Mumei Blades are one side of the medal..........but even more important is it for signed Kodogu and for signed blades in the high end level !
It can be very risky to put a lot of money in signed objekt of art without any guarantee that the Signatur is OK.
In the moment the only Papers which are more or less acceptable are the papers of the NBTHK.........in the high end level.
But like Stefes87 wrote :
You pay a considerable load of dollars (especially for non-USD earners), the item disappears for a while, then it may come back with a paper that has been produced by an un-known quantity, using an un-known reference source (how old, how complete, how updated?).
This exactly what i was something thinking by myself.
You want to know why it get not a paper or the item is rejected..as a fake.....Who can you ask ?
Especially if you are a foreign collector................for blades it is maybe possible to ask Tanobe sensei........and for kodogu ?
Who is in the Shinsa ?
What is the profession of the members in the Shinsa ?
Are they all studied and graduated Experts in their field ?