One of my favourite ceramic glazes is Japanese Shino, which is often used to create wonderful surfaces on ceremonial teabowls. It’s become very popular with wood-firing potters in the USA, where they now use it to glaze both functional and contemporary, sculptural ceramics. The recipes for shinos are fairly simple, but the glaze itself is usually sensitive to the atmosphere in the kiln during firing. The glaze may also develop colour from the clay body beneath, especially if iron oxide is present. As a result, an incredible variety of colours can be achieved, ranging from whites and greys through to oranges, reds, pinks, buttery browns, even lustrous golds. When soda ash is added to the mix, yet more effects are possible as the glaze may trap carbon and other impurities, creating blacks, greys, crystalline patterns and dappled effects. A potter could spend a lifetime just exploring the potentialities that this one type of glaze opens up.
It is thought that shino glazes came originally from the Mino region of Japan around the end of the 16th Century. At that time, ceramics production was bound up with the aesthetics of the buddhist tea ceremony. It is possible that shino glaze was named after the shogun, Shino Soushin, an important tea master. (Britt, 2007). A prominent exponent of shino glaze techniques in the UK is Lisa Hammond, who has been making ceramics at the Maze Hill Pottery in Greenwich, London, since 1994. Hammond fires her shino-glazed pots in a gas-fired kiln and she claims that one of the secrets of developing a good surface is the slowness of the firing, which may last four or five days! In 2003, Hammond spent three months in Japan, learning about wood firing and shinos from potter, Rizu Takahashi (Ceramic Review, November 2006).
Lidded box/caddy by Lisa Hammond
Stoneware, shino glaze over red iron
Shino glazes usually contain high levels of feldspar and clay. The feldspar mineral gives the glaze an opaque, milky whiteness which often reminds me of tooth enamel. When applied thickly the feldspar has a tendency to promote crawling, leaving areas of clay exposed or to create splits or pinholes in the surface. These irregularities, which would have traditionally been considered defects in the West, are highly prized by Japanese tea drinkers and ceramics collectors, as they add character and uniqueness to each piece. Also, the variation in glaze thickness helps to produce different colours with subtle shading. Usually, shinos are wood-fired and the glazes benefit from the ash which falls on the pieces over time. The kiln is deliberately starved of oxygen as the temperature rises, and the resulting “reduction” atmosphere activates the iron oxide, allowing it to migrate to the surface. Some potters suggest that a period of re-oxidisation is required to create the reds, oranges and pinks, typical of shino glazes.
Yohen-kin Shino Tea Ceremony Bowl
by Suzuki Tomio
This is something I have discovered for myself when firing shinos in a saggar (a sealed container) inside an electric kiln. When fired only in heavy reduction, the test samples came out a light grey colour, some with gold specking from the iron oxide. I’ll be writing more about “saggar-fired” shinos in my next post.
Reference:
The Complete Guide to High-fire Glazes by John Britt, 2007
April 15th, 2009 at 5:23 pm
The variety of colours that shino glazes give is amazing, wonderful technique!
April 26th, 2009 at 7:14 pm
Eftychia, thank you for your kind comments
June 29th, 2009 at 1:48 am
Thank you very much for such detailed explanation, I am a part time student and I am learning from you and people like you who keep blogs, I put your site in my favorites, I saw Rizu Takahashi this morning doing his presentation at the local ceramics fair, he was inspiring and great.
June 29th, 2009 at 4:22 am
You’re welcome, Natasha, I ‘m glad to share what knowledge I have. What a coincidence, I was at the same fair yesterday and I saw he was presenting today..I wish I could have seen it!