三國時，蔡瑁被曹操殺掉後，弟弟蔡中、蔡和就跑去向周瑜詐降，周瑜看他們沒帶任何家屬，知道是詐降，就想將計就計，並找來老將黃蓋演一場苦肉計。周瑜以前曾下軍令：「說『投降』的人，一律斬首。」第二天，周瑜下令要跟曹軍打戰，黃蓋說：「根本打不過曹軍大隊人馬，不如投降算了。」周瑜假裝生氣要把黃蓋斬首，大家聽到後全跪下求情，周瑜就說：「好吧！免你死罪，改打五十大板。」
黃蓋寫封投降信給曹操，蔡中向曹操表示黃蓋真的被打個半死，疑心病重的曹操相信了。黃蓋又寫信：「我今晚坐的糧船會插著青龍牙旗，在江上會合。」當晚，曹操看到整個船隊都插著旗子，高興說：「太好了，還帶份大禮來給我。」快靠近時，軍師大叫：「載糧的船很笨重，它們的船吃水淺，我們中計了，快回頭。」因為曹操的船全扣在一起，加上又吹東風，所以，當糧船起火時，曹軍的船也全被燒光了。
三十六計之第三十四計：苦肉計
指故意設計自己受傷，來取信敵人，進一步從事間諜方面的工作，達到離間及分化對方的作用，最後讓計謀成功。
In the Three Kingdoms Period, after Cao Cao executed Cai Mao, the victim's brothers, Cai Jhong and Cai He, plotted a false surrender to Jhou yu. Noticing that they did not bring their families with them, Jhou Yu knew that this was a trick. Pretending to be unaware, Jhou Yu called on his old comrade Huan Gai to perform a two-man show of "self-mutilation" in front of the two spies. Jhou Yu had previously given an order that said anybody who says the words "surrender" in his army will be executed. The next day Jhou Yu ordered an attack on the Cao army. Huan Gai was against it. He said, "We cannot possible defeat Cao Cao's huge army. Why not just surrender now?" Jhou Yu pretended to be furious at those remarks and ordered Huan Gai to be beheaded. Everybody fell on their knees to plead for Huan Gai's life. So Jhou Yu relented and said, "All right. I hereby commute your death penalty. But you shall be caned fifty times as punishment."
Afterwards, Huan Gai wrote a letter of defection to Cao Cao. And Cao Cao'spy Cai Jhong was able to verify that Huan Gai was nearly beaten to death. The usually paranoid Cao Cao therefore believed him. Huan Gai wrote, "The military supply ships I am going to take with me tonight when I defect will be flying the colors of blue dragons. We will meet in the middle of the river." That night, at the sight of a whole fleet flying blue dragon flags, Cao Cao said joyfully, "Magnificent! He even brought a big present for me." When the fleet came close, Cao Cao's military advisor suddently noticed something wrong and shouted out loud, "Supply ships are usually very heavy. These ships take on too little water. We have been tricked. Turn back immediately!"
As soon as he said that, the supply ships started to burn. At that time, there was an east wind blowing the fire from the supply ships towards Cao Cao's fleet. And because Cao Cao's fleet of ships were chained together, the ships could not turn around in time to get away from the fire. As a result, the fire spread from ship to ship, and Cao Cao's entire fleet was completely burned.
Strategy 34: The Strategy of Self-Mutilation
Injuring yourself in order to win the trust of your enemy. Then spy and sow discourse among the enemy to cause division and strife, weakening the enemy until final victory is achieved.
