This winged dog is a popular image in the city of Chikugo in Fukuoka Prefecture, and the dog itself is supposedly buried beneath a stone monument near the railroad station called Hainutsuka
("winged-dog mound"). Two conflicting stories are usually told about the winged dog's origins.
According to the first story, recorded in the Chikugo Kokorogashi in 1777, the winged dog was a ferocious creature which attacked humans and livestock. When Toyotomi Hideyoshi embarked on his Kyūshū Campaign of 1587, seeking to conquer the island, the dog stood in his way and had to be slain. Hideyoshi was so taken with the animal's pluck and courage, however, that he erected a memorial for it.
According to the second version, the dog was Hideyoshi's beloved pet, which died in the place where the mound now stands. There is some historical evidence for this latter version, and the imaginary winged dog of Chikugo's folklore may be based on a real dog of exceptional agility.1
1. City of Chikugo: Hainu Densetsu and Hainu Densetsu to Hainu no Tsuka