During the Spring and Autumn period, the powerful state of Chu attacked the weaker state of Zheng. The Chu army advanced with unstoppable force, quickly approaching the Zheng city of Jun.
Defending the city of Chengmi was Zheng's high official Huang Jie. When Chu forces attacked, he led his troops into battle, only to face Chu general Chuan Fengshu and Prince Wei, brother of King Kang of Chu. Huang Jie was no match for them; after just a few exchanges, he turned his horse and fled in panic. Chuan Fengshu and Prince Wei gave chase, refusing to let him escape. Chuan Fengshu's horse was faster, and he lunged forward to capture Huang Jie.
Chuan Fengshu escorted Huang Jie back to the Chu camp, locked him in a tent, and prepared to claim credit from the imperial advisor Bo Zhouli. But Prince Wei came demanding the prisoner, insisting he had captured Huang Jie himself and that the glory was his. Chuan Fengshu knew Prince Wei was vain and loved bullying others as a royal relative, but he wasn't one to back down, so the two started arguing.
The two could not settle their dispute, so they asked the Grand Steward Bo Zhouli to judge. Bo Zhouli, favoring Prince Wei, suggested letting the prisoner identify the target himself to appear fair.
Chuan Fengshu thought to himself, "I clearly captured Huang Jie myself—he can't deny it!" So he agreed without hesitation.
Huang Jie was brought before Bo Zhouli to await an immediate verdict. Bo Zhouli said to Huang Jie, "These two are arguing over who captured you. Now please identify which one actually seized you."
Then Zhou Bo Li, with pointed undertones, said, "Neither of them is without status—you must distinguish clearly!" Raising his hand high, he respectfully gestured toward Prince Wei and declared to Huang Jie, "This nobleman is our ruler's beloved younger brother, Prince Wei." Then, lowering his hand casually, he waved dismissively at Chuan Feng Shu and said, "This is a county magistrate from outside Fangcheng, named Chuan Feng Shu." After the introductions, he asked Huang Jie with a meaningful look, "Now, who do you think actually captured you?"
Huang Jie was no fool. Seeing Bo Zhouli present both sides' attitudes, he had already guessed the situation. Knowing Bo Zhouli was currying favor with the powerful, he was happy to go along and lied, "I met Prince Wei, was defeated by him, and captured!"
Chuan Fengshu was furious but helpless, forced to watch helplessly as Prince Wei stole the credit.
Later, people used the idiom "to work hand in glove" to describe colluding in cheating.
Source: *Zuo Zhuan*, "Duke Xiang's 26th Year"
Meaning of the Idiom: Later, the Chinese idiom "上下其手" came to describe colluding in cheating.