Mao Sui (fl. 3rd century BC), was born in the Zhao state (current Hebei province) during the Warring States period. He was a retainer of Lord Pingyuan, namely Zhao Sheng. Mao lived in Zhao for three years but success eluded him. In 257 BC, after the Battle of Changping, Zhao refused to cede territory to the Qin. As a result, Qin attacked Handan, the capital of Zhao. On its part, Zhao sought assistance from the Chu state. Mao Sui recommended himself to the Chu State and was successful in persuading the Chu to assist Zhao. In return, Mao Sui gained fame, and it was widely believed that: "A good tongue of Mao Sui is stronger than a million soldiers."