What is so special about Tongguan? Why is it called the first level in the world?

Tongguan has been a battleground for military strategists since ancient times and has a very important military strategic position, so it is called the first pass in the world. Many feudal dynasties established their capitals in the north, and Tongguan was the only way to the capital. It is also the last line of defense in Beijing. Its geographical position is that 10 thousand people can't force it, but one person guards it, which is a very favorable defensive position. Tongguan is surrounded by mountains, and only one gatehouse can pass through. If you want to pass Tongguan, you must directly win the Tongguan garrison. There are good fortifications here, which are usually guarded by heavy troops. If you don't have an absolute advantage, you can't get through here.

In the Qin Dynasty, this was the Hangu Pass, and the Qin Dynasty refused the other six countries to leave their own countries again and again by virtue of Hangu Pass. After Shang Yang's political reform, Qin became the most powerful country among the seven countries, and the other six countries wanted to unite against Qin. However, it was with this natural fortification that Qin disintegrated the offensives of other six countries again and again, and finally successfully unified the world and established the first feudal dynasty.

Li Yuan entered Chang 'an after the establishment of the Tang Dynasty. Heroes in the world are eliminated step by step. Finally, Dou Jiande's subordinate Liu Heita fought back badly. In a short time, I have been playing in Tongguan. Finally, Li Shimin defeated Liu Heita by virtue of Tongguan's geographical advantages and strong city, thus eliminating the last hidden danger in the Tang Dynasty.

Ancient wars paid attention to time, place and people. Geographical location refers to geographical location. Some geographical locations are beneficial to attack and some geographical locations are beneficial to defense. Tongguan is a natural fortification. No matter what kind of army wants to pass through here easily, it is impossible. Whoever gets Tongguan has a strategic advantage.