According to Records of Historical Records and Biography of Su Qin, after Su Qin failed to lobby Qin Huiwen and Wang Lianheng, he turned to lobby the six countries to unite against Qin. Su Qin is in charge of the seals of the six prime ministers, but there are contradictions between countries. Su Qin was assassinated by Qi people for some reason, and the alliance collapsed.
Strategically speaking, it is a strategy of "uniting the weak against the strong" to prevent the merger of powerful countries. Lian Heng is a "strong thing (subordinate) to attack the weak", which is a strategy for powerful countries to force weak countries to help them merge.
With the change of the situation of the merger war, the specific content of the United Front has also undergone some changes and developments. After the battle of Changping, it became the joint resistance of the six countries and the surrender of Lian Heng to Qin.
Extended data
Among the seven heroes of the Warring States, Qin was the strongest, which seriously threatened the survival of the six countries. A * * * once attacked Qin in four wars.
Gongsun Yan initiated the first battle of Chu, Wei, Han and Zhao Yan, and attacked Qin (3 18).
The second battle was initiated by Meng Changjun and led by the King of Qi (296 years ago).
The third time was the battle between Wei, Zhao, Chu, Han and Yan, which was initiated by Xin (247 years ago).
The fourth time was the battle of Zhao Chuyan and Wei Shikuo attacking Qin advocated by Pang Xian (24 1 year ago).
Baidu Encyclopedia-Zonghe