Yokai Encyclopedia: Japanese Yokai & Kami

What is a yokai?

Yokai (妖怪) is the Japanese word for the strange: shape-shifting animals, haunted objects, monsters of the mountains and the sea, and the eerie happenings people blamed on them. The folklorist Michael Dylan Foster describes yokai as something that resists any neat definition — the word can cover a startling sound in an empty room as easily as a creature with a name and a face. In everyday Japanese you will also hear obake or bakemono, "things that change", older and more casual words for much the same territory.

Yokai overlap with, but are not the same as, two neighbouring ideas. Kami are the gods and sacred powers of Shinto, honoured at shrines (see our guide to the Japanese gods) — though the line is porous: a yokai that is worshipped can become a kami, and a neglected or angry kami can behave like a yokai. Yūrei are ghosts, the spirits of particular dead people, often bound to the place or person tied to their death. Most yokai are nobody's ghost.

Their history is long. Oni, foxes and serpents fill the tale collections of the Heian period (11th–12th centuries). In the Edo period, artists such as Toriyama Sekien — whose Gazu Hyakki Yagyō appeared in 1776 — catalogued them in illustrated encyclopedias, and after the Second World War the manga artist Mizuki Shigeru brought them back to life for a new generation in GeGeGe no Kitarō.

Types of yokai

Japanese folklore has no official taxonomy; scholars and illustrators have sorted yokai by where they appear (mountain, water, house, road) or by what they began as. The filters in this encyclopedia follow the second approach:

Deities — kami and Buddhist-derived gods such as Amaterasu, Raijin, Fūjin and the Seven Lucky Gods: worshipped rather than feared, though some are fearsome. Dragons — serpent and dragon beings, from the sea god Ryūjin and the eight-headed Orochi to women transformed into great serpents, like Kiyohime of Dōjōji. Demons — oni and their kin, such as Shuten-dōji, the Hannya and the earth-spider Tsuchigumo: the monsters heroes fight. Spirits — ghosts and apparitions, from classical yūrei to modern urban legends like Kuchisake-onna and Hanako-san, proof that new yokai are still being born.

Animal yokai — real creatures with uncanny powers: foxes, tanuki, cats and dogs were thought to gain the power to shape-shift or possess people as they grew old. Nature spirits — spirits of a place or force: tree spirits, mountain crones, sea giants and whirlwind weasels. Household yokai — the yokai of the home: tsukumogami (objects that come alive after a hundred years), lucky house spirits like Zashiki-warashi, and pests like the bathroom-licking Akaname.

These boxes overlap — a cat yokai haunts a house, a fox can become a god's messenger — and many of the creatures pictured by Edo artists had no stories at all until later writers supplied them. Every entry below links to its own page, with its origins, its place in Japanese culture, and the sources behind it.