Dish with Bands of Geometricized Patterns 18th century Japan This dish is an excellent example of the sophisticated technique of early Nabeshima potters. The unglazed ware was painted with sumi (ink), decorated with underglaze cobalt blue and then covered in a light cobalt-blue glaze followed by a clear glaze. When fired, the sumi evaporates along with the cobalt-blue glaze, leaving the underlying white porcelain visible in a process known as sumihajiki.. Dish with Bands of Geometricized Patterns 50344