Zhang Yun (onyomi: Chō In) is either one of Liu Biao or Cai Mao's relatives (nephew in the latter case) who has little historically noted for him. He first served Liu Biao but after his master's death, he joined Cao Cao's forces with his new master, Liu Cong. Record of Xiangyang remarks he was well liked by Liu Biao and conspired together with Cai Mao. Aside from his surrender, he has no other mentions in history. Zhang Yun has greater significance in Romance of the Three Kingdoms.