Zhu Wenli, the inheritor of making Ru Porcelain, does research on different Ru porcelains in Ruzhou City, central China's Henan Province, April 25, 2018. Ruzhou City is famous for making Ru porcelain. Fired in kilns, Ru porcelain forms glazes naturally. It is mainly tinged with green and blue. The making of Ru porcelain was listed in the third group of National Intangible Cultural Heritages in 2011. (Xinhua/Feng Dapeng)