Noh mask is a wooden mask used by a “shite”, or lead actor, in Noh Theater, a Japanese traditional performing art.
Noh mask has countless varieties and the most appropriate mask is used depending on the role and scene in a play.
There are five categories of Noh masks: fierce gods, the elderly, men, women and spirits. Yase-onnna , or thin women, belongs to the spirits category.  
Boney cheeks with deeply caved eye sockets and dead eyes with no expression. She is a spirit that goes back and forth between the present world and the afterlife. Yet, she is adorned with lip stick. The mask horrifically embodies a woman’s obsession with her delusional love even after her death. The mask also shows the sorrow of the woman who died while waiting for her husband to come home. Yase-onna mask articulates these conflicting feelings so well that some Noh mask makers become captivated by the Yase-onna mask and use them to study and refine their mask making techniques.
It can be said that the look of Yase-onnna mask expresses the aesthetic sense of love’s transience between men and women, passed down from ancient times.