Ox Horns and a Tiger-Skin Loincloth — The Oni's Look and the "Demon Gate

Picture an oni. Two horns on its head, and around its waist a tiger skin striped in yellow and black. There's a well-known theory that this combination isn't random at all. Horns from an ox, a loincloth from a tiger. Put them together and you get "ushi-tora," ox and tiger: the name of the direction from which oni were said to come.

Horns and tiger skin, from "ox-tiger"

In old Japan, directions were named with the twelve animals of the Chinese zodiac. North was the rat, east the rabbit, south the horse, west the rooster. Northeast, falling between the ox and the tiger, was called "ushitora," the ox-tiger direction.

In Onmyodo, the traditional Japanese system of yin-yang divination, the northeast was believed to be where oni came and went. It was called "kimon," the Demon Gate, and people took care to avoid it. If oni come through the ox-tiger gate, the theory goes, then of course they wear ox horns and tiger skins. In other words, the oni's famous look is the name of a direction turned into a picture.

Some even say that the animals who help Momotaro, the Peach Boy, defeat the oni (a monkey, a pheasant, and a dog) were chosen because the monkey, rooster, and dog sit on the western side of the zodiac compass, opposite the Demon Gate. How much people really had this in mind, we can't know. But lined up like this, it makes a pretty neat story.

The northeast, the oni's doorway

The idea of guarding the Demon Gate is said to show up even in the design of the old capital. On Mount Hiei, northeast of the Heian capital (today's Kyoto), stands the temple Enryaku-ji, long described as the temple that protects the capital's Demon Gate.

The walls of the Kyoto Imperial Palace have a corner to match. Only the northeast corner is notched inward, and it's known as Saru-ga-tsuji, the "Monkey's Corner." Taking away the corner softens the Demon Gate, and under the eaves, it's said, a carved monkey stands guard against evil. The Japanese word for monkey, "saru," sounds like the verb "to leave," as in "evil, be gone."

Even today, some people still think about the northeast when they build a house. The Demon Gate is an oni's path that has stayed part of everyday life for a long time.

Oni were once invisible

So where does the word "oni" itself come from? A dictionary from the Heian period, the Wamyo Ruijusho, records a theory that "oni" is a changed form of "onu," a reading of the character for "hidden." Oni, it explains, hide in the shadows and don't want to show their shape.

In other words, the first oni are thought to have had no clear form at all. They were something frightening and unseen: disaster, sickness, a presence lurking in the dark. Over time, images of the oni who torment the dead in Buddhist hell, and the oni painted in picture scrolls, layered on top of that idea, and the horned, fanged, club-wielding figure we all know took shape. Perhaps it was precisely because oni were invisible that people gave them a direction to come from, and a shape, horns and tiger skin, that they could actually see.

Visitors at the turn of the year

The zodiac animals were also matched to the months: the ox to the twelfth month of the old lunar calendar, the tiger to the first. So ox-tiger isn't just a direction. It's also the boundary where the old year turns into the new. Throwing beans to drive oni away at Setsubun, the day before the start of spring, is said to come from the old belief that bad things slip in easily when one season turns into the next.

Not everything that arrives at the turn of the year gets chased off, though. The namahage of Akita are visiting deities who are welcomed with food and sake. You can read about the difference in our namahage story. For oni in folktales and in hell, see the oni's Yokaipedia page.