The hannya (般若) is a mask used in a traditional Japanese Noh theater, representing a jealous female demon. It is characterized by two sharp bull-like horns, metallic eyes, and a leering mouth.[1] In Noh plays, the type of mask changes according to the degree of jealousy, resentment, and anger of the female characters. The hannya is a mask that represents a female onryō (怨霊, vengeful spirit) even more resentful, jealous, and angry than the namanari (生成), a woman on the verge of becoming a demoness.[