King Helu of Wu defeated Chu and became the overlord of the south. The state of Wu had long been in conflict with the neighboring state of Yue (with its capital in present-day Shaoxing, Zhejiang). In 496 BC, King Goujian of Yue ascended the throne. Wu took advantage of Yue's recent mourning to attack it. A major battle was fought between the states of Wu and Yue at Zuilí (now in the southwest of Jiaxing, Zhejiang; "Zui" is pronounced "zuì"). King Helu of Wu was confident he would win, but instead suffered a defeat, was wounded by an arrow, and due to his old age, died after returning to Wu. After King Helu's death, his son Fucha succeeded him. Before dying, King Helu told Fucha, "Do not forget to avenge the death of your father by Yue." Fucha remembered this command and had people constantly remind him. When he passed through the palace gates, his subordinates would shout loudly, "Fucha! Have you forgotten the hatred for the king of Yue who killed your father?" Fucha wept and said, "No, I dare not forget." He ordered Wu Zixu and another minister, Bo Pi (pronounced "pǐ"), to train the troops and prepare to attack Yue. Two years later, King Fucha personally led his army to attack Yue. Yue had two capable ministers, one named Wen Zhong and the other Fan Li (pronounced "lí"). Fan Li told Goujian, "Wu has been training its soldiers for three years. This time they are determined to take revenge and their attack is fierce. We should defend our city and avoid fighting them." Goujian disagreed and sent his army to fight against the Wu forces. The two armies clashed near a large lake. The Yue army was indeed defeated. King Goujian led five thousand remaining soldiers and officers to Huiji, where they were surrounded by Wu forces. Goujian had no idea what to do. He told Fan Li, "I regret not listening to your advice and now I am in this situation. What should we do now?" Fan Li replied, "We should quickly seek peace." Goujian sent Wen Zhong to the Wu camp to request peace. Wen Zhong explained to King Fucha that Goujian was willing to surrender. King Fucha wanted to agree, but Wu Zixu strongly opposed it. After returning, Wen Zhong learned that Bo Pi of Wu was a greedy and immoral man. He secretly gave Bo Pi a group of beautiful women and treasures, asking him to speak well of Yue before King Fucha. After Bo Pi persuaded King Fucha, the latter ignored Wu Zixu's opposition and agreed to Yue's request for peace, but required Goujian to personally go to Wu. Wen Zhong reported back to Goujian. Goujian entrusted the affairs of the country to Wen Zhong and went to Wu with his wife and Fan Li. When Goujian arrived in Wu, Fucha placed him and his wife in a stone house next to King Helu's tomb, making Goujian feed his horses. Fan Li worked as a servant. Every time Fucha went out in a carriage, Goujian would pull the horse. After two years, Fucha believed Goujian had truly submitted, so he allowed Goujian to return to Yue.
Goujian returned to Yue and resolved to avenge and eliminate the humiliation. He feared that the current comfort might weaken his determination. He hung a bitter gourd in the place where he ate. Whenever he ate, he tasted the bitterness first and asked himself, "Have you forgotten the disgrace of Huiji?" He also removed the mat and used straw as a cushion. This is later known as the story of "lying on firewood and tasting gall" or "sleeping on firewood and tasting gall."
