Despite the fact that Japanese oni were born about 1400 years ago and—depending on your belief system—never strictly walked the Earth, you have likely seen an oni demon. It’s a sight not easily forgotten: a fearsome visage colored bright red, blue, pink or white, horned as the western Devil, brows furrowed and teeth bared (or hidden, scowling). If you are up on your Japanese prints, you’ll also know the oni’s trademark tiger-skin loincloth and club, a caveman’s accessories. These devils are well known today primarily because their faces survive as oni masks, dramatic, snarling art worn by performers of Noh, one of the world’s oldest theatre traditions.
Oni were once feared as though they lived down the street. The typical Japanese oni is a shapeshifter. When not disguised as a human or some dust, an oni is an enormous, multicolored, supernatural evil incarnate. He visits misery and death upon those so unfortunate as to cross its path. Because oni are typically showcased in traditional Japanese art forms, it stands to reason that this is a uniquely Japanese oni demon—and in a sense, it is. But this spector has tap roots that reach as far as Sri Lanka and over one thousand years deep, even before Buddhism began to take hold in Japan in the sixth century.
Perhaps the history of the Japanese oni is best told by its family tree, beginning with two figures from Hinduism: the yaksha and rakshasa. The human-eating, cemetery-haunting, shapeshifter rakshasa seem like pretty straightforward ancestors to the Japanese oni. Yaksha, on the other hand, embody a lesser-known, softer side of oni. It is a common misconception that all Japanese oni are evil. (“Not All Oni!” the demons protest!) Yaksha are a complicated forest nymph, occasionally hungry for the wayward traveller.
While oni are typically hideous, fearful agents of chaos, they could bring blessings just as easily as they do devastation. If religion exists as sublime explanation for our mystifying reality, then it makes sense that Japanese oni, born of Hindu, Buddhist, Taoist, and proto-Shinto beliefs, are so powerful that they would contain both good and evil. They were accordingly feared and abhorred, but oni were also worshipped.
The stories and teachings of Buddhism shifted as they passed through China and the Korean Peninsula, but what remained of the yaksha and rakshasa easily folded into the complex universe of Japanese kamisama and mono, sadistic, invisible spirits. Originally disembodied, these beings melded with Buddhist figures of good and evil and took on many forms: wicked and benevolent ghosts, animal-demon hybrids, and, depending on the politics of the day, any threatening force, ranging from itinerant performers to anyone perceived to be disloyal to the emperor. Once Japanese oni took physical shape, they took on the appearance very much like the features of the oni mask so familiar to us today.
So, who exactly are Japanese oni? We recommend a traipse through Japanese folktales for sinister tales of the oni demon and its affinity for disguises, subterfuge, and many ways to seize and devour women. One famous Japanese oni, Shuten-doji lived as the king of Mt. Oe outside of Kyoto, according to legend. At the time, families were reporting a large number of civilians missing, young women in particular. It was the 900s at the time. Rather than treat the situation as one might on Law & Order (which is to say, to investigate a case of either a serial killer, traffickers, or both), a famous seer was consulted. Abe no Seimei identified the cause of these deaths as oni demon king Shuten-doji. Warriors departed to battle the oni, and eventually he was defeated. Famously, he attempted, post-decapitation, to eat the head of his vanquisher. An eye for an eye, perhaps.
Japanese oni tend to fall into several categories: ghosts, very evil ghosts, very evil demons, humanoids, strangers, and, less frequently, protectors against other harmful spiritual agents. They are generally horned and colorful, but some notable exceptions are the sazae-oni, a large mollusk-like creature with golden testes, and kijo, female oni grown out of jealousy and resentment. The next time you’re around a campfire, pull out a good Japanese oni folktale and terrorize a friend or two. Or, stay up late and treat yourself to some good old insomnia. Read in the day, and you can analyze who the oni stands for in society. Japanese oni, though occasionally friendly, really are terrifying. Now that you’ve reached the end of this little primer on the demon, you are ready for a historically-informed scare. So, get moving! There are stories out there for you to read!