By that logic how did the first blade pass?
There has to be a first!
So if quality, condition and rarity and history are criteria for passing Juyo, then why wouldn't a very good quality blade that's in top condition, signed, dated, name of the samurai who commissioned the blade engraved on the nakago and NBTHK Tokubetsu Hozon be a good start to try Juyo? Just because there is little known about the smith or there are only a handful of his blades still in circulation?