Utsuro-bune (虚舟, hollow boat), also Utsuro-fune, and Urobune, was an unknown object that was allegedly washed ashore in 1803 in Hitachi province on the eastern coast of Japan. Utsuro means "hollow" and -bune (from fune) means "boat". Accounts of the incident appear in four texts: Oushuku Zakki (1815), Toen Shōsetsu (1825), Hyōryū Kishū (1835) and Ume-no-chiri (1844).
According to the legend, a young woman aged between 18 and 20 arrived aboard the "hollow boat" on February 22, 1803. Fishermen brought her inland, but she was unable to communicate in Japanese. The fishermen returned her and her vessel to the sea, and it drifted away.
Historians, ethnologists and physicists such as Kazuo Tanaka and Yanagita Kunio have discussed the legend as part of a longstanding tradition within Japanese folklore. Certain ufologists have claimed that the story is evidence of a close encounter with extraterrestrial life.
...