Various influences of Luoyang and Chang 'an with their capitals on the domestic situation.

the Ilo valley where Luoyang is located is relatively narrow, and the economic center of Shandong is not here, so the agricultural production in Luoyang area is not very developed. However, Luoyang's good geographical location and traffic conditions have become its greatest advantage. As mentioned earlier, during the Sui and Tang Dynasties, the economic center of China had already begun to be out of touch. At that time, the main grain producing areas were Shandong and Jianghuai areas in the lower reaches of the Yellow River, and the grain in Kyoto relied heavily on the transshipment of the two places. When Emperor Yangdi of Sui Dynasty dug the Grand Canal, Yongji Canal and Tongji Canal respectively extended to the northeast and southeast with Luoyang as the center. Luoyang has become the hub of the Grand Canal and the largest grain distribution center in China. In the Sui Dynasty, there were two granaries in Luoyang, including Jiacang and Luokoucang, but the grain was not used up during the Zhenguan period of the Tang Dynasty. If the grain is transported from Luoyang to Chang 'an, it will not only take more than 1 miles, but also capsize accidents often occur in Sanmenxia area. The easiest way to solve this difficulty is to move the capital to Luoyang. During the reign of Emperor Yangdi, he spent most of his time in Luoyang, the eastern capital, which replaced Daxing City as the actual capital. In the Tang Dynasty, the political center changed frequently between Beijing and Beijing for a long time. However, constrained by the northwest frontier, Chang 'an has been the capital for a long time than Luoyang. Luoyang controls the east, but it is too far away from the northwest to respond to emergencies in time. Moreover, in the late Tang Dynasty, Luoyang was located in the land of four wars, and the advantages in peacetime turned into disadvantages in wartime. Therefore, in the Sui and Tang Dynasties, Chang 'an and Luoyang were politically and militarily established, surrounded by mountains and rivers, easy to defend but difficult to attack, and condescending to the east, and they could open up the western regions to the west as a buffer zone to guard against grassland nationalities; The other is based on the transportation economy, extending in all directions, and there are benefits of water transportation in the world. From the end of the Tang Dynasty to the Five Dynasties, the political center moved from Chang 'an to Luoyang and from Luoyang to Kaifeng, which on the one hand reflected the shrinking trend in the border defense of the Central Plains dynasty, on the other hand, it also reflected that the dependence of the regime on the southeast financial tax was greatly enhanced. After the diversion of the Grand Canal, Kaifeng became a new shipping center. In the early years of the Northern Song Dynasty, Song Taizu had planned to move the capital to Luoyang first, and then to Chang 'an. However, due to the policy of strong cadres and weak branches in the Northern Song Dynasty, half of the imperial army in Kaifeng was concentrated, and all of them relied on the Grand Canal to transport grain and grass. At this time, both Chang 'an and Luoyang had declined, and most of their original advantages were gone, so they could not accommodate a huge population, so they had to give up their capital. In the later period of ancient society, the northwest frontier was gradually replaced by the northeast frontier, and the capital of the Central Plains regime began to move eastward, guarding the traffic arteries from north to south to facilitate border defense. For example, Beijing was the capital of the Ming Dynasty. This makes Chang 'an and Luoyang lose their qualifications as capitals forever. In addition to these factors, the political needs of the dynasty are also the factors that determine the location of its capital. Haojing, the capital of the Western Zhou Dynasty, is the birthplace of the Zhou clan in Guanzhong, which is very suitable for their farming economy. When Zhou Chengwang built Luoyi as the capital, it became Zhou, in order to monitor and deter the immigrants of the Shang Dynasty and control the eastern territory. After the reunification of the Qin dynasty, the original capital was used, and the country was short-lived, so the problem of capital migration was not considered in time. The capital of the Western Han Dynasty was originally in Luoyang, and later Lou Jing remonstrated, urging the danger and wealth of Guanzhong. The Western Han Dynasty finally made Guanzhong its capital,