Oolong tea, a type of green tea, is a well-known tea variety. The classification and practice of oolong tea vary depending on the region. In Chinese mainland, the tea processing classification of oolong tea belongs to the green tea in the six major tea series of green, red, yellow, white, black and green, which is partially fermented, with green leaves and red edges, and has both the freshness of green tea and the sweetness of black tea. Therefore, in Chinese mainland, oolong tea is equivalent to green tea, which refers to oolong tea and is regarded as the trade name of green tea. Famous teas such as Fujian's Tieguanyin and Taiwan's frozen top oolong tea belong to this category. Taiwan oolong tea, also known as "hemispherical bag tea", refers to the tea species that are "oolong tea and processed in the way of oolong tea".