Sanbanme came from a respectable middle-class family in a small town. He grew up sturdy but rough, leading playmates in mock fights with other local boy gangs. When he grew old enough, his family tried to use him as a rent collector, but he frightened the tenants so much they left. His family decided to send him to the Eastern Pagoda, a monastery famous for training sohei. The novice master trained him severely and despite taking numerous blows he did show signs of learning, but finally he struck down the prior of a neighboring rival monastery who was trying to collect dues from peasants claimed by the Eastern Pagoda. The prior did eventually regain consciousness, but Sanbanme's master sent him out "to be buffeted by the world for a while" and learn to control his temper.

He is 5'8" tall, a little above average, and strongly built. His face was never pretty and now shows marks of having been hit repeatedly by hard objects, as do his arms and hands. His head was once shaved but shows signs of hair growing out in irregular patches. He wears leather armor and carries a tetsubo (iron-shod staff) with a jo stick up his sleeve. He wears plain peasant garb, a plain cotton robe, sandals, a straw hat and when needed a straw raincoat.
He carries his prayer beads and recites his prayers whenever he remembers to.