The Spring and Autumn Period : Besiege Wei to Rescue Zhao 圍魏救趙

In 354 B.C., King Hui of Wei wanted to release the old hatred of losing Zhongshan, so he sent his general Pang Juan to attack Zhongshan. Zhongshan was originally a small state neighboring Wei in the Eastern Zhou Dynasty, which was conquered by Wei. Later, Zhao took advantage of Wei's loss of state to occupy Zhongshan by force. General Pang Juan of Wei thought that since Zhongshan was only a small piece of land and was very close to the state of Zhao, it would be better to attack the capital city of Zhao, Hanwei, in order to settle the old grudge and kill two birds with one stone. The king of Wei agreed to this and set aside 500 chariots, with Pang Juan as his general, and went straight to Zhao to besiege the capital city of Zhao, Hanwu. The king of Zhao was in a desperate situation and asked for help from Qi, promising to give him Zhongshan after the siege was lifted. King Wei of Qi agreed and made Tian Ji his general, and Sun Bi, who had been rescued from Wei, was appointed as his general to lead the troops. This Sun Bi was once a classmate of Pang Juan and was well versed in the art of war. The king of Wei recruited him with a lot of money, and at that time, Pang Juan was also serving the state of Wei. Pang Juan thought that he was not as capable as Sun Bu, and feared that he was better than he was, so he crippled Sun Bu with poisonous torture.