On May 27, 1644, the Qing army arrived at Shanhaiguan in April of the first year of Shunzhi. Wu Sangui switched to welcome them and the army entered the customs.

On April 25, 1644, the Dashun Army invaded Beijing. On May 15, Wu Sangui reported to Beijing that Shanhaiguan had attacked the Dashun Army. On May 18, Li Zicheng and Liu Zongmin led the Dashun Army to send troops to the capital, pointing at Shanhaiguan. On May 26, the Dashun Army arrived at Shanhaiguan, surrounded Wu Sangui, and began to attack Shanhaiguan. On May 27, the Qing army arrived and attacked at noon, and the Dashun army was defeated. On June 3, Li Zicheng held a ceremony to declare himself emperor in Beijing and left Beijing early the next morning. The Battle of Shanhaiguan played a very important role in China's history. This battle confirmed whether Dashun or Qing Dynasty came to achieve China's dominant position and had a profound impact on China's history.

The fall of the capital and the suicide of the emperor marked the end of the Ming Empire. The Dashun Army controlled the entire Yellow River Basin and parts of the Yangtze River Basin. Its governing areas included Shaanxi, Ningxia, Gansu, Qinghai, Shanxi, Shandong, Henan, Hebei, Beijing, Tianjin, and parts of Hubei, Jiangsu, and Anhui. At that time, the four major forces in China were: Li Zicheng's Dashun regime, the Qing regime that occupied Liaodong, the Nanming regime that owned half of the country south of Jianghuai, and the Daxi regime of Zhang Xianzhong who was entering Shu. Judging from the situation at that time, Dashun was the regime most likely to unify the country. Its huge military strength was enough to deter the other three major forces. The complete imperial central government officials taken over from Beijing could be used to quickly stabilize the domestic situation. However, the ensuing Battle of Shanhaiguan, the first battle between the Qing Army and the Dashun Army, changed the fate of Dashun and the destiny of China. From the time Li Zicheng entered Beijing to the time he left Beijing, in just over 40 days, Dashun's advantage quickly transformed into the advantage of the Qing Dynasty.

The Battle of Shanhaiguan in the late Ming Dynasty was a decisive battle related to the destiny of the Chinese nation. Although it lasted only two days, its influence on China lasted for nearly three hundred years. It was this war that caused the Manchu Tartars to gain power, and their legacy has not been eliminated to this day.

The situation at that time was that Li Zicheng had captured Beijing, Wu Sangui was guarding Shanhaiguan, and the Eight Banner Soldiers were waiting for opportunities outside the pass. The three forces were hostile to each other. Among the three forces, the Eight Banner Soldiers were the strongest, Li Zicheng's Peasant Rebellion Army was second, and Wu Sangui was the weakest, but it was the most critical party. Because Shanhaiguan was the barrier to entering the pass, the gains and losses of Shanhaiguan would determine which side the balance of history tilted.

After Chongzhen hanged Coal Mountain, Wu Sangui chose to take refuge in Li Zicheng. On the way to Beijing, he was shocked to hear that his "dream lover", Chen Yuanyuan, had been snatched away by Li Zicheng's subordinate, General Liu Zongmin. Therefore, he was "angry with the crown and turned into a beauty". He led his troops back to Shanhaiguan and turned to Manqing instead. Li Zicheng led the peasant army in pursuit, encircling Shanhaiguan, which caused a war, and the incentive was almost ridiculous. It was for the prostitute Chen Yuanyuan!

The war was very fierce. Both sides were littered with corpses and rivers of blood. Wu Sangui's Ningyuan Cavalry, known as the elite of the Ming Dynasty, could not stop the bravery of the Chuang Wang's army and showed a tendency of defeat. Wu Sangui hurriedly broke through the encirclement and brought the Manchu Tartars into the city. He begged to send troops several times, but Dorgun refused. He waited until more than half of the Chuang Wang's army and the Ningyuan Cavalry had been killed or injured, did he come out to take advantage. The Chuang Wang's army were caught off guard and lost despite all their efforts. When Li Zicheng returned to Beijing, his anger could not be dispelled. He beheaded Wu Sangui's father's family and abandoned the city. Beijing, the capital of the Ming Dynasty, was also stolen by the Tartars. In the ancient capital under the setting sun, the roof tiles seemed to be dyed with blood.

The outcome of the Shanhaiguan War was a profound disaster for the Chinese nation. Reflecting on this war and gaining inspiration from it is undoubtedly of great practical significance.

There are many reasons for Li Zicheng's failure, the most important one is that the law is not strict, there is a loss of popularity, the king's army in Beijing to plunder the Ming Dynasty officials' property, causing people to be distracted, is a major mistake, and Liu Zongmin forcefully robbed Chen Yuanyuan, but also forced Wu Sangui, the king's defeat on the surface was defeated by the military, but in fact it was defeated by politics. King Chuang is recognized as a rare military genius, but he lacks long-term plans and does not know how to win over the noble family. Such a peasant regime will not last long.

The reasons for Wu Sangui's surrender to the Qing Dynasty can be summarized as two: one is that Chen Yuanyuan was robbed, and the other is that his father was handcuffed and looted. From the perspective of battlefield performance, "being angry with the crown and becoming a beauty" is more reliable. Wu Sangui has long ignored his father's life and death. Since the moment Wu Sangui broke with Li Zicheng, his father has already died. Wu Sangui's offering of customs is of course a traitorous act, but it should be seen that Li Zicheng's political missteps were the cause. If the king of Trouble went to Beijing to restrain his subordinates, history would be another outcome.

The Chuangwang Army and the Ningyuan Cavalry were the most powerful troops of the Han Army at that time. The Chuangwang Army had about 100,000, and the Ningyuan Cavalry had 30,000. If they were united, not only could they defend Shanhaiguan, but even if they fought a decisive battle against the Eight Banner Soldiers, the odds were high. Unfortunately, for money and beauty, the two most powerful troops of the Han Army fought to death before the pass, destroying the great country. It was a tragedy of the times!

At the moment when the nation is in danger, the internal struggle for personal interests awaits this nation. Today, Xiongguan is still standing, as if reminding the Chinese people not to forget this bloody history!

Comments: The Battle of Shanhaiguan was a battle at the level of national annihilation. When dynasties were changed, there were unforeseen circumstances.