Jiming Yi is the relic of an old post house which was built in the Ming Dynasty. It is located in Jiming Yi Village, Huailai County, about 150 kilometers northwest of Beijing. Covering an area of 220,000 square meters, it was a major transit post station on the route from Beijing to Datong, Shanxi Province.
The name Jiming Yi is actually from the nearby mountain Jiming Mountain. Jiming Yi is a square-shaped town with a 2 km long wall and two gates, one in the east and the other in the west. It is the existing largest and most characteristic postal building complex, with great historical, cultural, artistic, and scientific values. In 1982, it was listed as a Provincial Cultural Relics Preservation Unit. In 2001, the State Council announced it as National Cultural Relic Preservation Unit. In 2003 and 2005, it was twice included into the List of World Heritage in Danger by World Monuments Fund. In recent years, the State has invested tens of thousands of RMB in restoration of the post house. The local government has set up the Jimingyi Relic Site Administration Committee to strengthen its protection.
Post houses played an essential role in ancient China when people rode horses to send messages and official documents. Because the physical strengths of horses were limited, they could not reach a very far destination in one run. Hence, people had to change horses frequently along the way, and stations were established along the main road for this purpose. Later, these stations also functioned as hotels to provide accommodation and meals for officials and businessmen passing by. As post houses aimed to convey information and mails, they also served as military fortresses to guard against enemies. Among a great number of post houses, the Jiming Yi is the largest one along the north main roads.