This small, flat piece made of light brown brass (called "sentoku" in Japanese) has a round diamond shape. It has a triangular shaped hole in the center and another round hole on one side. Artist’s name is signed between the two holes. The surface is slightly concaved from the rim. The front has relief design of a shrimp, blowfish, and bamboo branch. On the back, there are designs of a spiral shell, a barnacle, and water drops. The sea motifs are inlayed with gold, silver, copper, and shakudô (copper-gold alloy).
Tsuba (sword guard) is inserted between a sword handle and blade to protect hands from sharp blades. The center hole is where the sword is placed. The smaller hole is to insert an ornamental stick called kozuka. This particlar tsuba has a sea-related theme of shrimp and blowfish.