He has short hair and wears a judo uniform.
He doesn't like kids.
Since long ago, he’s been practicing Judo using a mat tied to a maple tree’s trunk at a Child Welfare Center.
He sought Rinne's help, when he mysteriously got tiny leaf prints over his right leg and face and suffered a wrong reputation of having been cursed for bullying kids. The cause is revealed to be the Maple Tree’s spirit having gone mad for receiving low kicks for years. Sanjirou tried to apologize, but the spirit challenged him in hope of satisfying his rage, only to be instantly defeated and so accepted to forgive Sanjirou. The leaves returned to the maple tree, and Sanjirou would stop his practice on it.
- He practically has the same name of a legendary judo fighter from a movie by Akira Kurosawa called Sanshirō Sugata, although the Kanjis are different “姿三四郎”.