Shi Siming
In 759, the Yan general Shi Siming, who had briefly submitted to Tang but then rose again against Tang, attacked Tang forces at Yecheng and, while not achieving a victory, caused the Tang forces to collapse by themselves. He subsequently killed An Qingxu and took over the Yan throne. Meanwhile, Yu blamed the collapse on Guo, and as a result, Li Guangbi was put in command of the armies. Shi Siming subsequently attacked Luoyang and captured it. After a failed attempt by Tang forces to capture Luoyang, instigated by Yu and opposed by Li Guangbi, Shi tried to attack west toward Chang'an, but was repelled by the general Wei Boyu (衛伯玉), who was under Yu's command, at Shan Prefecture (陝州, in modern Sanmenxia, Henan). After a joint Tang and Huige army recaptured Luoyang in 762, Yu stationed his elite Shence Army to Bian Prefecture (汴州, in modern Kaifeng, Henan). For his contributions in this battle, he was created the Duke of Fengyi. Later in 762, he moved back to Shan Prefecture.