A noppera-bō (のっぺら坊), or "faceless ghost," is a legendary Japanese creature.
Its appearance is that of a normal human being, except for its face, from which it can make the usual features, eyes, nose and mouth disappear at will, leaving only a smooth expanse of skin in their place.
As a rule, they frighten people by suddenly revealing their strange faces, in order to accentuate the surprise effect.
Although the reasons for this behavior are not always clear, the most likely ones seem to be the desire to play a trick or to punish their victim.
Noppera-bō usually impersonate someone their victim would not initially distrust, such as someone they know, or a young girl.
Afterwards, when the person is close enough to them, they rub their faces to erase their facial attributes and cause panic. Despite this, noppera-bō are not known to physically harm people.
They are sometimes - mistakenly - called mujina; this is an ancient Japanese word for raccoon dog (tanuki).
Although in Japanese folklore the mujina can take the form of other creatures including the noppera-bō to scare people, the real noppera-bō are usually human.
Lafcadio Hearn, in his collection of ghost stories, Kwaidan, uses the term mujina as the title of the legend dealing with these faceless creatures. This is probably the source of the misuse of this terminology.
There are a few tales featuring the noppera-bō, such as one in which a young woman is saved from a band of bandits by a samurai whose face disappears; or, stories of nobles who, going out on a date, discover that the courtesan they have in their sights is actually a noppera-bō.
The two main stories in this regard are: The Noppera-bō and the Koi Pond and The Mujina of Akasaka Road.
This tale tells the adventure of a lazy fisherman who decides to fish in the imperial koi ponds near Heiankyo Palace.
Despite his wife's warning that the pond is sacred and located near a cemetery, the fisherman goes there anyway. On the way to the pond, another fisherman also warns him not to go there; again, he ignores the warning.
When he arrived, a beautiful young woman came to meet him and implored him not to fish in the pond. He ignores her too and then, horrified, suddenly realizes that she has just erased the features of his face.
Running to his home, he runs into his wife, at least he thinks so, before she herself reprimands him for his ungodly act and erases his facial features.
The most famous story about the noppera-bō comes from Lafcadio Hearn's book, Kwaidan, or Stories and Studies of Strange Things.
It tells the story of an old merchant traveling along the road from Akasaka to Edo (now Tokyo), who happens to meet a young woman crying her eyes out near a ditch on Kii-mo-kumi-zaka Hill.
The old man, after trying in vain to console her and help her, sees that she turns her completely smooth face towards him; frightened, the man starts to run with long strides without ever looking back, until he stumbles, out of breath, on an itinerant soba seller.
Trying to recover from his emotions and explain his terrible adventure to the man, the old merchant is at the height of his horror when he sees the soba vendor, his last chance, rubbing his face to change into a noppera-bō in turn.