Since the 1970s coal has been used in the lighting process, but the main fuel is always firewood, preferably pine or bamboo. A keen watch needs to be kept on the kiln day and night, with fuels being fed to it constantly to keep the fire burning at full power for 40 hours. The temperature in the kiln can be as high as 1,200 C.

Workers invented a special stool, with its feet cut to fit its tilting positioning along the slope, enabling them to sit down for a rest during the long working hours spent near the fire.

"These stools are a trademark of the unique practice of Yixing ceramic making," Zhao says at the entrance of an exhibition hall by the Qianshu Dragon Kiln. Dozens of wooden stools with tilted feet are placed on the wall near the gate, greeting visitors.

Teapots and other objects are placed in protective boxes before they are baked in the kiln. These rough clay boxes can be used no more than five times before they crack and have to be discarded.