Oracle bones. [Photo provided to China Daily]

How many?

According to Song, there are about 150,000 individual oracle bones in the world.

About 93,000 pieces from 11 institutions on the Chinese mainland, including the National Library of China, the Chinese Academy of Social Sciences, and the Palace Museum, were included in the UNESCO Memory of the World Register. Academia Sinica in Taiwan is also a major institution that houses the bones.

Zhao reveals that images of about 3,800 fragments of oracle bones and 7,000 ink rubbings of bones have been uploaded to the website of the National Library of China for public use. He says the wider use of digital platforms has helped scientists locate broken fragments of bones kept at other institutions and rejoin them with their original host pieces.

For example, he points to rubbing of an upper part of turtle shell and explains that the lower part was found in Taiwan, thanks to the rejoining studies.

Nevertheless, Song says the digital approach still only plays an assisting role in their research. After being viewed digitally, certain pieces that looked like they would fit back together, were found not to match perfectly after experts checked the original pieces.

"It needs interdisciplinary expertise," he says. "Carrying out careful and indepth research is always crucial."