Thread by @FedeItaliano76

Utsuro-bune, a mysterious ship-like object that appeared on the Japanese coast in 1803.

According to legend, a young & attractive woman came aboard this ship. Fisherman questioned her, but she was shy and did not speak Japanese—so they returned her and her vessel to the sea

'Utsuro' derives from the Japanese term meaning 'hollow' and combines with '-bune', which translates to 'boat.' So: the hollow-boat... Records of this incident can be found in four texts: Oushuku Zakki (1815), Toen Shōsetsu (1825), Hyōryū Kishū (1835), and Ume-no-chiri (1844).

The incident occurred on 22nd February in the spring of the year 1803. On the sea, off a beach named Hara-yadori within the domain of the provincial governor Ogasawara Nagashige a boat was spotted from the shore. The fishermen brought the boat to the beach. It was round and resembled a kind of Kōhako, an incense burner, in its shape. Its diameter was more than 3 ken (approximately 5.4 meters)

On the upper part of the boat, there were latticed windows sealed with a kind of rubber. The bottom of the ship was reinforced with iron plates to protect it from destruction by rocks. Since the windows were translucent, people could see inside, where they observed a woman with exotic appearance...

Her hair and eyebrows were red, and her face was pink. It seemed as if long, white hair had been added to her natural hair. The long hair could be made of fur or braided strands. The style of the hairstyle was completely unknown and since her language was understood by no one, no one could ask her about her origin

The foreign woman held a square box in her hand, measuring about 2 Shaku (approximately 60 cm). It seemed that this box was very important to her, as the woman constantly held onto it and did not allow anyone to approach it. The contents of the boat were examined by the people. Inside, there were 2 Shō of water (approximately 3.6 liters) in a small bottle. There were two sleeping mats, a kind of cake, and a type of kneaded food. While people discussed what should be done with the boat, the woman observed them peacefully

Was she Russian? Irish-American? Or was it really an UFO?

Here I found a better version of the second image in the first post:

If you want a 'terrestrial' explanation, you need to consider the context in which the stories emerged. Kazuo Tanaka explains, in his essay "Did a Close Encounter of the Third Kind Occur on a Japanese Beach in 1803" (2000), that utsuro-fune is a genre of folk tale that represents the early days of Japanese immigration for political purposes.

The legend often narrates the arrival of a foreign noblewoman, an ancestor of a ruling family, crossing the sea by boat. Folklorist Kunio Yanagita, an expert in myths related to utsuro-fune, believed in a pattern where legends gradually transform into historical accounts, evolving through embellishments and cultural forgetfulness, turning simple sea-crossing vessels into elaborate watercraft over time