During the reign of Emperor Taizong of the Tang Dynasty, there was a renowned minister named Chu Suiliang, who served as the chief imperial advisor and enjoyed the emperor's deep trust.
As Emperor Taizong lay dying, he entrusted his advisors Chu Suiliang and Zhangsun Wuji with a sacred duty: to guide Crown Prince Li Zhi (later Emperor Gaozong of Tang) to the throne. In the early years of Gaozong's reign, these two men wielded immense power, shaping the empire's destiny.
Once, Chu Suiliang used his power to force someone to sell their land at a low price. At the time, Wei Siqian, an upright and fearless imperial censor, learned of this and prepared to submit a memorial impeaching him. Someone advised, "Chu Suiliang holds high power and rank—impeaching him will only bring you trouble!"
Wei Siqian declared with righteous indignation, "I am an imperial censor responsible for overseeing all officials. A true man must speak boldly and act decisively. No matter who violates the law, I will report it openly to the emperor to repay his great kindness. How could I be mediocre, only thinking of protecting my own wife and children?"
Wei Siqian submitted a memorial to Emperor Gaozong, accusing Chu Suiliang of using his power to buy land at unfairly low prices, violating the law and demanding punishment. The emperor found Wei Siqian's case compelling and demoted Chu Suiliang to the position of provincial governor.
However, Chu Suiliang was later recalled to court and reinstated to a high position by Emperor Gaozong. Bearing a grudge, Chu Suiliang retaliated by demoting Wei Siqian to the rank of county magistrate.
But Chu Suiliang's final fate was equally tragic. Repeatedly opposing Emperor Gaozong's decision to depose the empress and elevate Wu Meiniang (the future Empress Wu Zetian), he was demoted time and again, ultimately dying in exile.
The idiom "Mingmu Zhangdan" originally described someone bold and daring, but now generally refers to openly doing bad things without scruples.
Source: *New Book of Tang*, "Biography of Wei Siqian"
Meaning of the Idiom: Later, the Chinese idiom "明目张胆" came to describe openly doing bad things without scruples.