Intangible heritage

The ancient books preservation technique of the national library was listed as a national-level intangible cultural heritage in 2008.

Nonetheless, Du Weisheng, a senior ancient books conservator in the library, who has been devoted to this career for nearly 50 years, points out that ancient book restoration involves knowledge from multiple disciplines beyond traditional expertise.

In addition to possessing excellent restoration skills, a restorer must also have a certain level of understanding in fields such as physics, chemistry, printing and papermaking, Du says.

"In the context of improving cultural confidence, the valuable ancient books that have been preserved serve as the best evidence of that confidence," Du says. "Restoring these books is a significant effort in prolonging the life of ancient Chinese civilization."

The more ancient books Song restores, the more fun she has found in her line of work.

During the restoration process, she sometimes comes across surprising discoveries.

In 2021, she found some text faintly visible under the blue background of a painting featuring the image of a Buddha when it was dampened.

The text roughly conveyed the artist's intentions, and was hidden again when the paper dried.