During the Spring and Autumn period, the states of Wu and Yue clashed repeatedly in battle. In 494 BCE, King Fuchai of Wu crushed the Yue army, trapping King Goujian of Yue and his 5,000 remaining soldiers on Mount Kuaiji.
Goujian was filled with regret: because he had ignored the advice of Minister Fan Li and rashly led his army to attack Wu, only to be defeated. As he fled, the Wu army pursued him relentlessly. Now, surrounded on all sides with no plan left, Goujian stood on a hilltop, gazing at the ten thousand banners of the Wu army below, and sighed to the heavens:
“Is my career ending here?” Grand Physician Wen Zhong comforted him, “Misfortune can often turn into fortune, Your Majesty must not lose heart.”
Goujian calmed himself and, together with Wen Zhong and Fan Li, devised a plan. Wen Zhong bravely ventured to the Wu camp, bribing the Wu chancellor Bo Pi with treasures and beautiful women to secure an audience with the king. Wen Zhong then declared to the King of Wu, "Yue is willing to surrender and become a vassal state; our ruler and ministers will serve as slaves, and all our treasures are yours. Otherwise, we will burn our riches and fight to the death with five thousand men, costing Wu dearly."
The King of Wu agreed to peace, taking King Goujian of Yue, his ministers, and countless treasures back to Wu. Later, seeing the Yue ruler and his subjects diligently serving, the King of Wu believed they would not rebel and released them to return to their own kingdom.
After returning to his kingdom, King Goujian of Yue slept on brushwood and tasted gall, never forgetting the humiliation of being besieged at Kuaiji. He and his ministers worked as one to restore their strength. Minister Wen Zhong proposed a plan: "Use ten years to grow the population and gather wealth, then ten years to train and prepare for war." Goujian fully agreed. The state enacted policies rewarding childbirth: men who did not marry by twenty and women by seventeen faced parental punishment; families with two sons had one raised by the state, and those with three had two raised by the state. They also encouraged farming and sericulture, enriching the people and filling the treasury. Then, for the next decade, they strengthened military readiness, trained the army, and built up combat power.
King Goujian of Yue led his people with unwavering resolve, personally working the fields alongside his soldiers and farmers, and within a short time, the kingdom of Yue was restored and thriving. Meanwhile, King Fuchai of Wu abandoned state affairs, indulging in wine and women, and let his guard down against Yue.
Finally, taking advantage of King Fuchai of Wu being away on a northern campaign, the state of Yue launched a surprise attack on Wu, killing the crown prince. The Yue army, well-trained and battle-hardened from previous victories, went on to conquer Wu in 473 BCE, transforming Yue into a great eastern power spanning the Yangtze, Huai, and Zhejiang river regions.
"The policy of 'ten years of gathering strength, ten years of training' proved successful." The idiom "gathering strength and training" refers to diligently accumulating power after defeat, striving for national prosperity and military strength.
Source: *Zuo Zhuan*, "First Year of Duke Ai"
Meaning of the Idiom: Later, the Chinese idiom "生聚教训" came to describe gathering strength and training refers to diligently accumulating power after defeat, striving for national prosperity and military strength.