During the Spring and Autumn period, Duke Xian of Jin, infatuated with his concubine Li Ji, appointed her son Xi Qi as his heir, forcing his other sons, Chong'er and Yiwu, into exile abroad.
Chong'er first fled in haste to the Di state, where he settled for twelve years. After Duke Xian of Jin died, his sons Xiqi and Zhuozu successively took the throne, only to be murdered by the minister Li Ke. Then Yiwu returned from Liang to claim the title, known historically as Duke Hui of Jin. Fearing Chong'er would come back to seize his throne, Duke Hui sent assassins to kill him.
Facing such peril, Chong'er fled from state to state, seeking refuge first in Qi, then Cao, and Wei, but the rulers of those lands all looked down on him. When he finally reached Chu, King Cheng of Chu treated him with great respect, receiving him with the rites due to a feudal lord and showing equal honor to his followers, like Zhao Cui and Jie Zhitui.
One day, King Cheng of Chu prepared a lavish feast to entertain the exiled Prince Chong'er of Jin. Seated close together, the two spoke warmly and found each other's company delightful. As the wine flowed and spirits rose, King Cheng suddenly smiled and asked, "Today I honor you with such grand ceremony—if one day you return to Jin and become its ruler, how do you plan to repay me?"
“You have plenty of male and female slaves, jade, and silk; as for decorative feathers, animal teeth, and leather, these are also famous products of your noble state. I truly do not know how I should repay you!” Chong'er said with great difficulty.
King Cheng was dissatisfied with Chong'er's reply and said, "Though you say that, I think if you ever become the ruler of Jin, you should be able to repay me!"
At this moment, Chong'er had a sudden inspiration and said, "If I am fortunate enough to return to Jin, and we are forced to meet on the battlefield in the future, I will retreat three she to repay your kindness."
Later, Chong'er indeed returned to the state of Jin and became its ruler (Duke Wen of Jin). To aid the state of Song, he was forced to clash with Chu. As the two armies drew near, honoring his earlier promise to King Cheng of Chu, he ordered his entire army to retreat three she (90 li).
Later, the idiom "retreating three she" came to describe yielding and avoiding conflict.
Source: *Zuo Zhuan*, "Duke Xi's Twenty-Third Year"
Meaning of the Idiom: Later, the Chinese idiom "退避三舍" came to describe yielding and avoiding conflict.