Master craftsman fires up his kiln and passion to produce quality product, Yang Feiyue reports.

The dulcet background guzheng (traditional Chinese zither) music permeating the Prince Kung's Palace Museum somehow accentuates the coarse yet stentorian voice of Zhao Qing'an in mid-July.

The man in his 50s nimbly runs around a makeshift stage where bricks, iron and wooden tools, and a kiln model are on display in a hall of the museum in Beijing.

He speaks fast and uses skits to demonstrate the production process of Linqing bricks, also known as tribute bricks, from Linqing, Liaocheng city of East China's Shandong province.

The brick had been favored by ancient royal courts since the Ming Dynasty (1368-1644) and thus serves as an important part of many historical buildings in the capital city.

Having been engaged in producing the tribute bricks for nearly two decades, Zhao is at home with the brick craft that was named a national intangible culture heritage in 2008.

He has been invited to an ongoing exhibition at the Prince Kung's Palace Museum that showcases the craftsmanship of those special bricks and will last through to Sunday.

When explaining the firing process, Zhao picks up an iron fork and a rod before a mock kiln.

"This iron fork is used to take out the slag from the kiln, and the rod is used to stir and mix the bricks during firing," he explains to a roomful of visitors to the exhibition.

Both these tools are indispensable throughout the brick firing, he adds.

Then, he hops over to a pile of brick models and beats them with two sets of wooden boards.

"They are made to match and roughly flatten the surface of unfired brick before manual fine-tuning kicks in," Zhao says.

The production of tribute bricks in Linqing began in the early Ming Dynasty and ended in the late Qing Dynasty (1644-1911), spanning more than 500 years.

According to the chronicle of Linqing, the royal court of Ming set up a branch office there to supervise the firing of tribute bricks, which were then transported to the country's capital via the Grand Canal for the construction of historical buildings like the Forbidden City, the Temple of Heaven, as well as various city gate towers and Confucian temples.