Yìmén

Yimen lies in the mountains west of Dian Lake, where copper-bearing ground has long attracted miners. A Ming gazetteer records a copper levy here, placing the district among Yunnan's sources of the metal. Its administrative and military centres once stood apart: the county seat remained at Jiuxian, while a Ming garrison occupied a fortified town at Guishan. In 1574 the governor obtained permission to move the county seat to Guishan, bringing civil and military government together in one town.