In Beijing, there is a legendary line. This 7.8-kilometer-long virtual line is the epitome of the history and culture of the capital Beijing, and it is also the central line of Beijing's urban planning and layout-the Beijing central axis. Today, this central axis, which combines the essence of traditional culture with modern industry and modern architecture, is making preparations for applying for world-class intangible cultural heritage. What kind of hardships has the world's longest urban planning axis experienced in the process of formation, protection and urban construction? This article will trace back to the source, take you to the long river of history, and explore the past lives about Beijing's central axis.

The Yuan Dynasty was founded after three dynasties

As early as 3 years ago, there was a record of urban planning in Zhou Li Kao Gong Ji. The so-called "left-handed and right-handed society" and "facing the market outlook" are based on balanced symmetry, and there must be a central axis in the city. This axis is the central backbone of the whole city, and all the buildings are spread out on both sides of it, and only the supreme palace can be built on the axis.

Throughout the history of China, the rulers of various dynasties made such plans when they established their capitals, but due to various factors, Xianyang in the Qin Dynasty and Chang 'an in the Han Dynasty failed to realize them. Although the balanced and symmetrical planning of Chang 'an in Tang Dynasty began to take shape, it was not perfect. It was Yuan Dadu who really realized this idea, and Beijing further expanded it to Yongdingmen in Ming Dynasty. The Qing dynasty inherited it completely, that is, the pattern of the old Beijing city.

since ancient times, although the site of Beijing has changed, the basic pattern has always had an important element-it is controlled by the central axis of the city, which is a prominent feature of China, especially the capital. The central axis of Beijing began with the planning and design of the Yuan Metropolitan City, and reached its present scale in the Ming and Qing Dynasties. It starts from Yongdingmen in the south and ends at the Bell Tower in the north, with a total length of 7.8 kilometers. It is the longest city axis in the world, and many famous cultural relics and historic sites in Beijing are on this line. The existing major cultural relics include Yongdingmen (rebuilt), Yandun, Temple of Heaven, Xiannongtan, Zhengyangmen, Ancestral Temple, Shejitan, Tiananmen Square, Forbidden City, Jingshan, Beihai, Imperial City Wall, pudu temple, Wanning Bridge, Vulcan Temple, Drum Tower and Bell Tower. After the founding of New China, Tiananmen Square was expanded one after another, and the Monument to the People's Heroes and Chairman Mao Memorial Hall were built. At present, many areas with relatively mature functions have been formed around the central axis, such as Shichahai, Nanluoguxiang, Qianmen, Dashilan and other traditional commercial streets, the World Cultural Heritage Tourist Area around the Forbidden City and the Temple of Heaven, the Tiananmen Square, and the relatively concentrated government service areas in Zhongnanhai and Dongjiaominxiang.

Just when it is generally believed that the central axis is due south and due north, an expert's conclusion broke this 7-year-old knowledge.

While preparing to take a panoramic bird's eye view of Beijing, researcher Kui Zhongyu of China Academy of Surveying and Mapping suddenly found out from the aerial images, satellite images and maps of Beijing that the north-south central axis of Beijing is not due south, but offset. In order to prove the phenomenon that "the north-south central axis of Beijing deviates from the meridian", Kui Zhongyu first selected three points on the topographic map of Beijing, namely Yongdingmen, Di 'anmen and Bell Tower, and calculated that the deviation angle was 2 degrees and more than 1 minutes, and then conducted an "immediate" test on the north-facing Yong Road under Yongdingmen Gate Tower.

"We set up a 2-meter-long pole in the middle of Yong Road. From the bottom of the pole, stick a 6-meter-long black tape to the north along the center line of Yong Road, indicating the central axis. When the sun passes through the Yongdingmen meridian, the shadow of the pole is on the Yongdingmen meridian. The angle between the shadow and the black tape is the angle between the meridian and the central axis. After measurement and calculation, the deviation of Beijing's central axis from the meridian is also 2 degrees and more than ten minutes. According to this calculation, from the central axis starting from Yongdingmen to the bell tower, it has deviated from the meridian by 3 meters. "

after the fact that Beijing's central axis deviated from the meridian was revealed, there was a very influential saying that the designers of the Yuan Dynasty were Han Chinese, and they deliberately refused to let the emperor of the Yuan Dynasty sit on the central axis because they were dissatisfied with the hierarchy of the Mongols.

If you want to find out whether this statement has any basis, you must know what kind of designer Yuan Dadu is. Speaking of it, this designer is really a legendary figure.

Lu You, a poet in the Song Dynasty, wrote in the poem "Book Anger": "A teacher shows his true world, but who is equal in a thousand years?" Some people commented that after 1 years, there really is a person comparable to Zhuge Liang, and he is Liu Bingzhong, a famous minister in the Yuan Dynasty.

Liu Bingzhong was born in 1216 in an official family in xing zhou (now Xingtai, Hebei). Liu Bingzhong was not only good-looking, but also smart. He entered school at the age of 8 and "recited hundreds of pages a day". At the age of 17, he became a government official in Xingtai. Liu Bingzhong was not at ease with the job of making a copywriter, and he was unhappy all day. Finally, one day he went to Wu 'anshan to become a monk, and his legal name was Zi Cong.

Liu Bingzhong was not only a politician, but also a first-rate scholar, scientist and poet at that time. Zhang Wenqian, Wang Xun and Guo Shoujing, who studied with him in Zijinshan, Cizhou, southwest of Xingtai, all said that they learned from loyalty. Wang Xun, a teacher of Prince Zhenjin, was famous for his arithmetic. Later, Wang Xun and Guo Shoujing took the test day and night to create the Chronology Calendar. Liu Bingzhong's accomplishments in arithmetic, astronomy, calendar and water conservancy can be seen. His "Lotus Leaf Misty Cave" was included in Lu Qian's "Three Hundred Yuan Songs": "South Peak, north peak, bleak misty cave. Song Gaozong, with a sieve, Wu Shan is still full of wine and flags. Two Jiangnan dreams. " Mao Zedong is very appreciative and has written again and again.

Liu Bingzhong not only helped Kublai Khan design the blueprint for the founding of the People's Republic of China, but also was the designer of two capital cities in the Yuan Dynasty, namely Shangdu and Dadu, and left amazing achievements in the history of urban construction in China and even the world. Among them, Yuan Dadu was founded in 1267 and completed in 1285, which lasted for 18 years.

In view of the historical fact that the policy of ethnic oppression was carried out in the Yuan Dynasty, some historians put forward the view that the central axis was deliberately deviated by Liu Bingzhong and Guo Shoujing, the Han ministers, that is, they did not follow the emperor's intention to make the central axis affecting the urban layout on the meridian of due south and due north, in an attempt to resist the rule of the Yuan Dynasty.

Some scholars have questioned this, because there is no convincing evidence for the above statement. Therefore, there is a second view: it may be that the builder adopted the magnetic needle positioning method, which caused technical errors. However, Kui Zhongyu thinks this reasoning is not convincing. After all, Liu Bingzhong and Guo Shoujing were outstanding scientists at that time, and they would use astronomical measurements with high precision, but "it is unlikely to use magnetic needle positioning which proved to be extremely error at that time". In addition, there is also a saying that the central axis may be skewed due to the destruction of natural factors.

kui Zhongyu focused on Kublai Khan, the grandson of Temujin, the first emperor of the yuan dynasty. "This central axis was built during the reign of Kublai Khan. Is its formation also related to the local yuan where Kublai Khan rose?"

With questions, Kui Zhongyu and others continued to measure maps and conduct field trips. In the end, they found that the central axis of Beijing continued to extend northward, and the extension line just passed through Gukaiping, which is more than 27 kilometers away from Beijing, that is, Zhaonaiman Sumer of Xilin Gol League in Inner Mongolia Autonomous Region.

According to the local Mongolian historian, Zhaonaiman Sumer is the site of Shangdu in Yuan Dynasty. That's where Kublai Khan moved his capital to Yuandadu (now Beijing). As a matter of fact, Kublai Khan in Yuan Shizu implemented the "two-capital patrol system": working in the Yuan Dynasty in winter, the so-called "winter capital"; In summer, I work in the capital, which is called "Summer Capital".

from this, researcher kui Zhongyu believes that the fact that the central axis deviates is intentional by Kublai Khan, the founding emperor of the yuan dynasty. Because the archives of the "Mongolian Empire" in the Yuan Dynasty are incomplete, scientists and historians are still struggling to find the answer in specific textual research and reasoning.