Qingtian (Chinese: 青田; pinyin: Qīngtián; literally: "azure field"), is a county in southeastern Zhejiang Province, on the middle-lower reaches of the Ou River which flows 388 kilometers (241 mi) before finally reaching the city of Wenzhou and emptying into the East China Sea. Ouju, a form of Chinese Opera of the city of Wenzhou always derivers its name from Ou River. The county is known from AD 711 and was named for its rich rice paddy fields. Population 361,062, area 2,493 km2 (963 sq mi). Subtropical monsoon climate: annual average temperature 18.3 degrees, annual rainfall 1,747 mm (68.8 in). Hilly territory with many ravines. The county went under the administration of Lishui in 1963 as ruled by the central government. Its capital is Hecheng, also known as Qingtian City.