With their heads removed and bodies broken into pieces to be sold around the world, Buddhist statues taken from sacred grottoes in North China are being made whole again, but in digital form.

The painstaking restoration work is being done with the remnants of statues located around the world, advanced digital art techniques, and a verification process involving scientists and academics from China and the United States.

Once the digital image of a statue is complete, it appears as it would have centuries ago in its original setting — the Tianlong Mountain Buddhist Grottoes in Taiyuan, Shanxi province.

"The digital restoration of cultural relics preserves an accurate historical and cultural record for future generations, allowing more endangered ancient sites to be 'revived' and take their place in the world," said Zhao Hui, dean of the College of Art at Taiyuan University of Technology, one of the institutions involved in the project.

The restoration work "brings people closer to these relics, allowing more to revisit history and rediscover the original appearance of the artifacts", said Zhao.

Unprotected treasures

The grottoes, nestled between pine and cypress trees that dot Tianlong Mountain, were built from the Eastern Wei (534-550) to the Tang (618-907) dynasties, when Buddhism arrived in China and flourished.

Originally established as a sanctuary for the emperor, the caves gradually became a site of worship for locals.

In the 18th century, however, they fell into neglect and were largely forgotten until 1908 when visiting German architect Ernst Boerschmann "discovered" the grand caves filled with Buddha statues, embossed artworks, and frescos.

Foreign art historians and collectors visited the site, but it was not until 1921 that Japanese archaeologist Sekino Tadashi brought global attention to the grottoes through his photographs.

Unfortunately, international art dealers, thieves and smugglers descended on the unprotected treasure trove.

Between 1924 and 1925, thieves vandalized and looted the caves, bribing corrupt monks to break over 240 statues into fragments for sale. One of the major smugglers was Japanese art dealer Sadajiro Yamanaka who exploited the chaos of World War II to sell stolen artifacts to Western buyers.

The prized item for sellers and collectors was the Buddha head, but the statue's other parts were sometimes sold separately in another country.

About 120 statues located abroad are confirmed to be from Tianlong Mountain, making it one of the most damaged cultural sites in China, said Jia Chen, vice president of Taiyuan Cultural Relics Protection Research Institute.

"The grottoes are important cultural memories of Chinese history," he said. "The period when the grottoes were established marks an important phase in the localization of Buddhist cave art in China.

"We can see in the grottoes that in just over 100 years, the style of Buddha statues transformed from delicate and refined to robust and rounded, reflecting the evolution of Buddhist art in China," Jia said.