Thereupon he finally advanced with the army, which would later be reinforced by Guanqiu Jian's own forces in You Province, which included the Xianbei auxiliary led by Mohuba (), ancestor of the Murong clan. The Wei army reached Liaodong in June 238, and as Sima Yi had anticipated, Gongsun Yuan had sent his Grand General Bei Yan () and Yang Zuo () to face him. They built their camps along the Liao River in anticipation of him. The Wei generals wanted to directly attack the enemy on the banks of the river, but Sima Yi reasoned that attacking the encampment would only wear themselves out and deplete their valuable resources; on the other hand, since the bulk of the Liaodong army was at the Liao River, Gongsun Yuan's headquarters at Xiangping (襄平), the capital of the Liaodong Commandery, would be comparatively empty and the Wei army could take it with ease. Sima Yi therefore decided to dispatch Hu Zun with a contingent of his army south with numerous banners and drums, so as to indicate that he was going to make a sortie there with a large force. This deceived Bei Yan and his men, who pursued the decoy unit, whereby Hu Zun, having lured the enemy out, crossed the river and broke through Bei Yan's line, while Sima Yi managed to secretly cross the river to the north, sink the boats, burn down the bridges, build up a long barricade along the river, and then march for the capital itself. Once the opposing generals realised they had fallen for a feint, they started marching back in haste towards the capital, and in the night while heading north to intercept Sima Yi, as had been expected of them, they caught up at Mount Shou (首山; a mountain west of Xiangping), where Bei Yan was ordered to give battle, and was subsequently routed and crushed by Sima Yi and his army. Sima Yi then marched towards Xiangping unopposed, and started besieging it.