Utsuro-bune, the Hollow Ship
The account
Fishermen found a round boat on the beach carrying a foreign woman who spoke an unknown language.
What investigators found
Historians treat the case as an Edo-period folk legend, retold in books with fanciful drawings.
The story
According to Japanese texts from the early 19th century, in 1803 fishermen in Hitachi Province, on Japan's east coast, found a strange vessel, round like a pot, with windows and unfamiliar symbols. Inside was said to be a young woman of foreign appearance, holding a box and unable to speak Japanese. Frightened, the fishermen supposedly pushed her back out to sea.
Illustrations from the period show the vessel with a shape reminiscent of a flying saucer, which is why the case turns up on lists of ancient UFOs. Historians, however, point out that the story circulates in different versions, with locations and details that change, and that similar legends about exiled princesses set adrift in sealed boats already existed. The most accepted reading is that of a folk tale, not a historical record.