In the mid-Spring and Autumn period, Chu grew powerful and began to look down on its smaller neighbors. In 595 BC, King Zhuang of Chu sent Minister Shen Zhou as an envoy to Qi, instructing him:
“When you pass through the state of Song, there’s no need to ask for passage—just go straight through.”
Shen Zhou knew this was a breach of protocol, but he dared not defy King Zhuang of Chu's orders and had to comply. However, the state of Song, though weak, saw this as an infringement on its sovereignty. When the chief minister Hua Yuan heard the news, he ordered Shen Zhou to be detained and executed.
When King Zhuang of Chu learned that his envoy Shen Zhou had been killed, he flew into a rage and immediately appointed the general Zi Fan as commander, personally leading the army to attack the State of Song.
However, despite the Song state being small, conquering it proved difficult. Even with King Zhuang of Chu personally overseeing the battle, Hua Yuan led the Song army and people in united resistance, holding their ground unyieldingly. The Chu forces besieged them for an entire year but could not capture the Song state.
King Zhuang of Chu, feeling disheartened, considered withdrawing his troops. Minister Shen Shushi advised, "Your Majesty, retreating without capturing Song would damage your prestige. In my view, order the soldiers to build houses and farm, feigning a long siege. Song will surrender out of fear."
King Zhuang of Chu heeded the advice of Shen Shushi and issued the decree.
By then, the Song capital had run out of food. Seeing no sign of the Chu army lifting the siege, many defenders began to lose heart. Realizing the danger, Hua Yuan took a dagger, slipped out of the city one night, crept into the Chu camp, and entered the tent of the Chu commander, Zi Fan.
Zifan was sound asleep, completely off guard. Hua Yuan grabbed him, pulled him up, and pointed a dagger at him, saying:
"Our king has instructed me to inform you of the dire conditions in Song. Though our ruler, ministers, and people are on the brink of starvation, we will never allow you to destroy Song. We will fight to the death until only one person remains. If you retreat thirty li, we will sign a peace treaty with Chu!"
Fearful that Hua Yuan would kill him, Zi Fan hastily agreed to retreat thirty li. Hua Yuan then demanded that Zi Fan swear an oath with him: "I will not deceive you, and you will not deceive me." Zi Fan had no choice but to take the oath alongside Hua Yuan.
The next day, Zifan reported to King Zhuang, who had already been considering withdrawing his troops, and so he readily agreed, seizing the opportunity to order a retreat of thirty li; Huayuan then came to the Chu camp, where the two sides signed a peace treaty.
Later, the idiom "You Cheat, I Scheme" came to describe mutual deception and trickery.
Source: *Zuo Zhuan*, "Duke Xuan's Fifteenth Year"
Meaning of the Idiom: Later, the Chinese idiom "尔虞我诈" came to describe mutual deception and trickery.