Nang Ying Ying Xue (Light Reflected by Snow or Collected from Fireflies)
In the Jin Dynasty, there was a man named Che Yin who was fond of learning but because of his family's destitute conditions, his father could not afford to offer ideal conditions for studying. In order for them to have enough to survive, they could not even buy lamp oil for him to study at night, so he could only recite his poems in the daytime.
On one summer night, when he was practicing reading an article, he suddenly saw many fireflies lighting up the sky. They were a spot of brightness in the stark blackness of the sky. He had a thought: If many fireflies could be contained all together, they might be able to serve as a lamp. Upon having this thought, he found a white silk bag, caught as many fireflies as he could, and hung up this bag. Although it was not as bright as a lamp, it worked well enough that he could use the light to read by. From that time on, if there were fireflies around, he would use them as a lamp to study by. Due to all his diligent studying, and hard training, he became a senior official later on in his life.
Because they had no money to buy lamp oil, Sun Kang was unable to read at night time, he had no choice but to go to bed early. He thought that wasting time like this was a real pity.
One night, at midnight, he woke up from dreaming, and saw that there was a thread of light coming from the crack in the window. This light was reflected from the snow and the moonlight, and was bright enough to read by. He saw this, and decided to get dressed, immediately taking his books and going outside. The light reflected from the snow on the ground made the outdoors much brighter than it was indoors. Despite the coldness of the night, Sun Kang began to study by moonlight. If he became too cold, he took short breaks to run around and warm up his hands. From then on, whenever there was snow on the ground, he took the opportunity to study. His determination allowed him to progress in leaps and bounds, and gave him the opportunity to become a learned person. He too, became a senior official later on in life.
The idiom "Light reflected by snow or collected from fireflies" is now used to indicate those who study hard in difficult circumstances.