The old wok originated in the middle period of Edo in Japan (1780' s), but it was more widely spread in Meiji period. At present, the most popular old wok in Taiwan Province Province is probably the works around Showa, which is about 1925. Among the 80-year-old woks, the old Japanese wok is regarded as an antique in Taiwan Province Province, but the definition of Japanese antique may be pushed before Edo, which is about 1868. So for ordinary Japanese, iron pots are early household appliances. The commonly used material is pig iron, but the lid of the iron pot is mostly copper. Because the iron lid is easy to rust after steam fumigation, copper is used as the lid. Among the pot cover materials, there is a pot cover made of seven kinds of metal casting cars, commonly known as Qibao copper cover.