The scholar Yang Shi was already forty when he went to see the philosopher Cheng Yi in Luoyang. One day, Cheng Yi sat with his eyes closed. Yang Shi and You Zuo stood beside him and did not leave. When Cheng Yi woke, the snow outside the door was a foot deep. (History of Song)
Cheng men li xue, standing in the snow at Cheng’s gate, means to honor one’s teacher.