In 409, Yao Xing himself launched an attack on Liu Bobo, but when he reached Ercheng (貳城, in modern Yan'an, Shaanxi), he was nearly trapped by Liu Bobo, and escaped only after major casualties. This defeat forced Yao Xing to cancel a mission, commanded by his general Yao Qiang (姚強), to try to save Southern Yan from being destroyed by Jin. (Without Later Qin aid, Southern Yan fell in 410.) For the next several years, Xia and Later Qin forces battled constantly, often inconclusively, but with the wars becoming much more costly to Later Qin than Xia, with Southern Liang and Western Qin no longer being willing to be Later Qin vassals as a result. In 412, when Western Qin's prince Qifu Gangui was assassinated by his nephew Qifu Gongfu (乞伏公府), Liu Bobo considered attacking Western Qin despite its status as an ally, but at the counsel of his advisor Wang Maide (王買德) did not do so.