This Hishika kugihiki is a small Japanese flush cut saw for trimming plugs, pegs and the wedges or pins in through tenons level with the surface.
The 120 mm blade is 0.4 mm thick with unset teeth, so it lies flat on the work without scratching it. The teeth are 1 mm pitch (26 TPI) and cut a 0.4 mm kerf. The handle is paulownia, and a protective vinyl case is included.