This felt mat is called Shuhua Zhan in Chinese, or Shitajiki in Japanese. Due to the absorbancy and thinness of rice paper, you need to put a piece of felt underneath. The felt prevent the rice paper from sticking on the table when paint or write. It holds the extra ink or moisture in place but not absorbs too that much(that is why paper towel or newsprint won't do the same.) So the felt not only to keep your table clean but also help to bring out the best effects of watercolor and ink on rice paper.
