I checked the tang when I got home, and there are no other markings. I've tried to find a picture of the signature of this smith on the web, but haven't been able to find anything yet other than this mention of the smith in Osafune
http://mywebpages.comcast.net/ColHartle ... tterTo.htm
It mentions him as the sole remaining smith in Osafune. If this is the same smith, there surely must be examples of his work somewhere.