Now that the outer Great Wall has been built, why do we need to build the inner Great Wall?

To settle down in such a land of geomantic omen, we can't help asking: Why should we build the outer Great Wall first and then the inner Great Wall? The Great Wall is located in Shanxi and Hebei, and basically coincides with the provincial boundary of Monan Mongolia, which is the national boundary of northern Xinjiang in the middle and late Ming Dynasty. In the early Ming Dynasty, in order to fight against the Northern Yuan Dynasty and the subsequent separatist Tatars and Warras, the Ming army attacked many times and built the Great Wall along the front line. Important sections of the city are covered with rammed earth and stones, and enemy platforms, fortresses and passes are all set up for garrison. At the same time, a long-term hereditary military service system will be established along the border, so that they can defend the border for generations. After Emperor Taizong of the Ming Dynasty moved to Beijing in the 19th year of Yongle (142 1), many Ming Di built the Inner Great Wall along the Taihang Mountains in Shanxi and Hebei as the second line of defense to protect themselves and maintain border stability and security. The inner and outer sections of the Great Wall meet at Piantouguan (commonly known as Piantouguan, the headquarters of Shanxi Town in Ming Dynasty) in Xinzhou City, Shanxi Province. (The Great Wall and the Yellow River shake hands at Piantouguan) The total length of the Inner Great Wall is 1.600 km. From west to east, it starts from Gejiaodun, Laoyingbao, Pianguan County, Shuozhou City, Shanxi Province, along the boundary line between Shuozhou City and Xinzhou City, turns southeast to Pinglu District of Shuozhou City, and then passes through Shenchi County of Xinzhou City, Shuocheng District of Shuozhou City, ningwu county of Xinzhou City, Yuanping County of Xinzhou City, Shanyin County of Shuozhou City, Daixian County of Xinzhou City (Yanmenguan), Yingxian County of Shuozhou City and Fan Shi of Xinzhou City (the present appearance of Yanmenguan Great Wall). It passes through Laoyingbao in Pianguan County, Pinglu District, Shuozhou City, Hohhot City, Inner Mongolia, Yanggao County, Zuoyun County, Datong City, and Mashikou, Xinpingbao, Tianzhen County, and turns northeast into Huai 'an County, Wanquan County and qiaoxi district (the night view of Badaling Great Wall). The Great Wall branches southward at Niubangkou, Lingqiu County, Datong City, along the Hebei-Shanxi border, along Taihang Mountain, passing through Niangziguan and Guguan, and ends at Dongyang Pass, Licheng County, Changzhi City. Military significance: The Great Wall is not only a defensive front for farming people, but also a forward base for launching counterattacks against nomadic people. Behind the Great Wall, mobile troops are equipped in depth to deal with the war. The Great Wall is not the forefront of defense, but the starting line and traffic line of attack. The observation post deployed in front of the Great Wall goes very far, and the front line is north of the Great Wall 1000 km. The ancient nomadic cavalry had excellent mobility and strong attack power, but they could do nothing about the wall defense system, so building the Great Wall could effectively resist the invasion of northern nationalities. But the passive defense of the Great Wall alone cannot stop organized large-scale attacks. "The Deeds of Beilu" records: On the 22nd day of the first month of the tenth year, more than 20,000 people rode to the north town of Huamachi and stopped at Shijinger Wharf. They opened one or two walls and plundered in Guyuan and other places. On July 22nd this year, 20,000 people rode in, set out from Liuyang Pier in the north of Huamachi to Qingyang Pier, demolished 16 wall, went deep into Pingliang Gong Lin, and reached Longzhou, where they plundered. Zhang Deng, the general manager of the Right Empire, transferred the loyalists in Yulin and other places to Guyuan, which was unable to defend. "In the twenty-ninth year of Jiajing (1550), in the Change of Gengxu, when Mongolian Khan attacked Gubeikou head-on, he demolished the Great Wall from Huangyugou, and the Ming army collapsed without fighting. Anda attacked outside Beijing and returned with a lot of trophies. Cultural significance: The Great Wall is one of the most magnificent projects built in ancient China, which played an important defensive role in later generations. The existence of the Great Wall was also a spiritual defense against invasion for the ancients. Especially in modern times, people in China regard the Great Wall as a symbol of China. March of the Volunteers, the national anthem of the people of China, has the lyrics of "People who don't want to be slaves, build our new Great Wall with our flesh and blood", calling for resistance to aggression at the most critical moment of the country. Negative comments on the Great Wall have existed since ancient times, such as Chen Lin's "Drinking Horses in the Cave of the Great Wall": Men would rather die than build the Great Wall. The negative view is that the ancient Great Wall is a symbol of "closed door". Chang Bao, a writer, once wrote The Great Wall, describing the ancient Great Wall as a "sad history" and a "symbol of cultural stupidity" and rejoiced at the opening of the Great Wall today. Great Wall has become a brand name widely used by various products and enterprises, such as Great Wall Motor, Great Wall Airlines, Great Wall Movie, Great Wall Ham Lunch Meat, Great Wall Computer, Great Wall Electric Fan, Great Wall Lubricating Oil and Great Wall Cigarette. In "The Story of the Earth" published by 1937, Long Fang guessed that the Great Wall in China was the only building that astronomers could see on the moon. Whether the Great Wall can be seen with naked eyes from space has always been controversial. The Great Wall is almost as wide as an ordinary highway. It is neither a luminous body nor a reflector. At an altitude of several hundred kilometers, it is impossible to observe with the naked eye without the help of instruments. Shenzhou 5 astronaut Yang Liwei said that he didn't see the Great Wall during his space trip in 2003.