Pu'er or pu-erh is a variety of fermented tea produced in Yunnan province, China. Fermentation in the context of tea production involves microbial fermentation and oxidation of the tea leaves, after they have been dried and rolled. This process is a Chinese specialty and produces tea known as hēichá (literally, "black tea") commonly translated as dark tea. This type of tea is different from what known as black tea in English, which in Chinese is called hóngchá (literally, "red tea"). The best known variety of this category of tea is pu'er from Yunnan Province, named after the trading post for dark tea during imperial China.