During the Spring and Autumn period, King Goujian of Yue was defeated in battle, captured by King Fuchai of Wu, and imprisoned for three years, enduring every humiliation. Upon finally returning to his own kingdom, Goujian resolved to seek revenge against Wu. He slept on brushwood and tasted gall daily to remind himself of his bitterness, working tirelessly to strengthen his state.
King Goujian of Yue knew clearly that without the people's support and a strong state, revenge was just empty talk. So he implemented a series of recovery policies, exempting taxes for ten years, allowing the people to prosper and the nation to grow powerful.
After the war had claimed many lives, the population of the Yue kingdom plummeted. King Goujian then decreed incentives for childbirth, encouraged population growth, and welcomed immigrants from other states. Within a decade, Yue's population surged dramatically.
After several years, the Yue kingdom grew prosperous and strong, its soldiers well-trained and united in their hatred of the enemy. The officers and men, burning with a shared desire for revenge, repeatedly petitioned King Goujian for permission to attack the Wu kingdom and wash away their shame.
King Goujian agreed. Before the campaign, he addressed his troops: "I have heard that wise rulers of old did not worry about having too few soldiers, but only about their lack of self-reliance. I want you to use strategy to defeat the enemy, not mere brute courage. I want you to move as one, unite against the foe, advance and retreat together, and never rest until victory is ours!"
The soldiers' morale soared as they encouraged one another, each eager to serve their country and their king. With this spirit, King Goujian led his army to attack the state of Wu. King Fuchai of Wu was defeated, and Wu was ultimately conquered by Yue.
Later, the idiom "courage of a common man" came to describe someone who has personal bravery but lacks wisdom.
Source: *Guoyu*, "Discourses of Yue"
Meaning of the Idiom: Later, the Chinese idiom "匹夫之勇" came to describe how someone has personal bravery but lacks wisdom.