Abura-akago (油赤子, "oil baby") is a Japanese type of infant spirit or ghost. It is a yōkai that appeared illustrated in Toriyama Sekien's mid-Edo period Konjaku Gazu Zoku Hyakki, as an infant spirit lapping oil out of an andon lamp.
Sekien's accompanying notes describe it:
The words after "long ago in the village of Shiga" were quoted from a story about a mysterious fire called the "abura-nusumi no hi" (the oil-stealing fire), which featured in the Edo period books, the Shokoku Rijin Dan (諸国里人談) and the Honchō Koji Innen Shū (本朝故事因縁集).[2] In those books, it is stated that there was a folk belief where an oil merchant from Ōtsu, Ōmi Province steals oil from a Jizō statue at the crossroads so that he can sell them, and became lost and turned into a mysterious fire after death. In Mount Hiei, it is said that a mysterious fire called the abura-bō appears, and in the Shokoku Rijin Dan, this fire is seen to be the same as the "abura-nusumi no hi."[3][4] It is inferred that Sekien's abura-akago was a made-up tale based on this "abura-nusumi no hi" in the Shokoku Rijin Dan and other books.[2]
In more modern yōkai literature, it is interpreted that this yōkai takes on the appearance of a ball of flames and flies into people's houses, shapeshifts into that of a baby and licks the lanterns (andon lanterns), and returns to being a ball of fire and leaves.[5] There's the theory that in the countryside in the past, unrefined materials like fish oil were used, so when cats licked the lamps, they might have looked like an abura-akago (baby licking an oil lamp).[5]
Resembling this interpretation, in the book Tōhoku Kaidan no Tabi by the novelist Yamada Norio, a collection of kaidan, there was one Akita Prefecture kaidan titled "abura-name akago" (oil-licking baby) in which a baby-carrying woman in Akida stayed at the house of a shōya, and there the baby sucked completely dry all the oil of a lantern.[6] Specialists have pointed out that Tōhoku Kaidan no Tabi includes many Sekien-created yōkai that have not originated from folklore, leading to the theory that this "abura-name akago" was also created based on Sekien's abura-akago.[7] In Ihara Saikaku's early Edo period ukiyo book the Honchō Nijū Fukō (本朝二十不孝), an oil lantern-drinking baby also appears, but it has also been noted to be something made up.[7]
Like the abura-nase and the ubagabi, there are many yōkai legends related to an attachment to oil.[8] In this background, oil was a valuable resource used as food and as illumination in Japan, becoming even more of a necessity since the middle ages due to an improvement in refining technology, leading to the theory that these yōkai were born as a warning against wasting oil by licking and sucking it.[9]