Sweet Blue Flowers: Chizu Hanashiro, Kuri Sugimoto, Sakiko Okudaira, and Yoshie Manjoume.

 Chizu was Fumi's first love, but after college Chizu got married breaking Fumi's heart.  Fumi fake an illness to avoid going to her wedding.

Kuri is one of the Sugimoto sisters, she has a blunt personality and smokes.  Back in high school she was very popular and had a crush on Kasusa's fiancé. 

Sakiko is Akira and Shinobu's mother.  She can get excited easily and often has to deal with Shinobu's over protection of his sister. 

Yoshie is Fumi's  mother and is friends with Sakiko.