Jewels brought home - but it takes patience

During the Boxer Rebellion in 1900 a fire set off in the uprising in the Hanlin Library in Beijing destroyed copies of one of its most prized treasures: the Yongle Dadian, the world's largest paper encyclopedia, from the Ming Dynasty (1368-1644).

Some of the copies that survived were looted later by the invading Eight-Power Allied Forces from the imperial library of the Qing Dynasty (1644-1911). Exactly how many copies of the encyclopedia were taken remains a mystery.

Among the 300-odd precious ancient books now on display in the National Library of China to celebrate the 110th anniversary of the founding of the library are some of the country's cultural treasures that were eventually returned from overseas.

Two copies of Yongle Dadian, among 67 such books that were returned by governments of the Soviet Union and of East Germany during the 1950s as a token of friendship, are among them. However, water stains mar some of their pages.

"Some copies of Yongle Dadian are now housed in libraries or are in collectors' hands around the world," Zhao Qian, a researcher at the National Library of China, says. "However, the opportunities for their being returned as a result of such intergovernmental cooperation are few and far between."

In 2009 the National Cultural Heritage Administration allocated a special fund to buy one copy of Yongle Dadian at what was said to be "a relatively low price" from a Canadian-Chinese collector. The books was transferred to the national library in 2013.

Zhao, an expert on ancient Chinese books, says that sometimes repatriating the country's precious books is like a race against time. In the world antique's market, ancient Chinese books are a particularly sought-after genre, a set of books sometimes fetching as much as 100 million yuan ($14 million).

"There's a long approval process if a public institution wants to buy a collection," Zhao says. On one occasion, minutes before a private collector was about to seal a deal on one particular book, the institution managed to contact the seller and buy the book.