During the Warring States period, Pang Juan, a disciple of the military strategist Guiguzi from the State of Wei, became a general for King Hui of Wei before completing his studies. He tricked his fellow disciple Sun Bin into coming to Daliang, the capital of Wei, where he brutally severed Sun Bin's legs.

After returning to Qi, Sun Bin became the national preceptor for King Wei of Qi. He twice employed the strategy of "批亢捣虚" (striking at the enemy's vital points and exploiting their vulnerabilities), leading to the complete defeat of the Wei army and Pang Juan's suicide, thereby successfully rescuing the states of Zhao and Han.