Chiyako told her son that she met Jin for the first time in Hawaii, but this was a lie to keep Yuu unaware of her past. Jin dated Chiyako during college, but had a falling out because she was believed to have an affair with her employer, Miwa Yoshimitsu. She became pregnant with Jin's child, but before she could tell him, he left and married Rumi. Youji, her dear friend, decided he wanted to marry her and be a father to the unborn child. Chiyako lost her baby, but Youji wanted to marry her anyway.

Matsuura Chiyako is Yuu's mother. She is originally married to Youji, but divorces him and marries Koishikawa Jin, Miki's father. Chiyako is a serious mother who cared deeply for her son and for Miki. When Miki felt depressed about not seeming mature enough, Chiyako sensed her depression and brought her some make-up that her company was designing for teens. She has a great rapor with Miki. Unlike Rumi, Chiyako is a terrific cook. She has a checkered past because Yuu discovered a letter from his grandmother stating that Chiyako became pregnant by another man before Yuu was born.