An antique early 20th-century Japanese sterling silver ring with an oval shakudo central piece. The black shakudo is decorated with a gold-overlayed lotus leaves. Hallmark Sterling is on the inner side of the ring. Weight: 15 grams. Shakudo work, a billon of gold and copper, was used in Japan during the Samurai period by artisans who made ornaments to adorn swords and other weapons. The technique became popular in the jewelry industry in the late 1800s. Collectible Luxury Oriental Jewelry.