Why is China so rich in the south and so poor in the north?

The main reasons for the difference between north and south are topography and economic location. The south is mountainous and plain, and most of the population in the south lives in coastal areas. Ports are distribution centers of economy, international culture and commodities. During the Ming and Qing dynasties, the main ports in the south were already important distribution centers for goods throughout Asia. At that time, overseas Chinese almost immigrated to all parts of the world, especially Southeast Asia, for trade and business activities. During the Ming and Qing Dynasties, Europe, Arabia and the Indian Peninsula had to go by sea from the Indian Ocean and then to China. The nearest places are Guangzhou and Fujian, and Zheng He's voyages to the West also started from Fujian. The south is in line with international standards earlier than the north of China or the Central Plains. Looking at Shanghai again, we can see that Shanghai in the early Qing Dynasty was a barren land in the eyes of Suzhou people. Later, the Qing Dynasty was forced to open to the outside world and developed into the largest city in China after trading with foreign countries.