The Ru kiln served the imperial court but operated for only about 20 years in the late Northern Song Dynasty. The famed sky-blue glaze of Ru porcelain was only achieved when the kiln's position and firing temperature were perfectly balanced. Thus, the success rate was extremely low, and very few pieces have survived to this day. Among archaeological finds at the Ru kiln site, a Northern Song goose-neck vase with sky-blue glaze and carved lotus pattern, now housed at the Henan Museum, stands out as the only complete item. Its carved decoration makes it an exceptionally rare masterpiece, a true national treasure.
