Hidden heritage behind Nuo show masks

Dedicated engraver hopes to pass old craft on for future generations to enjoy

In the deep valleys of southwest China's Guizhou province the sounds of drums and gongs signal Nuo performances, which are held about 10 times a month to drive away evil spirits and pray for good.

Nuo, which means to exorcise bad, was a popular type of sorcery that can be traced back to the Shang Dynasty (16th century - 11th century BC) or even earlier.