During the reign of Empress Wu Zetian in the Tang Dynasty, the literary scholar Su Weidao was appointed as chancellor.
Su Weidao knew that Empress Wu Zetian ruled with an iron will and was difficult to serve, so he tread carefully in all matters, never daring to contradict the emperor's wishes, speaking with smooth diplomacy to preserve his position as prime minister.
In 695 AD, Su Weidao was implicated in a case involving the imperial censor Li Dezhao and was demoted to governor of Jizhou, but he was later recalled and reinstated to his original position.
Years later, he again offended Empress Wu Zetian and was dismissed from office, imprisoned in the "Three-Rank Court," a facility reserved for criminals of the third rank and above. Inside, many disgraced high officials continued to feast and drink as usual, but Su Weidao trembled with fear and anxiety. He dared not sleep on a proper bed, instead spreading a mat in a corner of the room. He ate no meat for three meals a day, subsisting on simple tea and plain food.
After Empress Wu Zetian learned of his conduct in prison, she restored him to his original post. Once reinstated, he became even more cautious in every matter, terrified of offending her again.
In the late spring of that year, a sudden heavy snowfall blanketed the capital
Unexpectedly, a censor reported to Wu Zetian, "It is already late spring; this heavy snow will bring disaster to crops. Those who congratulate are all flatterers."
Empress Wu Zetian shot Su Weidao a piercing glare, then swept her sleeves and withdrew from court.
Su Weidao, feeling anxious, returned to his residence. Just then, a close student came to seek advice on governance. Su Weidao sighed and said, "When handling any matter, never make a decisive judgment, for if there is an error, you will surely be punished. Therefore, just like feeling the edges of a square object with your hand, it is best to remain ambiguous."
After this remark spread, people secretly gave him a nickname: "Su Moleng." Later, the idiom "Moleng Liangke" came to describe someone who agrees with both sides of an issue, showing no clear attitude or stance.
Source: *Old Book of Tang*, Biography of Su Weidao
Meaning of the Idiom: Later, the Chinese idiom "摸棱两可" came to describe how someone agrees with both sides of an issue, showing no clear attitude or stance.