Ru ware is a fabled form of celadon ceramics produced in China in the region of Ru in Henan province during a 20-year period from 1086 to 1106. Considered by many art connoisseurs to be the finest ceramics ever produced in history, it is estimated that less than 70 examples survive today throughout the whole world. The largest collection is a group of 21 pieces held by the National Palace Museum of Taiwan.
Other than its extreme rarity, what sets Ru ware apart is its color. A breathtaking pale sea green, the glaze used on Ru ware is said to have been the ceramicists' attempt to capture "the color of the sky just after the rain stops and the clouds part." Very close examination also reveals a faint rose-colored overtone believed to be the result of mixing powdered agate into the glaze.
Ru ware is rare in part because it was only produced for a short time, and not much of it was produced to begin with. But the rarity was exacerbated by the fact that Ru ware was deemed so outstanding that a rule was promulgated that the Emperor would have the first chance to purchase any item of Ru ware that was created. The Emperor ended up purchasing the vast majority of Ru ware, meaning that almost no examples of Ru ware circulated on the general market. Moreover, whereas many other types of Chinese ceramics were widely copied and forged in later years, no one has ever been able to replicate the secret glaze that makes Ru ware so distinctive.