By the Yellow River lived a poor family who wove reed mats and baskets for a living. Despite working tirelessly day and night, they remained destitute.
One day, the family's son went to the riverbank to cut wormwood. Growing tired from his labor, he sat down by the shore to rest.
He stared blankly at the river, suddenly recalling elders often said the deep waters held countless treasures, but no one dared dive for them. He thought: Since my family is so poor, why not take the risk and try?
So he found a deep abyss and, relying on his excellent swimming skills, bravely dove to the bottom. The deeper he went, the darker it became, until he could see nothing at all.
Suddenly, his eyes caught a glimmer—a sparkling object not far away. The young man swam eagerly toward the light. Drawing closer, he found a crystal-clear pearl, gleaming and flawless. Overjoyed, he plucked it from its resting place and surfaced, clutching the treasure in his hand.
When the young man returned home, his mother was overjoyed to see the pearl he had fished out, but his father, a man of wide experience, immediately pressed him for its origin. The son recounted the entire story of how he had found the pearl.
The father exclaimed, "How dangerous! Such a pearl is worth a thousand gold pieces—it must be from under the jaw of a black dragon in the abyss. You can only retrieve it when the dragon sleeps; otherwise, you'll die without a burial place!"
With the black dragon pearl in their possession, the family's life became prosperous and wealthy.
Later, people used the idiom "Touching the Dragon's Beard to Get the Pearl" to describe gaining wealth by luck. Today, it also refers to writing that hits the key point.
Source: *Zhuangzi*, "Lie Yukou"
Meaning of the Idiom: Later, the Chinese idiom "探骊得珠" came to describe gaining wealth by luck.