The Utsuro-bune (Hollow Ship) of Hitachi, 1803

Kyōwa 3. The 2nd month, the 22nd day. English writers usually give it as 22 February 1803, though it is a date in the old lunisolar calendar, and one manuscript places it in the 8th month. No eyewitness account or named witness survives. What remains is a set of manuscripts compiled by or for scholars in Edo between about 1815 and the 1860s.

Local fishermen on the coast of Hitachi Province saw a strange vessel offshore. They towed it to the beach, in the fief of Ogasawara Etchū-no-kami. It was round, like an incense burner or incense box, about 3.3 metres tall and 5.4 metres wide, with red-lacquered rosewood above and metal plates below. Windows of glass or crystal sat behind bars, sealed with tree resin. Inside were letters in an unknown language.

Then there was the occupant, a woman about 18 to 20 years old and about 1.5 metres tall, with very pale skin and red hair and eyebrows lengthened with white extensions. Her long, smooth clothes were made of fabrics nobody recognised. She could not speak Japanese. With her were two bedsheets, a water bottle, sweets and kneaded meat. She held a square box, about 60 centimetres on each side, and let no one touch it.

An old fisherman offered a theory. She was a foreign princess, sent away after an affair. The box held the head of her executed lover.

The villagers weighed their options. If the lord ordered an inspection of the woman and boat, it would be costly. So they put her back inside and pushed the vessel out to sea. It drifted away. Nothing more is recorded about her.

The folklorist Tanaka Kazuo began researching the case in 1997. Writing in Skeptical Inquirer in 2000, he noted that Harayadori and Haratono-hama appear on no map of the time, and stressed that the vessel never flies but simply drifts. In 2014 Tanaka confirmed that the Ban-ke monjo names Hitachi-hara Sharihama, a real place on the map surveyed by Inō Tadataka in 1801. Today it is Sharihama beach, in Hasaki, Kamisu City, Ibaraki Prefecture. Tanaka now suggests that a brief Kashimanada sighting may have merged with older lore, and he still says the woman was not an alien.

The manuscripts keep surfacing. Tanaka counted 11 by 2014. In 2026 staff at the National Archives of Japan identified the Enkai kibun, compiled by Saitō Gesshin, which draws the vessel as a sphere of about 5.5 metres. Its tone is matter-of-fact. Tanaka reads such plain records as closer to an incident report than to folklore.

Scepticism came early. The folklorist Yanagita Kunio called the version by Kyokutei Bakin a tall tale, arguing that the glass and iron were added later. Bakin himself had compared the woman's clothes and white-powdered hair with records of Russia. Others propose a Western lifeboat, a blend with the Konjiki-hime silkworm legend, or ornamental faux-European lettering from woodblock prints. In 2022 Satō Hideki read the symbols as alchemical signs.

Ufologists later saw a flying saucer in the round hull and compared the symbols with the marks at Rendlesham Forest. None of that comes from the texts. What endures is the image itself: a lacquered dome in the surf, a woman holding a box, and a village that chose to say nothing. Novels, manga, anime, games and exhibitions keep returning to it.