Battle of Rang 穰城之戰

Zhang Xiu, who had attacked Cao Cao in the Battle of Wancheng in the 2nd year of Jian'an (197), went to Rang and joined Liu Biao, and that winter Cao Cao advanced south again and took Huyang and Wuyin. Returning to Xu in the 1st month of the 3rd year of Jian'an (198), Cao Cao established the post of Military Libationer for the first time. Records, Wei 1 §43 · 45–46

The Military Adviser Xun You said that Zhang Xiu and Liu Biao had grown strong by relying on each other, but that Zhang Xiu, with his roving army, depended on Liu Biao for food and Liu Biao could not supply it, so they were bound to split; if Cao Cao slowed his army and waited, Zhang Xiu could be lured over, but if he pressed them hard they would come to each other's rescue. Cao Cao did not follow this, advanced to Rang, and surrounded Zhang Xiu in the 3rd month. Records, Wei 10 §55Records, Wei 1 §46

In the 5th month, in summer, Liu Biao sent troops to rescue Zhang Xiu and cut off the rear of Cao Cao's army. When Cao Cao tried to lead his army back, Zhang Xiu's troops came in pursuit, and Cao Cao's army could not advance, but moved forward little by little with its camps linked together. Cao Cao wrote to Xun Yu that although the enemy was pursuing him and he could cover only a few li a day, he would surely defeat Zhang Xiu once he reached Anzhong. When he reached Anzhong, Zhang Xiu joined Liu Biao's troops in holding the rough ground, and Cao Cao's army faced enemies front and rear. Records, Wei 1 §46

Cao Cao cut through the rough ground by night to make tunnels, got his whole baggage train through, and then placed surprise troops. At daybreak the enemy, thinking Cao Cao had fled, came after him with their entire army, and Cao Cao attacked from both sides with the infantry and cavalry he had hidden and heavily defeated them. The biography of Xun You records that when the army was at a disadvantage Cao Cao told Xun You that he had come to this pass by not using his advice, and that he placed a surprise force, fought again and heavily defeated the enemy; the biography of Li Tong records that when Liu Biao was aiding Zhang Xiu and Cao Cao's army was at a disadvantage, Li Tong arrived at night with his troops and, leading the way, heavily defeated Zhang Xiu's army. Records, Wei 1 §47Records, Wei 10 §56Records, Wei 18 §13

In the 7th month, in autumn, Cao Cao returned to Xu. When Xun Yu asked why he had earlier reckoned that he would surely defeat the enemy, Cao Cao answered that he had known he would win because the enemy had blocked his homeward-bound army and fought him when he was in a place of death. Li Tong was appointed Assistant General and enfeoffed as Marquis of Jiangong. In the 9th month of that year Cao Cao set out east to attack Lü Bu. Records, Wei 1 §47–48Records, Wei 18 §13