Tried out my much adored Kohiki technique today! So so so tiring grinding the kaolin down.
Kohiki 粉引き is a form of decoration of a piece using white slip. Interestingly enough, it’s a technique that came about when the early Japanese craftsmen were attempting to mimic the whiteness of the porcelain from Chinese ceramic wares that were being imported to Japan. Since certain areas only had naturally occurring red clays, they used white slip to cover it up. In my opinion though, there is an incredible beauty to Kohiki wares, especially after they’ve gone through reduction firing because the iron of the red clay comes through usually unevenly in these beautiful pinkish, reddish hints. If there’s something I would want to focus my ceramic crafts on in the future, it would definitely be Kohiki. I’d never tried it before though and though Sensei deals primarily with white clay in his studio, he was so incredibly kind to let me get some red clay from the clay shop to try out. It was definitely more tedious recycling my red clay in a way that wouldn’t contaminate the rest of the studio’s white clay, but for the chance to try out that method, I was more than willing and simply grateful for the opportunity.
M-san had some kaolin powder in her own studio and was so so generous in letting me have a go at it. What I didn’t expect though, was the sheer amount of time and energy required to grind down that Kaolin into the finest powder ever. But looking back, it made complete sense, because in order to get a creamy, smooth suspension to cover your piece smoothly, you’d first have to grind up the powder as fine as possible before mixing it with water. It’s a little like sieving matcha powder to avoid getting lumps in your drink after. There are numerous recipes for Kohiki slip but the one we tried that day was pure kaolin + water + CMC (a type of chemical glue to harden/make the slip more sticky/viscous).
We used a huge ass mortar that she had and spent ages grinding it down bit by bit… So touched that she even helped me out despite her busy schedule. Definitely helped that Sensei was busy that week with an exhibition in Nagoya so whenever he was out of the studio, I would work on the Kohiki.
It was also the day that we tried creating one of Mandy’s feldspar glazes. She’d bought a bag of glaze raw materials from the glaze shop in town and this was a purely Feldspathic type glaze. We mixed it up with water then adjusted the consistency with CMC according to M-san’s guidance. (How she knew what consistency was just right when it all looked pretty similar to me… I put it down to genius/experience ^^)
Was working at night in the studio with the newest addition to the studio, L. A recent university graduate from HK, she was doing a bit of travelling and planning a gap year while thinking about whether she wanted to work in her area of study or not. She’s been learning ceramics for about 2 years but had hitherto only worked with porcelain. That night, she decided to slice up all her cups for ‘post-mortem’ analysis. The funniest part was that she laid them all out on the main table in the room almost like an exhibition. Felt such adoration/admiration for her! I probably did end up slicing up the same number of cups as her but she did so with such gusto and glee… I couldn’t help but hope that I would have that courage…or bravado to destroy/dissect my work as she did. Ended up destroying more pre-bisque firing items which had dried out completely but I didn’t quite like anymore. Always feel a bit of heartache when destroying something I know I’d put much energy/effort into making but… it does get easier each time. And without a doubt, I do make better stuff the next round so. Onward.
Wrote in my journal that night:
Kaolin -> clay
Versus feldspar -> with glass components
Add in water bit by bit while stirring the mixture.
Testing glazes with a paintbrush and adjusting accordingly
eg. If it doesn’t flow well/sticks very quickly -> can try to use more CMC
When mixing glaze, always just use water first to dilute it out. Add CMC only after. If you add in CMC too early, it will make the glaze more viscous but the actual glaze material to water ratio may not be high enough. It will mask a thin glaze.
Learnt some tricks -> folding over from outside to inside for rim of tea pot
Tricks about slip casting for handle and for complicated lids
M-san is such an incredible wealth of knowledge
Plus her work ethic – so inspiring
Heartache breaking my pieces but it’s such a metaphor for life.
You can only move forward and create new things by destroying the old and putting those items back in the past
Worked on vase forms and tea pots
Some days better than others
Worked hard for today and I’m glad I did