Of course, many people will compare the strategic differences between Li Zicheng, the late Jin Dynasty and the western invaders. In fact, in terms of absolute combat power, their combat power is actually almost a level. For example, compared with Li Zicheng's army and the late Jin Dynasty, the western invaders had obvious disadvantages, fewer personnel and insufficient supplies, but at that time, the weapons of the western invaders were very advanced, that is, their absolute combat power was much stronger than that of the Ming Dynasty.
For example, Zhu Wenda, a famous Japanese exterminator in Wanli, told the Dutch people after the war. Hongyi's bravery is unparalleled, and his fighting equipment is exquisite, which is not enough to compete with Fujian. ? According to historical records, the most advanced monk machine in the Ming Dynasty was introduced from Portugal during the Zheng De period, and the bird spear was the later European musket rope. But in Portugal, especially during the war with the Dutch, Europeans have been ahead of Daming in firearms and shipbuilding technology for more than ten years. After all, when British warships were in Humen Yaniang Shoe Fort (1637), we can imagine the great technological gap between the Ming Dynasty and Europe.
Therefore, in the south, the Ming Dynasty could defeat the Japanese aggressors, Spain, the Netherlands and Britain (not counting Portugal) almost at the same time, but it could not defeat the late Jin and Li Zicheng in the north. What is the biggest problem of this problem? In fact, it was the north-south gap at that time. What was this gap? Drought in the late Ming Dynasty? And then what? Plague in the late Ming Dynasty? Brought, and the north is the most severely affected area. According to historical records, the Ming Dynasty experienced a national drought with the longest duration and the widest influence between 1637- 1643, which was the worst in 500 years. Prior to this, although there were extreme droughts, the duration was mostly two to three years. In addition to the drought, 1633, a large plague broke out in a small area at the end of the Ming Dynasty, and then spread to the whole of North China with the Li Zicheng Uprising. Li Zicheng rebelled because of the famine in the Central Plains at that time, and because of the weather conditions, the worm's work and rest were also disrupted. The massive plague of locusts gave the dying people in North China the last glimmer of hope. According to the literature, 80% of Gansu's population died in this continuous attack for years. Even when Li Zicheng attacked Beijing, Beijing was empty.