Bagua Guancheng, also known as "Bagua Ecstasy Matrix", is unique in the military defense facilities along the Great Wall. It covers an area of 40000 square meters, and sets roads and courtyards according to the orientation and symbols of Fu Xi's eight diagrams. The center of the city is the Tiaodiao Office. Starting from the northwest, the city is arranged clockwise in eight directions: Qian, Kan, Gen, Zhen, Sung, Li, Kun and Chang. It is divided into eight divinatory areas, and more than 40 streets and more than 100 houses are built. They are crisscrossed, turning left and right, and blocked and blocked. Along the way into a desperate situation, no road suddenly see the road, people fall into a state of confusion, the Eight Diagrams of the Ecstasy is named. In the past, if the enemy troops ventured into the city, there would be no return. Today, people walk around like mazes, confusing, and witty.
The east, South and West towers were converted from the platforms with only pheasant bars to the smaller single-eaved Xieshan Peak Tower of the Ming Dynasty, in which the South Gate battlements were 13.2 meters wide, 10.1 meters deep, 6.9 meters high and 11.2 meters wide. The wooden doorway on the platform, 3 wide, 9.34 meters long, into a large room, embedded with the "Huangyakou Pass" forehead plaque. The East and west two doors are similar. In the northeast corner and the southeast corner of Guancheng, there are 1 repair points, the northeast corner tower and the first floor area of 4 square meters. There are 5 arrow windows on both sides of the north and south, and 2 doors and windows for L doors. The front altar of the southeast corner tower area is 62 square meters, with 2 arrow windows on each side or 1 doors and 1 arrow windows. The wooden structure archway was repaired at 31.5 meters outside the south gate.
The East and west parts of the city are the side walls extending from the north wall to the East and west sides. Xixiaocheng, from Zhengguan to the west, is more than 800 meters long, rising step by step, rising 250 meters, is one of the highest wall sections of Huangyaguan. There are three enemy towers along the city wall, one of which is square in the Northeast corner, the base side is 16 meters long, 5.8 meters high, is a five-arrow window hollow enemy tower; the southeast corner of the city, an enemy tower, square, more than 10 meters wide base; the south side of the West Gate, an enemy tower, 5 meters wide, is a horse-shaped building with a prominent wall. There is a hollow enemy tower, a group of lighted pools of fire and a battle command post on the top of the king's hat.