Among the outstanding figures of Chinese history, famous either for their intelligence or treachery, Cao Cao is one of the foremost.
One hot day, he marched out with his troops under a burning sun into a mountainous area. Bewildered, he lost the way. The journey was long and the sun was scorching. After their fruitless and tiresome march, one and all voiced their great dissatisfaction with the leadership of Cao Cao. Troops bitterly complained of their great thirst. The antagonism of the soldiers was growing fast and they were on the verge of staging a mutiny. The subordinate officers were helpless to cope with the situation. Cao Cao, however, in the nick of time cleverly and treacherously gave orders for his troops to march to some nearby plum trees for a rest and announced that soldiers would be allowed to eat as much as they desired of the juicy sour fruit.
At the thought of the sour fruit the soldiers' complaints of great thirst as well as their antagonistic feelings were quickly forgotten.Based on the story later generations created the proverb "to quench one's thirst by looking up at plums", to illustrate a case where one takes comfort in believing that they have already attained that which was expected or desired.