As far as the situation of the six countries is concerned, the biggest advantage is to unite with Qin, and the biggest disadvantage is to compete with Qin. Unity can achieve stability, and confrontation can lead to disaster. This is the general trend.
Therefore, the Three Kingdoms are about to be robbed, but Qi, Chu, Yan and Zhao are worried about the cold teeth, which is not counted.
If the three countries around Qin State are destroyed by Qin State, then the remaining countries such as Qi, Chu, Yan and Zhao will bear the fear of losing their lips and teeth, so this joint method is not the best policy.
Guy Su Qin didn't win the final trust in the six countries, while Zhang Yi's ambition was dominant in Qin. The reason why these six countries met in Qin is also.
It is also for this reason that Su Qin finally failed to gain the trust of the six monarchs, and Zhang Yi resolutely defected to the State of Qin. It also led to the situation that Qin ruled the country.
These words come from He Feifei's six-state theory.
This paper summarizes the objective reasons why Qin unified China.
Non-professionals, translation is not professional enough.
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