春秋末年，中国东南方的吴国和越国是一对宿敌。先是越王勾践在檇李打败吴军，吴王阖闾受伤而死；他的儿子夫差即位后日夜练兵，发誓报仇。
At the end of the Spring and Autumn period, the states of Wu and Yue in southeast China were bitter rivals. First, King Goujian of Yue defeated the Wu army at Zuili, where King Helü of Wu was wounded and died. His son Fuchai took the throne, drilled his troops day and night, and swore revenge.
两年后，夫差在夫椒大败越军，并把勾践包围在会稽山。勾践走投无路，听从大夫范蠡的建议，向吴国求和，愿意带着妻子去吴国做臣仆。
Two years later, Fuchai crushed the Yue army at Fujiao and trapped Goujian on Mount Kuaiji. With no way out, Goujian followed the advice of his minister Fan Li and sued for peace, offering to go to Wu with his wife and serve as a subject and servant.
在吴国的三年里，勾践住石头房子，为夫差养马驾车，甚至在夫差生病时尝他的粪便来判断病情。夫差终于相信勾践已经真心归顺，不顾大臣伍子胥的反对，放他回国。
During his three years in Wu, Goujian lived in a stone hut, fed and drove Fuchai’s horses, and — when Fuchai fell ill — even tasted his stool to judge the illness. Fuchai finally believed that Goujian had truly submitted. Ignoring the objections of his minister Wu Zixu, he let him return home.
回国以后，勾践担心舒适的日子会磨掉自己的斗志。他撤下席子，睡在柴草上；又在座位旁挂上一颗苦胆，坐着躺着都能看见。
Back home, Goujian worried that a comfortable life would wear away his fighting spirit. He took away his mat and slept on firewood; he also hung a gall bladder beside his seat, where he could see it whether sitting or lying down.
每次吃饭前，他都要先尝一尝苦胆，问自己：“你忘了会稽的耻辱吗？”他亲自下田耕种，夫人亲手织布，与百姓同甘共苦。
Before every meal he tasted the bitter gall and asked himself: “Have you forgotten the shame of Kuaiji?” He plowed the fields himself; his queen wove cloth with her own hands. Ruler and people shared the same hardships.
越国奖励生育、发展生产，对外则恭恭敬敬地侍奉吴国，又不断送礼离间吴国君臣。吴王夫差越来越骄傲，北上争霸，还逼死了忠臣伍子胥。
Yue rewarded families for having children and built up production, while outwardly serving Wu with great deference — sending gifts that sowed discord between Fuchai and his ministers. Fuchai grew prouder and prouder, marched north to compete for hegemony, and even drove his loyal minister Wu Zixu to death.
等吴国精锐尽出、国内空虚，勾践乘机攻入吴国。此后越国又连续多年攻打，最终包围吴都。夫差想求和，勾践不答应。
When Wu’s best troops had marched away and the country lay empty, Goujian seized the moment and invaded. Yue attacked year after year, until at last it surrounded the Wu capital. Fuchai begged for peace; Goujian refused.
夫差后悔莫及，用衣服遮住脸自杀了，说是没有脸在地下见伍子胥。越国灭吴，勾践成为一方霸主。
Filled with regret, Fuchai covered his face with his robe and killed himself, saying he had no face to see Wu Zixu in the underworld. Yue destroyed Wu, and Goujian became a hegemon of his age.
从此，“卧薪尝胆”用来形容一个人忍辱负重、发愤图强，甘愿吃苦，也要实现目标。
From then on, 卧薪尝胆 — “sleeping on firewood and tasting gall” — has described a person who bears humiliation, works with grim determination, and willingly endures hardship to reach their goal.