Why did civilization revert to primitive society after the fall of the Bohai Kingdom?

Of course, civilization will regress, such as the Dark Ages of the Middle Ages after the fall of Rome. Not to mention, even the civilization of Xinjiang in China has also undergone several transformations, especially the Turpan Basin has been a region dominated by Han culture from the Wei and Jin dynasties to the Tang Dynasty, and later its civilization has also completely deformed, which can be said to be "degenerate" from the perspective of Han culture. The reason for the overall regression of sinicization is nothing more than the loss of power (the withdrawal of the Tang Dynasty), and then the gradual reduction and even disappearance of the local Han people.

In short, the carrier of civilization no longer exists, and the original civilization of the region naturally regresses and dies.

The same is true for the Bohai Sea. In 926, the Khitan destroyed the Bohai Sea, and in 928, Yelu Yuzhi put forward a proposal to migrate the people of the Bohai Sea (Dongdan) to the Liaohe River Valley, and the Liao Taizong Yelu Deguang gave it, not only migrating its people to Liaoyang (Dongping), but also destroying Tianfu City (Longquan Mansion, Shangjing, the capital of the Bohai Sea), and at the same time, "the edict is poor and cannot be moved, and the rich people of Shangguo (Khitan) are allowed to support and belong to it." It can be seen that except for some "needy" people, most of the Bohai elites have migrated to the Liao River Valley.

Although under the efforts of the Bohai regime, agriculture accounts for most of the economy of agriculture, hunting, fishing and animal husbandry, and rice has been cultivated. However, at that time, agriculture could not be better than that of North China in the south under the national organization of the Bohai State. Once the big tree of the Bohai Kingdom falls, the Chinese people are in exile in an unorganized state.

Agricultural production cannot be guaranteed, and if agriculture cannot be guaranteed, we can only return to the old road of fishing and hunting.

And now the Northeast is facing the problem of population migration to the south. Not to mention the Bohai Sea, which died thousands of years ago. The country perished, and the Khitans were not interested in setting up prefectures and counties in the Far North, so for fear of the resurgence of the Bohai Kingdom, they adopted a large number of migrations and bloody suppression.

Among the remaining people, there are those who have the ability to go south, and those who have no ability to stay in the local area. But farming was not enough to feed the family, so the final choice was to put down the hoe and pick up the bow and arrow.

In addition, a considerable number of people defected to Goryeo and Jurchen, such as in 935, the prince of Bohae, Daguangxian, led tens of thousands of people to defect to Goryeo, and then there was an endless stream of Balhae people who fled to Goryeo. The central region of the Bohai Kingdom is empty, or the carrier of civilization is shifted, and the degree of civilization in this region will naturally decline significantly. On the other hand, the culture of the Bohai people is still very high, and later the Jin Dynasty was founded, and it was Yang Pu of the Bohai who made an important contribution to the establishment of the system, and it is said that he persuaded Aguda to "take the king as the surname and the Min as the name", and there were many proposals for the construction of a Han-style regime, which promoted the sinicization of the early Jin Dynasty.

To some extent, it can be said that the Bohai people were the teachers of the Jurchens in the Jin Dynasty.

However, due to the loss of the main political power of the Bohai people (some remnants of the political power such as Ding'an State survived until the 11th century), they were scattered all over the country, and they were all minorities in various places, and it was inevitable that they were assimilated by the Han people of the Central Plains, the Jurchens of Northeast China, and the Goryeo people. All in all, the most critical factor that led to the cultural distortion of the Bohai ruling area was the Khitan demise of the Bohai Sea and the subsequent immigration vacant land policy.