[Photo provided to China Daily]

According to Zhang Zhiqing, deputy director of the National Center for Preservation and Conservation of Ancient Books, there are 50 million sets of ancient books in China.

"We have to set different layers of protection when facing such a huge number (of books)," Zhang says. "Once added to the list, the priority will be to keep a close watch on them."

Compared with rescuing or restoring them later, it is better to preserve them in the first place, he adds.

Changes in temperature, humidity and safety conditions must be monitored when it comes to housing key ancient texts.

Fourteen more libraries and institutions were also named "national key protection units of ancient books" last week, which take the number of such registered institutions to 180.

Zhang says the move is also to safeguard national cultural security.

"But new challenges keep coming up. We need to use different kinds of protective methods," he adds.

Tibetan Buddhist monasteries house a large number of ancient scriptures and about 100 monasteries applied for their collections to be listed this time.

"Pilgrims worship these books and they are protected through local traditions," says Zhang. "So, it's not realistic to use a ubiquitous standard and move them into modern warehouses."

He also expects more ancient books from non-Han ethnic groups to be added to the list in the future.

Meanwhile, ancient Chinese books that were taken abroad are now being bought back to China, he says. There are many precious copies held by private collectors in the country as well.

"So, we have more diverse channels to choose from."

Zhang also says that a two-month exhibition displaying some of the newly listed books is scheduled to begin at the National Library of China in June.

wangkaihao@chinadaily.com.cn