The Origin of overglaze-blue enameling in Japan: New discoveries and a reassessment

The production of overglaze-blue decorated porcelains in Japan has traditionally been associated with Chinese technology, but the puzzling issue of the early firing of a striking overglaze-blue enamel has remained unresolved for almost a century. This work presents the first systematic scientific study of shards excavated at kiln sites in Arita, the center of porcelain production in Japan. The study was carried out in an attempt to resolve the issue of the origin of overglaze-blue enameling on early polychrome Imari wares (Shoki Iro-e) which started around 1640, way before the same technology spread in Jingdezhen in the late Kangxi period (1700). In particular shards excavated at the Yanbeta kiln site, where it has recently been discovered that polychrome overglaze decoration started, and shards from other early kilns were analyzed for the first time. Energy-dispersive X-ray fluorescence (ED-XRF) was used to identify the chemical composition of the coloring agents present in the overglaze-blue enamels in order to determine their geographical area of origin. Experimental results provide groundbreaking information regarding the materials and technologies used in the different kilns, and show how the earliest attempts at firing overglaze-blue enamels in Arita involved the use of imported cobalt ores. For the first time, it has been scientifically proved that the successful use of an overglaze-blue decoration was a precise effect Japanese potters aimed at achieving by means of selected materials and technologies obtained from Europe, thus resolving the issues that emerged from the traditional approach of a Chinese origin for all technologies. Furthermore, comparisons between scientific analysis of late-16th and early-17th century Japanese paintings in Western style and the results presented in this work revealed that materials used for overglaze-enameling were also used for pigments employed in traditional paintings. Technologies from distant geographical areas proved crucial in pre-modern Japan.5s