Hello
As for the Japanese auction, junk is 90%.However, there are a serious sword and a serious seller of 10%. As for ebay, It will be the same.I talk a few about my experience. I bought aoe tsugutada of kamakura and senjyuin kuniyuki of kamakura and tosanokami tadayoshi of keicho era with out paper at once Japanese auction. As for all of them, it was got NBTHK paper. Anyway, Please choose a seller, and own study is important.
Nakamura