406 years ago today, April 14, 1619 (March 1, 1619, the 1619 lunar calendar), how did the Battle of Saerhu break out? On February 25, the 47th year of Wanli, the Ming Dynasty's army officially set out; on the first day of March, the West Route Army was attacked by Nurhachi, outnumbered and completely annihilated, and the commander Du Song died in battle; on the third day of March, the North Route Army was attacked, outnumbered and completely annihilated. The commander Ma Lin fled back in confusion; on the fifth day of March, the East Route Army was ambushed by the Later Jin Army, caught off guard and completely annihilated. The commander Liu Ting died in battle; On the sixth day of March, the South Army hurriedly withdrew after receiving the news of the defeat of the three armies. The Later Jin Army took advantage of the situation to pursue, causing heavy losses. The result was the same as our group of Zhuge Liang analyzed after the event, but unfortunately our analysis was also the same as the opinion of Kaiyuan Commander Ma Lin, and the outcome of this war was never changed. The Battle of Saerhu was a critical battle between the Ming Dynasty and the Later Jin Dynasty for Liaodong. In this battle, the Battle of Saerhu was defeated by the few. The Later Jin Army used the policy of concentrating troops and defeating each other in combat command. Within five days, they defeated three Ming troops in succession, annihilating about 50,000 Ming troops, and seizing a large amount of military supplies. It became an outstanding battle in the history of war in which troops were concentrated to defeat each other. The Later Jin Dynasty was established during the Ming Dynasty by the Jianzhou Department of the Jurchen nationality living in the Changbai Mountains of my country. At the end of the Northern Song Dynasty, Wanyan Jurchen and other tribes established the Jin Dynasty and entered the Yellow River Basin from the northeast. Other tribes still stayed in the northeast. In the early years of the Ming Dynasty, these tribes that stayed in the northeast were divided into three major parts: Haixi, Jianzhou and Donghai. In the 11th to 16th years of Wanli of Shenzong of the Ming Dynasty (1583-1588), Nurhachi (surnamed Aixinjuruo), the leader of the Jurchen Dynasty in Jianzhou, unified the various ministries of Jianzhou, merged the Haixi and Donghai, and controlled the vast areas bordering the sea in the east (today's Sea of Japan), bordering the Eastern Liaoning Dusi area in the west, reaching the Yalu River in the south, and the Xing 'an Mountains in the north north. In the process of unifying the various departments of the Jurchen Dynasty, Nurhachi established an eight-banner military system that combines military, administrative and production functions. When soldiers of the Eight Banners go out, they become soldiers, and when they enter, they become people. At the beginning, there are only four flags: yellow, white, red and blue. In the forty-second year of Wanli (1614), four flags inlaid with yellow, white, red and blue were added, making a total of eight flags. Nuzhen are divided into eight banners, each banner can send 7500 troops, with a total of more than 60,000 troops, mainly cavalry. In addition, castles such as Hetu 'ala (now Xinbin, Liaoning) were built to replenish horses and combat equipment, open up farmland to accumulate food, and actively prepare for war. In the 44th year of Wanli (1616), Nurhachi established the Later Jin Dynasty. The year was named Tianming and was called the Jin Khan, with Hetuala as the capital. After the Ming Dynasty unified the whole country, officials were set up in the northeast, and guards were built and fortifications were built. In the fourth year of Hongwu (1371), the Dingliao Capital Guard was established in Liaoyang, which was later changed to the Liaodong Capital Command Division; in the first year of Yongle (1403), the Jianzhou Guard was established, and in the seventh year of Yongle, the Nuergandu Command Division was established in Telin near the Heilongjiang Estuary. Later, health stations were successively added in these areas. During the Wanli period,"Jiubian", or nine important towns, were set up from the Yalu River to Jiayuguan, of which Liaodong governed most of today's Liaoning. During the Ming Dynasty's rule over the various Jurchen tribes, on the one hand, it used a policy of restraining people to win over their leaders, and granted them officials, promoted titles, and rewarded them with property; On the one hand, divide the various Jurchen tribes and make them oppose each other so that they can be divided and governed. Later, due to the increasing political oppression and economic exploitation of the Jurchen people, it aroused strong dissatisfaction and resistance from the Jurchen people. After Nurhachi established the Later Jin regime, he took advantage of this dissatisfaction and actively harassed Xiangdong Dusi. During the confrontation between the Ming Dynasty and the Later Jin Dynasty, the Yehe tribe of the Jurchen ethnic group living near Kaiyuan attached itself to the Ming Dynasty and opposed the Later Jin Dynasty in order to avoid being annexed by Nurhachi. The Li Dynasty in Korea east of the Yalu River also leaned towards the Ming Dynasty. The Chahar tribe of Mongolia lived between Guihua City (now Hohhot, Inner Mongolia) and Chengde. It was opposed to Jin, but its relationship with the Ming Dynasty was also volatile. The Horqin Tribe of Mongolia living in the south of the Daxinganling Mountains and the Karka Tribe of Mongolia living north of the Daling River tended to and adhered to the Later Jin Dynasty, often cooperating with the Later Jin Dynasty to harass Liaodong. Under this situation, although the Ming Dynasty could use the Ye He tribe to shield Liaodong and the Li Dynasty of Korea to contain the Later Jin Dynasty, the Ye He tribe was small and weak, and the Li Dynasty of Korea was unable to help the Ming Dynasty due to Japan's invasion and the harassment of the Later Jin Dynasty. Therefore, the Ming and Later Jin Dynasties were at a disadvantage from the beginning in their struggle for Liaodong. In the late Ming Dynasty, because they were busy suppressing the people's uprising in the Pass and were unable to take care of the defense of Liaodong, the Ming army stationed in Liaodong was poorly trained, outdated equipment, and lacked food and pay. The total number was more than 100,000, but the actual number was only tens of thousands of soldiers. Coupled with the long-term peaceful environment and extremely scattered defenses, the military's combat effectiveness is poor. In the first month of the forty-sixth year of Wanli (1618), Nurhachi took advantage of the fierce internal strife and lax defense in the Ming Dynasty to decide to use troops against the Ming Dynasty. In February, he convened his ministers to discuss the strategy of war and decided to attack the Ming Army in Liaodong first, then merge Ye He's troops, and finally seize Liaodong. In March, we stepped up preparations to expand the army, repair equipment, send spies, bribe Ming generals, and spy on the actual situation of the Ming army. After careful preparation and careful planning, Nurhachi vowed to fight against the Ming on April 13 and led 20,000 infantry and cavalry to launch an attack. The next day, the troops were divided into two groups. The soldiers of the Fourth Banner of the Left captured Dongzhou Fort,(now Dongdongzhou, Fushun County, Liaoning Province) and Magendanbao; they led the soldiers of the Fourth Banner of the Right and the elite inner soldiers (protective troops) of the Eighth Banner to Fushun Station (now Fushun City, Liaoning Province). When Fushun City was besieged in the early morning of the 15th, Li Yongfang, the defending general of the Ming army, surrendered without fighting. The Ming army's fortresses around Fushun were all occupied by the Later Jin Army. On April 21, 10,000 reinforcements from Zhang Chengyin, the Ming commander, who set out from Guangning (now Beizhen, Liaoning), arrived. The two sides engaged in a fierce battle. Zhang Chengyin died and the Ming army suffered many casualties. On April 26, the Jin army withdrew to the capital. In May, the Later Jin army once again crossed the border wall and conquered 11 Ming fortresses. In July, the Later Jin army entered and besieged Qinghe Fort (now northeast of Benxi City, Liaoning Province) and captured Qinghe Fort after fierce fighting. At this point, most of the fortresses east of Fushun City were captured by the Later Jin Army. After the Later Jin army attacked Fushun and Qinghe, it planned to attack Shenyang and Liaoyang. However, due to lack of strength, it was threatened by Ye He's troops on the flank. At the same time, it was discovered that the Ming Dynasty had decided to reinforce Liaodong so that it could withdraw voluntarily in September. After a period of rest, Nurhachi personally led his army to attack Yehe's troops in the first month of the following year, giving them heavy blows and damage, basically stabilizing the flank, and then devoted all his strength to deal with the Ming Dynasty.