foxes and human beings lived close together in ancient japan; this companionship gave rise to legends.
kitsune is the japanese word for fox. it is often translated as fox spirit as it is believed all long-lived foxes gain supernatural abilities, magical powers as well as superior intelligence.
a kitsune may take human form, an ability learned when it reaches a certain age—usually 100 years. as a common prerequisite for the transformation, the fox must place reeds, a broad leaf, or a skull over its head.
foxes are particularly renowned for impersonating beautiful women. common belief in medieval japan was that any woman encountered alone, especially at dusk or night, could be a fox.
kitsunetsuki literally means the state of being possessed by a fox. the victim is always a young woman, whom the fox enters from beneath her fingernails or through her breasts.
folklorist lafcadio hearn describes the condition in his Glimpses of Unfamiliar Japan:
strange is the madness of those into whom demon foxes enter. possessed folk are said to speak and write languages of which they were totally ignorant prior to possession. they eat only what foxes are believed to like — tofu, aburagé, azukimeshi.
in medicine, kitsunetsuki is a culture-bound syndrome unique to japanese culture. symptoms include cravings for rice or sweet red beans, listlessness, restlessness, and aversion to eye contact. kitsunetsuki is similar to but not distinct from clinical lycanthropy.