This netsuke features several miniature masks carved from ivory. The seven masks, connected to each other somewhat haphazardly, represent oni (demons): some have horns and fangs, for example, while most of them have somewhat grotesque expressions and features. Some of the masks have mother-of-pearl eyes (one has lost its mother-of-pearl inserts) and black-painted hair, eyebrows, and/or beards.
Oni, a kind of yokai (supernatural creature) from Japanese folklore, are considered to be creatures similar to demons, ogres, and trolls. Oni are very often represented in visual art, literature, theater, and popular culture in Japan. Oni may take varying forms, but fairly consistently are large and grotesque creatures with claws and horns. They have human-like bodies but are often red or blue and may have extra eyes or fingers. They are usually shown wearing loincloths and carrying clubs (their weapon of choice). Oni are known for being exceptionally strong.