符存審
In 917, Khitan's Emperor Taizu launched a major attack on You Prefecture (幽州, in modern Beijing) – the former capital of Yan and now the capital of Jin's Lulong Circuit (盧龍), where Zhou served as military commander. Zhou sought emergency aid, but Li Cunxu was initially unsure what to do, given that he was in constant battles with Later Liang and was hesitant to divide his army to go to Zhou's aid. However, Li Siyuan, Li Cunshen, and Yan Bao (閻寶) all advocated for an army to be sent to aid Zhou. Li Cunxu agreed, and sent Li Siyuan as the commander of the forward troops, followed by Yan Bao, and then by Li Cunshen. The Jin relief forces were subsequently able to defeat the Khitan siege troops and lift the siege on You.