During the Warring States Period (475 BC-22l BC), in order to defend each other, the vassal States built tall walls on their respective borders, connecting the fierce city and the beacon tower, which was endless, so it was called the Great Wall. At that time, the territory of the vassal States was different, so the Great Wall of each country was also long and short. According to documents and relics, the Chu Great Wall starts from Zhushan, Hubei Province in the west, crosses the Hanshui River, and passes through Dengxian and Yueshan in Neixiang to Qinyang, with a total length of nearly 500 dry meters. The Great Wall of Qi started in Pingyin, Shandong Province, passed through Tai 'an, Laiwu, Zhangqiu, Zichuan, Lin Xiong, Anqiu and Zhucheng, and reached Jiaonan, with a total length of 500 dry meters. The Great Wall of Wei starts from Huashan in the north and reaches the Yellow River in the north, with a total length of 300 meters. There are two Great Walls, and the south Changcheng is about 250 kilometers long. The North Great Wall is about 650 meters long. These Great Walls are self-contained and unconnected, greatly inferior to the Great Wall of Qin and Han Dynasties.
Qin Changcheng starts from today's eastern Gansu in the west, passes through today's Gansu, Ningxia, Shaanxi, Shanxi, Inner Mongolia, Hebei and Liaoning provinces, and reaches the Yalu River directly, with a total length of more than 5,000 dry meters. The Great Wall of Han Dynasty is even longer than Qin Changcheng, reaching more than l0000 dry meters. Up to now, the remains of the Han Great Wall scattered between Xinjiang and Hebei provinces can still be seen everywhere. Since then, the Northern Wei and Sui Dynasties have recorded the construction of the Great Wall. During the 5th and 7th centuries, the Great Wall built in the Northern Wei Dynasty, the Northern Qi Dynasty and the Northern Zhou Dynasty had 650,1000 and l000 dry meters respectively. In the12nd century, the Jin Dynasty also built more than 4,000 kilometers from the eastern part of Inner Mongolia Autonomous Region to the outer Baikal region. The Great Wall in the North was built continuously in the Ming Dynasty to prevent the forces of the Yuan Dynasty from fleeing northward and invading southward. The construction of the Great Wall in Ming Dynasty lasted for more than 200 years. The Great Wall built in the early days starts from Yalu River in the east and reaches the foot of Qilian Mountain in the west, with a total length of more than 7,300 dry meters. After the middle period, the repaired Great Wall from Shanhaiguan to Jiayuguan was relatively complete, so it was mistaken for the beginning and end of the Great Wall in history.
In fact, during the Spring and Autumn Period and the Warring States Period, the total length of the Great Wall built by many vassal states and later dynasties exceeded 50,000 dry meters. Therefore, the Great Wall can be called a great engineering miracle of "two thousand years up and down, hundreds of thousands of miles across". The great project of building the Great Wall is really amazing. The Great Wall built in the Ming Dynasty alone is estimated to require 50 million cubic meters of masonry and/kloc-0.50 billion cubic meters of earthwork. If it is used to pave a road with a width of 10 m and a thickness of 35 cm, it can be measured around the earth for two weeks. The labor used to build the Great Wall in past dynasties is also considerable. According to historical documents, the slender machinery of the Qin Dynasty not only used 300,000 to 500,000 troops, but also requisitioned 400,000 to 500,000 civilian workers, sometimes reaching1500,000. During the Northern Qi Dynasty,1800,000 civilian workers were recruited to build the Great Wall. In the history of Sui Dynasty, tens of thousands, hundreds of thousands or even millions of civilian workers were recruited to build the Great Wall.
Complex terrain and peculiar structure.
As a defense project, the Great Wall crosses mountains, mountains, deserts, grasslands, cliffs and rivers. Its complex terrain and unique structure are a great miracle in the history of ancient architectural engineering. In desert areas, dry land has quicksand and lacks masonry. The Great Wall of Han Dynasty was built with local gravel and red willow separately, giving full play to the compressive properties of gravel and the tensile properties of willow branches. The city built by combining these two materials is very strong. After two years of wind, sand, rain and snow, many areas still stand as high as several meters. In the northwest loess plateau, the Great Wall is mostly rammed with rammed earth or adobe, which is as solid as brick and stone. For example, the wall of Jiayuguan Great Wall in Gansu Province was specially dug and transported from Heishan, more than ten kilometers away from Kansai, and it was compacted very tightly when rammed. This kind of wall is closely combined with soil and is not easy to deform and crack. In the Ming Dynasty, the Great Wall was mainly built with masonry and mixed masonry. The wall surface is made of stone or brick, and the joints are filled with white mortar, flat and sealed. Grassroots and roots are difficult to grow at the joints, and there is a drainage ditch at the top of the wall to protect the wall from rain.
The Great Wall is located at the junction of important crossings, steep mountain passes and mountains and seas, which can be used for both traffic and defense. Where the river crosses, the Great Wall has a sluice to let the river pass. For the need of defense, prominent city wall platforms are built at intervals on the city to facilitate shooting enemies near the city wall from left to right; There are enemy buildings within a certain distance, which are used to store weapons, food and grass for guards to live in, and can also be used as bunkers in wartime. There are also independent beacon towers along the Great Wall, which are used to raise fire and smoke and transmit information when the enemy attacks.
The Great Wall has profound cultural connotations.
Since the Great Wall was built, many magnificent historical dramas have been staged inside and outside the Great Wall. There have been many thrilling battles here, and many regime changes are related to the gains and losses of sticking to the Great Wall. It can be said that the history of China, a great country, was written inside and outside the Great Wall. With the occurrence of famous war cases inside and outside the Great Wall, many famous figures emerged, including many military strategists and politicians, which greatly enriched the cultural connotation of this ancient bean building in Xie Chang. During the Warring States Period, Li Mu built the Great Wall in Zhao, urged Portugal to resist the Huns' invasion, and created a brilliant example of the defensive war of car barriers, which was thanked by the broad masses of the people. In order to commemorate his achievements, later generations built an axe-hunting cave in Yanmenguan as a memorial, and the site of Ci Tang has been specially preserved so far.
The Great Wall is an ancient defense project with the longest construction time and the largest engineering quantity in China and even in the world. Since the 7th and 8th centuries BC, it has been built continuously for more than 2,000 years, which is distributed on the vast land in northern and central China, with a total length of more than 50,000 kilometers. It is called "more than 2,000 years up and down, and more than 100,000 miles in vertical and horizontal directions". Such a huge project is unique not only in China, but also in the world, so it was listed as one of the seven wonders of the Middle Ages with the Colosseum and the Leaning Tower of Pisa hundreds of years ago.
The history of building the Great Wall can be traced back to the Western Zhou Dynasty in the 9th century BC, in order to defend against the attack of nomadic people in the north. Once built a continuous arrangement of castles "Fierce City" as a defense. In the 7th and 8th centuries BC, during the Spring and Autumn Period and the Warring States Period, in order to compete for hegemony and defend each other, governors of various countries built the Great Wall on their own borders according to their own defense needs. In the 7th century BC, the Great Wall of Chu was first built, and then the vassal states of Qi, Han, Wei, Zhao, Yan, Qin and Zhongshan also built the Great Wall to protect themselves. At this time, the Great Wall is characterized by different directions in the east, south, west and north, and its length is short, ranging from several hundred kilometers to l000~2000 kilometers. Historians call it "the Great Wall of Pre-Qin Dynasty" to distinguish it from the Great Wall of Wan Li built by Qin Shihuang later.
In 22 1 BC, Qin Shihuang destroyed the governors of six countries and unified the world, ending the disputes in the Spring and Autumn Period and the Warring States Period, and completing the great cause of the first feudal centralized and unified country in the history of China. In order to consolidate the security of the unified empire and the stability of production, and to resist the invasion of slave owners of the powerful Xiongnu nomadic people in the north, the Great Wall was overhauled. In addition to using the original Northern Great Wall of Yan, Zhao and Qin, many parts have been added and expanded, "Lintao in the west, Liaodong in the east, spanning a Vandory", hence the title of Wan Li Great Wall. Since Qin Shihuang, almost all dynasties that ruled the Central Plains have built the Great Wall. More than ten dynasties, including Han, Jin, Northern Huai, Eastern Wei, Western Wei, Northern Qi, Northern Zhou, Sui, Tang, Song, Liao, Jin, Yuan, Ming and Qing, all built the Great Wall of different scales, among which the Great Wall of Han, Jin and Ming dynasties was the largest, reaching 5000 kilometers 10000. Their status is different. Judging from the ruling nationalities who built the Great Wall, besides the Han nationality, many dynasties in which ethnic minorities ruled China also built the Great Wall, more than those ruled by the Han nationality. During the reign of Emperor Kangxi of the Qing Dynasty, although the large-scale construction of the Great Wall was stopped, it was later built in some places. It can be said that the construction of the Great Wall has never stopped for more than two thousand years from the Spring and Autumn Period and the Warring States Period to the Qing Dynasty.
The defense engineering system of the Great Wall spans the Great Wall of Wan Li. It is not just a single city wall, but a complete defense engineering system composed of various fortifications, such as the city wall, watchtower, Guancheng, Dunbao, Yingcheng, Wei Shuo and Zhencheng beacon tower. This national defense engineering system is commanded and controlled by military command systems at all levels. Taking the Great Wall of Ming Dynasty as an example, nine military jurisdictions, Liaodong, Yuji, Fu Xuan, Datong, Shaanxi, Yulin, Ningxia, Guyuan and Gansu, were set up on the defense line of Wan Li Great Wall to defend and repair the Great Wall, which is more than 7,000 kilometers long from Yalu River in the east to Jiayuguan in the west, and is called "Jiubian Town". Every town has a company commander as the military chief of this section of the Great Wall, under the command of the Ministry of War. The defensive forces along the Great Wall in the Ming Dynasty were about 1 10,000 people. The company commanders are generally stationed in the town, while other officials at all levels are stationed in health centers, city camps, Guancheng and enemy towers and piers on the city walls.
The defense engineering construction of the Great Wall has accumulated rich experience in the construction process of more than 2,000 years. First of all, in terms of layout, when Qin Shihuang built the Great Wall in Wan Li, he summarized the experience of "blocking roads because of dangerous terrain". This principle has been followed for more than two thousand years and has become an important basis for military deployment. Based on the principle of "using local materials and teaching students in accordance with their aptitude", many structural methods have been created. There are rammed earth, rubble, masonry and other structures; In the desert, the structure of willow branches, reeds and sand grains is also used, which is called "ingenuity". In today's Yumenguan, Yangguan, Xinjiang and other places in Gansu Province, this section of the Great Wall remains in the Western Han Dynasty more than 2,000 years ago.
The Great Wall is the main part of this defense project. It is built on steep mountains or plains, and it is built according to the needs of topography and defense function. All places built on plains or main roads are very tall and strong, but they are relatively low and narrow in steep mountainous areas, in order to save manpower and cost. Even in some steep places, the methods of "dangerous mountain wall" and "splitting mountain wall" are conveniently adopted. In Juyongguan, Badaling and Hebei, Shanxi, Gansu and other regions, the Great Wall is general. On the top of the city wall, there is a building wall on the inside, more than one meter high, to prevent patrol soldiers from falling. Outside is the crib wall, about 2 meters high. The upper part of the stack wall is provided with a lookout, and the lower part is provided with a shooting hole and a rolling stone hole, which are used for observing the enemy situation and shooting rolling stones. On the top of some important city walls, there are layers of barriers to resist the enemies who climb the city walls in case. In the middle of Ming Dynasty, when the famous anti-Japanese star Qi Jiguang was transferred to Yuji Town as the company commander, the fortifications of the Great Wall were greatly improved, and enemy towers or platforms were set at the top of the wall to accommodate patrol soldiers and store weapons, food and socks, which greatly strengthened the defensive function of the Great Wall.
Guancheng: It is the most concentrated defensive stronghold on the defense line of Wan Li Great Wall. The position of Guancheng is very important, because it is chosen on a favorable defensive terrain, and it receives the effect of resisting powerful invaders with very few troops. In ancient times, it was called "one person guards it, and ten thousand people can't force it", which vividly explained the importance of Guancheng. Guancheng along the Great Wall is large and small, with a large number. As far as the Guancheng of the Great Wall in the Ming Dynasty is concerned, there are nearly 1,000 Shanhaiguan, Huangyaguan, Juyongguan, Zijingguan, Daomaguan, Pingxingguan, Yanmenguan, Pianguan, Jiayuguan, Yangguan and Yumenguan in the Han Dynasty. There are many small passes near some Daguancheng. For example, there are more than a dozen Xiaoguancheng near Shanhaiguan, which together constitute the defense engineering architecture system of the Great Wall of Wan Li. Some important passes have several lines of defense, such as Juyongguan, Nanguan, Beiguan and Shangguan. Badaling, the north entrance, is the most important outpost of Juyongguan.