Mishima is a technique of inlaying slip, underglaze, or even clay into a contrasting clay body, the main clay body of the pottery piece. This technique allows for extremely fine, intricate design work with hard, sharp edges that can be difficult to reliably replicate in any other way.
Although we know this technique by the name “mishima”, the term is misleading. Mishima is actually a city in Japan.
Although many Japanese pottery techniques are called after their city of origin or the family name of the first practitioners (i.e. Raku), this is not the case with mishima.
What we know as mishima was first produced in Korea during the Koryo Period (935-1392 AD). The technique reached stunning heights in the 12th and 13th century Korean celadons. The term we now use took hold as this type of pottery, introduced from Korea, was compared to the script used on calendars created at the shrine at Mishima.
Read this book for background information. Available at Amazon for <$5
Sgraffito is a similar technique. The term comes from the Italian word sgraffiare which means “to scratch.” A layer of colored slip is applied to the surface of a leather-hard clay piece before firing. The design is carved through the colored slip, revealing the color of the clay beneath the slip. The vase below was made with black slip brushed over porcelain (white) clay.