Mari Yaguchi (矢口 真里, Yaguchi Mari?, born January 20, 1983 in Kanagawa, Japan) is a member of the Hello! Project and former member and leader of Morning Musume. She was a member of Tanpopo, one of the first sub groups, and also founded Minimoni, was leader of Morning Musume Sakuragumi when Natsumi Abe graduated and ZYX, and was in Romans..