In 1803, Japan had an encounter with an unidentified floating object www.avclub.com

Translating roughly to “hollow ship,” utsuro-bune was a mysterious vessel shaped like an incense burner, which washed ashore in Hitachi (present-day Ibaraki Prefecture) on Japan’s east coast in 1803.
But to this day no one knows who she was or where she came from, but the story is well-documented enough that somebody was likely in the hollow ship.
(A Google search tells us that a quadratic box is a mathematical tool in which you draw a foursquare to work out a quadratic equation.
The strange woman clutched the box and refused to let anyone look inside, although she was otherwise very friendly.
AdvertisementAlso noteworthy: Dr. Tanaka’s research also concluded that Harayadori, the region in Hitachi where the hollow ship washed up, never actually existed.