The woman had pale skin and red hair. She spoke an unknown language that the fishermen could not understand and carried a box. Her story and that of the ship have been mentioned in three different manuscripts: Toen Shōsetsu (1825), Hyōryū Kishū (1835), and Ume-no-chiri (1844).
Firstly, there was a hypothesis that it was an edited story about the wreck of a Russian whaling ship but in the official documents, there is no description of cases of wrecks. According to professor Kazuo Tanaka, he came across to Utsuro-Bune after learning American UFO stories and Japanese legends where he saw flying saucer images in the text of the Edo period.
At first, Tanaka thought it was an edited story about the wreck of a Russian whaling ship, but he could not find any reference in the official documents to support his theory. As he started digging, he found more information and materials about Utsuro-Bune. According to him, he found 11 such documents that tell the tale of Utsuro-Bune from the Hitachi province. Out of them, two described the legends that allegedly that took place in 1803: Mito bunsho and Banke bunsho.
From “Mito bunsho,” Tanaka found an illustration of a woman who was in similar clothing to that of a Buddhist statue of Shofukuji at the Shōfukuji temple in Kamisu. The document credits a legend about Princess Konjiki (Golden Princess), who came from India to Hitachi province in a cocoon-shaped boat via sea. The locals helped to gain her health back and she repaid them by teaching sericulture.
While another document Banke bunsh tells that the exact location of the ship where it had arrived. According to a map produced by famous cartographer Inō Tadataka, it came ashore of Hitachihara Sharihama, now Hasaki Shirahama in Kamisu.
According to some sources, an 800-ton monolithic, carved from a single piece of granite, known as Masuda-no-iwafune at Asuka Park in Japan resembles the description of the Utsuro-Bune. It has a length of 36 feet, width 26 feet, and 15 feet tall. The rock also has two three-foot square holes.