Ash glaze is made from burnt plants and is one of the oldest glazes applied on ceramics in ancient Japan. Potters in Sanage, which is located between today's Toyota and Seto in the central Japan, started using ash glaze in the 9th century. Since then, ash glaze application served as a basis of development in glazing technology that have been used for creation of Japanese ceramics. Seto, which has been Japan's one of the largest ceramic production centres for centuries, is the successor of the ash glazing developed in Sanage.
Among so called the Ancient Six Kilns where ceramics production has been continued since medieval times, Seto was the only site where glazes were developed. While the other five sites have kept their tradition of unglazed ceramics, Seto has created colours using ash glaze to decorate ceramics for many centuries. Techniques and creativity for glazing have made Seto and neighbouring Mino prosper in ceramics production.
Ash glaze turns clear green after firing. It is the simplest and most primitive glaze. Even though it is an old glaze which has a long history, its beautiful green still fascinates us. In the photos are Kato Tsunasuke's ash glaze lipped bowl. The melted glaze makes a pool at the bottom of the bowl and the colour changes in deep green. And then the kannyu (crazing deliberately made for decoration purpose using shrinkage after firing) provides decorative effect on vitrified glaze.
Kato Tsunasuke's works