In his later years, Lu You lived in his hometown of Shaoxing and wrote a book called "Notes on the Old School". The old school was the house where he lived. In this note, he wrote about some current events and passages that he saw or heard.
One paragraph says that the phenomenon of encircling lakes and making fields during the Southern Song Dynasty was very serious. For example, there is a mirror lake near his place of residence, and at that time, he "worked hard for people."
And this is a national phenomenon, for example, today's Tianfu Square in the center of Chengdu, in the Sui and Tang Dynasties was once a big lake, called Maha Chi, was once the most prestigious tourist attraction in Chengdu, just like the West Lake in Hangzhou. But in the era of Lu You, it was also filled in to make fields.
Not only that, on the song Dynasty Chang'an folk field trading contract, it was impressively written that the paragraph "somewhere to the calyx tower, somewhere to the Hanyuan Hall", these original styles were prominent, but what was left in the Song Dynasty was a piece of golden wheat field.
For example, it's as shocking as someone waking up and traveling into the 22nd century only to find Wall Street and Broadway turned into farmland.
There is a term in the field of historiography called "Theory of Tang and Song Reform", which says that from the Tang Dynasty to the Song Dynasty, there were great changes from the Middle Ages to modern times. Geographically, the center of gravity of Chinese civilization shifted eastward, which in the eyes of Lu You's generation represented the disappearance of traces of traditional civilization.
The most typical is Chang'an, on the occasion of the Tang and Song dynasties, the Song people's favorite thing to do is to lament the glory of Chang'an.
If you look at the area within the city wall, the area of Chang'an City in the Tang Dynasty is 84 square kilometers, including three parts: Waiguo City, Imperial City, and Miyagi. The Chang'an of the Song Dynasty only used the old site of the former imperial city to be transformed, and the area within the city wall was only 1/16 of that of the Tang Dynasty.
In terms of population, the population of Chang'an City in the prosperous Tang Dynasty exceeded one million, and the population density of some parts exceeded 10,000 people per square kilometer, which was comparable to today's modern cities with high-rise buildings.
However, the population of Chang'an City in the Song Dynasty did not exceed 200,000 people, and the commercial tax received in the middle of the Northern Song Dynasty was only 80,000 yuan, about 1/5 of the capital Kaifeng, ranking sixteenth in the country, and it was already an ordinary local city.
However, it is worth noting that if the urban and rural population of the Chang'an area of the Song Dynasty is included, the population of the entire region is not less than that of the Tang Dynasty. In the Tang Dynasty, Chang'an administered 23 counties, with an average population of 15,000 people per county in its heyday, with a total population of about 360,000 households and nearly 2 million people.
In the Song Dynasty, Chang'an had 13 counties under its jurisdiction, which was less than half of the jurisdiction of the Tang Dynasty, but the average population of each county reached 18,000 people in its heyday. The total population is about 230,000 households, with a population of about 1.15 million.
Therefore, the total population has not decreased significantly, and the total population density has even increased, only the number of people living in Chang'an City has declined. Today, from the Tang Dynasty to the Song Dynasty, the Chang'an region was "anti-urbanized", and the original officials, merchants, craftsmen, and monks disappeared and were replaced by a large number of farmers.
This is reflected in the place name is obvious, the former "Xia Ma Ling" has become "Shrimp Toad Tomb", "Jianzhang Palace" has become "Virgin's Building", from the place name style has dropped significantly. The original elegant Tang Dynasty court culture was replaced by the rustic local atmosphere.
Why would losing the status of the capital hit Chang'an so hard?
Here we will talk about the logic of urban development. Modern cities focus on industry first, and cities are rich because of industry, attracting population gathering, infrastructure can be renewed, and then further absorbing more industries. Bring in more people.
And what does industrial development look at? Although the policy reasons should not be underestimated, in the final analysis, it still depends on the geographical and natural and social environment.
For example, why did Shougang move from Beijing to Tangshan?
What's in Tangshan? There is an island called Caofeidian, which is surrounded by the sea on all sides, suitable for the construction of excellent deep-water ports, steel mills built here, regardless of raw material input and output are very convenient. At the same time, surrounded by the sea on all sides, the pollution emitted by steel mills is not easy to pollute the urban area. That's why most developed countries build steel mills near ports.
But in traditional China before the Industrial Revolution, the logic of urban development was not like this. (The whole world is actually similar)
China's traditional large cities have been developed with political and military objectives as a priority. In the more than 1,200 years from the western Zhou Dynasty to the Tang Dynasty, the capital of Chinese civilization basically did not leave Chang'an. All decent dynasties will be in Chang'an. Here Dingdu itself has political legitimacy BUFF.
In addition, militarily, the Guanzhong Plain is surrounded by mountains on three sides to facilitate defense, plus military fortresses such as Xiaoguan, Dashanguan, Wuguan, Hanguguan, and Tongguan, which are artificially built by relying on the terrain. In the eyes of any military commander, it is the perfect place to build a capital.
In addition, at that time, there were also economic considerations in the capital here.
Today when we talk about the land of Tianfu, we mean Chengdu, but in the pre-Qin period, the word was used to describe the Guanzhong Plain. During the Warring States period, the Zhengguo Canal built by the Qin State made the Guanzhong Plain fertile and wild, becoming the best agricultural land at that time. The development of agriculture provides sufficient resources to support the huge off-the-job population. The historical record even says that although the population and area of the Guanzhong region account for only 1/3 of the world, it concentrates 60% of the world's wealth.
Therefore, from the Zhou dynasty to the Sui and Tang Dynasties, the capital was fixed in Chang'an, which was to combine the three major advantages of politics, military and economy. Therefore, the status of Chang'an as the capital is certainly golden.
But in the Tang Dynasty, although the population of Chang'an City continued to rise, the proportion of the population in the Guanzhong Plain continued to decline. During the period from the early Tang Dynasty to the Middle Tang Dynasty, the population proportion of the Guanzhong region began to be lower than 10% of the country, and the population density was much lower than that of Henan, Hedong, Hebei, Huainan, and Jiangnan.
That is to say, before the Anshi Rebellion, the economic center and population center had moved east, while the political center remained in the Guanzhong Plain. This poses a hidden danger. The Guanzhong Plain was unable to support Chang'an on its own.
As the saying goes, a hundred miles do not sell trees, and a thousand miles do not sell millet. If the food production center and the consumption center are farther apart, then there is no way to solve the problem by relying on the law of the market, and hunger will occur.
Therefore, when the Tang Dynasty was strong, it used political power to expropriate grain from Hebei and Jiangnan, and then transported it to Chang'an for the palace and management consumption----- and the price of grain in Chang'an was generally far lower than the cost of transportation. This means that Chang'an was supported by the blood and sweat of the people of the tang dynasty, and Chang'an in turn provided the "art of management" for the whole country.
The Tang Dynasty Chang'an needed 4 million stones of imported grain every year, most of which relied on the Yellow River for transportation. However, on the way of the grain ship to Chang'an, there was a roadblock. This roadblock is called Sanmenxia.
Today, when Sanmenxia is mentioned, everyone only knows the Sanmenxia Hydropower Station, but in the history of the Qin Dynasty to the Sui and Tang Dynasties, Sanmenxia has always been a major problem in the country, because the Yellow River entered a narrow canyon after arriving here, the flow rate accelerated, and the water was covered with boulders and reefs, as well as whirlpools. Very unfavorable for boating.
Grain ships crash into pieces if they are not careful, and it is said that one out of every three ships is sunk. During the Tang Dynasty, the people who held up boats around Sanmenxia were called "door craftsmen", usually pinglu people in Shanxi. Since ancient times, there is a saying "since ancient times there is no door craftsman's tomb", why not? Because sooner or later the doormen will all die in the water.
Not only that, because to combat the huge countercurrent impulse, it often takes hundreds of people to pull fibers on the shore to pass a boat, and the river channel is narrow, sometimes it is difficult to pass a boat a day. Therefore, the grain was unloaded from the boat, transported in ox carts on the winding and steep mountain road, and then transported to the ship after this section.
However, under the conditions at that time, the mountain roads were not easy to walk, the narrow and steep often could only accommodate a car, and often encountered rock slides, even mudslides, landslides------------, etc. In a word, before the advent of modern explosives, the large-scale transportation problem from the eastern region to Chang'an could not be completely improved.
Therefore, no matter how obvious the political and military superiority of Dingdu is in Chang'an, the economic factors have always demanded that the emerging dynasty abandon Chang'an and settle in a further eastern position.
Dynasties after the Tang Dynasty no longer wanted to carry this heavy burden, and directly east of Sanmenxia, where water transport was more convenient. From Luoyang, Kaifeng, to Beijing, Nanjing. All in order to reduce logistics costs.
What is even worse is that due to the deforestation of the past generations, the serious erosion of water and soil in the Guanzhong area, the intensification of human social problems caused by environmental damage, civil wars and riots, so the population of modern Xi'an has further decreased, in the Republic of China period, people talk about Xi'an, has not regarded him as a major city, in 1930, Xi'an city population was only 125,000, only 40% of 1840.