In 960 AD, Zhao Kuangyin, a general of the Zhou Dynasty, launched a mutiny in Chen Qiaoyi, seized the power of the Zhou Dynasty and established the Song Dynasty. Since the end of the Tang dynasty, it has always been "where the military power lies, it will prosper, and when the military power comes, it will die." The warlords of the Five Dynasties publicly declared that Mazhuang could be an emperor if he was strong. An Chongrong, a warlord at that time, said: "The son of heaven, the strong man in Mazhuang, would rather have seeds!" Take Zhao Kuangyin as an example. In the later Han Dynasty, he defected to Guo Wei and took part in the state-building mutiny in Guo Wei. After Zhou Shizong and Chai Rong acceded to the throne, he was promoted to our German army, starting from the military school, then taking charge of the imperial power and finally winning the throne. Therefore, after the establishment of the Northern Song Dynasty, it actively absorbed the historical lessons of the disadvantages of the late Tang Dynasty and the Five Dynasties, and formulated a set of "ancestral laws" that integrated military power, financial power, political power, legislation and judicial power to strictly guard against the autocratic dictatorship of civilian military commanders. Its essence refers to the basic principle of governing the country, which has been gradually formed since Song Taizu and Taizong, and many practices and expressions under the guidance of this principle. Its characteristics are based on a relatively stable and relaxed political tone and the main line of the ruling policy of combining leniency with severity. In the imperial edict of Song Taizong's accession to the throne in the ninth year of Kaibao (976), "preventing things and making music" pointed out the spiritual essence of the law of ancestors.

Therefore, under the guidance of this policy, Zhao Kuangyin directed a play of relieving the military power by drinking a glass of wine at the beginning of his reign. Militarily, he first removed the military power of the imperial generals Shi Shouxin and Wang Shenqi who fought against him, and further "prevented malpractices" from the management system of the imperial army in terms of reducing the position of the imperial commander-in-chief, weakening the authority of the imperial commander-in-chief, and alienating the relationship between the imperial generals and soldiers. While weakening the power of the commander-in-chief of the imperial army, we should recruit local elite soldiers to enrich the imperial army and try our best to weaken local forces; Financially, local tax authorities are under the central control, and all local taxes are turned over except some local expenditures. In the Northern Song Dynasty, in addition to setting up various transshipment departments, it was also responsible for finance, taxation and water transportation. Administratively, Zhao Kuangyin divided the power of the prime minister, taking the affairs under the same book as the prime minister, and set the governor who participated in politics as the deputy prime minister, and divided the military power with the Privy Council (the chief executive is the Tang Dynasty) to separate the prime minister from the Tang Dynasty. The financial power was divided into three divisions (the Salt and Iron Division, the Branch Division and the Household Division), which was called the "planning phase". As a result, the prime minister was in charge and the Tang envoys were in charge of the military. At the same time, the Song Dynasty further improved the power and status of the censorate, the suggestion court and other supervisory institutions, and investigated, corrected, impeached and impeached officials at all levels to ensure that officials such as the Prime Minister had to be careful everywhere; In terms of employing people, the Song Dynasty has always been permeated with the principle of "harmony without difference, that is, each dare not make mistakes" and the principle of combining civil and military affairs, giving consideration to both inside and outside, and rolling up and down. To put it bluntly, people can't be the only minister who has the right to speak.

? Therefore, when studying the establishment of the bureaucratic political system in the Song Dynasty, Deng Xiaonan, an expert in contemporary Song history, summarized the basic contents of the Law of Ancestors as follows: restricting the rights of imperial clan, consorts and eunuchs, separating powers to check and balance, ruling the world by literati, not killing officials, advocating "loyalty", and maintaining harmony and frugality among the imperial families in the harem, "internal deficiency is not enough"

? However, overcorrection, the "anti-malpractice" of the ancestral law in the Song Dynasty brought new disadvantages, and the central government monopolized the power and managed it too tightly. For example, in the Song Dynasty, the military policy of governing the army with culture and even the emperor's practice of commanding foreign generals to fight with "battle plans" made it difficult for the Song Dynasty to give full play to the wisdom and talents of military commanders in the wars with Liao, Jin, Xixia and Mongolia, thus causing the country's military strength to be poor and weak.