Qimenguan is located in the mountain of Qimen, 20 kilometers north of the county seat, is an important pass on the Great Wall, known as "risk", known as "China's first pass", there is "the world nine plugs, the first", and Ningwuguan, partial customs called "foreign three customs". The siege was built with the mountain, and the southern end was connected to the east and west wings of Guancheng, and the north side was extended along the ridge to the valley floor and the city gate was built. The southern control of the central Plains of the Anmenguan and the northern chokehold of the desert were magnificent military defense projects of ancient China. Beitong Datong, South Taiyuan, into the main vast grassland, retreat can be kept thousands of miles, strategic position is very important.