[katana]

Had this Tulwar for a few months, only recently cleaned it. Could anyone identify the hilt design.
The edge has suffered old damage, one of the nicks has removed a 'lump' of the blade from one side (see pics) suggesting the blade is either laminated, pattern welded or has a hardened edge 'welded' to a softer spine?....I am reluctant to etch the blade and loose the patina. Could anyone tell by the photos?
Any other information or comments, as always, gratefully received