also: イヨマンテ
Iomante; Ainu bear-sending ceremony
A traditional Ainu ritual in which a brown bear cub is raised for about two years and then sacrificed to send its spirit back to the divine world. The term is a cultural proper noun; used mainly in ethnographic or historical contexts.
from Ainu
Iomante is one of the most important ceremonies of the Ainu.
At this museum, you can see an exhibit recreating the Iomante ceremony.