Why can't Goguryeo be regarded as a dynasty or regime in ancient Korea?

First of all, because of the war between Sui Dynasty and Koguryo. In the eighteenth year of the founding of the People's Republic of China, Emperor Wendi of Sui Dynasty took Hanwang Yang Liang as the marshal and led 300,000 Sui troops to expedition Koguryo. Koguryo quickly sent messengers to apologize: Yuan, Minister of Dung in Liaodong? . Six years later, Wendi died and Sui Yangguang succeeded to the throne. Yang Guang continued to implement Wendy's Northeast Asia policy.

Moreover, Koguryo was defeated by civil strife. While sending troops to Baekje, Li Zhi also plans to send troops to attack Koguryo. Li Zhi ordered Qi Bi and Li Ren to March on Liaodong Road, while Su marched on Pyongyang Road, leading Tang Hujun to attack Koguryo from both land and water. This expedition, the two armies have achieved great victory, but when Sue besieged Pyongyang, Li Zhi suddenly ordered Qi Bi and Li Huichao. In order to capture Pyongyang, Li Zhi sent another water army, but this water army was stopped by Goguryeo's army in Sheshui, and Pang Xiaotai, the commander in chief, and his thirteen sons were killed.

Secondly, because of the war between Tang Dynasty and Koguryo. After the establishment of the Tang Dynasty, under the management of Tang Gaozu and Emperor Taizong, the Turks in the north and Gaochang in the west were conquered, and the rule of the Tang Dynasty over the western regions was re-established. After stabilizing the situation in the north and northwest, the Tang Dynasty began to focus on the northeast.

In addition, the Tang Dynasty conquered Goguryeo and rewritten the pattern of Northeast Asia since then. The political vacuum left by Koguryo was partly replaced by two fans. With the rise of the forces of Qidan and Xi, the Tang Dynasty established Fanyang and Heping Land in the northeast. Our time, life An Lushan for two. The other part was acquired by Silla. After the withdrawal of troops from Korea in the Tang Dynasty, Silla ruled Korea. At the same time, Japan sent envoys to learn the system and culture of the Tang Dynasty, and Northeast Asia entered the Middle Ages. Emperor Taizong issued a letter to attack Goguryeo. The commander in chief of Tang Jun is Li Ji, a famous soldier in the early Tang Dynasty. Chi Lee led the army to bypass the Great Wall built by Goguryeo in Liaodong and successfully crossed the Liaohe River. The war went smoothly for a while, and then it met the same situation as the Sui Dynasty. In the confrontation with Koguryo, Tang Jun encountered extremely cold weather in Liaodong and had to retreat.