Helian Chang
In 426, a decisive battle would largely end Western Qin as a threat to Northern Liang. Qifu Chipan and his crown prince Qifu Mumo were launching a major attack on Northern Liang. Juqu Mengxun sent messengers to persuade the Xia emperor Helian Chang (Helian Bobo's son and successor) to make a surprise attack on the Western Qin capital Fuhan (枹罕, in modern Linxia, Gansu). Helian Chang, in response, sent his general Hulu Gu (呼盧古) to attack Wanchuan and Wei Fa (韋伐) to attack Nan'an (南安, in modern Dingxi, Gansu), and while Western Qin was able to hold Wanchuan, Nan'an fell, at great loss. In winter 426, Xia forces commanded by Hulu and Wei attack Fuhan, forcing Qifu Gangui to move the capital to Dinglian (定連, also in Linxia), and Hulu and Wei then captured another important Western Qin city, Xiping (西平, in modern Xining, Qinghai), and while they then withdrew, Western Qin had been dealt a major blow. Later that year, with Emperor Taiwu of Northern Wei having in turn defeated Helian Chang in battle, capturing Chang'an and nearly capturing the Xia capital Tongwan (統萬, in modern Yulin, Shaanxi) as well, Juqu Mengxun sent messengers to Northern Wei offering to submit as a vassal.