Qin Shihuang worked hard to conquer the country, why couldn't his descendants keep it?

You have to ask his descendants, namely Qin II. Ask him why he can't keep his father's inheritance and is willing to be a coward and a tyrant? Don’t you know how much effort Qin Shihuang put into conquering the country and how many people he killed? You're a prodigal, you don't know how to cherish. Hahaha! Personally, I estimate that asking this question would be more uncomfortable and aggrieved than killing him. After all, "Baby's inner pain" cannot be explained clearly in a few sentences, but is gradually accumulated over a long journey.

Okay! That's too far. To paraphrase a common saying, "It's easy to build a country, but it's hard to sit on it". This is often said by the people to describe the difficulty of starting a business. By the way, I don’t know if Qin Shihuang has heard this sentence, but I am very curious. Does Qin II know? It seems that there is a high chance that they don't know, otherwise the Qin Dynasty would not have perished so quickly, and even a sudden collapse would not be too much.

Also, the fact that Qin Shihuang conquered the country with great hardships does not mean that his descendants will definitely be able to defend the country, especially when he meets Qin II, a treasure, it is even more uncertain. In other words, conquering the country and defending the country are not the same thing, but two different things. Looking at it, it can be seen that those who conquer the country very quickly, especially a guy like Qin Shihuang who has been fighting for six generations, are even faster. It is amazing. It is like destiny coming to sweep away the troubled times and restore peace. On the other hand, it is extremely difficult to defend the country. If you are not careful, you will die and the country will be destroyed. Precisely, Qin II fell into this category, as did the later Sui Yang Emperor. In this case, let’s not mention how hard it is to build a country, because building a country is never without hard work, and starting a business is the same. Besides, in a feudal society, no matter how hard you work, you still have to change dynasties. Do you really think that Da Qin can live forever? No one believes it even if I say it, it just adds to the joke.

This kind of imperfection in the management functions of the central government existed in the later Han Empire, Tang and Song Empire, and Ming and Qing Empires. Mr. Huang Renyu's "China's Great History" specifically discusses this issue.

The important reason why the Qin Dynasty had the shortest life span was largely because it was China's first empire with a vast territory and had no previous experience to draw from. In the Han, Tang, Song, Ming and Qing dynasties, profits and losses could be made with slight adjustments based on the gains and losses of the previous dynasties.