Why did the Qin Dynasty build the Great Wall?

Qin dynasty is a country dominated by farming society. Therefore, in the territorial expansion of Qin, the first consideration is the area suitable for farming. The six countries destroyed by the Qin Dynasty were all areas with relatively developed agriculture after the Spring and Autumn Period and the Warring States Period. /B& gt； & lt/B& gt； Why did Qin Shihuang build the Great Wall of Wan Li? /B& gt； The ranges of the two are roughly coincident. The first picture is the first 350 years, and the last picture is the first 22 1 year, with a difference of 129. In 129, most of the parts that were not included in the previous map had been annexed by the seven countries at that time and were gradually becoming an agricultural society.

First of all, Bashu, which was not in the map of the Seven Kingdoms during the Warring States Period, is located in the Chengdu Plain, with fertile land, warm climate, abundant water resources and developed agriculture. It is one of the earliest agricultural areas in ancient China, with economic strength independent of the Central Plains. Qin Chu had fought with Bashu before, but because of Bashu's national strength and unique terrain, it didn't achieve any success. However, 34 years after the first painting, that is, in the ninth year of Yuan Geng, King of Qin Hui (3 16 BC), the State of Qin used Shu to form an alliance with Ba and Ju, and Ju formed an alliance with Qin to defend Chu, asking Qin for help. On the one hand, the two countries made peace with South Korea, which was at war at that time, on the other hand, they destroyed Shu in one fell swoop by imaginary enemies. Then, taking advantage of the armed forces of the two countries, they destroyed the two countries in one fell swoop and completed the annexation of Bashu land. Four years later, in the thirteenth year of King Hui of Qin (3 12 BC), the three kingdoms of Qin, Han and Wei jointly attacked Chu, and Chu was defeated. Qin occupied Hanzhong of Chu State, connecting the local Guanzhong of Qin State with Bashu area, and further strengthening its control over Bashu area. Therefore, when Qin was unified, Bashu, as a mature agricultural area, had long been the territory of Qin.

Besides, the land of Lingnan, the State of Chu once conquered Yangyue, that is, South Vietnam, and captured Guangdong, Guangxi, southwestern Jiangxi and southern Hunan. Chu Weiwang (reigned in 339-329) was located in the central county of Guizhou, named after Qian Shan, and governed western Hunan and northeastern Guizhou. This also proves that Guangdong, Guangxi, southwestern Jiangxi, southwestern Hunan and northeastern Guizhou, which were originally controlled by the State of Yue, were partly owned by the State of Chu during the Warring States period.

After the Qin Dynasty destroyed the Six Kingdoms, it can be seen from Figure 2 of Forty-two Counties of Qin Dynasty that the areas of the four counties in central Guizhou, Changsha, Jiujiang and Huiji are obviously larger than other counties, which is determined by the low overall development level of the local area, indicating that although Chu and Yue controlled these areas, the population density and economic development level are far from comparable to those of traditional agricultural areas. However, because the soil and climate in this area are still very suitable for agricultural development, Qin strengthened its control over these areas after unifying the six countries. After Wang Jian commanded 500,000 troops to destroy Chu, he continued to March toward Baiyue. According to. Huai Nan Zi recorded that Li Yue's rhinoceros horn, ivory, jade and pearls killed 500,000 people in Wei Tu, and it was five armies: one army blocked the city (ridge), one army guarded the nine doubts, one army guarded the capital Panyu, one army guarded the border of Ye Nan, and the other army guarded the dry water. The verbs "stop", "keep", "place" and "knot" used here are interactive and all mean to be stationed. "I can't understand armor for three years" means that I am still in a state of confrontation and defense. Therefore, from the above historical facts and the second picture, we can know that the boundary between Qin and South Vietnam is roughly Wuyishan in the east and Nanling in the south. On the one hand, Qin controlled the four counties of central Guizhou, Changsha, Jiujiang and Huiji because it was the hometown of Chu and Yue and had a certain agricultural foundation; On the other hand, the soil and climate conditions in these areas are suitable for farming. This is, of course, an unwilling part of the Qin State, which is based on agriculture. Since then,10000 to150000 people have been forcibly moved to these old places in South Vietnam to strengthen the development of this arable land. As for the Qin Dynasty finally leaving Nanling, breaking with South Vietnam and establishing Guilin, Xiang Jun and Nanhai counties, I think it is of great significance to restrain the regime.

From the above two points, it can be preliminarily understood that the main goal of Qin's land occupation is whether it is suitable for farming, while the land outside the Great Wall is grassland and desert, which has no farming value. Therefore, Qin did not require much land in Xiongnu area. What he hopes is that nomads will not plunder the wealth of agricultural areas. In this case, it is a favorable choice to build the Great Wall with suitable farming as the boundary and take the defensive position in the north. What's more, this policy was the same choice for Qin, Zhao and Yan, three countries bordering Xiongnu during the Warring States period. Why did Qin Shihuang build the Great Wall of Wan Li?

Qin destroyed six countries and its territory expanded many times. However, the occupation of land does not mean the ultimate reunification. Although Genghis Khan established a great empire across Europe and Asia, it vanished in a hundred years, mainly because he did not unify the cultural and ideological systems and other aspects of social life in these countries. After years of development, the six countries have formed their own different cultures, and each has its own cultural preferences and policies for governing the country. What's more, these countries have different languages, different economic systems, different folk customs and different political systems. The country has just died, and people are old. If they are not careful, they may fall into a split situation again. Therefore, Qin Shihuang began a series of reforms. He unified writing, currency and weights and measures, implemented centralized system, divided administrative regions, established counties and built official roads. Qin Shihuang was sober after unifying the six countries. He knows where his political center of gravity should be. His series of measures greatly improved the centripetal force of subjects who originally belonged to various countries, made them integrate with each other, and gradually gained a sense of identity with this unified country, thus firmly controlling the situation in the world and providing a reference model for future generations, so that Liu Bang's state and county settings were based on the Qin system when the founding of the People's Republic of China, while the political system of future generations was mostly repaired and innovated on the basis of the Qin system.

As can be seen from the above, after the unification of the six countries, Qin Shihuang put a lot of energy into digesting and absorbing the areas that originally belonged to the six countries, and it was not easy to establish such a huge country. The effective control of this area and its eternity were the key points considered by the first emperor. As for the wilderness beyond this, as long as you don't offend me, I will stick to it. It is hard to guarantee that the first emperor didn't think so: solve the problem, hehe, leave it to future generations to exert their wisdom. Therefore, we are more determined to build the Great Wall of Wan Li. Why did Qin Shihuang build the Great Wall of Wan Li?

There is no doubt that Qin Jun's fighting capacity is very strong. Crossbow is one of the best weapons against cavalry. The strongest crossbowman in China's history came from the Qin Dynasty. Qin crossbow is different from ordinary bows, and it can only be wound with the help of the whole body. Some experts estimate that the range of this Qin crossbow should reach 300 meters, and the effective killing distance is within 150 meters. The lethality of Qin crossbow was much higher than that of any kind of bow at that time, and it could easily penetrate ordinary armor. In the history of Qin Jun's crusade against Huns, he used this crossbow to drive Huns to the north of the Yellow River in a short time. Qin Jun also has a heavy infantry, equipped with heavy spears. The complete spear is close to 7 meters, which is used to level the phalanx of the pack and is invincible. These two armies played an important role in the process of Qin Jun's unification of the six countries. And these two arms are absolutely not inferior to tarkan.

But one factor that can't be ignored is the logistics support of the army. Qin destroyed the six countries, and the land of the six countries is agricultural areas, so the collection of rations can be based on local materials. In addition, the six countries and Qin Jun are fighting positional warfare, and they are fighting farmland according to farmland. When Qin destroyed the six countries, it had a population of only 67 million, but it supported1100 million troops to fight all the year round. In addition to its own developed farming, the local solution of materials is an aspect that cannot be ignored. Dealing with the Huns is completely different. Huns are nomadic people and mobile troops. Strong mobility, it is not appropriate to find a decisive battle opportunity soon. Later, Han failed to attack Xiongnu several times because he could not find the main force of Xiongnu for a long time. Moreover, we should go deep into the land of Xiongnu and stay away from the agricultural areas, and all supplies should be taken from the agricultural areas. In the era of low productivity and mode of transportation, the shortage of supply directly restricts the combat effectiveness of the troops.

The inconvenience of ancient war materials can be understood from Meng Qian Bi Tan written by Shen Kuo in the Northern Song Dynasty. This passage is translated into the following meaning:

How to get food from the enemy is the most urgent thing in all marching operations. It is not only expensive to transport grain by yourself, but also difficult to transport it far according to the situation. I have calculated that a civilian worker can carry six bushels of rice, (a soldier can take five days of dry food, and a civilian worker can supply a soldier for eighteen days at a time. Six bushels of rice, two liters per person per day, and two people for eighteen days. If you want to plan a return trip, you can only go forward for nine days. If two civilian workers supply one soldier, you can last 26 days at a time. Two buckets of rice with one stone, three people eat six liters a day. Eight days later, one of the civilian workers ate all the rice on his back, so he was given six days' rations to go back first. For the next eighteen days, the two of them ate four liters of rice every day. Eat six liters of rice every day for the first eight days, and four liters of rice every day for the last five days and the return trip. ) Three civilian workers can supply a soldier for three days at a time, and two people carry rice and one stone and eight fights. For the first six and a half days, four people ate eight liters of rice a day, MINUS one civilian worker, and gave him four days' rations. After seventeen days, three people have to eat six liters a day, MINUS one civilian worker, and give him nine days' rations. If you want to count the return trip, it can only be sixteen days in advance. You eat eight liters a day for the first six and a half days, six liters a day for the next seven days, and four liters a day for the last eleven days and the return trip. ) Three civilian workers for one soldier have reached the limit. If we want to send100000 troops, the trench should account for one third, and only 70000 soldiers can participate in the war, we will use 30000 civilian workers to transport food. It is difficult to expand the scale again. Repatriation of migrant workers should be escorted by soldiers, because there will still be deaths and diseases during transportation, and these reduced food supplies should be used to escort soldiers. The number of six bushels of rice carried by each person is also calculated according to the total number of civilian workers, because the captain can't carry it himself, and the person in charge of drawing water and cutting wood can only carry half of it, and what they reduce will be spread on all heads. In addition, there will be people who die of illness, and their backs will be shared by everyone. In fact, everyone carries more than six buckets. So there are no idle people in the army, and it is not enough for one idle person to provide two or three people for him. If transported by livestock, camels can carry three stones, horses or mules can carry five buckets of one stone, and donkeys can carry one stone. Compared with manpower, although it can carry more and cost less, if it can't graze or feed in time, the animal will die of emaciation, and even the food it carries will be abandoned when an animal dies. So compared with labor, each has its own gains and losses.

From this passage, we can see the difficulties of ancient material transportation. Moreover, the design of Shen Kuo is still in an ideal state, and it is difficult to reach such a high level under normal circumstances. Assuming that an army can advance and retreat at an average speed of 40 kilometers per day, with the supply of 300,000 civilian workers, the activity radius of 70,000 combat soldiers (another 30,000 are responsible for the trench) is only 640 kilometers. Assuming Xianyang as the starting point, Qin's army can only reach a place not far outside the Yellow River Hetao. So after the Qin Dynasty destroyed the Six Kingdoms, Qin Shihuang asked Meng Tian to attack the Huns with 300,000 troops and recover the Hetao area. It also proves that the operational radius can only be in Hetao area. Besides, after the reunification of Qin at that time, the national population was about 20 million. Excluding women, the elderly and officials at all levels, the total number of soldiers and civilians who can be recruited is 5 million. At this time, 700,000 Epang Palace and Lishan Mausoleum were recruited all the year round, as well as 500,000 troops stationed in South Vietnam, migrant workers with logistics support, migrant workers stationed in various places and migrant workers who built post roads. Imagine that 65,438+10,000 troops need 300,000 civilian workers as a guarantee, and 300,000 troops need millions of civilian workers to transport supplies. The civilian workers that can be used in the Qin dynasty are a bit insufficient.

Therefore, from the point of view of military logistics support, more than one million soldiers and civilian workers have repeatedly attacked the highly mobile Xiongnu troops with a small operational radius, creating a desert with difficult agricultural production. For Qin, it is not worth the loss, and the Great Wall of Qin, Zhao and Yan has not been connected, so it is more practical to defend it. So Qin chose to build the Great Wall to resist the Huns.

As for Emperor Wu of the Han Dynasty, after a long period of recuperation, the national treasury was sufficient and the population increased to 50 million. Only then did the decisive battle against Xiongnu begin, and it was defeated several times. However, the treasury of the Han Dynasty also dried up, which planted the seeds of decline.