The advantages of Shang Yang method are:
First, strengthen centralized rule, in order to help unite national strength. Shang Yang recovered the fiefs and related privileges of the old clan, vigorously promoted the county system, concentrated power in the central government, weakened local power, and enabled the country to gather national strength and expand continuously.
Second, it has promoted the development of productive forces. Shang Yang abandoned the well field system, opened buildings and distributed land to slaves and civilians, which improved the people's enthusiasm for production and improved the level of agricultural production. Shang Yang broke up large families, promoted small families, and gathered villages into cities, which improved the efficiency of administrative management and increased the country's fiscal revenue. In addition, Shang Yang's farming aristocrats also improved the people's enthusiasm for production.
Third, the combat effectiveness of the army has been improved. Shang Yang's rank is the second way for Qin people to improve their status and treatment besides farming. The more enemies you behead, the more military achievements you get, and the more benefits you get, which is the main motivation for Qin soldiers to fight hard on the battlefield. In addition, Shang Yang trained a new army, all iron weapons, and was a real iron army.
The disadvantages of Shang Yang method are:
First, it weakens the power of the office. One of the main purposes of Shang Yang's political reform was to strengthen the monarchical power, so the other children of the royal family had little power, and the power was concentrated in the hands of the king or powerful ministers. In those days, Ying Zheng had to rely on the strength of Lv Buwei and Wang Jian, who could not be supported by other royal families, to quell the Lao Ai rebellion. Another prominent feature of Shang Yang's political reform is fairness, so the children of the royal family can't be knighted in vain, and they can't inherit the title without great achievements. In this way, the collateral power of the royal family has been greatly weakened. If the monarch is not strong, the royal family will have no counter-insurgency power. This is also the reason why the royal family did not win when the Six Kingdoms were restored.
Second, the law is very strict and cruel. One of the purposes of Shang Yang's political reform is to reward and punish severely. The world did not see Shang Yang's reward, but the heavy punishment was publicized and beautified. Generally speaking, Shang Yang's sentencing principles are: heavy punishment for misdemeanors and suspended death for felony; Regardless of good and evil, regardless of good and evil, regardless of merits and demerits, regardless of intentional or unintentional breaking the law, as long as you break the law, you will definitely die or be disabled.
Third, there are too many times to surpass. Shang Yang's law pursues the spirit of rule of law, and there is no room for turning around. It is said that "everything is French". On the other hand, there are many loopholes in the rule of law in modern society, and law enforcement is not very strict. Far less perfect and precise than the rule of law in Qin dynasty, there is still a lot of room for the rule of man. Shang Yang's pursuit of the perfection of the spirit of the rule of law in that era was too advanced for many people to adapt. So as soon as Qin Shihuang died, the freemen and the nobles restored to the Six Kingdoms overthrew the Qin Dynasty and changed the Qin law.