doesn't focus on her needs as much as other mother's do. She cannot cook and is constantly reminded by her daughter of that lack. Like her daughter, she is athletic and was a member of the tennis and ski circle in college.