This hairy beast, whose name means "red tongue", appears leering out of a black cloud over a floodgate in the third volume of Sekien Toriyama's Gazu Hyakki Yakō
It appears to have been based on the akakuchi
(赤口, red mouth), a monster from a Kano school picture scroll.2
This creature's name may have been taken from one of the six auspicious labels of the Japanese calendar, shakkō (also 赤口, red mouth), which indicates a day of terrible luck and atrocity.2,3,4. Sekien's creature, with its lolling tongue, may have itself been based on the Shakuzetsu-jin (赤舌神, red-tongue deity) of Onmyōdō, a name that indicates a god who guards the Western gate of Jupiter, or else one of the Indian Rakshasha.2,3,5
1.Toriyama, p. 62.
2. Fujisawa Morihiko to Toriyama Sekien - Akashita
3. Mizuki vol. 5 2004, p.5.
4. Yahoo Japan: Daijisen Dictionary Definition: Shakkō.
5. Yahoo Japan: Daijisen Dictionary Definition: Shakuzetsu-jin.