Gaiwan is the most commonly used brewing vessels in China. You can see it everywhere in tea house, people's house, tea shops and others.
Gaiwan has many sizes for different brewing purpose. Big, huge volumes of Gaiwan is used a lot in northern parts of China, such as Sichuang, Beijing, Hangzhou, Suzhou for brewing the green teas, flower teas. However, small volumes of Gaiwan is commonly seen in northern parts of China, where it is used to brew Oolong tea, Pu Er, black teas as well.
Gaiwan has three parts; lid for you to stir the tea leaves; cup to hold the leaves and water; plate to hold the cup, so that the drinkers will not get hurt from the hot water inside of the cup.