In the middle and late Warring States period, Qin relied on Shang Yang's political reform, and its national strength gradually became stronger, which made Qin much higher than the six eastern countries both economically and militarily. In the face of the rise of this country of tigers and wolves, the six eastern countries were in deep crisis, and they were all worried that Qin would destroy themselves in the future, and their own strength was far from being able to confront Qin. So the six countries adopted Lian Heng's strategy to attack Qin at the suggestion of Su Qin's lobbying.
Facing the attack of six countries, Qin also showed a tense situation. However, Qin Huiwen, the monarch of the State of Qin, was not afraid of it. He knew that the victory would eventually belong to the State of Qin and the six countries of Lian Heng would eventually fall. As King Huiwen of Qin had expected, contradictions began to appear immediately after the six countries finalized Lian Heng. How many troops are there in which country? Which country is responsible for logistics support? Which country took the lead in containing the state of Qin? These have never been used to properly divide responsibilities. Although every country wants to defeat Qin Jun, it also wants to get the maximum benefit at the least cost. In this way, in the case of internal discord, the massive six-nation Lian Heng gradually disintegrated. For the state of Qin, the six countries, Lian Heng, fell apart, as early as expected.
In the disintegration of Lian Heng, the diplomatic means adopted by Qin also played a promoting role. The King of Qin sent Zhang Yi to unite with other countries and used different diplomatic means to provoke contradictions among the six countries, which made them hate each other and even led to a situation in which the six countries met each other. These are exactly what Qin wants to see.