The territory of the Ming Dynasty shrank greatly in the late Ming Dynasty and it was unable to control its borders. Why was the Qing Dynasty able to defend many borders?

The Northeastern region is roughly located to the north of Shanhaiguan, east of the Daxinganling Mountains, and south of the Outer Xing'anling Mountains, covering an area of ??approximately 2.5 million square kilometers. According to the geographical environment, it can be divided into three parts: Liaodong, Liaoxi and Heilongjiang basins. Liaodong is suitable for agricultural production and was the stronghold of the ancient central dynasty in the northeast; Heilongjiang has a high latitude and a severe cold climate, which was not suitable for agricultural production in ancient times. The ancient central dynasties generally were unable to go deep into the area to manage; western Liaoning is in the transition between a nomadic area and an agricultural area. However, in ancient times, they were mainly inhabited by nomadic peoples, such as the Wuhuan in the Han Dynasty, the Khitan in the Tang Dynasty, and the three tribes of Uliangha in the Ming Dynasty. In ancient times, the ethnic groups here generally implemented kinship management.

The situation in the Northeast in the late Tang Dynasty

After the establishment of the Ming Dynasty, it basically followed the ancient central dynasty's management model of the Northeast: establishing a stronghold in Liaodong and managing western Liaoning, North Korea and the Heilongjiang River Basin. It should be noted that the Ming Dynasty did not set up civil affairs agencies such as chief envoys, prefectures, and prefectures in Liaodong, but only military agencies such as the Liaodong Dusi. This was a relatively backward step compared to the Qin and Han Dynasties who established county management here. However, the Ming Dynasty's control over Liaodong was always strong and was not completely lost until the end of the Ming Dynasty. In the western Liaoning region, the three tribes of the Uuliangha tribes of Mongolia lived. During the Hongwu and Yongle periods, the "Three Guards of the Uuliangha tribes" were canonized. However, the three tribes rebelled and surrendered at times, making them very unstable. After Yongle, he basically invested in the Mongolian headquarters. In the Heilongjiang Basin, Nuergandusi was established during the Yongle period. But the capital was abolished in 1434. Although the Ming Dynasty conferred a large number of guard posts in the Jurchen area, after Nuergandusi was abolished, these guard posts existed in name only. From the beginning of Ming Yingzong, the Ming Dynasty and the Jurchen tribe were in a state of war, which lasted until the demise of the Ming Dynasty.

The Northeast was the "Longxing Land" of the Qing Dynasty. Based on the base area, the Qing Dynasty's control over the Northeast was obviously stronger than that of the Ming Dynasty. During the more than 200 years of the Qing Dynasty, rebellions could occur everywhere, but not in the Northeast. In the early Qing Dynasty, the management of Northeast China generally retained the system before entering the customs. For example, Shengjing was made the capital of the Northeast, and the five departments of household, rites, punishment, industry, and military were retained; the Eight Banners organization was implemented, and the most elite Eight Banners army in the country was stationed here; after that, the three generals of Shengjing, Jilin, and Heilongjiang were established. He is in charge of the defense of the Northeast. Under the general, he also sets up deputy commanders, assistant leaders, assistant leaders, defense officers, and knight commanders to manage the banner people in various places. In the Liaodong area, the Qing Dynasty also established administrative agencies such as Liaoyang Prefecture to manage Han affairs.

During the Second Opium War, a large number of Eight Banners troops in the Northeast were transferred to the interior to deal with the British and French forces and the Taiping Army, leaving the Northeast defense empty. Russia occupied 1 million square kilometers of land in the Northeast in 1858 and 1860. After the Qing Dynasty, the immigration ban was relaxed, causing a large number of refugees to flow into the Northeast, and the population in the Northeast increased rapidly. At the end of the Qing Dynasty, the three provinces of Fengtian, Jilin, and Heilongjiang were officially established in the Northeast region. Although the Qing Dynasty lost 1 million square kilometers in the northeast, it was still stronger than the Ming Dynasty, which had been shrinking in Liaodong for 200 years after 1434. In the entire ancient Chinese history, only the Jin Dynasty and the Qing Dynasty did not restrict the management of Heilongjiang.