Thanks Bungo for your translation !
First I read TADAYOSI ?
I'm afraid to clean this plate , I have not any experience and I may damege this tsuba's surface.
To Brian !
In Poland are some collectors of nihonto but we have not especially so big knowledge about Japanese art.
My main page http://www.yogoro.org/index2.htm is dedicate Japanese clan notes - hansatsu and include as addition my own tsuba's collection .
Sorry , but now ... only in Polish language
Mikolaj