As a non-national defense, the Great Wall of Wan Li mainly defends against the harassment of which ethnic groups?

The Great Wall and the National Defense of Qin Dynasty

Qin Shihuang destroyed the six countries in the east, attacked Xiongnu in the north, and Baiyue in Nanping. In order to maintain and consolidate its unprecedented unified feudal empire, he has taken a series of major strategic measures for national defense construction and border defense. Such as the large-scale construction of the Great Wall of Wan Li, the construction of equator, straight road, new road and Wuchi road in inland and border areas, the establishment of a national strategic grain reserve system, and the dispatch of heavy troops to border areas and areas where immigrants live. , is a huge obstacle to the national defense of the qin dynasty. Since then, China has established an unprecedented unified and powerful national defense in its history.

Section 1 The Great Wall of Wan Li-a Great Military Project

First, the appearance of the Great Wall and the construction of the Great Wall in Wan Li.

During the Spring and Autumn Period and the Warring States Period, due to the frequent, fierce and expanding scale of wars, military fortification technology was widely developed. In order to defend against the sudden attack of neighboring countries, vassal States often built some garrison facilities such as gates, blockade lines, pavilions and barriers on the border, and later further connected or expanded the dikes of the great river with city walls, resulting in the so-called Great Wall. The earliest Great Wall in the history of China is Fangcheng of Chu State, which was built in the 7th century BC and located in Zhushan, Hubei Province and Biyang, Henan Province. By the middle and early Warring States period, with the intensification of the annexation war, all the major vassal States in the middle and lower reaches of the Yellow River had built the Great Wall for mutual defense. In today's Shandong Province, there is the Great Wall built by Qi, which starts from Pingyin in the west (now northeast of Pingyin) and ends at Langxie in the east (now Jiaonan). In today's eastern Shaanxi, there is the "Luo Qian" Great Wall built by Qin along the west bank of Luoshui; On the east bank of Luoshui, there is the Hexi Great Wall built by Wei. In today's central Henan, there is the Great Wall outside the river built by Wei. There are Zheng and Han Great Walls built by Zheng and Han successively. In today's Hebei province, the Yishui Great Wall was built along the north bank of Yishui. There is the Great Wall of Zhao Xiujian in Linzhang and Cixian today. There is also the Great Wall of Zhongshan built by Sun Yat-sen at the junction of Hebei and Shanxi today. In addition to these inland governors jointly defending the Great Wall, in the middle and late Warring States period, due to the continuous growth and southward migration of nomadic tribes such as Xiongnu, Donghu, Loufan, Qin, Zhao and Yan Dou built a large-scale Great Wall on the border. Among them, the Great Wall on the border of Qin State was built after Wang Zhao destroyed the Iraqi Qu. It starts from Lintao (now Minxian County, Gansu Province) in the west, goes north along the east bank of Taoshui to Didao (now Lintao, Gansu Province), turns southeast to Weiyuan, Gansu Province, crosses Liupanshan Mountain in the northeast, passes through Guyuan, Huanxian County, Shaanxi Wuqi, and divides into two branches in Ansai, Shaanxi Province: one branch goes east, passes through Suide, and ends at Qin Shangjun Branch. One reaches the northeast, passes through Hengshan, Yulin and Shenmu in Shaanxi, and reaches the bank of the Yellow River near Shiliancheng in Tuoketuo County, Inner Mongolia. The Great Wall on the border of Zhao was built after King Wuling broke the Hulin. There are two Great Walls: Yinshan South Great Wall, which starts from Urad Qianqi in Inner Mongolia in the west, crosses Wula Mountain in Baotou City in the north, crosses Nanban in Daqing Mountain in the east, crosses Hohhot in the north and exits in the east; Yinshan North Great Wall starts from Gaoque in the west (now northeast of Hangjinhou Banner in Inner Mongolia), reaches the east of Wujiahe in the north, and reaches the northwest of Hohhot. The Great Wall on the border of Yan State was built after Qin Dynasty broke the East Lake. It starts from the northwest of Huai 'an City in Hebei Province in the west, reaches the southwest of Zhenglan Banner in Inner Mongolia in the northeast, passes through the paddock in Hebei Province, the south of Chifeng City in Inner Mongolia, the north of Fuxin City in Liaoning Province, reaches the southeast of Kaiyuan County in the east, and then turns south to reach the mouth of Tanbei Water (now Qingchuan River in North Korea). This is the distribution of the Great Wall in the mainland and the Great Wall in the border areas before the reunification of Qin.

After Qin Shihuang unified the Central Plains, on the one hand, in order to facilitate national reunification, he ordered "battlements to be destroyed and obstacles to be removed", thus tearing down all the princes in the mainland and taking the Great Wall as a precaution. On the other hand, in order to resist the Huns and strengthen national defense, the Great Wall along the border was not demolished, but was further repaired, connected and added on a large scale on the basis of the Great Wall along the border of Qin, Zhao and Yan countries, thus the famous Great Wall of Qin and Wan Li appeared in the history of China.

The construction of the Great Wall in Wan Li, Qin Dynasty is divided into two stages, *** 12 years. The first stage is from the 26th year to the 32nd year of Qin Shihuang (22 1-2 15). At this time, the six countries have just been eliminated, and a series of reforms and measures to consolidate and unify are being carried out in China, and a strategic defense policy is adopted against the Huns. At this stage, in order to ensure the security of the border and prepare for the next strategic counterattack against the Huns, the Great Wall on the border of Qin, Zhao and Yan was mainly repaired and several new connections were built. Historical Records of the Twenty-sixth Year of Qin Shihuang: "The ground is east to the Haichao, west to Lintao and Zhong Qiang, south to Beihu, north to the river, and Yinshan to Liaodong." This historical data not only points out the boundary of the early Qin Dynasty, but also points out the trend, maintenance and new construction sections of the Great Wall in the early Qin Dynasty and the time when the Great Wall began to be built. Since the middle and late Warring States period, the vassal states of the Central Plains and the northern nomads have been neighbors, and the Great Wall has been built as the boundary. Wherever the boundary is, the Great Wall is built. This is especially true in the Qin Dynasty. The so-called "Merging Yinshan Mountain into Liaodong", as Zhang Shoujie said in Justice in the Tang Dynasty: "From Yinshan Mountain by the river in the east to Liaodong in the east, the Great Wall is built as the northern boundary." In other words, the maintenance and new construction of the Great Wall began in the year when Qin destroyed the six countries. Here, the Yinshan South Great Wall of the former Zhao State (the Yinshan North Great Wall was controlled by the Huns in this way) and the border Great Wall of the Yan State were preserved, and a new paragraph between them was built to connect them. The so-called "northern dike" refers to a section of the Yellow River between the eastern end of the Great Wall in the border area of Qin State and the western end of the Great Wall in Yinshan Mountain of Zhao State. This section used to be uninhabited, but now it connects Qin and Zhao Great Wall by building a fortress. The so-called "Lintao in Zhong Qiang, West Asia" refers to the maintenance of the Great Wall on the border of the former Qin State, and further extends to Zhong Qiang. Qiang refers to the settlement of Qiang people, all over the east of Qinghai Lake today, and here refers to Yongjing and Lanzhou in Gansu today, that is, the Great Wall connected with the Yellow River newly built from Didao along Taoshui to the northwest. The so-called "east facing the sea and east facing Korea" means that the Qin border faces the sea in the east, and its northeast border extends to the original Great Wall of Yan State in Qin Dynasty to the southeast end of Liaodong County. This is the first phase of the maintenance and new construction of the Great Wall in the early Qin Dynasty. In the past, people often thought that the construction of the Great Wall in Wan Li in Qin Dynasty began in the thirty-third year of Qin Shihuang, that is, after Meng Tian defeated Xiongnu and recovered Henan, or in the thirty-fifth year of Qin Shihuang. The above historical data show that it began in the 26th year of Qin Shihuang, and Biography of Historical Records of Meng Tian said: "The 26th year of the first emperor. Due to his family background, Meng Tian was a general of A Qin, who attacked Qi, broke it and worshipped it as a civil history. Qin has been integrated with the world, making Meng Tian connect with more than 300,000 people in the north. Building the Great Wall, because of the terrain, was blocked by a dangerous system, stretching from Lintao to Jiangdong to Vandory. So crossing the river, according to Yangshan, the snake went north. The violent teacher has been away from home for more than ten years and lives in Shang Jun. " This record shows that the construction of the Great Wall in Wan Li was carried out under the leadership of Meng Tian. In order to attack the Huns and build the Great Wall, Meng Tian left the country for more than ten years. In the thirty-second year of Qin Shihuang, Meng Tian began to attack the Huns, and in the thirty-seventh year of Qin Shihuang, Meng Tian was granted death by Qin Ershi, which lasted only six years, far less than "ten years". The fact is, since Qin Shihuang broke Qi in the 26th year, Meng Tian began to lead troops to defend the Huns and build the Great Wall. After a long period of preparation, he sent troops to fight back against Xiongnu, and after defeating Xiongnu, he further built the Great Wall. This is why he has been a "violent teacher for more than ten years". However, because the first phase of the key task is to maintain the old Great Wall, there are not many new parts, and the engineering quantity is not large, which is mainly completed by the troops led by Meng Tian and the soldiers and civilians in border counties, and there is no large-scale mobilization of manpower, material resources and financial resources nationwide, and the history books reflect this situation less.

In the second stage, Qin Shihuang lived from 33 to 37 years (2 14-2 10). At this time, the situation has changed dramatically. Qin Shihuang's work of consolidating internal affairs has been completed, the restoration of the Great Wall at the border has basically ended, the border defense has been consolidated, all preparations for the Xiongnu War have been made, and the strategic defense has turned into a strategic attack, which has achieved great victory. In the thirty-second year of Qin Shihuang, Meng Tian defeated the Xiongnu army and recovered Henan in one fell swoop; The following year, he crossed the Yellow River, captured Gaoque, and took control of Yangshan and Beifake, thus pushing the border of the Qin Dynasty far north. In order to consolidate the newly occupied areas, the second phase of the construction of the Great Wall began. There are two tasks in the second stage. 1. "From Yuzhong (now Yuzhong, Gansu) to the east of the river, it belongs to Yinshan Mountain, and it is thought that (4) fourteen counties, the city river is blocked" 6. That is, from today's Lanzhou City and Yuzhong County in Gansu Province, it is connected with the Great Wall extending from Didao along Taoshui to the northwest in the first stage, along the Yellow River to the east, until it is connected with Yinshan Mountain, that is, it is connected with the western end of Yinshan South Great Wall in Zhao Guoyuan, and 44 blocks are built along the river to establish 44 counties to strengthen the defense along the river. The second is to build pavilions in Gaoque, Yangshan and Beifake to drive away Rong. That is to say, the Yinshan North Great Wall, built by King Wuling of Zhao, was rebuilt and extended from Gaoque to the southwest for a long time until it was connected with the quicksand at that time (now the general name of Badain Jaran Desert, Tengger Desert, Wulanbuhe Desert); After joining the Yinshan Great Wall in the south of Zhao to the east, it turns to the northeast in Zhuozi area of Inner Mongolia today, winding in Shangdu County in the north of Inner Mongolia today, Huade County in the south of Hebei Province and kangbao county in the south, and connecting with the Great Wall of Yan State in Taibus Banner of Inner Mongolia today. These two tasks mainly focus on new buildings, including the restoration of the North Great Wall of Wang Yinshan Mountain in Zhao Wuling, which is similar to new buildings due to the long-term damage of Xiongnu. In addition, the terrain is complex and running in the mountains, and the task is very arduous. It is difficult to accomplish this task only by the troops led by Meng Tian and the soldiers and civilians in border counties. Therefore, the manpower and material resources of the mainland are used on a large scale. "Huai Nan Zi Ren Xun" said: "Qin Huang recorded the map and saw its biography:' If Qin dies, it will be. "Because of the death of five hundred thousand soldiers, Meng Gong and Yang Wengzi will build a city to build a city, which belongs to quicksand in the west, Liaoshui in the north, North Korea in the east, and China counties will pay for it. Sima Qian had personally visited Qin Changcheng, and he said in the conclusion of Biography of Historical Records and Meng Tian; I'm in the north, and I'm going straight home. I want to see Meng Tian build the Great Wall Pavilion for Qin, which goes straight through the ravine and is light for the people. Yang Quan's Theory of Things is quoted from Notes on Water Classics and Rivers, saying, "The first emperor ordered Meng Tian to build the Great Wall, and the dead belonged to each other. The folk song says,' Be careful when you give birth to a man, but you can't see under the Great Wall when you give birth to a woman, and the bodies are holding hands everywhere'. It is estimated that about 500,000 troops and 500,000 civilian workers were put into the Great Wall at that time, and the total manpower was not less than 6,543.8+0,000. Therefore, the working people of the Qin Dynasty paid a lot of sacrifices and huge costs to build the Great Wall of Wan Li!

Second, the structure and layout of the Great Wall in Wan Li

The Great Wall is not a simple isolated wall, but a defense system with the wall as the main body and a large number of cities, obstacles, pavilions and landmarks. The city wall is a tall, solid and continuous long wall, which is used to limit the riding action of the enemy. Generally, it is built on the ridge with steep mountains or on the edge of deep valleys of rivers to "stop the danger because of the terrain"; Only in grasslands, deserts and places where there is no danger in Sichuan can cities be built on the ground. Compaction is the basic method to build a city. Today, the site of Qin Changcheng on the slope of the Great Wall in Lintao County, Gansu Province is rammed. The Great Wall Slope is about 50 miles east of Lintao, with two mountains in the middle. The situation is dangerous. Qin Changcheng straddles two high mountains, and the situation is dangerous. There is a huge gap on the half slope, commonly known as the mouth of the Great Wall. The mouth of the Great Wall is actually an ancient pass. From the collapsed section in the south of the Great Wall, the lowest floor is raw soil, which is about l.5 meters high. Above the raw soil is compacted loess with a thickness of about 3m and a depth of about10m. There is a rammed earth wall above the loess, with a residual height of about 2 meters and a width of about 3.5 meters. The thickness of rammed soil layer is 6, 7 and 10 cm respectively. Its structure, like the Great Wall on the north and south sides, is interconnected. The Great Wall on the north and south sides of the mouth of the Great Wall has been preserved for about 200 meters, and its extension is hard to recognize. The part of the Great Wall connected with the mouth of the Great Wall is trapezoidal, with a height of about 2.5 meters, a top width of about 2 meters and a bottom width of about 3.6 meters. The compacted soil is yellow clay with gravel. Seen from the section, the upper part of the Great Wall has collapsed into a pointed pile. The existing height is about 2.8 meters, the bottom width is about 2.9 meters, the rammed soil layer is 6-9 cm thick, and the rammed nest is irregular, with a diameter of 3-4 cm, which belongs to the early tamping method. Seen from the side, the Great Wall stands on the mountain ridge. If it is interrupted, it will rise and fall like a long dragon. From this, we can imagine the majestic posture of the Great Wall in Qin Dynasty.

Combined with the Great Wall, there are a lot of cities and obstacles along the border. The so-called "city" refers to the wall around Du Yi, which is used for defense. Called the city inside, called Guo outside, that is, "the city is the city, and the city is Guo outside" in Guan Du Du. The city closely connected with the Great Wall here refers to the military fortress built along the Great Wall, which is mainly used for garrison troops and residents, facilitating the combination of military and civilian, guarding and developing the frontier. For example, in the thirty-third year of Qin Shihuang, Meng Tian was ordered to "plug the city river" and set up 44 counties, that is, while building the Great Wall along the Yellow River, many city blockades were built in major risks to strengthen control and defense of key areas. For example, next to the ruins of the Qin and Han Great Wall in Hebei paddock today, many small towns closely connected with the Great Wall have been found. The area of the city is not large, ranging from city to city for dozens of miles, and there are some small towns in the depth direction inside and outside the Great Wall. These cities are used to strengthen the defense in key areas. The so-called "barrier" is a castle used as a defense in a dangerous place. Yan Shigu explained in "The History of the Han Dynasty, Emperor Wudi": "It is also an obstacle for the Han system to not build a city where it is important, but to put it on the garrison." So did the Qin system. In the thirty-third year of Qin Shihuang, Meng Tian was ordered to "build pavilions and barriers to drive people away" during Yangshan and northern holidays, which is evidence that a large number of barriers were built at the same time as the Great Wall. The difference between barriers and cities lies in their different sizes and functions: cities are larger than barriers and used to strengthen defense in key areas; The barrier is smaller than the city, only officers and soldiers live there, and there are no residents, so the guards at dangerous places should be strengthened. Both the city and the barrier are important parts of the Great Wall. With these two facilities, the defensive function of the Great Wall can be fully exerted and strengthened. There are a lot of pavilions supporting the Great Wall. Pavilion refers to the sentry box on the ancient border to monitor the enemy's situation. It has the functions of lookout, fighting and communication, and is often combined with obstacles and embarrassment, so it is often called pavilion obstacle and pavilion embarrassment. This refers to the ancient early warning beacon. The actual facility is a high platform, guarded by soldiers and guarded by guards below. When the enemy is found, it burns smoke during the day and ignites at night, so it is also called beacon tower or Wolf Yantai. After the Great Wall appeared, the combination of pavilions and pavilions became an important supporting facility and an indispensable part of the Great Wall. Qin Shihuang ordered Meng Tian to "build pavilions on the Great Wall", including a large number of pavilions. Pavilions and pavilions are generally located in high places, about ten miles apart according to the terrain conditions. Some pavilions are located on both sides of the Great Wall, which facilitates the communication between the sections. Some extend beyond the Great Wall to facilitate early warning; Some lead to the capital in order to reach the military situation as soon as possible; Some of them lead to nearby garrisons and counties to coordinate the actions of all parties concerned against the enemy.

On the basis of the above structural system, the overall layout of the Great Wall in Wan Li, Qin has distinct strategic characteristics, that is, according to the enemy's situation and terrain, defense systems with different depths and levels are established in the northwest, north and northeast sections respectively. Xianyang, Qin Dou, based in Guanzhong area, has been struggling with Guanzhong veterans for a long time since its establishment. When the Huns occupied Henan, the threat to Guanzhong was particularly direct and serious. Therefore, the Qin Dynasty paid special attention to the security of the northwest frontier defense. The main direction of Meng Tian's attack on Xiongnu is here, and the main project of building the Great Wall of Wan Li is here. The layout of the Great Wall of Wan Li in the northwest section consists of three lines of defense, which constitutes a multi-level depth system. The first frontier defense line is the Great Wall built by King Qin Zhao, which starts from Lintao East in the west and reaches the Yellow River near Tuoketuo in Inner Mongolia in the west, that is, outside the northwest of the early Qin Dynasty. Meng Tian used to focus on maintenance, but later it turned to the inner side because of the development of the border. The second line of defense is the Great Wall, starting from Didao in the west, reaching Yuzhong in the south and Changcheng Wang in Qin Zhao in the east. It was newly built in Meng Tian, with the river as the defense and the dike as the city. A large number of forts were built along the river and 44 counties were built, thus shielding the three counties of Beidi, Longxi and Jiuyuan. This is the most important defense line in northwest Qin. The third line of defense, namely, the pavilions and terraces built by Meng Tian in Gaoque, Yangshan and Beifake areas, the restoration of the Northern Great Wall of Wangyinshan in Zhaowuling and its connection with the Yan Great Wall, is the northernmost and longest Great Wall in the Qin Dynasty, and the western section of the Great Wall constitutes the northwest of the Qin Dynasty, becoming the third line of defense in the northwest, covering Henan and blocking along the river. Therefore, the layout of the northwest section of the Great Wall of Wan Li in Qin Dynasty has three lines of defense, with a depth of seven or eight hundred miles, thus effectively removing the threat of Xiongnu to Guanzhong and consolidating the security of Guanzhong. Except for the northwest section, the layout of the Great Wall of Wan Li in the north and northeast sections, with the gradual weakening of Xiongnu forces, consists of two border defense lines and one border defense line respectively. The second line of defense in the northern section is the Yinshan South Great Wall built by Zhao Wuling and the Yinshan North Great Wall built by Meng Tian. The former was outside the northern territory of the early Qin dynasty, which effectively prevented the Huns from going south and then turning to the inside; The latter, outside the northern territory of Qin, blocked the Xiongnu in the north of Yinshan Mountain, further consolidating the security of the Central Plains. A border defense line in the northeast, namely the Yan Great Wall maintained by Meng Tian, is mainly defended by Donghu, which is not as powerful as Xiongnu, so there is no multi-channel defense system. This is the strategic overall layout of the Great Wall in Wan Li in the Qin Dynasty.

Third, the role and significance of the Great Wall in Wan Li

The reason why Qin overhauled the Great Wall of Wan Li was not because the national strength was weak and Qin Jun was afraid of war, so it was stronger than Xiongnu, but because of the particularity of the contradiction between the ancient agricultural economic nationalities in the Central Plains and the nomadic economic nationalities in the north. Agricultural production needs a peaceful, unified and stable environment, which is conducive to the harvest of farming and the development of economy and culture. Nomads, on the other hand, live on weeds and drift from place to place. Xiongnu, which is in the stage of transformation to slavery, has an intrusive and predatory ruling group. The central plains attacked it with the army, and the Huns fled; As soon as the army retreated, it was the same as before. As Chao Cuo, a Han Chinese, said, "When conference semifinals eat meat, drink cheese, wear fur and clothes, there must be a family in the city. For example, birds and animals are in the wild, beautiful grass is sweet, and grass will move when it is used up. From this perspective, it is a matter of conference semifinals, and China is far away from Nanmu. Today, the number of conference semifinals will be transferred to grazing and hunting under the fortress, or when they are in Yan State, or when they are in counties, northern areas and Longxi, so as to prepare for the death of the fortress, and if they are less, they will enter. If your majesty doesn't save you, the border people will despair and have the heart to surrender to the enemy. Save it, less hair is insufficient, and more come to distant counties, then Hu will go again. It is expensive to get together constantly; If you stop, you will get back into it. For so many years, China has been poor and the people are uneasy. " This is the fundamental reason why Qin, Zhao and Yan overhauled the Great Wall at the border since the mid-Warring States period.

Qin Shihuang knew that his military strength was strong and he could destroy the six eastern countries and defeat the Huns in one fell swoop. However, defeating the Huns can not conquer and occupy the Huns, change their living conditions, environment and habits, nor can they eradicate their capriciousness and capriciousness. It is from the once-and-for-all century-long plan that Qin Shihuang decided to take a strategic policy of active defense against Xiongnu, on the one hand, severely attacking Xiongnu militarily, on the other hand, overhauling the Great Wall of Wan Li to ensure the consolidation of border defense and national security. Judging from the history of the Qin Dynasty, the role and significance of the Great Wall in Wan Li mainly include the following three aspects:

The first is to turn short into long and consolidate border defense. Compared with the Xiongnu army, Qin Jun is well-organized, well-equipped and well-trained. It is better at large-scale group operations with coordinated vehicles, steps and riding, but its flexibility and mobility are poor, and it is more restricted by terrain conditions, shorter than over mountains, long-distance raids and scattered operations, and its logistics support is also very difficult. Compared with Qin Jun, the Xiongnu army, on the contrary, has no strict organization and training, relatively simple and backward weapons and equipment, and no multi-arms coordinated operations. But everyone is used to riding and shooting, brave and good at Mercedes-Benz raids. "If you are favorable, you will advance, if you are unfavorable, you will retreat. If you leave, you will not be ashamed." 10, so you can be flexible, unpredictable and decentralized without logistical support. Being short of siege and reinforcement is one of its major weaknesses. It is precisely because the Great Wall of Wan Li served as a barrier for frontier defense in Qin Dynasty that tarquin's activities were restricted and it was difficult to easily enter and leave the frontier fortress. Qin Jun, on the other hand, has become shorter and longer, making it more defensive. Therefore, there was no great harm of Xiongnu invasion at the end of Qin Dynasty, which was inseparable from the role of the Great Wall in Wan Li.

The second is to guarantee the attack and consolidate the victory. Meng Tian's victory over Xiongnu benefited from Qin Jun's powerful and correct operational guidance, but it was closely related to his earnest maintenance of the Great Wall in the first stage. The border between Qin and Hungary is as long as Wan Li. Without the protection of the Great Wall, it would be difficult for Qin Jun to concentrate on launching a strategic offensive. Even if they can attack, the Huns can advance and retreat, move and move, and disturb. It is precisely because the Great Wall effectively consolidated the border defense and ensured the safety of Qin Jun's flank that Meng Tian was able to concentrate hundreds of thousands of troops, launch a storm in the main strategic direction, win quickly, recover Henan in one fell swoop and win Yinshan Mountain, which gave the Huns a great blow. On the one hand, Xiongnu was defeated militarily, on the other hand, because the Great Wall was everywhere in Qin, there was no gap to use, so they were forced to retreat to the north of Yinshan Mountain. Meng Tian won a military victory, and then overhauled the Great Wall in the second stage, thus consolidating the victory. It can be seen that the Great Wall of Wan Li is not only an important means of defense, but also an important means to guarantee the attack and consolidate victory.

The third is to promote the development and construction of border areas. The Great Wall of Wan Li not only protected the economy and culture of the Central Plains from the Huns, but also made great contributions to the development and construction of the border areas. Along the Great Wall in Qin Dynasty, there were 12 counties such as Longxi, Beidi, Shang Jun, Jiuyuan, Yunzhong, Yanmen, Dai Jun, Shanggu, Yuyang, Youbeiping, Liaoxi and Liaodong, and some counties were far away from the Great Wall. Under the protection of the Great Wall, people live and work in peace and contentment, and the land in these areas has been developed and agricultural production has been developed. Especially in Henan and along the Yellow River, Qin Shihuang immigrated in large numbers, and after establishing 44 counties, it soon became a new economic prosperity area.

Since the Qin Dynasty, the Great Wall of Wan Li has been inherited by rulers of many feudal dynasties. After more than 2000 years of continuous renovation and expansion, its scale is becoming more and more magnificent. It is one of the miracles in the history of China's military fortification, and it is still the pride of the Chinese nation.