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Oni

Japanese mythological creatures

  • 13 min read
  • 7 chapters

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During the Heian period (794–1185), oni were often depicted in Japanese literature, such as setsuwa, as terrifying monsters that ate people. A prominent depiction of oni is that they eat people in one mouthful, which is called "onihitokuchi". In Nihon Ryōiki, The Tales of Ise and Konjaku Monogatarishū, for example, a woman is shown being eaten in one mouthful by an oni. There is the theory that the reason why stories of onihitokuchi were common is that wars, disasters, and famines where people lose their lives or go missing were interpreted as oni from another world appearing in the present world who take away humans.

It was not until the legend of Shuten-dōji was created that the oni began to be depicted in paintings, and the 14th century Ōeyama ekotoba (大江山絵詞) is the oldest surviving emakimono (picture scroll) depicting Shuten-dōji. Shuten-dōji has been regarded as the most famous and strongest oni in Japan. The legend of Shuten-dōji has been described since the 14th century in various arts, traditional performing arts and literature such as emakimono, jōruri, noh, kabuki, bunraku, and ukiyo-e. The tachi (Japanese long sword) "Dōjigiri" with which Minamoto no Yorimitsu decapitated Shuten-dōji' in the legend is now designated as a National Treasure and one of the Tenka-Goken (Five Greatest Swords Under Heaven).

They are popular characters in Japanese art, literature, and theater and appear as stock villains in the well-known fairytales of Momotarō (Peach Boy), Issun-bōshi, and Kobutori Jīsan. Although oni have been described as frightening creatures, they have become tamer in modern culture as people tell less frightening stories about them like Oni Mask and Red Oni Who Cried.

Etymology, change of meaning

Oni, written in kanji as 鬼, is read in China as guǐ (pinyin), meaning something invisible, formless, or unworldly, in other words, a 'ghost' or the 'soul of the dead'. On the other hand, the Japanese dictionary Wamyō Ruijushō (和名類聚抄) written in Japan in the 10th century explained the origin of the word oni as a corruption of on/onu (隠), meaning 'to hide'. The dictionary explained that oni is hidden and does not want to reveal itself. When the character for 鬼 was first introduced to Japan, it was pronounced as ki (キ) in the on'yomi reading.

The character 鬼 has changed over time in Japan to become its own entity, and there are significant differences between the Japanese oni (鬼) and the Chinese guǐ (鬼). The Chinese guǐ generally refers to the disembodied spirits of the dead and are not necessarily evil. They usually reside in the underworld, but those with a grudge sometimes appear in the human world to haunt, and Taoist priests and others have used their supernatural powers to exterminate them. Japanese oni (鬼), on the other hand, are evil beings that have substance, live in certain places in the human world, such as mountains, have red or blue bodies with horns and fangs, are armed with kanabō (metal clubs), and can be physically killed by cutting with Japanese swords.

The Izumo no Kuni Fudoki (出雲国風土記) and Nihon Shoki (日本書紀) are the earliest written examples of oni as entities rather than soul of the dead. The Izumo no Kuni Fudoki, whose compilation began in 713, tells the story of a one-eyed oni who ate a man. Nihon Shoki, completed in 720, tells of a hat (kasa)-wearing oni watching the funeral of Emperor Saimei from the top of Mount Asakura. The character for 鬼 is believed to have been read as oni when the Nihon Shoki was completed, and was also read as kami, mono, and shiko in the Heian period. In Konjaku Monogatarishū (今昔物語集), the character for 鬼 is read as mono. It was not until the end of the Heian period that the reading of oni for the character 鬼 became almost universal.

Particularly powerful oni may be described as kishin or kijin (literally "oni god"; the "ki" is an alternate character reading of "oni"), a term used in Japanese Buddhism to refer to Wrathful Deities.

The oni was syncretized with Hindu-Buddhist creatures such as the man-devouring yaksha and the rakshasa, and became the oni who tormented sinners as wardens of Hell (Jigoku), administering sentences passed down by Hell's magistrate, King Yama (Enma Daiō). The hungry ghosts called gaki (餓鬼) have also been sometimes considered a type of oni (the Kanji for "ki" 鬼 is also read "oni"). Accordingly, a wicked soul beyond rehabilitation transforms into an oni after death. Only the very worst people turn into oni while alive, and these are the oni causing troubles among humans as presented in folk tales.

Some scholars have even argued that the oni was entirely a concept of Buddhist mythology.

Oni bring calamities to the land, bringing about war, plague/illness, earthquakes, and eclipses. They have the destructive power of lightning and thunder, which terrifies people through their auditory and visual effects.

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Source and licence. Adapted from the Wikipedia article “Oni” (this version, 2026-10-05) by its contributors, shared under CC BY-SA 4.0. Lablypedia has left out its tables, references and most pictures, and linked it to other Lablypedia articles.