A younger son of Huizong fled to the south and established the Southern Song as the Gaozong Emperor (1127–1163), but the Ru kiln was now in enemy territory, and production of Ru ware ceased, if it had not already done so.a rather tiny quantity by imperial standards, suggestive of their rarity.Apart from the last, these other styles would not normally be called "Ru ware", and fall within the range of other contemporary northern ceramics.The excavations also found sherds of "official" quality, but in more elaborate shapes than found among the surviving whole pieces.
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.
continues over the rims at top and bottom of the pieces, in contrast to the rival porcelain Ding ware, fired upturned and so with a rough unglazed rim, often covered with a band of metal.
Instead Ru ware was kept off the kiln stack surface by being supported on three or five small spurs or prongs, presumably of metal, which left little unglazed oval spots called "sesame seeds" on the underside.
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.