Zhao Zaili, styled Ganchen, was a man from Zhuozhou
When soldier Huangfu Hui started a rebellion, he killed two men who refused to join him
In the main hall, Huangfu Hui pressed a steel blade against Zhao Zaili's neck and said, "Zhao Zaili, if you agree to rebel with us, you will be our leader; if you refuse, your fate will be the same as these two." With that, he threw two bloody heads before Zhao Zaili.
Trembling with fear, Zhao Zaili repeatedly begged for mercy and agreed. Thus, Zhao Zaili led his troops to resist the imperial court.
Emperor Zhuangzong sent Li Siyuan (later Emperor Mingzong) to suppress the rebellion of Zhao Zaili
After Emperor Mingzong ascended the throne, he appointed Zhao Zaili as the military governor of Yicheng Circuit.
Zhao Zaili once governed several regions including Heng Sea and Taining, where he abused his power to oppress the people and ruthlessly extorted their wealth, amassing a fortune of millions in gold and silver. While stationed in Songzhou, the locals suffered greatly under his rule. Later, when Zhao Zaili was ordered to lead troops against the Khitan as the Imperial Cavalry Commander of the Northern Campaign, the people of Songzhou rejoiced upon hearing the news, clapping their hands and saying, "Pulling the nail from our eye—could there be greater joy?"
Zhao Zaili returned empty-handed after failing to reward the troops. Learning of the Songzhou people's remarks, he harbored a grudge. He falsely wrote a memorial claiming the Songzhou people begged him to stay. Upon returning to Songzhou, he ordered each resident to pay a "nail-pulling fee" of one thousand coins, with death for those who refused.
Later, the idiom "a nail in the eye" came to describe someone who is deeply hated or detested.
Source: *New History of the Five Dynasties*, "Biography of Zhao Zaili"
Meaning of the Idiom: Later, the Chinese idiom "眼中之钉" came to describe how someone is deeply hated or detested.