Cashew Lacquer

Cashew lacquer is a synthetic resin finish made from cashew nutshell oil rather than lacquer tree sap. A Japanese company, later renamed Cashew Co., Ltd., commercialized it in 1950 specifically as a substitute for real urushi: cashew nutshell oil contains compounds chemically related to urushiol, so it produces a similarly glossy, dark finish, but it cures through ordinary solvent evaporation at room temperature in a day or two, rather than needing the warm, humid curing environment real urushi requires.

That’s also the main practical reason it exists: it’s faster and cheaper to produce at scale than genuine urushi, without the tapping, refining, and slow humidity-cured application that real lacquerware demands. Japan’s Household Goods Quality Labeling Act requires products finished in cashew lacquer to be labeled “cashew coating” (カシュー塗装) rather than “urushi coating,” and items using it can’t legally be sold simply as shikki; they’re labeled as synthetic lacquerware instead.