During the Warring States period, Han and Wei fought for more than a year, and Qin Wanghui wanted to send troops to intervene. Chen Fu, an emissary of Chu, told Qin that Bian Zhuangzi would be injured if he fought with two tigers, so he killed the two tigers in one fell swoop, urging Qin to take the tactics of sitting quietly and watching the tigers fight and wait for the opportunity to destroy the two countries.

Metaphorically speaking, when two strong men fight, one of them is bound to be seriously injured.