no way to repel Sima Yi without the empty city ruse[不用空城计,退不了司马懿]
The following story is found in The Romance of Three Kingdoms by Luo Guanzhong of the Ming Dynasty. one of the four literary masterpieces of ancient China.
Prime Minister Zhuge Liang of the Kingdom of Shu led an attack on the Kingdom of Wei in the north. Because of his poor placement of personnel, the Shu army lost the strategic stronghold of Jieting. Assessing the hopelessness of regaining Jieting, Zhuge Liang dispatched several detachments to tackle the Wei army, leaving only 2,500 soldiers and a few civil officials with him. Suddenly a soldier showed up and reported that Wei's general Sima Yi, leading an army of 150,000, was quickly nearing the city. Walking up to the city tower, Zhuge Liang saw flying dust in the distance and the Wei's army closing in on them along two routes. Zhuge Liang hastily ordered that all the four city gates be opened , and twenty soldiers disguised as street sweepers be deployed at each gate. He warned his men not to panic when the enemy came, and sitting on the rostrum of the city tower with two servants he began playing a stringed instrument amidst the smoke of burning incense sticks.
As they drew near the city and saw this scene, the Wei army did not dare to advance and reported the situation to Sima Yi. Sima Yi ordered the troops to stop at once and personally went to the city wall to check out the situation. To his surprise, Zhuge Liang indeed was playing a stringed instrument and smiling leisurely on top of the gate tower, and below him about twenty civilians were sleeping the street as if nobody was around. Suspicion clouded Sima Yi's mind and he ordered the whole army to make a hasty retreat. His son Sima Zhao asked why and Sima Yi answered:" Zhuge Liang is careful man and never takes risks. But today he opened every city gate so it must be a trap. If I attack I will for sure fall into his ambush." Just like this,both camps of the Wei troops retreated.
Seeing the withdrawal of the Wei's army, Zhuge Liang clapped his hands and laughed. When the officials asked why he laughed, Zhuge Liang said:"It wasn't that I wanted to take a risk. I really had no other choice . If we abandoned the city we surely would not have gotten very far before being caught by Sima Yi." At these words , admiration wellled up in everybody's heart.
This story gave rise to the proverb" no way to repet Sima Yi without the empty city ruse," implying that it is impossible to defeat the enemy without a good stratagem.