Ru Yao Kiln celadon wares originate from Henan province. The technique was perfected in the Song Dynasty. The glaze used is unique and contains some small amounts of iron giving the fired glaze a luminescent look to it. Small veins exist after the firing process and with seasoning the veins will grow more prominent and will take on a golden brown color. Ru Yao wares should be cleaned with tea water or spring water and will develop a luster with repeated use.