From Han Zhong, Ts’ao Ts’ao planned to stage the invasion of Shu, but Kung Ming followed the dictum “the Best Defense is Offense”, so instead, he led the Shu forces in attacking Han Zhong.
In the Second Battle of Han Zhong, Kung Ming would apply the same tactic Alexander the Great did against the Persians many centuries before. He ordered his men to hit the drums and cymbals all night. This kept Ts’ao Ts’ao’s men on alert, but there was never an attack on the Wei camp. When the Wei soldiers were thoroughly exhausted from being alert all night, Kung Ming ordered the well-rested Shu army led by Chao Yun to attack. The exhausted Wei soldiers were easily exhausted and forced to retreat closer and closer to the main fortress of Han Zhong.
In one battle, Ts’ao Ts’ao barely escaped with his life. The Shu general Wei Yan shot an arrow at him. Luckily, the arrow only hit Ts’ao Ts’ao’s teeth and bloodied his mouth, but he escaped with his life.
In another battle, Wei reinforcements led by Xu Zhu arrived. Xu Zhu knew he was easily given over to alcohol and made the point of not drinking, but he hath traveled for so long he thought “One drink couldn’t hurt”, so he took a gulp, but one drink followed the other, and soon he was drunk. Chang Fei led the Shu army against him. Xu Zhu was an even match for Chang Fei in good times, but he was drunk that day and badly injured. He was almost killed and barely escaped with his life.
During the siege of Han Zhong, however, his second son, Ts’ao Chang, showed brilliance in battle and was able to combat both Chao Yun and Chang Fei. Ts’ao Ts’ao was very pleased with this son. He said, “My third son Ts’ao Zi was a renowned poet, and my second son Ts’ao Chang is a great warrior. I am certainly a blessed father.”
Nevertheless, it was quite clear that the Wei army was being decimated by the numerically inferior Shu troops. Without Xu Zhu’s reinforcements, Ts’ao Ts’ao seemed endangered. He pondered upon his retreat. One day, he was eating chicken leg and told the general Hsiahou Tun that the password for the army today would be “Chicken Leg”.
Now, in Ts’ao Ts’ao’s camp, there was a brilliant man called Yang Siu who has Ts’ao Zhi’s tutor. His brilliance was such that it made Ts’ao Ts’ao jealous and suspicious of him. One time, Ts’ao Ts’ao wished to test his sons to see who would be a better leader between his eldest son Ts’ao Pi (after the death of the really first one Ts’ao Ang in the battle against Chang Siu) and Ts’ao Zhi. The two sons were ordered to meet him, but when the guards said Ts’ao Ts’ao did not want to meet him, Ts’ao Pi turned back in sorrow.
At Yang Siu’s advice, Ts’ao Zhi did the unbelievable. He pretended to turn away and then took the guards by surprise, murdering both of them. In another instance, Yang Siu wrote a book and tutored Ts’ao Zhi on how to answer Ts’ao Ts’ao’s questions.
At first, Ts’ao Ts’ao was much impressed that Ts’ao Zhi could answer the questions so well, and was thinking of making him heir. However, Ssuma I, a brilliant scholar who hath become Ts’ao Pi’s tutor, discovered the existence of this book and revealed it to Ts’ao Ts’ao, making him even more suspicious of Yang Siu.
That day, Yang Siu told Hsiahou Tun that Ts’ao Ts’ao meant to retreat after hearing the “Chicken Leg” passcode. Once again, Ts’ao Ts’ao was angry that Yang Siu could read his mind. How did Yang Siu know? Well, the chicken leg is a delicious part, but you have to throw the bone away finally. In the same situation, Ts’ao Ts’ao wanted very much to hold on to Han Zhong, but his supplies were dwindling and the army’s morale hath suffered in the defeats by Kung Ming, so Yang Siu knew that Ts’ao Ts’ao was contemplating retreat, much as one would have to throw away the “Chicken Leg”.
When Ts’ao Ts’ao heard this, he accused Yang Siu of making false assumptions and beheaded him. He then ordered Hsiahou Tun to prepare for further war against Kung Ming, but the war went badly and he was eventually forced to retreat.
Once again, his choice to listen to Yang Siu backfired, but despite all his brilliance, Yang Siu was a man to die from a mere chicken leg. The incident was a disgraceful defeat for Wei at the hands of Shu. Kung Ming succeeded in capturing Han Zhong in less than a year after it fell to Wei. With this, Liu Pei proclaimed himself Marquis of Han Ning (Han Chong) and became archrival to Ts’ao Ts’ao in greatness.