after promoted to him to be the secretary in Wang Chuzhi's role as governor (觀察使, Guanchashi). About two years later, in 921, Wang Du seized control of the circuit from his father Wang Chuzhi in a coup. As one of Wang Du's close associates, He Shaowei (), had previous disputes with Liu Xuan, he made false accusations against Liu Xuan, and Wang Du killed Liu Xuan. Liu Xu fled the circuit, and took up residence at Cang Prefecture (滄州, in modern Cangzhou, Hebei), in Jin territory. The military governor of Henghai Circuit (橫海, headquartered at Cang Prefecture), Li Cunshen, invited him to serve as secretary. During Later Tang During Li Cunxu's reign After Li Cunshen's lord and adoptive brother Li Cunxu the Prince of Jin claimed the title of emperor (of a new Later Tang) in 923, he made Liu Xu a Taichang Boshi (), a scholar at the ministry of worship (太常寺, Taichang Si), and shortly after an imperial scholar (翰林學士, Hanlin Xueshi). He was also made Shanbu Yuanwailang (), a low-level official at the ministry of rites (禮部, Libu), and later promoted to be Bibu Langzhong (), a supervisory official at the ministry of justice (刑部, Xingbu). He later left governmental service for some time when his mother died, to observe a period of mourning. After the period was complete, he was made Kubu Langzhong (), a supervisory official at the ministry of defense (兵部, Bingbu), and also resumed his role as imperial scholar. During Li Siyuan's reign Li Cunxu was killed in a mutiny in 926, and his adoptive brother Li Siyuan became emperor. After Li Siyuan became emperor, Liu Xu was made a Zhongshu Sheren (), a mid-level official at the legislative bureau of government (中書省, Zhongshu Sheng); he later also assumed the posts of deputy minister of census (戶部侍郎, Hubu Shilang) and scholar at Duanming Hall (). It was said that Li Siyuan respected him for his gracefulness and favored him for his mild disposition. In 933, Liu was given the titles of Zhongshu Shilang (中書侍郎, deputy head of the legislative bureau) and Tong Zhongshu Menxia Pingzhangshi (), making him a chancellor; he was also made the minister of justice (刑部尚書, Xingbu Shangshu). After Li Siyuan's reign Li Siyuan died in 933, and was initially succeeded by his son Li Conghou the Prince of Song. However, in 934, Li Conghou's chiefs of staff (Shumishi) Zhu