During the Jin Dynasty, Che Yin was exceptionally diligent in his studies from a young age. As his family was poor and could not afford lamp oil for him to read at night, he came up with a resourceful solution. On summer evenings, he would catch fireflies, place them in a white gauze bag, and hang the bag above his books, using their faint light to read.

In the same dynasty, there was another scholar named Sun Kang who also came from a poor family. On snowy nights, he would read by the light reflected from the bright snow outside his window.

Both stories exemplify remarkable perseverance and dedication to learning despite challenging circumstances.