Chiharu is a 15 year old student who just started attending Zashono Academy.
Chiharu is an innocent girl who has a slightly romantic relationship with Densuke. They both like each other but are embarrassed to show it.
She is the eldest of her six siblings; unlike most of the other members of her family she is much more conserved. She gets embarassed when males and especially Densuke look at her, which she thinks they are staring at her chest, and tends to cover herself with an arm and shy away which tends to ironically make her admirers find her more appealing.
Her bust size grows rapidly through the manga and the anime from the original 88cm to over 100cm, it was said by her mother Keiko Shinonome that her own bust was the same size as Chiharu's when she was that age, so it may be possible Chiharu will stop growing around her mother's size of 123cm, or even surpass that.
In the OAV she is voiced by Miwa Ohshiro in Japanese and Becky Chiang in English.