With this story coming out of the Edo period, one has to take into account the enormous number of ghost stories which were made up at the time. A popular form of entertainment was ‘Hyaku Monogatari Kaidankai’, or ‘One Hundred Ghost Stories’, where 100 candles would be lit and a group of people would take turns telling ghost stories. After each story, one candle was blown out, with the act of extinguishing the final candle supposedly summon a supernatural being. There was great demand for ghost stories in light of the popularity of the game (obviously, one wouldn’t want to hear the same story multiple times in a night, and someone who told the same story every time wouldn’t get invited to many parties), so collections of supernatural tales were printed by the truckload in the Edo period.

As for the ‘unexplainable’ fact that there are many reproductions of the Utsuro-bune story all over Japan, each with similar illustrations and identical text, the Hyaku Monogatari Kaidankai game explains it. Every printer had to make their own woodblock reproductions of various stories to sell. If the Utsuro-bune story became popular, then they would, of course, make their own illustration and sell their own copy of it. It’s no more unexplainable than the fact that many artists made woodblock prints of other stories, like tales of Kappas (each artist drew the Kappa differently, but all had the same behaviors and traits in their descriptions). I don’t think it was a mass sighting of anything, simply the story getting passed from one town to another as a new tale for Hyaku Monogatari.

As for the strange characters, I cannot so easily explain them, as they are clearly not Japanese. They could, however, be a Japanese person attempting to describe, say, Korean Hangul characters or even Russian Cyrillic characters to someone who has never seen Hangul or Cyrillic writing. If I showed some random guy off the street a Japanese character, and then told them to describe it to someone else, the attempt to describe the character would garble the production of the final piece beyond recognition like a hyper-speed version of Telephone. (Even someone who can read Japanese attempting to reproduce a character they know on sight, but cannot remember how to write can produce a similar effect.)

http://www.blogtalkradio.com/brightside1

What a shitty assload of frickin´? donkey-feces!!!
ANYONE who´s ever learned how to use their eyesight,
probably knows the difference between
an exiled Russian “gaikokujin”
and something truly foreign and unknown!!!
You know that a lion is a lion, and you know what a bear looks like!
So when you see something “womanlike” coming out from a
flashing “walnut”, God damn – I think you can tell the difference!!!
Or are you deliberately ignorant and introverted – much like a troll?!
Even the simple thought of trying
to claim something else is just fake and gay – much like two camels in a car!!!
God damn it, it irritates me so much just to think some
turdbarrell could write something like that!
Frickin´debunking douchedud!!

And if it was an advanced craft, it would have been unnessary and probabley a stuped choice to fly it in front of an undeveloped society. Becides there is the possability of it being a USO, you do know there are advanced under water extraterrestrial bases right.
the chances of that are high, mutch higher than what you claim. Althow I am not discrediting you at all.