This mask was used in the noh play Yamanba. The Yamanba of the title is a female demon who lives alone deep in the mountain. She looks for flowers in spring, longs for the moon in autumn, and invites snow in winter. She walks around the mountains, but cannot escape her deep delusions. The play is a profound look at the suffering of Yamanba living in the midst of nature.
This mask has a very strong expression and is rare because it shows the gums of the Yamanba’s teeth. The Yamanba masks by carvers such Yamato Sarugaku Yoza, Kanze, Konparu, Hosho, and Kongo are not this strange in appearance. During the Meiji era, this mask was in the possession of the Umewaka family of noh performers. At the time, it was used for the role of a shinja (or han'nya, a type of demon). There are no traces of horns, but copper nails from tusks attached to the left and right ends of the upper teeth are still present. However, there are traces of implantation holes between the nose and mouth and on the chin, and an X-ray CT study shows traces of implantation holes on the head as well.
It may have been created initially as an akujō (female demon). Negoroji temple in Wakayama prefecture has an akujō mask similar to this one. However, since akujō masks typically do not have hair, it may have been carved before this kind of noh masks became more standardized, a kind that no longer existing today.
The carvings are deep and strong, which suggests that the mask is from the Nanbokuchō period when noh masks started being made. The text "shinja by Shakuzuru" is written on an accompanying document. The noh playwright and performer Zeami called this mask "a demon mask masterpiece," and although the author of this mask is unknown, it is one of the most famous noh masks ever made.