Yōkai (妖怪, ghost, phantom, strange apparition) are a class of supernatural monsters in Japanese folklore. The word yōkai is made up of the kanji for "bewitching; attractive; calamity" and "apparition; mystery; suspicious". They can also be called ayakashi (妖), mononoke (物の怪), obake (お化け), bakemono (化け物) or mamono (魔物). Yōkai range eclectically from the malevolent to the mischievous, or occasionally bring good fortune to those who encounter them. Often they possess animal features (such as the Kappa, which is similar to a turtle, or the Tengu which has wings), other times they can appear mostly human, some look like inanimate objects and others have no discernible shape. Yōkai usually have a spiritual supernatural power, with shapeshifting being one of the most common.
Japanese folklorists and historians use yōkai as "supernatural or unaccountable phenomena to their informants". In the Edo period, many artists, such as Toriyama Sekien, created yōkai inspired by folklore or their own ideas, and in the present, several yōkai created by them (e.g. Kameosa and Amikiri, see below) are wrongly considered as being of legendary origin.
Types
There are a wide variety of yōkai in Japanese folklore. In general, yōkai is a broad term, and can be used to encompass virtually all monsters and supernatural beings, even including creatures from European folklore on occasion (e.g., the English bugbear is often included in Japanese folklore to the point that some mistakenly believe it originates from said folklore).
Main types
The types of yōkai according to the folklorist Tsutomu Ema's yōkai's "true form" division.
Human form
Main article: Human form
There are a large number of yōkai who were originally ordinary human beings, transformed into something horrific and grotesque usually during an extremely emotional state. Women suffering from intense jealousy, for example, were thought to transform into the female oni represented by hannya masks. This category includes the yūrei group and other similar human-derived creatures.
Animal form
Main aticle: Animal form
Many indigenous Japanese animals are thought to have magical qualities. This category may also be referred to as kaiju - animals or insects with mysterious and magical powers. Most of these are henge (変化), which are shapeshifters (obake, bakemono) that often appear in human form, mostly women.
Plant form
Main aticle: Plant form
This category includes all yōkai related to flora.
Object form
Main article: Object form
The creatures related to all kinds of objects, also known as tsukumogami, are an entire class of yōkai, comprising ordinary household items that have come to life on the one-hundredth anniversary of their birthday.
Natural phenomenon
Main article: Natural phenomenon
This category includes all yōkai related to natural phenomena, i.e. all yokai related to the weather, for example.
Additional types
In addition to the ones mentioned above, there are also several types of Japanese creatures that absolutely should be mentioned.
Oni
Main article: Oni
One of the most well-known aspects of Japanese folklore is the oni, which has traits of demons and ogres, usually depicted with red, blue, brown or black skin, two horns on its head, a wide mouth filled with fangs, and wearing nothing but a tigerskin loincloth. It often carries an iron kanabo or a giant sword. Oni are depicted as evil.
Tengu
Main article: Tengu
A goblin from Japanese mythology that has several supernatural powers and skills in martial arts, the tengu were originally extremely dangerous demons and enemies of Buddhism. Over centuries, their behavior changed from spirits of the damned to active defenders of Dharma.
Kami
Main article: Kami
Kami are the deities, divinities, spirits, phenomena or "holy powers" that are venerated in the Shinto religion. They can be elements of the landscape, forces of nature, or beings and the qualities that these beings express; they can also be the spirits of venerated dead people.
Unknown
Some yōkai are extremely specific in their habits. This category includes all other yōkai that cannot be simply categorized.