As an important pass of the Central Plains Dynasty, the Shanhaiguan of the Ming Dynasty has always been an important barrier against the invasion of northern nomads. During the Ming Dynasty, Shanhaiguan was regarded as the gateway to the capital, and its defensive position was particularly important. Therefore, during the Ming Dynasty, the defense engineering of Shanhaiguan was very complete.
First of all, Shanhaiguan is strategically located, located at the mouth of the Haihe River, the terrain is dangerous, easy to defend and difficult to attack. At the same time, the Ming Dynasty built defensive facilities such as city walls, city towers, and arrow towers around Shanhaiguan, which greatly improved the defense capability of Shanhaiguan. In addition, the Ming Dynasty also set up heavy guards, equipped with sophisticated equipment, to ensure the safety of Shanhaiguan.
However, even if Shanhaiguan's defense works are so complete, it doesn't mean that it can completely block the Qing army outside the pass. First of all, the Qing army's combat effectiveness was very strong, and they were good at cavalry archery and guerrilla warfare, which made the Ming Dynasty's fortifications seem somewhat powerless in front of the Qing army. Second, the rulers of the Qing Dynasty were adept at using tactics, and they might employ tactics such as detours and sneak attacks to break through the defense line of Shanhaiguan. In addition, the Qing Dynasty may also undermine the Ming Dynasty's defense system by bribing traitors and rebelling against generals. Therefore, although Shanhaiguan was the gateway to the capital during the Ming Dynasty, and its defense projects were very complete, it did not mean that it could completely block the Qing army outside the pass. The war situation during the Ming Dynasty was very complex, and the outcome of the war often depended on the combined effect of multiple factors. In the war between the Ming and Qing dynasties, although Shanhaiguan was an important strategic location, it was not the only determining factor.