In 430, when it appeared that Emperor Wen of Liu Song was about to attack, Northern Wei's southern defense forces suggested making a preemptory attack against Liu Song, but Cui Hao opposed it, pointing out that if the attack were not quickly successful, it risked causing Liu Song to counterattack across the Yellow River, endangering Northern Wei's existence. Rather, it was probably at Cui Hao's suggestion that, when Liu Song forces did attack later that year, Emperor Taiwu withdrew Northern Wei forces south of the Yellow River, judging that all Emperor Wen intended was to recapture the region south of the Yellow River, and that once the Yellow River froze in the winter Northern Wei could counterattack easily. It was definitely at Cui Hao's suggestion that despite the loss of territory to Liu Song at this time, Emperor Taiwu instead launched one final attack against Xia's emperor Helian Ding (Helian Chang's brother), seizing what remained of Xia territory and forcing Helian Ding to flee west, where he was captured by Tuyuhun's khan Murong Mugui (慕容慕璝) in 431. Meanwhile, even without Emperor Taiwu, Northern Wei forces were able to advance south in winter 430, quickly recapturing most of the territory that Liu Song had captured, and regaining all of it by spring 431.