Hei Cha (黑茶) is a category of post-fermented teas. Hei Cha means literally "black tea" but as this term is used to describe fully oxidized tea in western languages (Hong Cha, red tea) it's common to describe Hei Cha as "dark tea". This category includes teas like Pu-erh, Hunan Hei Cha, Sichuan Hei Cha, Liu An Cha etc.