O koumori

Back to the katana... The nakago looks dry and flakey to me - could it have been in a fire?

two more?

Hawley

Difficult to say from this photo,

Thanks for the images - beautiful!

Yes, it's real. It is a Hozon paper - not likely to be forged.

Rest in peace Guido.

Nobody has mentioned attempting to ensure that the 'new' owners employ careful stewardship and care for these historical and culturally important objects. Perhaps in this community that goes without saying. Personally I'd rather take a monetary loss, knowing that they will be properly cared for, than realize a large profit dispersing them to a hack...And I'd like to think that my heirs are of the same opinion. just my 2 cents... Dan K

Forensic laboratories can use neutron activation analysis to discern serial numbers after they have been filed off (firearms, etc.) This is a non-destructive test. I wonder if it would work in this case?

I have an identical one that I bought about a year ago. They are repros.

from http://www.ksky.ne.jp./~sumie99/treatment.html

https://www.tsukamaki.net/

Just for clarification - you want to 'practice' with a papered Nihonto?

Check out: https://www.nihontocraft.com/Ko_Naminohira_Katana.html

Thank you for this amazing contribution Jussi!