"Blue and white pottery" (Chinese: 青花; pinyin: qīng-huā; literally: "Blue flowers") covers a wide range of white pottery and porcelain decorated under the glaze with a blue pigment, generally cobalt oxide. The decoration is commonly applied by hand, originally by brush painting, but nowadays by stencilling or by transfer-printing, though other methods of application have also been used.
Blue and white decoration first became widely used in Chinese porcelain in the 14th century, after the cobalt pigment for the blue began to be imported from Persia. A style of decoration based on sinuous plant forms spreading across the object was perfected, and most commonly used. It was widely exported, and inspired imitative wares in Islamic ceramics and later European tin-glazed eathenware such as Delftware and after the techniques was discovered in the 18th century, European porcelain. Blue and white pottery in all these traditions continues to be produced, most of it copying earlier styles.
Cobalt blue was first used in decorating Islamic pottery, especially in Persia, where the main source was located in mines near Kashan.
The first Chinese blue and white wares were as early as the ninth century in Henan province, China; although only shards have been discovered. Tang period blue-and-white is even rarer than Song blue-and-white and was unknown before 1985. The Tang pieces are not porcelain however, but rather earthenwares with greenish white slip, using cobalt blue pigments. The only three pieces of complete "Tang blue and white" in the world were recovered from Indonesian Belitung shipwreck in 1998 and later sold to Singapore. It appears that the technique was thereafter forgotten for some centuries.