New discoveries

Xie Dezhi, an associate researcher at the NLC, said, "Thanks to Yongle Dadian, many chapters of ancient works that disappeared in the past were recovered."

For example, during the Qing Dynasty, scholars were able to find a total of 385 books and excerpts from works that were thought to be lost by referring to Yongle Dadian. In the 1930s, even with the encyclopedia in pieces, Zhao Wanli, a librarian, located another 200 works in its pages.

By referring to the character shui (water) in two copies of the encyclopedia on display at the NLC, visitors can learn about the original text for Commentary of the Water Classic, a geography book from the 6th century.

Chen, from the NLC, said: "When a new page of Yongle Dadian is found, it is big news for us. We always have new findings, which allow us to correct previous misunderstandings. These findings can perhaps offer much inspiration for our daily lives today."

For example, in one copy of the work that was found in Shandong province in 1983, and refers to the character men (gate), scholars discovered a detailed record of evolving styles of front doors in ancient China, which was rare in earlier copies.

For the NLC, obtaining just a single copy of Yongle Dadian is no easy task.

Zhao Qian, a researcher from the library, said ancient Chinese books have been in high demand on the auction market in recent years, and prices have risen significantly. As an example, Zhao cited the two copies in France that fetched 65 million yuan.

In other countries, copies of Yongle Dadian have been listed as key cultural relics, making it difficult to repatriate them to China.

Meanwhile, digitization has opened a new door to building a database for the encyclopedia.

The NLC has acquired a total of about 70 copies from the United Kingdom, Germany, the US, Japan and Ireland through photocopied duplicates. Digitized versions of all copies of the encyclopedia collected in public institutions on the Chinese mainland have been published by the national library.

Zhang said, "People in the Ming Dynasty left a huge knowledge graph for us. With new technical approaches, we can manage and analyze digitized information in a scientific way and construct a framework to better understand Chinese civilization."