A kumiho or gumiho (Korean: 구미호; Hanja: 九尾狐, literally "nine-tailed fox") is a creature that appears in the folktales of East Asia and legends of Korea.
The old Chinese text Classic of Mountains and Seas, the earliest record to document the nine-tailed fox, mentioned that the fox with nine tails came from and lived in the country called Qingqiu three hundreds miles east, the term meaning "green hill" interpreted as the country or region of the east and was later historically used to refer to the region of Korea at least since the era during the Three Kingdoms of Korea.
[citation needed] In later literature, kumiho were often depicted as bloodthirsty half-fox, half-human creatures that wandered cemeteries at night, digging human hearts out from graves.
Bakh Mun-su and the Kumiho (박문수와 구미호) records an encounter that Pak Munsu has with a girl, living alone in the woods, that has a foxy appearance.
One version of the mythology, however, holds that with enough will, a kumiho could further ascend from its yogoe (spirit) state, become permanently human and lose its evil character.
Explanations of how this could be achieved vary, but sometimes include aspects such as refraining from killing or tasting meat for a thousand years, or obtaining a cintamani and making sure that the Yeoiju saw the full moon at least every month during the ordeal.