First, geomantic superstition China was very superstitious in ancient times. When ordinary people build houses and bury them after death, they have to find Mr. Feng Shui, and as the master of the world, they attach great importance to building their capital. There are also some dynasties in the history of our country that established their capitals in the south of the Yangtze River, but these dynasties did not exist for a long time. Any emperor with a capital can inherit his inheritance from generation to generation, so with the lesson of building a capital in Jiangnan, he will not build a capital in Jiangnan. On the other hand, although the Jiangnan area is vast, there are many plains, and there are no peaks that can resist invaders.
Second, the topography of the south of the Yangtze River, we can find that there have been invasions of northern nomads in all previous dynasties. Because compared with the harsh living environment in the north, the vast and resource-rich Central Plains has become a fragrant bun for northerners. Moreover, most northerners are good at riding and shooting, and they are all brave and good at fighting. If the Jiangnan area is designated as the capital, then once the northern nomads come to invade. Sharing the terrain in the south of the Yangtze River in Cairo will promote the attack of nomadic people in the north. If the country does not make good defense, it is in danger of extinction. Therefore, for these reasons, the country will not build its capital in Jiangnan.
Third, the importance of the capital We can see that Beijing, the capital of China, has mountains as natural barriers to the north and west, and the Great Wall as a military defense line. Once a war breaks out, it has a unique geographical advantage. Therefore, Beijing was chosen as the capital in order to meet the requirements for China to build its capital in ancient times.