Shakudō

Unpatinated shakudō visually resembles bronze; the dark color is induced by the niiro artificial patination process, involving boiling in a solution, generally including rokushō.

The characters in the name shaku-dō mean "red" and "copper" but combined they represent this material which begins with a darkened coppery-bronze color and is then modified to black or near-black.

Materials like shakudo were historically thought to be specific to the Chinese and Japanese, and perhaps other Asian, milieu, but recent studies have noted close similarities to certain decorative alloys used in ancient Egypt, Greece, and Rome.

[1] The origins of shakudo date back to a period when Japan was still importing significant techniques and materials from Korea and China, but accounts of production all derive from much later, and little is known of their evolution.

Modern artisans have revived the use of shakudō as a striking design element, in the making of jewelry, vessels, and for the technique of mokume-gane.