In 496 BCE, King Helu of Wu attacked Yue but was struck in the right foot by a general under King Goujian of Yue and died of his wounds; his son Fuchai succeeded him. Three years later, seeking revenge for his father, Fuchai led his army against Yue again, this time surrounding the Yue capital of Kuaiji (modern-day Shaoxing, Zhejiang Province) so tightly that King Goujian was forced to surrender.
After his overwhelming victory, the triumphant King Fuchai of Wu proudly paraded the captured King Goujian of Yue and his wife back to Wu. To appear magnanimous before the other feudal lords, Fuchai decided not to execute them, instead ordering them to live in a stone hut before Helü's tomb, where they tended the grave and raised horses as penance. Whenever Fuchai rode out, Goujian would walk ahead of the carriage, holding the horse's whip.
Goujian was a man of extraordinary resolve. Captured and humiliated by the King of Wu, he chose to endure every torment and indignity, biding his time for a comeback. On the surface, he acted with utmost obedience and loyalty toward Fuchai, the King of Wu, all to win his trust and secure his release.
Once, King Fuchai of Wu fell ill. To demonstrate his unwavering loyalty, King Goujian of Yue actually tasted Fuchai's excrement. When Fuchai asked why, Goujian replied, "This allows me to predict the day of your recovery." As luck would have it, Fuchai recovered exactly on the day Goujian had predicted. From then on, Fuchai believed Goujian was truly devoted and let his guard down.
Three years passed, and King Fuchai of Wu felt that Goujian's punishment had been sufficient—surely he would no longer oppose him—so he released Goujian and his wife back to the state of Yue.
After returning to his kingdom, Goujian was determined to avenge his defeat. To steel his resolve, he slept on a bed of brushwood instead of soft bedding, and hung a gall bladder in his living quarters—seeing it whenever he sat or lay down, and tasting its bitterness before every meal. He would often weep and ask himself, "Kuai Ji, Kuai Ji, have you forgotten the shame of your defeat at Kuai Ji?"
King Goujian of Yue took numerous measures to boost production, personally plowing fields and having his wife weave cloth, eating no meat and wearing no fine silks, sharing hardships with his people. He also rewarded childbirth to increase the population and strengthen the state's power.
Meanwhile, Goujian continued to show outward obedience and loyalty to Fuchai, sending envoys to Wu each month with greetings and rare treasures as gifts. Delighted, Fuchai completely let down his guard, even granting Goujian more territory.
A few years later, seeing the kingdom's production booming and the people's morale high, Goujian planned to attack the state of Wu. However, his loyal ministers advised him, "The time is not yet ripe; we must wait a little longer."
Through a decade of building up resources and another decade of training his people, Goujian finally made the state of Yue strong and prosperous.
Later, King Fuchai of Wu launched an attack on the State of Qi. Goujian, the King of Yue, saw this as his moment. He personally led a massive army to strike Wu, swiftly capturing its capital, Gusu (present-day Suzhou, Jiangsu Province). Fuchai, unable to repel the Yue forces, sent an envoy to Goujian to sue for peace. Goujian, after analyzing the situation and the relative strength of both sides, concluded that his forces were not yet strong enough to completely crush Wu, and so he agreed to the peace negotiations.
Four years later, Goujian raised his army once more to attack the state of Wu
King Goujian then led his army north into the Central Plains, convening a grand assembly of feudal lords at Xuzhou (south of present-day Teng County, Shandong Province), and rose to become the hegemon of the late Spring and Autumn period.
Later, people summarized King Goujian of Yue's experience into the idiom "Sleeping on Brushwood and Tasting Gall," symbolizing enduring hardship to achieve a goal, refusing comfort, striving with determination, and vowing to avenge one's country.
Source: *Records of the Grand Historian*, "Biography of King Goujian of Yue"
Meaning of the Idiom: Later, the Chinese idiom "卧薪尝胆" came to describe enduring hardship to achieve a goal, refusing comfort, striving with determination, and vowing to avenge ones country.