(b) / Date unknown / Rota Island (Northern Mariana Islands) / Shell implement / Anthropology and Prehistory department, UMUT

The exhibited materials are adze bits made from large Tridacna shells. These were collected from Rota Island of the Northern Mariana Islands as a part of the 1910-30s anthropological expeditions of the University of Tokyo. The adze bits are made from the shell bodies, a style characteristic of the Mariana Islands region. In prehistoric Japan, a different style of shell adzes is known from the southernmost Ryukyu Islands.