After Qin Shi Huang unified the six countries, the territory expanded more than three times at once, resulting in the empire facing a grassroots ** is not enough, although the previous Qin ancestors are expanding, but step by step, only the first emperor has taken a big step, the territory has expanded more than three times, but the country can not get more than three times the number of grassroots **. Coupled with the fact that the nobles of the Six Kingdoms were not wiped out, the two factors superimposed and caused rebellions in various places.
At the same time, the end of Qin also faced a problem, that is, the centrifugation of the general to the empire. The First Emperor roughly divided the army into two groups, the Great Wall Army in the north was the elite of the authentic Qin State, and the army of Zhao Tuo's expedition to Baiyue was composed of the remnants of the Six Kingdoms. This kind of centrifugation is also manifested in Zhang Han, the battle of Julu, Xiang Yu first eliminated Wang Li's Great Wall Legion, at that time Zhang Han's army was in Zhangshui as a logistics department, when Wang Li fought, Zhang Han did not have reinforcements, Wang Li was defeated. Zhang Han chose to surrender to Xiang Yu, Xiang Yu did not accept Zhang Han's surrender at first, but he did not win against Zhang Han, and finally could only accept Zhang Han's surrender.
Qin Shi Huang did not have an empress and a crown prince in his life, and Fusu was only the eldest son, who was sent to the Great Wall Army by Qin Shi Huang. And Hu Hai has been taken by Qin Shi Huang all the time, obviously cultivating Hu Hai as an heir. It's just that Qin Shi Huang left too quickly, and he didn't expect it himself, the result was that Hu Hai had not been cultivated well, and Fusu was too far away, which gave Zhao Gao and Li Si the possibility of operating, Zhao Gao instructed Qin II to kill the direct bloodline, it should be because Hu Hai's succession legitimacy is relatively fragile, so he wants to kill other possible successors.
The fundamental reason for the demise of the Qin Empire was that the internal contradictions were very fierce before the unification, but suddenly there was an unprecedented emperor like Qin Shi Huang, who forcibly suppressed all these and then unified the six countries. After that, the contradictions of the Qin Empire became more complicated and intense, and when Qin Shi Huang was alive, a large number of elite soldiers and strong generals under his command, plus the remnants of the Six Kingdoms, were all smart and did not make much move, avoiding being liquidated.
When Qin Shi Huang died, Qin II found a very serious problem, no one listened to him, when a person who nominally has power, but in fact has a part of the power, he can't make the whole country run according to his wishes, he will choose the simplest and most effective way to kill, but the fact is that an immature ruler through this means, it will further weaken the control of the state.
The Qin Dynasty has made extraordinary achievements, unifying weights and measures, building Chi Road, building the Great Wall, and conquering Baiyue in the south, but this is only his achievement, and has nothing to do with the living standards of the people, his military achievements only play a role in the military, and do not have any effect on the lives of the people. Judging from the last three things alone, his merits are in the contemporary era, and the benefits are in the future, especially the Great Wall, whose positive role has been continuously played in the Ming Dynasty, becoming the decisive geographical advantage of the Central Plains Dynasty against the nomadic dynasty, and becoming a powerful advantage for our side. But at that time, it did bring a huge burden to the people at that time, and also brought a huge financial burden to the Qin Empire at that time. Of course, ordinary people think that the Qin Dynasty is a tyrannical Qin, because a huge amount of life has died in this process, and it is impossible for the Qin Dynasty to love the people like a son, because just these three projects, the manpower, material resources, and lives consumed are astronomical.
Liu Bang quickly controlled the territory of the Qin State during the Warring States Period with only three chapters and four words, which fully shows that the internal contradictions of the Qin Dynasty are acute, and the merits of the Thousand Autumns and the losses at that time coexist, and it is not possible to use the merits of the Thousand Autumns to cover up the problems that arose at that time, which is not objective, maybe there must be a benefit and a disadvantage, Qin Shi Huang can only do this, in order to ensure the confrontation against the nomads in the north, but the pros and cons exist at the same time, not alone.