Ru ware

Ru ware, Ju ware (Chinese: 汝瓷), or "Ru official ware" (Chinese: 汝官瓷) is a famous and extremely rare type of Chinese pottery from the Song dynasty, produced for the imperial court for a brief period around 1100. Fewer than 100 complete pieces survive, though there are later imitations which do not entirely match the originals. Most have a distinctive pale "duck-egg" blue glaze, "the colour of the sky after rain, glimpsed through a parting in the clouds" according to a medieval connoisseur, and are otherwise undecorated, though their colours vary and reach into a celadon green. The shapes include dishes, probably used as brush-washers, cups, wine bottles (carafes in modern terms), small vases, and censers and incense-burners. They can be considered as a particular form of celadon wares. Ru ware represents one of the Five Great Kilns identified by later Chinese writers. The wares were reserved for the Imperial court, with according to one contemporary source only those they rejected reaching a wider market. The source, Zhou Hui, also says the glaze contained agate, and when the kiln site was located in recent decades it was indeed very close to a site for mining agate, which is very largely composed of silica, a usual component of ceramic glazes. However, experts now discount any influence of agate in achieving the Ru glaze colour. The bluish colour may be due to dissolved iron oxide with a very low amount of titanium dioxide. Ru ware is perhaps the first "official ware" specifically commissioned by the imperial court. Their normal practice seems to have been to review the large quantities of "tributary ware" given to them by the provinces making ceramics, effectively as a form of tax. The court kept what they wanted and redistributed the remainder as part of their lavish gifts to...