An Ojimi is a bead that serves as a fastener on the cord of an inro box.  It serves as a locking system.   It is often carved into an animal or other object.  It is typically smaller than an inch  but with great detail.   Traditionally ojime beads, netsuke, and  inrō boxes would be items worn on a traditional kimono. They are also treasures as tiny works of art.  This amazingly detailed carved basket is home to several little mice.

Folk Art from japan