In the final years of the Warring States period, Qin's army conquered Han, captured its king, then attacked Chu to the south and Zhao to the north. Yan, a neighbor of Zhao, grew terrified. Crown Prince Dan of Yan sought advice from the chivalrous warrior Tian Guang, who replied, 'This is beyond me—consult the assassin Jing Ke instead.'
Prince Dan met Jing Ke and asked, "Do you understand the current situation, sir?" "The State of Zhao is about to fall, and the State of Yan is in imminent danger," Jing Ke replied. "Do you have any good strategies, sir?" "First, tell me your plan."
Prince Dan hesitated for a moment, then said, "The King of Qin is a greedy man. I want you to offer him gold and treasures, demanding he return the lands he has seized. If he refuses, you will assassinate him."
Jing Ke thought of the heavily guarded Qin palace and said, "I don't have the ability, I won't go!" Prince Dan knelt and pleaded, "If you refuse, the Yan state will be finished." Jing Ke thought for a moment and said, "Alright, I agree."
Prince Dan of Yan then honored Jing Ke as his highest-ranking guest, visiting him daily with warm greetings and thoughtful care.
After some time, the Qin army captured the state of Zhao, took the King of Zhao prisoner, and deployed troops at the border of Yan. Crown Prince Dan said fearfully to Jing Ke, "The Qin army is about to cross the Yi River. Please, sir, act soon."
Jing Ke explained, "For this mission, I must first gain the King of Qin's trust. Fan Yuqi, once a Qin general, fled to Yan after offending the king, who now offers a thousand gold pieces for his head. I plan to bring Fan's head along with a map of Yan's Dukang region, claiming Yan wishes to cede it to Qin. When the king is pleased and I present your terms, if he refuses, I will assassinate him on the spot."
Prince Dan hesitated and said, 'I cannot bear to kill General Fan.' Jing Ke secretly visited Fan Wuji and asked, 'The King of Qin has slaughtered your entire family—do you want revenge?' Fan Wuji ground his teeth and replied, 'I dream of it day and night, but I have no way.' Jing Ke said, 'I have a plan that can avenge you.' Fan Wuji urged, 'Please, tell me, sir.'
Jing Ke laid out his plan in detail, and Fan Wuji, without a word of hesitation, drew his blade and took his own life.
On the day of Jing Ke's departure, Crown Prince Dan personally saw him off at the Yi River
Those who saw them off, hearing the song and thinking of the tyrant King of Qin, glared with fury, their hair bristling with rage.
Later, the idiom "hair-raising" came to describe extreme anger.
Source: *Records of the Grand Historian*, "Biography of Assassins"
Meaning of the Idiom: Later, the Chinese idiom "令人发指" came to describe extreme anger.