Chen Zhao: How long is China's Great Wall?

As the oldest and largest piece of architecture ever built by mankind, and the most popularly known World Heritage Site in China, the Great Wall has become a magnificent architectural feat and significant cultural contribution to the history of human civilisation, within. As China redefines the concept of the Great Wall on the national level, and research pertaining to the Great Wall penetrates deeper, the assumption that “the Great Wall is 6,700 kilometres long from Shanhaiguan in the east to Jiayuguan in the west”, is now open to question. How long is the Great Wall of China? Why is it so difficult to measure the length of the Great Wall? What are the controversies surrounding the eastern and western starting points of the Great Wall in China? Professor Chen Zhao of Northeastern University and Director of the Great Wall Institute of China was recently interviewed by East Meets West to discuss such topics.

Chen Zhao is Director of the Great Wall of China Research Institute, PhD supervisor and Professor of Northeastern University. He is the director of the Research Committee on the Cultural Heritage of Ancient Architecture in China, head of the National Excellence Course and the National Excellence Resource Sharing Course, and the main lecturer of the National Video Open Course. He is the Deputy Editor-in-Chief of the Great Wall Volume of the Encyclopedia of China.

What changes have occurred in our understanding of the Great Wall as research on the Great Wall has advanced? What are the features of the Great Wall within China?

Our understanding of the Great Wall has always been incomplete. When the Great Wall is mentioned, most people think of the long wall that existed during the Ming dynasty, like the one at Badaling in Beijing. When talking about the length of the Great Wall in China, most people talk about the length of the Ming Great Wall. However, the Ming wall is only one of the most important segments of the Great Wall’s 2,700-year construction history. The Great Wall was formed three times in Chinese history: the Great Wall of the Qin Dynasty, the Great Wall of the Han Dynasty and the Great Wall of the Ming Dynasty. In order to count the full length of the Great Wall, it is necessary to include the Great Wall built by all the dynasties.

Diagram of the Great Wall of China during the Qin, Han and Ming dynasties. Credit: The Great Wall Institute of China

Secondly, traditionally, it was thought that only the long wall was the Great Wall. For many years, calculations of the length of the Great Wall have been made by measuring only the length of the wall, ignoring the fact that the Great Wall was a complete military defence system that with groups of garrisons and beacons that also belonged to the Great Wall system.

The Great Wall with its supporting walls and beacon towers, Jinshanling Great Wall, Luanyuanping County, Hebei Province. Credit: Chen Zhao

Why is it so difficult to measure the length of the Great Wall of China?

Nowadays, the concept of the Great Wall has changed. Originally, only the length of the long wall was counted, but now beacons, garrisons, post stations and passes are all included, which makes a calculation of new length difficult.

In fact, the Great Wall is not a single line as such, but a systematically distributed belt of structures. As a fortification, its structure contains not only a long wall, but also beacons and garrisons on both sides of the wall that are distributed vertically with the wall. This is one way to calculate the linear length of the Great Wall.

Another way is to consider the Great Wall as a belt, with two sides of the wall interacting, and to calculate not only the length from east to west, but also the length from north to south. In addition, there are the branch walls that extend out (a separate section of the defensive wall that divides from the main line of the Great Wall, with palisade walls on both sides).

Overlooking the Great Wall and its supporting walls, Huang Yaguan, Jixian County, Tianjin. Credit: Chen Zhao

Moreover, most of the Great Wall in China is not actually connected, and many sections rely on natural barriers without the need to build long walls. So, should the length of mountain and river barriers be counted? Or should only the length of the Great Wall itself be counted? There is no consensus among academics on this issue. In addition to the mountain and river barriers, the Great Wall also has the natural defense of snowy mountains and deserts. The question of what criteria should be used to calculate the length of the Great Wall is one that needs to be resolved.

The picture shows HuangYiaguan in Jixian County, Tianjin. Credit: Chen Zhao

As we all know, apart from the Great Wall on land, China also has the Great Wall of the sea, such as the Old Dragon Head Great Wall in Shanhaiguan District, Qinhuangdao City, Hebei Province, the Great Wall of the Shanhai City and Island Defence System in Xingcheng Ancient City, Liaoning Province, the Jiangnan Great Wall in Linhai City, Zhejiang Province, and the military system of sea defence built by the Ming and Qing Dynasties, etc. There is also the Great Wall on water, such as the Great Wall on water at Jiumengkou, which crosses the Jiujiang River in Suizhong County, Liaoning Province, and the Great Wall on water at Jiuhukou in Shuozhou City, Shanxi Province.

The Great Wall on the Water, Jiumengkou Great Wall, Suizhong County, Liaoning Province. Credit: Chen Zhao

Counting the length of the Great Wall is not a simple task and requires a unified understanding of the Great Wall among surveyors, a unified standard of measurement and a unified method of calculation in order to minimise errors in the measurement of the length of the Great Wall.

It is important to note here that it is not that the previous statistics were incorrect, it is just that as the times and our perceptions have changed, our definition of the Great Wall has changed and with it the calculation and lengths of the Great Wall have changed.

What controversies still exist about the eastern and western beginnings of the Great Wall in China?

As the length of the Great Wall has been further explored, new discoveries have been made about the eastern and western beginnings of the Great Wall in China.

In the 1980s, scholars believed that the Jiayuguan was the westernmost point of the Great Wall, based on records in ancient books. So, is there a Great Wall west of the Jiayuguan? As we learn more about the Great Wall, the Great Wall continues to the west at a distance of more than 300 kilometres in a straight line to the Yumenguan, an important pass on the Great Wall established during the Han Dynasty. In 1997, academic organisations identified the Beidili Beacon in Xinjiang as the westernmost beacon of the Great Wall of China.

Is there a Great Wall to the west of the Beidili Beacon? For this reason, the Great Wall of China Research Institute has visited Xinjiang several times and finally discovered a new Great Wall site in Wucha County at a distance of 394.65 kilometres in longitude to the west of the Beidili Beacon, confirming that the Mashrep Beacon in Ucha County is the westernmost Beacon of the Great Wall of China that can be found at present.

The Mashrep Beacon in Ucha County, Xinjiang, is the westernmost beacon of the Great Wall of China that can be found. Credit: Chen Zhao

The Great Wall of China Research Institute has proposed four “western starting points”, namely the line between the Mashhep and Atushi beacons in Ucha County, Xinjiang, the line from Gongzhongbao to Jianggaal and Shicheng in Taxian County, Xinjiang, the line between the Beidili beacons in Ush County and Ahechi County, Xinjiang, and the line between the beacons in Ili Kazakh Autonomous Prefecture, Xinjiang. These four “Western Beginnings” are the four sections of the Great Wall that run westwards, leading to different mountain passes and to different border countries.

In October 2022, the Great Wall of China Research Institute conducted a field study at the Sino-DPRK border in Kuandian Manchu Autonomous County, Dandong City, Liaoning Province, and discovered that the Xinglongbao beacon, currently located in Hongshi Town, Kuandian Manchu Autonomous County, may be the easternmost beacon on the Yalu River in China from the Sino-DPRK border- the first beacon at the eastern end of the Great Wall of China. Located on the main peak at an altitude of 209 metres, this beacon is likely to be a relic of the early Great Wall.

The first beacon at the eastern end of the Great Wall of China - the Xinglong Fort beacon in Hongshi Town, Kuandian Manchu Autonomous County, Dandong City, Liaoning Province. Credit: Chen Zhao

It must be said that the wisdom of the ancients in adapting to local conditions, as shown at the “Eastern and Western Beginnings of the Great Wall” will continue to be explored and discovered in the future during fieldwork.　　