During the Spring and Autumn period （770－476BC）, the State of Wu launched an attack against the State of Yue. The King of Wu was seriously wounded and soon died. His son Fu Chai became the new King. Fu was determined to get revenge. He drilled his army rigidly until it was a perfect fighting force. Three years later, he led his army against the State of Yue and caught its king Gou Jian. Fu took him to the State of Wu.

In order to avenge his father's death, Fu let him live in a shabby stone house by his father's tomb and ordered him to raise horses for him. Gou pretended to be loyal to Fu but he never forgot his humiliation. Many years later, he was set free. Gou secretly accumulated a military force after he went back to his own state. In order to make himself tougher he slept on firewood and ate a gall-bladder before having dinner and going to bed every night. At the same time he administered his state carefully, developing agriculture and educating the people. After a few years, his country became strong. Then Gou seized a favorable opportunity to wipe out the State of Wu.

Later, people use it to describe one who endures self-imposed hardships to strengthen one's resolve to realize one's ambition.

    春秋時期，吳國和越國之間進行了一場戰爭，吳王不幸受了重傷，不久就死了。他的兒子夫差作了吳國的新國王，他發誓要替父親報仇。于是，他嚴格的操練他的士兵，把他們訓練成了一支非常厲害的軍隊。三年以后，他對越國發動了戰爭，抓住了越王勾踐，把他帶回了吳國。

為了復仇，夫差讓勾踐住在他父親墓旁的破石屋里天天看墓、喂馬。勾踐表面上服從，心里面卻想著復仇。幾年以后，勾踐被放回越國。他立刻開始秘密聚集一支軍隊。為了提醒自己不要忘了報仇，他睡在柴上，還每天在吃飯睡覺前嘗一嘗苦膽。同時，他專心治理國家，大力發展農業，加強民眾教育。幾年后，越國又變得強大起來，然后，勾踐抓住一個適當的機會消滅了吳國。

后來，人們用它來形容人刻苦自勵以達到自己定下的目標。