Maruo is correct (and, well, StevenK is not...)  This is definitely Chinnan Sennin.  Here's why.  First, Handaka Sonja is one of the sixteen rakan or arhats and they are almost alway depicted bald, and the person on both of your tsuba has a full head of hair.  Second, the rakan (and Handaka Sonja) are almost always shown wearing Buddhist style clothing (i.e., one bare shoulder), and the person on your tsuba is not.  Third, Pietro was correct about mugwort leaves often being a clue to the person