Gaiwan translates into 'bowl with a lid' in Chinese. It is composed by three parts: a lid, a cup (or cup shape bowl) and a source. It is traditionally used as a tea brewing vessel in Kung-Fu tea, although many who are naive to Chinese tea culture mistakenly assume it is a drinking tea cup due to its shape and size.
Gaiwan is commonly used to brew semi-fermented Oolong teas or fully fermented black teas. As is has not got a inbuilt strainer, a strainer and a tea sever are often used in combination.
Similar to a teapot lid, a Gaiwan's lid is ideal to experience the aroma of a premium tea after enough steam from the tea brewing has cumulated and condensed on it.