The akaname is a Japaneseyōkai depicted in Toriyama Sekien's 1776 book Gazu Hyakki Yagyō. Meaning "filth licker", they are stated to lick the filth that collects in bathtubs and bathrooms.
Classics
In classicalyōkai depictions, children with clawed feet and cropped heads are depicted by the bath place sticking out a long tongue. These depictions do not feature any kind of explanation, so anything related to them can only be inferred, but in the Edo periodkaidan book Kokon Hyakumonogatari Hyōban, there are writings about a yōkai called akaneburi and it is inferred that the akaname is a depiction of this akaneburi. According to Kokon Hyakumonogatari Hyōban, the akaneburi is a monster that lives in old bathhouses and are said to lurk in dilapidated estates. In those times, it was believed that fish were born from water and lice were born from dirt, and seeing how fish intake water and lice eat dirt, all things were thus believed to eat the material that spawns them, the akaneburi being the ones that transform from the air of the places that gather dust and filth and therefore live by eating filth.
Shōwa, Heisei, and beyond
In literature about yōkai from the periods of Shōwa, Heisei, and beyond, akaname and akaneburi were interpreted the same way as above. These interpretations state that the akaname is a yōkai that lives in old bathhouses and dilapidated buildings that would sneak into places at night when people are asleep using it’s long tongue to lick the filth and grime sticking to bath places and bathtubs. It does not do anything other than lick filth, but since yōkai were considered unsettling to encounter, it is said that people worked hard to ensure that the bath places and bathtubs are washed clean so that the akaname wouldn't come. There were none who saw what the akaname truly were, but since aka can remind people of the color red, they are said to have red faces or be entirely red. Also, aka also has connotations to the idea of "impurities" such as "depravities", "sins", or "worldly desires" and other things that are not necessary, which leads to the theory that it wasn't simply a lesson to keep bath places clean, but also to keep such impurities from lurking in one's own self.
