In the last years of the Ming Dynasty, there were four forces in the depths of the northern Cyprus, and they were spying on the Ming Dynasty, they were the remaining forces after the fall of the Yuan Dynasty, the Southern Mongolia (present-day Inner Mongolia), the Northern Mongolia (present-day Mongolia), the Dzungar tribe of The Western Mongolia (west of the Present-day Alxa League in Inner Mongolia), and the Qing Dynasty (Later Jin) Nurhaci, which was entrenched in the northeast.
Mo nan, mobei is closest to Nurhaci, followed by moxi mongolia, and south is the Ming Dynasty that Yao Yao wants to fall.
The shrewd Manchu leaders saw an opportunity to replace the Ming Dynasty in the Central Plains, and from the forty-sixth year of the Ming Dynasty (1618) to the fifteenth year of Chongzhen (1642), the Later Jin (Qing) entered the Central Plains in order to seize Liaodong and enter the Central Plains, and engaged in intermittent wars with the Ming Dynasty. As the saying goes, the skinny camel is bigger than the horse, although in the last years of the Ming Dynasty, political corruption, Li Zicheng's peasant uprising entered a climax, and the crisis within the Ming government was increasingly intensifying, but it was not an easy task to defeat the Ming Dynasty and enter the Central Plains. On April 13, 1946, Nurhaci led a 20,000-point two-way expedition. The throat of Liaodong was smoothed, opening the prelude to the Liaodong War. Using the tactics of combining wisdom and strong attack, Li Weihan (Inspector of Liaodong) hurriedly ordered the commander-in-chief Zhang Chengyin to lead an army of 10,000 to counterattack. The Qing army fought in three ways, and the total annihilation of the Ming army won a complete victory, and captured more than 500 forts, and the initial battle was successful, which strengthened Nurhaci's confidence in entering the Central Plains
So Nurhaci made a plan, united the forces of the Mongol tribes, strengthened himself, and the recent Mongolian tribes married their own girls to the Mongol ruler Wang ye and chief, not only to do it himself, but also to let his subordinate Beyler and the Mongolian tribes extensively marry, take two-way marriage, marry out and marry in, through this time-saving and low-cost means, without a single soldier, the two major tribes of Mongolia in the south and the north of the desert submitted to submission, Nurhaci also concurrently served as the Great Khan of Mongolia. Nurhaci, who had tasted the sweetness, set peace as a national policy to implement.
But the headache is that the Dzungar department of Western Mongolia still remembers Genghis Khan, wants to absorb the southern and northern desert, and rebuild the Great Yuan Dynasty, which is also the real reason for the three western expeditions of Kangxi to Dzungar later, but the powerful Dzungars of the Kangxi Emperor used 100,000 troops, 100,000 troops against Gordan's 30,000 troops, and Gordan and the Qing Empire lost two battles and two defeats because of the disparity in strength. Betrayed by his nephew Alabutan, he lost his base area, was cornered, committed suicide by drinking, and the Western Mongolia of The Desert was completely suppressed, and the tribes of the Western Desert Mongols were pacified, and the northern part of the Great Desert was unified into the Qing Dynasty, laying the foundation for resisting the Ming Dynasty.
Just when the east wind came, Wu Sangui, the Ming Dynasty general stationed at Shanhaiguan Customs, for his own selfish interests, "rushed to the crown and was angry for the red face" to open the gate and let the Qing soldiers enter the customs, when Li Zicheng raised his troops and snatched the well-thought-out Chen Yuanyuan from Wu Sangui's hands, so he led the Qing troops into the customs, the Ming Dynasty fought on the northern and southern fronts, the internal crisis intensified, there was Li Zicheng in the south, there were Qing soldiers in the north, the Ming Government was unable to cope, the Qing soldiers effortlessly broke into the Central Plains, destroyed the Ming Dynasty, and sat on the Emperor of the Central Plains.