Puerh History - Pu-erh.Net

„Yunnan Tea Company standardized the trade number for Pu Erh Tea in 1976 for the purpose of export. Each bingcha has 4 digits: the first 2 digits indicate the manufacturing year, the third digit indicates the leaf grade, the last digit indicates the tea factory (e.g. Kun-Ming 1, Meng-Hai 2, Xia-Guan 3, Pu Erh 4). The loose-leaf tea has 5 digits with the third and fourth indicating the class level of raw materials. Examples of early trade numbers for Puerh Tea are 7452, 7562, 7572, 75671, 76563.“

„Pu'er Tea; 普洱茶. That 'Puer Tea' was given this name suggests that historically this kind of tea - post fermented camelia sinensis assamica must have come from the south and west of Puer for there to have been any sense in transporting it through that city. The majority of good Puer tea still comes from the Xishuangbanna region. Puer County itself was not an historically important tea producing region.“