The Jin Dynasty writer Zuo Si was once a mischievous and uninterested child in his early years. His father often became angry about this, but young Zuo Si remained very mischievous and refused to study seriously.

One day, while Zuo Si's father was chatting with his friends, his friends admired him for having a smart and lovely son. Zuo Si's father sighed and said, "Don't mention him anymore. Young Zuo Si's studies are not as good as mine when I was his age. It seems he won't have much success." As he spoke, a look of disappointment appeared on his face. All of this was seen and heard by young Zuo Si, who felt very sad. He realized that it was indeed shameful not to study hard. So he secretly made up his mind to study diligently.

Day after day, year after year, Zuo Si gradually grew up. Because of his persistent and hard work, he eventually became a learned person with excellent writing skills. He spent one year writing the "Fu of Qi Capital," demonstrating his talent in literature and laying the foundation for him to become an outstanding literary figure. After that, he planned to write the "Fu of the Three Capitals," which would focus on the customs, people, and products of the capitals of Wei, Shu, and Wu during the Three Kingdoms period. To ensure that the content, structure, and language reached a certain level, he devoted himself to research and carefully wrote the work, working so hard that he neglected meals and sleep. It took him a full ten years, and finally, the literary masterpiece "Fu of the Three Capitals" was completed.

The "Fu of the Three Capitals" received widespread praise, and people compared it to the Han Dynasty's literary masterpiece "Fu of the Two Capitals." Since the printing press had not yet been invented at that time, those who loved the "Fu of the Three Capitals" could only compete to copy it. Because so many people were copying it, the paper in the capital city Luoyang was in short supply, and the price of paper in the city rose sharply for a time.

This story comes from "The Book of Jin: Literary Figures: Biography of Zuo Si." The idiom "Luoyang Paper Expensive" is used to praise an outstanding work that becomes widely popular.