In Japanese folklore, the hitotsume-kozō is a one-eyed yōkai traditionally depicted as a young monk with a single eye.
The name combines hitotsume, meaning “one eye,” with kozō, a term for a young Buddhist acolyte or boy attendant. He is commonly shown with one large eye in the middle of his face and a shaved head, wearing simple monk-like clothing.
Hitotsume-kozō is generally portrayed as more mischievous or startling than physically violent. Stories and images often use his unexpected appearance to frighten people. His visual form reflects a recurring feature of yōkai art: familiar social types, such as children or monks, are transformed by one uncanny feature.
He is sometimes confused with other one-eyed beings or with the karakasa-kozō, an umbrella yōkai that usually has one eye and one leg. The names and images are distinct. Hitotsume-kozō’s defining combination is the single eye and the young monk-like body.