Old Katana, or is it?

[Surpmil]

The menuki look a bit like one of Hiroshige's waves behind that shell and the fat little fellow might be Hotei, a good luck deity IIRC.

Or maybe Bodai Daruma, but Hotei is sometimes shown with monkey attendants and a stick, and that might be one on the figure's right arm/stick?

Probably a bit of a stretch to suggest there is an allusion there to "wave men" as the ronin were called!