Why did the Sui Dynasty hit Koguryo? Why do you have to recruit millions of troops and ruin the country?

1. The area under the jurisdiction of Koguryo originally belonged to the Central Plains Dynasty. According to Records of the Historian, after the destruction of the Shang Dynasty, the widow of the immigrants led by the minister of the Shang Dynasty went to Dongdu to establish the country and surrendered to the Zhou royal family politically, so she was named "Hou of the Northern Dynasty". At the end of the Qin dynasty, there was chaos in the world. Yan people crossed the Yalu River eastward, destroyed Jizi Korea, and established their own country, known as "Weishi Korea" in history, with Pyongyang as its capital. During the period of Emperor Wudi of the Western Han Dynasty, Emperor Wudi sent troops to destroy Wei's Korea because Wei Youqu, the ruler of North Korea at that time, did not let the surrounding tribes tell the Han Dynasty. In addition, Wei Youqu sent troops to kill a captain in eastern Liaodong, so he set up counties in Le Lang, Xuantu, Lintun and Fan Zhen, and implemented the same management mode as the Central Plains dynasty. At the end of the Eastern Han Dynasty, Gongsun Kang, the prefect of Liaodong, set up a county in the south of the county. It was not until the end of the Western Jin Dynasty that North Korea broke away from the control of the Central Plains dynasty and gradually fell into the hands of Koguryo people.

Koguryo was originally a minority regime active in Changbai Mountain area in northeast China. It invaded many territories of Liaodong Peninsula in the north and south of the Korean Peninsula during the Five Dynasties Rebellion. Because the Central Plains dynasties conquered each other during the Southern and Northern Dynasties and had no spare capacity to manage the Korean Peninsula, the Korean issue was put on hold again and again. It was not until Emperor Wendi of Sui Dynasty ended the separatist regime in the Northern and Southern Dynasties and unified China that the issue of the return of Korea was put on the agenda. Pei Ju, an expert on ethnic issues in Sui Dynasty, once said: "The land of Korea is the land of solitary bamboo. The Zhou Dynasty was sealed in Ji Zi, the Han Dynasty was divided into three counties, and the rulers also unified Liaodong. Today, I am not a minister or a foreigner. Therefore, my late emperor was ill and wanted to levy for a long time. When I was your majesty, I was safe, making this crowned land still a beautiful hometown. Today, his emissary will face the Turks, see the people with his own eyes and unite with Conghua. He will be afraid of the far-reaching spirit of the emperor, he will be afraid of the future, and he will die first. Threatening to enter the DPRK can lead to. " 2. Sui Dynasty and Koguryo competed for hegemony in East Asia. In the long-term development process, Goguryeo absorbed a large number of cultures from the Central Plains, with a high degree of civilization, and the surrounding ethnic groups (Qidan, Xi and Shiwei in the north and west) were threatened by it. Silla in the south of the Korean peninsula. Baekje was also suppressed by it, and Goguryeo's ambition to separate Liaodong from the Korean peninsula continued to expand. With the rise of the Sui Dynasty, Koguryo stopped paying tribute to the Sui Dynasty and began to actively prepare for the war. During the reign of Emperor Wendi of Sui Dynasty, the Sui Dynasty was restrained by Turks and could not attack Koguryo. During the reign of Yang Di in Sui Dynasty, Turks had surrendered to Sui Dynasty, which created conditions for expedition. 3. Koguryo colluded with the East Turkistan privately, and the great cause of Yang Di the Great lasted for three years (607). When Yang Di visited the North, Qimin Khan, who was fostered by the Sui Dynasty, informed him about the activities of Koguryo emissaries in Turkic, which made the Sui Dynasty feel the double threats from the East and the West-Turkic and Koguryo. During the first expedition to Koguryo, Emperor Yang Di was too arrogant and underestimated the enemy, which was reflected in the announcement of the pre-war military plan of the Sui Dynasty: attack route, number of troops, strength and so on. The army even carries a large number of ceremonies, honor guards and wives. In the war against Korea, Emperor Yang Di even asked Yuwen Kai to build a people's temple in an attempt to surrender Koguryo with the dignity of the empire, and ordered Koguryo to stop attacking as soon as he surrendered. As a result, Koguryo took advantage of this and surrendered many times, which made the war protracted. Secondly, the army is advancing slowly in a long snake array (one army is dispatched every day, with a distance of 40 miles, and the company is advancing gradually), which makes the army unable to take care of each other from beginning to end. The so-called million-strong army actually has very limited combat effectiveness. Third, Emperor Yang Di stipulated that all troops should not take bribes and bend the law, and all military actions must be reported in advance and approved by Emperor Yang Di himself, which greatly reduced the adaptability of the army. The rainy season in Liaodong has always been an important reason why Koguryo is difficult to conquer. Muddy roads in rainy season are not conducive to material transportation. During Emperor Wendi's reign, troops were sent to conquer Koguryo, but they failed because of the unfavorable rainy season. During the second expedition to Koguryo, Emperor Yang Di partially learned the last lesson and corrected his mistakes. However, the problem is that the Sui Dynasty has just experienced the troubled times of the Northern and Southern Dynasties, and it should focus on economic development and peace and people's livelihood. The second expedition to Koguryo was only half a year away from the first expedition, which caused a huge burden to the people. When the second expedition was about to win, Yang Xuangan, the minister in charge of supervising the grain and grass transportation of the Sui Expeditionary Force, was in Liyang, Henan. As a last resort, Yang Di ordered the troops to retreat lightly, resulting in a large number of losses of food, materials and weapons and equipment in North Korea. The third expedition was in the 14th year of Daye (6 14). At this time, the peasant uprising at the end of Sui Dynasty had swept the whole country, but Yang Di persisted in his crusade. However, when the soldiers were besieged, King Koguryo surrendered voluntarily. The reason is that Goguryeo suffered huge losses because of the two expeditions to the east in the Sui Dynasty, and the country was rich and strong during the reign of the Sui Dynasty. Under the pressure of domestic situation, Yang Di accepted Koguryo's resignation. Ironically, when I returned to Li, it was already winter. Shortly after New Year's Day, Emperor Yang Di ordered Gao Yuan to take part in the pilgrimage, but Gao Yuan still refused to make the pilgrimage. Koguryo did not go on a pilgrimage because of an expedition. After three expeditions, Koguryo refused to make a pilgrimage. It can be seen that Emperor Yang Di made three trips to the Western Ocean, wasting money and shaking the whole country. However, in the end, the book The Dead Song of Undirected Liaodong Waves published by Shandong people at the end of Sui Dynasty was the ending of Changbai Mountain. The long knife invaded the sky and a half, and the knife shone in the sun. Go up to eat roe deer and go down to eat cattle and sheep. Suddenly, when the government troops arrived, he swung his knife forward. For example, if Liaodong dies, what will happen to the beheading injury?