Hannya demon mask
“Hannya” is the Japanese rendition of the Sanskrit word prajna—wisdom—as in the name of the Heart of Wisdom Sutra, or Hannya Shingyō. But when you say Hannya in Japan, people usually think of the demon mask from Noh theater. The character Hannya represents a jealous and vindictive woman.
The connection between the sutra and the mask may come from the scene in the Tale of Genji.
in which Genji’s wife Aoi is possessed by the living spirit of the Rokujō Lady. The Hannya Shingyō is chanted to exorcise the spirit.