Noh is the classical theatre of Japan which was codified in the 14th century under the father and son actors Kan'ami and Zeami under the patronage of the Shogun (supreme military leader) Ashikaga Yoshimitsu; the plays frequently utilise masks and the actors wear fine robes.

This is the demonic Noh mask of Ko-Beshimi (Small Compressed Lips). Masks of this character are used to portray sorrowful demons in plays such as Nomori and Ukai. The mask was carved from a thick piece of wood to which a thin layer of gesso (J. gofun) has been applied. Most of the pronounced features have been created through the initial carving, and the gofun acts mostly as the medium to which the red painting of the face has been applied. The brow is perhaps less pronounced than is usual, but nevertheless the overall carving represents a powerful image of this malicious demon. The broad forehead with flat top is creased by wrinkles caused by the furrowing of the brows. The sides of the eyebrows stand out as if the veins at this point of the head are throbbing with anger.

The eyes, now lacking the gilt metal disks common on demon masks, are almost human and do not protrude. The interior of the mask is in a natural wood finish, but has attained an elegant patina of age and wear. The chisel marks are firm, but let the natural grain of the wood show through to good effect. The cord holes show considerable wear on the inside of the mask, although the holes may have been deliberately cut away at an angle to allow the cords to fit into a recess. The outer edges of the cord holes show signs of rubbing by the silk cords, indicating that the mask has been frequently used in performance.