Goguryeo's 500,000-strong army repeatedly attacked the Central Plains, which has always been a great disaster for successive dynasties.

In the history of China, there is a very strange phenomenon. Five emperors in Sui and Tang Dynasties attacked Koguryo continuously. From Emperor Wendi of Sui Dynasty, Emperor of Sui Dynasty to Li Zhi and Tang Gaozong, it finally ended. During this period, Emperor Yang Guang of Yang Di and Emperor Taizong Li Shimin also made personal expedition, but both ended in failure. So what kind of country is Koguryo? In the absence of deep hatred, why did Sui and Tang Dynasties spare no effort to attack Koguryo? In more than 70 years, what did this country rely on to defeat the repeated attacks of the Central Plains Dynasty?

1. Koguryo's army of 500,000 troops has become a menace to the Central Plains Dynasty. Koguryo was a country that occupied the northeast and north of the Korean peninsula during the Southern and Northern Dynasties. This country has nothing to do with Korea, the predecessor of Korea. However, Koreans who are bent on building national pride are now confessing their ancestors to their ancestors without conscience. In their textbooks, Koguryo is the predecessor of North Korea. The vast area, including northern Korea, was China's territory from the Qin Dynasty to the Western Jin Dynasty. During the May 4th Movement, this region became independent and Koguryo was the country. This country was originally a nomadic country, but it gradually absorbed the farming civilization of the Central Plains Dynasty. By the time the Northern Zhou Dynasty confronted the Northern Qi Dynasty, Koguryo had become a country that could not be ignored. During the Northern Zhou Dynasty's attack on the Northern Qi Dynasty, Goguryeo sent troops to help the Northern Qi Dynasty, and Emperor Wendi, the actual head of the Northern Zhou Dynasty, hated Goguryeo. Koguryo at this time is not easy to deal with, with a population of more than 5 million. Because it belongs to a semi-agricultural and semi-nomadic country, it has retained more than 500,000 standing troops with strong combat effectiveness.

After the establishment of the Sui Dynasty, Emperor Wendi of Sui Dynasty focused on attacking Nan Chen. However, just after Sui Jun's main force went south, Goguryeo sent 200,000 troops to attack western Liaoning in the Sui Dynasty. Emperor Wendi flew into a rage and assembled 300,000 troops to launch a counterattack. At first, Sui Jun won, but was later defeated by Koguryo's army. After a long time, Goguryeo became a heart disease of Emperor Wen of Sui Dynasty. In the view of Emperor Wendi of Sui Dynasty, Koguryo was more difficult to deal with than Chen Nan. Goguryeo was not idle, and often joined the East Turkistan to invade the border areas. Moreover, Koguryo has a different model from the Turks, who are nomadic and will withdraw after robbery. In addition to goods, Koguryo will plunder people to return to China. This move was used by later Liao countries and Manchu, and it further strengthened itself. After the death of Emperor Wendi of Sui Dynasty, Yang Guang became the second emperor of Sui Dynasty. This man is brilliant but ambitious. He takes a tougher attitude towards Koguryo.

Second,1180,000 troops marched eastward to Goguryeo, and the Tang Dynasty did not spare Goguryeo. After Yang Di ascended the throne, besides building Luoyang City and opening the Grand Canal, another important event was attacking Koguryo. 6 1 1 year, Yang Guang led1180,000 troops to attack Koguryo. There are more than 3 million migrant workers serving these troops, which seriously delays production. Results Due to the weather and terrain, the progress in Sui Jun was not smooth. Koguryo's army was not a soft persimmon, and the number of cavalry even surpassed that of Sui Jun. Finally, Sui Jun was defeated, and it was a fiasco. Yang Di's own commander in chief has 300,000 Central Route Army, which was less than 1 10,000 when he retreated. Two years later, Yang Di assembled a million troops and attacked Koguryo twice. However, due to the turmoil in the domestic situation, the withdrawal can only be ordered. The peasant uprising at the end of Sui Dynasty destroyed the Sui Dynasty, and Yang Guang was killed in Yangzhou. His cousin and son-in-law Li Shimin began to clean up the mess, and finally the Tang Dynasty unified the world.

After Li Yuan abdicated, Li Shimin became the ruler of the Tang Dynasty. At that time, the emperor was bent on developing westward and opening up the Silk Road. However, there are still many opponents in the west, and Gaochang and West Turk are still on the road. Before developing westward, Li Shimin must first destroy the domestic threat, namely East Turkestan. Excavate lived up to expectations, and East Turkistan Khan was captured alive. Then Tang Jun destroyed Gao Changguo, and Li Shimin shouted happily, "The Silk Road has been opened." But just then Goguryeo took the initiative to die, and the country began to attack Silla, an ally of the Tang Dynasty. Li Shimin decided to settle old scores and new scores together, and he personally signed Koguryo. Facts have proved that this place is really difficult to fight, and Li Shimin's result is not much better than his dead father-in-law. After Li Shimin's defeat, he learned a lesson and did not continue to attack Koguryo, which is the difference between him and Yang Guang. Li Shimin left this task to his son. He thinks Koguryo has always had civil strife.