I had this tsuba for quite a few months, I found similar in books, and I was sure it was a kamakura-bori piece of late Muromachi period, ca. 1400-1550.
It was even papered.
Recently, I acquired a look alike tsuba, also attributed to kamakura-bori style by the seller, a knowledgeable person.
The second tsuba, however, was signed Kunihide, whoever he was, and had clear mokume treatment of the surface.
Now, there are two similar pieces in books:
1) Dr. Walter