I am still trying to imagine what has happened to this blade.
Possibly it was in shirasaya, registered, and someone had the bright idea of putting together a koshirae package. The saya and bashin seems to be iron-based.The tsuka however is shakudo with a nice pair of matching menuki, and ... maybe the fuchi and kashira are random, or as you say, perhaps the fuchi has been changed? The blade does kind of fit, but not perfectly; the two mekugi holes are too near the habaki to allow for a fat tsuba, or a even a super thin tsuba and seppa set.
It looks like a new hole for either the nakago or the tsuka if a tsuba is to be fitted.
Anyway, thanks everyone for the thoughts so far, nudging me in hopefully in the right direction for this blade. I always end up trying to 'improve' what I find out there, in some small way righting the wrongs that others have found too troublesome or too expensive to bother with. :nuts: