Immediately after Cao Cao's defeat at Wulin in the Battle of Red Cliffs, Zhou Yu led 30,000 troops into Nan Commandery in a move to capture Jing Province's capital city, Jiangling. Zhou Yu's army camped on the southern bank of the Yangtze River. Before engaging Cao Cao's general Cao Ren, Zhou Yu ordered Gan Ning to take Yiling as a preemptive move to secure the entrance to Yi Province. In addition, if Yiling was captured, Cao Ren would be isolated from Yi Province's governor Liu Zhang, who was sending reinforcements to support him.
The commander of Yiling, Xi Su, was originally an official under Liu Zhang and he hated Cao Cao. When Gan Ning's troops reached Yiling, Xi Su surrendered without a fight. As Gan Ning's force reached 1,000, Zhou Yu wanted to merge Xi Su and his 300 troops into Lü Meng's unit to strengthen the main force. Lü Meng refused the offer and appealed to Sun Quan not to reassign Xi Su and his 300 men, but rather, keep Xi Su with Gan Ning to reinforce defenses at Yiling. Sun Quan agreed to Lü Meng's proposal. When Cao Ren learnt that Yiling had fallen, he immediately sent 6,000 cavalry to retake the city. Under intense pressure, Gan Ning remained calm and stabilized his army's morale.
Lü Meng's strategies
As Gan Ning's request for reinforcements reached Zhou Yu, nearly "everyone pointed out that there were not enough men to spare as a relief force". However, Lü Meng stood up and urged his colleagues to go and support Gan Ning, and guaranteed that Ling Tong could defend their main camp on his own for at least ten days. Ling Tong took up the burden of facing Cao Ren and Xu Huang alone, in order to buy time for Zhou Yu, Lü Meng, and others to help Gan Ning at Yiling. Cao Ren did not expect Zhou Yu to ignore his massive army at Jiangling, and was consequently defeated at Yiling, suffering more than 3,000 casualties. Meanwhile, Ling Tong deceived Cao Ren into believing there was still a sizable army left in Zhou Yu's main camp, so Cao did not launch an all-out assault on Ling. Instead, Cao Ren sent Xu Huang to attack Ling Tong but failed. En route back to the main camp, Lü Meng suggested a plan to capture enemy warhorses: he would lead 300 soldiers to block the enemy's retreat route with bundles of firewood so the horses were unable to pass through. As Lü Meng expected, in order to escape from Zhou Yu's pursuit, Cao Ren's cavalry abandoned their steeds and fled back to Jiangling on foot. Zhou Yu returned with over 300 captured enemy warhorses and Yiling remained firmly in Sun Quan's control for the rest of the war.
Aftermath
The fall of Yiling meant that Sun Quan's forces had opened up the entrance to Yi Province. It also implied that Cao Ren, who was in Jiangling, would no longer receive any reinforcements from Liu Zhang.
Order of battle
Cao Cao forces
General Who Attacks the SouthCao Ren, stationed in Jiangling
General Who Sweeps Across the Wilderness" Xu Huang, stationed in Jiangling
*General Xi Su, from Yi Province, stationed at Yiling, later defected to Sun Quan
Sun Quan forces
General in the Center Protecting the Army Zhou Yu
*Colonel Who Praises the Army Lu Su, served as Zhou Yu's deputy
*Right Area Commander Cheng Pu
*Commandant of Danyang Huang Gai, served as vanguard of the navy
*General of the Household Who Swipes Across the WildernessLü Meng