World Cultural Heritage: The Great Wall (2)

The history of the Great Wall's construction: The history of the Great Wall's construction can be traced back to the 9th century B.C. during the Western Zhou Dynasty as a way to resist attacks from the nomadic people to the north. Many fortresses were built to resist the invasion. Around the 7th or 8th century B.C., in order to strive for supremacy and defense, the rulers from the Spring and Autumn period began building the Great Wall on their border lines based on their own defensive needs. The Great Wall of the State of Chu in the 7th century B.C. was the first wall built, and then the states of Qi, Han, Wei, Zhao, Yan, Qin and Zhongshan also began constructing walls in succession for self defense. At that time, the characteristics of the Great Wall were: the walls were different in the east, south, west and north, and their length ranged from hundreds of kilometers to around 2,000 kilometers. In order to distinguish these walls from those built by Qin Shi Huang, the historians called them "the Great Wall of the pre-Qin Dynasty" as a whole.

In 221 B.C., Qin Shi Huang eliminated the six states, unified the whole of China, ended the chaos of war in the Spring and Autumn period, accomplished the great cause of national reunification, and established the first centralized feudal state in China. In order to ensure safe and stable production and to prevent invasions and harassment from the strong nomadic nationality to the north, the Qin Dynasty began constructing the Great Wall. In addition to using the original parts built by the states of Yan and Zhao in northern areas, the Great Wall was extended to Lintao County in the west and Liaodong in the east with a length of over 5,000 kilometers. Therefore, it was also praised as the "Wanli Great Wall," meaning it is very long.

After Qin Shi Huang, almost every emperor extended the Great Wall during their reign in central China, including the Han, Jin, Northern Wei, Eastern Wei, Western Wei, Northern Qi, Northern Zhou, Sui, Tang, Song, Liao, Jin, Yuan, Ming and Qing dynasties. Among them, the Han, Jin and Ming dynasties had the largest construction scale, and the walls built during the three dynasties were all 5,000 to 10,000 kilometers in length and had different locations. As for the nationalities that once took part in the construction of the Great Wall, many minorities also renovated and extended the Great Wall during their reign in addition to the Han nationality. More parts of the Great Wall were built during the reign of minority nationalities than the Han nationality. During the Kangxi Emperor period in the Qing Dynasty, although the large-scale construction of the Great Wall was stopped, some similar walls were indeed built in a few places. It can be said that during the more than 2,000 years of history from the Spring and Autumn period to the Qing Dynasty, the construction of the Great Wall had never been truly stopped.

The defense engineering system of the Great Wall: The Great Wall stretching thousands of miles is not just a single wall but a complete defensive system composed of many defense equipment including walls, watch towers, fortresses and beacon towers. The defensive system was controlled by all levels of the military chain of command. Taking the Great Wall of the Ming Dynasty as an example, nine military jurisdictional areas including Liaodong, Datong, Yulin, Ningxia, and Gansu were established on the Great Wall for defense and maintenance of the Great Wall, ranging from the Yalu River in the east and Jiayuguan in the west. Therefore, the nine military jurisdictional areas were called the "nine major defensive areas," with a chief military officer taking charge of defending each section of the Great Wall or supporting the adjacent regions. There were about a million soldiers guarding along the Great Wall in the Ming Dynasty. The military chief normally lived and worked inside the cities and other officials at all levels were stationed in the watch towers and fortresses in defense areas, campsites and walls.