Photo taken on Jan. 4, 2020 shows a white porcelain ware of Tang Dynasty (618-907) displayed at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province. (Photos: Xinhua)

Photo taken on Jan. 4, 2020 shows a white porcelain ware of Tang Dynasty (618-907) displayed at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province.

A visitor takes photos of the white porcelain wares of Tang Dynasty (618-907) at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province, Jan. 4, 2020.

A visitor watches the white porcelain wares of Tang Dynasty (618-907) at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province, Jan. 4, 2020.

Visitors watch the white porcelain wares of Tang Dynasty (618-907) at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province, Jan. 4, 2020.

A visitor watches the white porcelain wares of Tang Dynasty (618-907) at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province, Jan. 4, 2020.

Photo taken on Jan. 4, 2020 shows white porcelain wares of Tang Dynasty (618-907) displayed at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province.

Photo taken on Jan. 4, 2020 shows a white porcelain ware of Tang Dynasty (618-907) displayed at an exhibition in a museum in Xi'an, capital of northwest China's Shaanxi Province.