Qingbai (‘green–white’) wares were first produced in the early Northern Song dynasty at kilns in Jingdezhen, which at the time were successfully manufacturing celadon wares for the local market. Their icy blue–green tinge was produced by applying a glaze with small amounts of iron to a fine porcelain stone and kaolin clay body, which was fired in an oxygen–deprived atmosphere. They were produced in a variety of forms for the domestic market, including utilitarian bowls, dishes and teapots for daily use and more elaborate figures and jars for burial. Though not generally made for the imperial court, qingbai wares were appreciated by Song connoisseurs, who likened them to jade.