Chinese researchers have finished digital video filming of six more caves of the Dunhuang Mogao Grottoes this year, a listed World Heritage Site in the remote northwestern Gansu Province.

This brings the total number of caves being filmed to 47 since the project started in 2008 amid efforts to preserve the ancient murals in a modern way, said a spokesman with the Dunhuang Academy, the official supervisory institution of the Dunhuang grottoes.

It took researchers eight months this year to film the six caves, including five built in the Tang Dynasty (618-907) and one in the Yuan Dynasty (1279-1368), the spokesman said.