What is the difference between a copper tsuba and a copper alloy tsuba?
Updated Feb 2026
Pure copper tsuba are cast or worked from unalloyed copper, producing the characteristic reddish-warm tone and relatively soft surface that takes fine engraving detail well. Copper alloy tsuba — such as those made from shakudo (copper with a small percentage of gold), shibuichi (copper and silver), or bronze (copper and tin) — alter the base metal's color, hardness, and patina behavior. Shakudo, for example, develops a deep blue-black patina when treated with a traditional Japanese chemical solution called rokushō, producing the dark grounds often seen on high-end historical tsuba. Shibuichi yields a soft grayish tone. Bronze is harder than pure copper and holds fine detail with slightly less surface softness. In this collection, tsuba described as gold alloy or copper alloy reference these blended compositions, while pieces listed as real copper tsuba use the unalloyed metal. Both categories are legitimate collectible formats with distinct visual and aging properties.