type of bead used to secure an inro in one's belt

Netsuke is a Japanese miniature sculpture. It appeared in the 17th century. Originally It looked like a hanging keychain on Japanese traditional clothing called kimono. Netsuke was a button fastener on the cords of an inro box.

Netsuke from ivory
Orinigal netsuke

Netsuke is made of various materials: ivory, boxwood, metal, boar tusk, clay and so on.