Cao Cao, a renowned politician and military strategist of the Three Kingdoms period, was known for his exceptional political acumen, resourcefulness, and skill in warfare.
One summer, Cao Cao led his troops on a long march to attack the enemy from the rear. As they traveled under the scorching midday sun, the sky was clear and the heat unbearable. The soldiers, weighed down by their weapons, trudged along a cracked, sunbaked mud road, drenched in sweat and desperately thirsty. Many were suffering from heatstroke, and the army's pace slowed to a crawl. Seeing this, Cao Cao raised his hand and called out, "Men, I know a shortcut ahead! There's a vast plum orchard with sweet, juicy fruit. Hurry, and we'll quench our thirst there!" At the mere mention of plums, the soldiers' mouths watered, their spirits lifted, and they pushed forward with renewed energy, finally reaching a water source. This story gave rise to the idiom "Quenching Thirst by Thinking of Plums," meaning to console oneself with illusions.
Cao Cao, though on horseback, was also hot and thirsty. Seeing his soldiers suffering from thirst, he grew anxious. He summoned the guide and quietly asked, "Is there a water source nearby?" The guide shook his head and said, "It hasn't rained for many days, so I'm afraid there's no water."
Cao Cao ordered his troops to halt and rest, sending scouts in all directions to find water. After a long while, they returned with empty buckets—this was a barren wilderness with no rivers or springs, utterly devoid of water.
Cao Cao, with no other choice, immediately ordered his troops to dig a well on the spot. The soldiers sweated as they dug, but after a long time, there was not even a trace of water to be found.
Cao Cao knew his army couldn't stay in this barren land—they had to push on. But the soldiers were so parched they could barely move. What could he do?
He had a sudden inspiration. Climbing to a high spot, he shouted to the soldiers, "Water! We have water!" The soldiers all rose and asked excitedly, "Where? Where is the water?"
Cao Cao pointed in the direction they had originally intended to go and said, "I know this road well. Not far ahead there is a large grove of plum trees, with many big plums. Their sweet and sour juice can quench our thirst. Let's muster our spirits and hurry there to eat the plums!"
The moment the soldiers heard the word "plums," they imagined the sour taste, and their mouths involuntarily watered, instantly quenching their thirst.
Cao Cao seized the moment to command his troops to march swiftly. After some time, they finally led the army out of the waterless wilderness and arrived at a place with a water source. Everyone drank their fill heartily and regained their spirits to continue the march.
The idiom "Quenching Thirst by Thinking of Plums" was derived from this story. Sourness can stimulate saliva production in soldiers' mouths, temporarily relieving thirst. Later, this idiom came to describe finding comfort through imagination.
Source: *A New Account of the Tales of the World*, Chapter "Guile and Deception"
Meaning of the Idiom: Later, the Chinese idiom "望梅止渴" came to describe finding comfort through imagination.