Netsuke

Ivory netsuke. Figure with tortoiseshell on the back. In the right hand, a mallet. It represents an "oni" (little demon). Piece used to attach the inro (box of herbs) to the kimono belt.
The netsuke is a small carved ornament, used attached to a cord and affixed to an inro or to a smoke box, to prevent them from opening. The netsuke could also be a seal, coat of arms, abacus or sundial.