During the Warring States period (战国时期, 公元前475-221年), the state of Qin (秦国) besieged (包围) the capital of the state of Zhao (赵国). Prince Pingyuan (平原君) of Zhao went to Chu (楚国) to ask for help. He wanted 20 talented people to go with him. But he could only find 19. The prince was worried. Then, a man named Mao Sui (毛遂) came and recommended himself (推荐自己).