In 354 BC, Wei Huiwang wanted to get rid of his old hatred of Zhongshan, so he sent general Pang Juan to attack. This Zhongshan was originally a small country in the northern part of Wei in the Eastern Zhou Dynasty and was conquered by Wei. Later, Zhao took advantage of Wei's national mourning and seized Zhongshan. Juan thinks that Zhongshan is just a small place, close to Zhao. If you don't fight directly to Handan, the capital of Zhao, you will kill the old enemy and kill two birds with one stone. From then on, Wang Wei took Pang Juan as the general and took Handan, the capital of Zhao and Wei. Zhao Wang had to ask Qi for help in an emergency and promised to give it to Zhongshan after the rescue. Qi Weiwang agreed to appoint Tian Ji as the general and Sun Bin as the strategist to lead the troops. This classmate Sun Bin and Pang Juan are very familiar with the method of fighting. Wang Wei hired him with a large sum of money. At that time, Pang Juan was also working for Wei. Pang Juan's conscious ability is not as good as Sun Bin's, and he is afraid of being better than himself. So he poisoned Sun Bin, broke his grandson's foot and tattooed his face in an attempt to make him unable to walk and ashamed to meet people. Later, Sun Bin pretended to be crazy, but thanks to the help of Qi's messengers, he fled to Qi. This is an old story about Pang Juan and Sun Bin.

When Tian Ji and Sun Bin led the troops into the border of Wei and Zhao, Tian Ji tried to push Handan, Zhao, but was stopped by Sun Bin, saying: No punching, no settling, no fighting. To solve disputes, you should seize the key point and take advantage of it, so the two sides can naturally be separated because of constraints. Now the elite of Wei has left this country, if I attack Wei directly. Pang Juan will return to Li to save him, and the siege of Handan will solve itself. If we ambush Pang Juan in the middle of the road again, his army will be defeated. Tian Ji followed the plan. Sure enough, Wei Jun left Handan, was ambushed on his way back, and fought Qi in Guiling. Wei Bing traveled long distances, exhausted, and fled everywhere. Pang Juan reluctantly cleaned up the mess and returned to the girder. The division of the Qi army won a great victory, and Zhao Zhiwei was thus solved. This is the famous story of "encircling Wei to save Zhao" in history.