During that time, Zhuge Liang moved his army west to the Wuzhang Plains and prepared to cross to the northern bank of the Wei River. Sima Yi sent Zhou Dang () to station at Yangsui (陽遂; the area north of the Wei River in present-day Mei and Fufeng counties, Shaanxi) and lure Zhuge Liang to attack him. However, Zhuge Liang did not mobilise his troops for several days, and Sima Yi reportedly exclaimed: "Zhuge Liang wants to take control of the Wuzhang Plains and won't advance towards Yangsui. His intention is obvious." He then sent Hu Zun and Guo Huai to defend Yangsui. Several days later, Guo Huai received news that Zhuge Liang was planning to launch an attack in the west, and his subordinates therefore wanted to strengthen their defences in the west. Guo Huai was the only one who recognised that it was a ruse, and that Zhuge Liang was actually planning to attack Yangsui. He was proven right later as the Shu forces attacked Yangsui at night. However, as Guo Huai had set up defences earlier, the Shu forces failed to capture Yangsui. Zhuge Liang could not advance further, so he retreated back to the Wuzhang Plains.