Seihakuji (blue-white porcelain), known in English as celadon, is produced using porcelain clay made from white stone. It is pottery that has been biscuit-fired and painted with a glaze containing a small amount of iron, which turns a bluish tint when fired again. This technique originated in China. There is also hakuji (white porcelain), which is painted with a glaze that turns transparent when fired, and seiji (blue porcelain), made with clay containing iron coated with a glaze that turns blue when fired.
Did you know?
In seihakuji (blue-white porcelain), designs are inscribed on the pottery, and after firing, bluish glaze that has collected in the indentations looks like beautiful pools of water. The difficult thing about seihakuji is that glaze must be applied very thickly, which places a strain on the pottery and makes it tend to crack during firing.
How to make seihakuji
"What Are Traditional Crafts? -A Guidebook to Seeing, Learning, and Enjoying-" Edited by the Japan Kogei Association Eastern Branch. Published by Unsodo ／ List of works English translation: Kazuko Todate (Art critic / Art historian)