During the Jin Dynasty, two young scholars named Sun Kang and Che Yin became legendary for their relentless pursuit of knowledge despite extreme poverty. Sun Kang, too poor to afford lamp oil for studying at night, discovered that snow on winter nights reflected enough moonlight to read by. He would sit outside in the bitter cold, using the snow's glow to illuminate his books. Meanwhile, Che Yin, equally impoverished, captured fireflies in a thin silk bag and used their faint, flickering light to study through the summer nights. Their stories of ingenuity and determination have been passed down for centuries, inspiring generations to overcome any obstacle in the quest for learning.
Sun Kang was a naturally bright and quick-witted young man who had been devoted to his studies since childhood, always clutching a book and reading every spare moment he could find. But his family was so poor they couldn't even afford lamp oil. In winter, when days were short and nights long, no matter how hard he tried, daylight was never enough. He racked his brain for a way to read after dark. Moonlight came to mind, but winter's moon cast such a faint, feeble glow that he couldn't make out a single character.
One snowy night, frustrated by his inability to continue reading, a scholar stepped outside and noticed the ground was far brighter than usual—moonlight reflecting off the snow. Delighted, he found he could just make out the words in his book. He rushed to a snow-covered field and, using the reflected light, read hungrily. But the bitter cold soon numbed his hands and nearly froze him. Realizing this wouldn't work, he devised a new method: he piled snow beneath a moonlit window, then read from inside, using the snow's glow to extend his study time without freezing. From then on, snowy nights became his perfect reading hours.
Sun Kang's dedication to learning eventually paid off, and he rose to become the Imperial Censor-in-Chief, the highest-ranking official just below the Chancellor.
Similarly, Che Yin, a man from Nanping, was also an avid reader from childhood but too poor to afford lamp oil. As darkness fell, he could no longer see the words and had to stop. One summer evening, while others enjoyed the cool air outside, Che Yin sat on a small stool, distressed by the wasted time, pondering how to get light. Then, fireflies flickered around him in the dark. Watching them, a sudden idea struck him: "A single firefly's light is faint, but if I gather many together, won't their combined glow be bright enough?"
So he immediately gathered dozens of fireflies, placed them in a small bag made of white silk, and found that their light shining through the thin fabric was enough to read by. Overjoyed, Che Yin continued his studies every night by the glow of the fireflies.
By the time he reached adulthood, he was already brimming with talent and learning. Later, Huan Wen took notice of him, and he rose to high office, becoming a prominent figure at court. He was yet another man who gained fame through humble origins and vast erudition.
The two stories above later formed the idiom "Snow Window Firefly Desk," a metaphor for studying hard in poverty.
Source: *Sun Family Records*, *Jinyang Spring and Autumn Annals*
Meaning of the Idiom: Later, the Chinese idiom "雪窗萤几" came to describe a metaphor for studying hard in poverty.