Took another photo of my new addition, brings out the figures more clearly. I can make out seated sages (?) at 5:00 and 8:00, a fox at 6:00, kikumon at the top, perhaps a genie figure in profile at 11:00. I cannot identify the figure at 1:00.
These early tsuba are not seen very often, and I've found very little written about them (in English). There was one other at DTI, asking 1M yen. They are bronze castings, and the designs tend to be crude compared to the contemporaneous mirrors, which leads some to argue that they were likely not made by mirror-makers as the name implies. There have been prior discussions on this forum in the 2010-15 time frame, several started by Marius.