According to the family tree, the Tokugawa clan is supposedly descended from Tokuami, a wandering Buddhist priest who married into the Matsudaira clan, which ruled Mikawa Province (present day Aichi Prefecture).
系図によると、ルーツは三河国（愛知県）の在地領主の松平氏に婿養子に入った時宗の遊行僧と伝えられる徳阿弥である。