The lotus shaped warm bowl from the Ru kiln of the Northern Song Dynasty was used to produce porcelain. The original vessel should be paired with a holding pot and was commonly used for warming wine during the late Tang and Song dynasties. Currently housed in the National Palace Museum in Taipei. Ru kiln was once used in the palace, but due to the method of covering and firing, the mouth had defects. Therefore, there was a move to "order Ruzhou to burn celadon in the palace". The selection of Ru kiln and the use of fully glazed support should be one of the reasons.

Ru porcelain, originated in the mid Tang Dynasty and gained great fame in the Northern Song Dynasty, ranking first among the "Five Famous Ceramics" of the Song Dynasty. It was named after its production in Ruzhou City and has formed a prosperous scene of "a hundred miles of scenery on both sides of the Ru River, with continuous fire everywhere". It occupies a significant position in the history of Chinese ceramics. Ru porcelain's sky blue glazed porcelain contains agate in the glaze, with a green and vibrant color. The glaze is rich and shiny, like a pile of grease, and looks like jade. The sound of clasping is like a fragrance, and the texture is very good. There is a saying that "it looks like jade, not jade, but better than jade". The color is elegant and natural, and it is known as "the rain falls on the sky and the clouds break through".