The Mitochondrial Eve is more definitive than you put it, in that it essentially debunks the multi-origin theory. It is also the most statistical, mathematical evidence out there of human origins. I guess until DNA testing on some new groups of peoples provide startingly new and different results, it is accepted as the de facto evolutionary history.

Mendoza isn't a "speculating" guy but a respected Portuguese historian whose works form the basis of many sinologist historians' research into Sino-Euro contact and relations.

I believe Jared Diamond, the Pulitzer winning historian, arrived at a similar conclusion which he expanded in a April 1999 New York Times Magazine article about the printing press. I can't find an online copy, just a reference to it by Googling. Carter's book is still used as an academic reference in universities as a background bibliography to the history of printing/books, which means that it isn't debunked and discredited. Anyway, knowing the origin of a particular invention doesn't detract from the achievements of Gutenberg and many others of his contemporaries in Europe who innovated in other ways and made optimum use out of the technology. Printing in China didn't help accelerate literacy in the same way at all because of the nature of the language and culture.

Ok, back to battling revisionists! I'm curious, are you Japanese or teaching in Japan? How do you accumulate so much knowledge about Japan?