In an Oz story that we were working on together, Joe Bongiorno pointed out the similarity between the character Quiberon and the Japanese legend of Yofune-Nushi. This was a sea dragon that lived in the Oki Islands in the Sea of Japan, described as shaped like a snake twenty-six feet long, with legs and scales, a glowing body, and flaming eyes.
The story is known to us through Richard Gordon Smith, a British traveler who heard it during his time in Japan. Smith dates it to the Hojo regency over the Kamakura shogunate, likely in the early fourteenth century. The regent banished a samurai named Oribe Shima to the Okis for an unknown offense, and his daughter Tokoyo went off in search of him. She sailed to the islands on her own and encountered a priest who was about to push a fourteen-year-old girl into the sea, explaining that Yofune-Nushi demanded a virgin sacrifice just under fifteen years of age every year on the Day of the Dog in early summer. A quick Google search revealed that the Day of the Dog is, in Buddhist tradition, a day in the fifth month of a pregnancy. And in modern Japan, it’s an observance on 1 November. I’m not sure why Smith identifies the Day of the Dog as 13 June, but I assume it has to do with the Western association of that time of year with the star Sirius and the Dog Days. If the dragon did not get his sacrifice, he caused devastating storms in the area.
Tokoyo took the place of the maiden and swam to Yofune-Nushi’s cave with a dagger, which she used to stab the monster first in the right eye and then the heart, killing him. She then returned to the surface with a cursed wooden statue of the ruling regent, which had brought the serpent in the first place. Returning it to the surface cured the ailing regent, and he rescinded Oribe’s banishment.
As several sites point out, the idea of an evil dragon demanding virgins to eat is more of a European idea than an East Asian one, with Asian dragons being proud and bad-tempered but ultimately good. Smith’s book is the only source we have for the legend, and he admitted that he just wrote it as he’d heard it, without verifying its authenticity.
The similarity to Quiberon, who appears in Ruth Plumly Thompson’s The Giant Horse of Oz, lies in the fact that he’s also a sea dragon who demands that the people of the nearby islands bring him girls. When Jewlia, daughter of the court jeweler, tells him stories about the mortal girls Dorothy, Betsy Bobbin, and Trot who live in the Emerald City, the serpent demands one, threatening to destroy the islands otherwise. He doesn’t want to eat the girl, though (he has no taste for land food), just keep her as a caretaker. The Wizard of Oz turns Quiberon to stone, but Bongiorno brings him back, associating him with the blue dragon who pulls King Cheeriobed’s carriage to the Emerald City in Wishing Horse. He also states that Yofune-Nushi was his father. The story is due to be released in an upcoming anthology.