Japan black (also called black japan and bicycle paint[1]) is a lacquer or varnish suitable for many substrates but known especially for its use on iron and steel. It can also be called japan lacquer and Brunswick black. Its name comes from the association between the finish and Japanese products in the West.[2] Used as a verb, japan means "to finish in japan black". Thus japanning and japanned are terms describing the process and its products.
Its high bitumen content provides a protective finish that is durable and dries quickly. This allowed japan black to be used extensively in the production of automobiles in the early 20th century in the United States.