What makes pu-erh tea so special? It is a green tea that is blacker than the blackest tea in the world. It is believed to be the oldest tea sourced from the southwestern part of China's Yunnan province, the land of eternal spring. According to traditional Chinese philosophy, tea has the properties of yin and yang, which together represent a dynamic whole and keep the body in balance. According to the method of production, the tea is very different from the production of other teas and with its rich, strong and earthy taste reigns at the very top.