Why does the central axis of the Forbidden City deviate from the central axis of Beijing?

What causes the deflection of the central axis can be traced back to more than 700 years ago.

Researcher Kui Zhongyu and many historical researchers conducted in-depth discussions. First of all, it is clear that the existing central axis of Beijing follows the central axis of the Yuan Dynasty.

“When Genghis Khan conquered Jingzhongdu (today’s Beijing), he completely destroyed it. After that, the Yuan Dynasty established Yuanzhongdu on the basis of Jingzhongdu; in the Ming Dynasty, in order to prevent the Mongols, On the basis of the Yuan Zhongdu, a line of Deshengmen was added, while the east and west city walls followed the earth city of the Yuan Dynasty to enclose the city wall, and the direction of the central axis remained unchanged; the Qing Dynasty used the Ming City, and the central axis has not changed. To this day It has been more than 730 years."

There are different interpretations of the central axis mystery. One theory is that "the Han people did it intentionally."

Why is the central axis skewed? The focus of attention naturally focuses on the person in charge of the project. So who presided over the construction of the central axis of the Yuan Dynasty? Kui Zhongyu said that the person in charge of "supervision of construction" was Liu Bingzhong, an important minister of Kublai Khan. It is generally believed that the construction of the central axis of the Yuan Dynasty was presided over by Liu and his student Guo Shoujing, both of whom were from Xingtai, Hebei.

In view of the historical facts of the Yuan Dynasty’s policy of national oppression, some historians have put forward the view that the central axis was deliberately deviated by Han ministers Liu Bingzhong and Guo Shoujing, that is, they did not follow the emperor’s intention. The central axis that affects the city's layout was placed on the meridian of true south and true 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. So there is a second opinion: it may be that the builder used the magnetic needle positioning method, which caused a technical error. However, Kui Zhongyu thinks this reasoning is not very convincing. After all, Liu Bingzhong and Guo Shoujing were outstanding scientists at the time. They would use higher-precision astronomical measurements, and "use the magnetic needle positioning which proved to be extremely inaccurate at the time. It’s unlikely.” In addition, there is also a theory that the central axis may be deflected due to damage by natural factors.

Kui Zhongyu was surprised to find that the central axis pointed to the site of Shangdu in the Yuan Dynasty.

Kui Zhongyu focused his attention on Kublai Khan, the first emperor of the Yuan Dynasty and the grandson of Temujin. "This central axis was built during the reign of Kublai Khan. Is its formation also related to the rise of Kublai Khan in the Yuan Dynasty?"

With doubts, Kui Zhongyu and others continued to measure Calculate maps and conduct field trips. Finally, they discovered that the central axis of Beijing continued to extend north, and the extension line happened to pass through ancient Kaiping, which is more than 270 kilometers away from Beijing, which is now Zhaonai Mansumo in Xilingol League, Inner Mongolia Autonomous Region.

According to local Mongolian historians, Zhaonai Mansumo is the location of the ruins of Shangdu in the Yuan Dynasty. Kublai Khan moved his capital from here to Yuan Dadu (today's Beijing). In fact, Kublai Khan, the founder of the Yuan Dynasty, implemented the "two-capital patrol system": he worked in Dadu of Yuan Dynasty in winter, and Dadu of Yuan Dynasty was the so-called "winter capital"; in summer, he worked in Shangdu of Yuan Dynasty, and Yuan Shangdu was the "summer capital".

Thus, researcher Kui Zhongyu believes that the deviation of the central axis was intentional by Kublai Khan, the founding emperor of the Yuan Dynasty. Due to the incompleteness of the Yuan Dynasty archives of the "Mongol Empire", scientists and historians are still struggling to find answers in terms of specific research and reasoning.

Kui Zhongyu said that from the Yongding Gate in the south to the Bell Tower in the north, Beijing’s current central axis is 7.7 kilometers long (the media often reported it as 8 kilometers). It should be regarded as the distance from the Yuan Dynasty ruins to Beijing. The 270-kilometer "southern end of the Liangdu Line".

Background knowledge

The 7.7-kilometer central axis from Yongding Gate to the Bell and Drum Tower is the central symbol of the ancient capital Beijing and is also the longest existing urban central axis in the world. Beijing was called Jingzhongdu more than 850 years ago, specifically referring to the location of Guang'anmen. In 1620, Genghis Khan attacked the central capital three times, and Kublai later established the capital of the Yuan Dynasty on this basis.

Emperors in ancient China all claimed to be the emperor, so they built a nine-layered heavenly palace, "facing north and south, with the palace connected to the sky", trying to create the illusion that the king's power was "ordained by heaven".

However, from the Yuan Dynasty to the fall of the Qing Dynasty, the places where 33 emperors worked and slept were not oriented "south and north" - in the architectural pattern of Beijing for more than 700 years, the central axis starting from It plays a very important role, but today's experts and scholars have discovered that it does not coincide with the meridian...

Aerial survey experts looked at the panoramic view of Beijing and found that something was wrong.

Kui Zhongyu, a researcher at the China Academy of Surveying and Mapping, successfully "captured" a panoramic image of Beijing with a special camera. This expert in aerial photography and remote sensing has participated in several famous military reconnaissance missions in the early 1960s and is experienced and sophisticated.

Faced with the large-scale "Beijing Satellite Imagery" and "Beijing Aerial Imagery", the old man felt that something was "wrong". His gaze at that time stayed on the central axis - this was enough to affect The "backbone" of the entire urban structure, "whether in Paris, London, Tokyo, or Beijing."

On that day, Kui Zhongyu's sight went "north" along the central axis of Beijing on the image map, and his head turned to the left unknowingly, which surprised him - the central axis should be the same as the central axis of Beijing. It is facing "due south and due north". "Is there something wrong with the aerial photography?"

The central axis on the map is "offset", and "the bell tower is offset by about 300 meters."

“When you print the geographical coordinates, it (the central axis) deviates from the meridian by more than two degrees, but less than two and a half degrees.” Kui Zhongyu told reporters - before making a comment on the panorama. After measuring, he came to this conclusion.

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Kui Zhongyu introduced that on a precise topographic map, the central axis shows this “deviation”: starting from the starting point at the southern end (Yongding Gate), it begins to deviate in a counterclockwise direction as it extends northward. Meridian, and the actual distance after conversion from the end point (bell tower) is about 300 meters away from the meridian!

Did the surveying experts and mapmakers collectively make a mistake?

In Beijing during the feudal imperial era, the central axis coincided with the meridian and was in the direction of "true south and true north". In the "common sense" of most people, this was a "natural and logical" truth, and it is still present to the world today. Why is the central axis in front of me "crooked"? Is it a collective mistake made by surveying and mapping experts and map makers?

Researcher Kui Zhongyu found the "experts who participated in the map making". Explain to him that they drew the map strictly based on field measurements. After drawing it, they also found that the central axis was crooked. Some people suggested that the central axis on the map be "corrected"...

During the search, Kui Zhongyu further learned that in the early days of the founding of New China, in order to plan municipal construction, Beijing surveying experts had already discovered this "deviation". It is said that they had reported this issue to the relevant departments. It has been reported, but the historical facts cannot be changed. Because the deviation is relatively small, the citizens cannot feel it at all.

The experiment shows that the central axis in reality does deviate from the meridian.

In order to clarify. Regarding the direction of Beijing's central axis in reality, researcher Kui Zhongyu conducted an experiment at the end of last year, called "Immediate Results." Under the newly built Yongding Gate, the researcher made a sundial and erected a 2-meter-high pole facing the Yongding Gate. On the northern Yong Road, a 6-meter-long piece of black tape was posted. "The direction of the tape is the direction of the central axis, and the shadow of the pole represents the meridian."

After consulting the 2004 astronomical calendar, After calculating the parallax correction value and the longitude correction value, the experimental report was released: the black tape and the shadow clearly showed an angle, and the measured angle was roughly 2 degrees and a dozen minutes!

“The central axis is indeed off. "Kui Zhongyu said, "Beijing's central axis does not run due south or north. ”