Hi,
You have a Koto period, Japanese katana mounted shikomizue koshirae.
I cannot see all the kanji properly and the holes seem to have obscured the first half of the smiths name which ends with "Mitsu". The other visible kanji looks to be half of "Osafune", which was a school of smiths in the Bizen province. 'X Mitsu' was a common Bizen smith name - Nagamitsu, Kiyomitsu, Sukemitsu, amongst others.
The signature probably read "Bizen or Bishu Ju Osafune X Mitsu'.
Which smith would need a Japanese Shinsa team to pinpoint, if possible.
The style of signature with the steel bent over the end and inlaid into the opposite side is called orikaeshimei. It was done because the sword was shortened and the signature wanted preserving.
A hamon is visible and it is a thin Suguha. This was a trait with Bizen smiths so it backs up the signature a little.
Shikomizue koshirae were made to emulate walking sticks during a period in Japanese history called the Haitorei in 1876 when the Samurai were no longer allowed to publicly wear their swords.
