Unlike the earlier Song period, during which a wide range of types was produced in kilns throughout China, during the Yuan and Ming dynasties the majority of ceramics was produced at the Jingdezhen kiln complexes located in Jiangxi Province. Some of the earliest porcelain in the world was manufactured at this complex, the site of some of the most important technical innovations and refinements in the history of ceramics. The most important and far-reaching of these was the perfection of the technique for painting decoration under the glaze using a blue pigment derived from cobalt. This technology led to the creation of the famous blue-and-white wares of China and eventually to the production of the enormously popular blue-and-white wares around the world.