Many counties in the area joined the uprising. Some civilians escaped to Hanzhong via Ziwu Valley () to avoid the war. In response, Cao Cao sent Cao Ren against the coalition at Tong Pass (in present-day Tongguan County, Shaanxi) and gave strict orders to his generals to refrain from engaging the enemy. Crossing of the Wei River In late July or August 211, Cao Cao personally led an army against the rebels, leaving behind his son Cao Pi to guard his base in Ye (in present-day Handan, Hebei). Some of his subordinates advised him: "The Guanxi soldiers are warlike and they specialise in using long spears. Only an elite vanguard force can stop them." Cao Cao replied: "I am in charge of the war, not the rebels. They may be skilled in using long spears, but I will make them unable to use their spears. Gentlemen, just watch." Upon reaching Tong Pass, Cao Cao ordered Xu Huang and Zhu Ling to lead their units across the Wei River via Puban Ford () at night and set up a camp on the west bank. While Cao Cao and his men were preparing to cross the Wei River to the north bank, they suddenly came under attack by Ma Chao's forces, but Cao remained seated and refused to move. Zhang He and the other officers saw that the situation was very critical, so they led Cao Cao on board a ferry. As the river current was very strong, Cao Cao's vessels quickly sailed four or five li away from the south bank. Ma Chao ordered his troops to rain arrows upon the enemy boats. Ding Fei (), a colonel under Cao Cao, had released the cattle and horses to distract the enemy, so the Guanxi soldiers immediately gave up on attacking and started to seize whatever livestock they could lay their hands on. Cao Cao's officers were worried and panicky when they lost sight of their lord during the chaos, and they shed tears of joy when they reunited with him later. Cao Cao laughed and remarked: "I was almost trapped by that little scoundrel today!" Construction of sand walls After crossing the river, Cao Cao and his forces then headed south along the riverbank. The coalition retreated and made camp along the Wei River. Cao Cao set up many decoys to confuse the enemy while secretly sending troops to sail across