Yang Shi, a renowned philosopher and educator of the Song Dynasty, passed the imperial exams during Emperor Shenzong's Xining era and served as magistrate in Liuyang, Yuhang, and Xiaoshan, as well as a professor in Jingzhou. Under Emperor Huizong, he rose to Right Remonstrance Advisor and Director of the Imperial Academy, and later, under Emperor Gaozong of the Southern Song, held the posts of Vice Minister of Works and Direct Scholar of the Longtu Pavilion.
During the Northern Song Dynasty, the Cheng brothers, Cheng Hao and Cheng Yi, were renowned Neo-Confucian scholars and educators of great prestige. Yang Shi, after passing the imperial examinations and being appointed to an official post, chose not to assume office. Instead, he traveled to Yingchang in Henan (modern-day Xuchang, Henan) to study under Cheng Hao, humbly seeking knowledge and forming a close bond with his teacher. When Yang Shi completed his studies and prepared to return home, Cheng Hao watched his departing figure and remarked, "My philosophical teachings will be carried southward by him!"
Four years later, Cheng Hao passed away. Upon hearing the tragic news, Yang Shi set up a memorial altar at home, wept in mourning, and then wrote letters informing his fellow students of the misfortune. Shortly after, he traveled to Luoyang to pay respects to Cheng Yi, now nearly forty years old.
One snowy day, Yang Shi and his friend You Zuo visited the scholar Cheng Yi, but found him napping. Rather than disturb him, they stood respectfully outside the door, waiting in the heavy snow. When Cheng Yi finally awoke, the snow outside had piled over a foot deep.
Later, the idiom "Standing in Snow at Cheng's Gate" came to describe showing great respect for one's teacher.
Source: *History of Song*, "Biography of Yang Shi"
Meaning of the Idiom: Later, the Chinese idiom "程门立雪" came to describe how showing great respect for one's teacher.