Coincidentally, in this very famous city, the six dynasties, which once built their capital here, were very short-lived. Wu Dong in 69 years, the Eastern Jin Dynasty 102, the Southern Song Dynasty in 59 years, and the Taiping Heavenly Kingdom made Nanjing its capital for only 9 years. Why are dynasties so short-lived?
First of all, because of its geographical location, the Yangtze River passes through Nanjing. If others seize the upper reaches of the Yangtze River and descend along it, even if there are millions of troops outside Nanjing, they can't resist the enemy's attack. The second is that the dynasties with Nanjing as their capital were too weak. Dongwu, Eastern Jin, Song, Qi and Liang all used Nanjing as their capital, but most of them were in the southeast. In the era of cold weapons, the military strength could not keep up with the nomadic people in the north.
Economically speaking, Jiangnan has been a land of plenty since ancient times, and rich economic conditions have also accelerated the corruption of rulers. The rulers at that time were addicted to the harem. Apart from geo-economic and external factors, several dynasties with Nanjing as their capital did not have the determination to win the Central Plains and unify the whole of China.
Various factors eventually led to the short life of these dynasties, and there was a superstition. People think that Qin Shihuang cut off Long Mai in Nanking, and even cut off Ma 'anshan and Shishishan, so the dragon was cut off. It is also said that Zhuge Liang didn't want the rising sun, and tricked Sun Quan into changing the structure of Xuanwu Lake and reversing Long Mai, which eventually led to the leakage of dragon gas.