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.“

„Yu Shui Cha; 雨水茶. Literally Rain water tea. Summer Tea. Less prized than Spring Tea or Autumn Tea. The flavour is usually less fulsome than Spring tea. Also, it is often oven-dried (hong qing; 烘青) as it is harvested in the rainy season.“