Regarding Takeshita Chiaki, if she is an actress or involved in the series OBA-107, finding her profile on Japanese entertainment databases or her filmography could provide more insights into her work and possibly cross-reference it with the drama series you're interested in.
Chiaki Takeshita is a recognized figure in the JAV industry, often appearing in "drama-style" adult entertainment. OBA-107 Takeshita Chiaki JAV CENSORED
Disclaimer: This article is for informational and academic discussion of niche film genres. Viewer discretion is advised regarding adult content. All models featured in referenced works are of legal age per Japanese production standards. Regarding Takeshita Chiaki, if she is an actress