Quote Originally Posted by osakajoe View Post
A bit tough but I think this I the closest I can get.

正宗二十四代?
Masamune 24th generation

_?_広作
___hiro saku
(note 広 is the way they right hiro today. The kanji on the knife is the old version)
Saku means made by or maker

Had to ask my colleague on this one and even with her knowledge if working at the knife museum she couldn't tell me that one kanji.
http://www.sword-masamune.com/en/info.html