A Deocrative Technique
Chattering is a decorative tecnique where a flexible metal tool is allowed to ‘jump’ across the surface of a leatherhard pot, making regular incisions on the surface. Japanese potters call such a tool a ‘jumping’ kanna, or ‘tobikanna’. In Japan, turning tools are known collectively as ‘kezuri no dogu’. The tools which potters originally made from the soft, strap iron used to bind boxes (from the late 19th century on) are called ‘kanna’, or literally ‘planes’. Depending on the speed of the turning pot and the way the tool is held, a regular pattern can evolve, as can be seen in the pot on the left, by Nichibei Potters.
The origins of chattering are unclear, but it can be assumed that it is a technique that was ‘discovered’ accidentally, when a metal turning tool involuntarily began to ‘jump’ on a pot’s surface, giving rise to a regular pattern.
According to Herbert H. Sanders and Kenkichi Tomimoto, in The World of Japanese Ceramics, it is a technique which originated in China. ‘Kasuri – mon’, as the technique is known in Japanese, dates back to the Sung Dynasty. Potters used a white body, covered with a dark slip or engobe. When the flexible metal trimming tool (kanna) was held onto the turning pot, it would skip across the surface, digging into it in a sgrafitto manner, revealing the lighter body beneath. In some areas of Japan such as Koishiwara and Onda, a white slip was used over a darker body, in which case the chattered decoration appears as dark marks on a white background.
The technique may have made it’s way to Japan via Korea. It is said that in 1682, the lord of the Kuroda family of Koishiwara Village (Fukuoka Prefecture, which lies in Southern Japan, opposite the Korean Peninsula) invited a potter from Imari to teach village potters decorative techniques from the Asian Continent, amongst which was ‘tobikanna’ or ‘chattering’.
Chattering is a technique that is still practised today in the villages of Koishiwara and Onda and by individual potters such as Brad Sondahl and the Nichibei Potters. Brad Sondahl gives a description of how to make the tobikanna tool. According to Damon Moon, a fail-safe method is this: the ‘hoop’ tool is best made from the spring-steel of old clock-springs, bent in the reverse direction to which they were wound. These also have the advantage of being of very high-quality steel, which in effect sharpens itself against the clay, so they get better with use. Chatter marks will form successfully, as long as the pot is not too wet or dry.