Tea bowls specifically for Matcha tea have many subtle characteristics that make them most suitable for the enjoyment of Tea. Over the last 60 years I have made and sold a variety of chawan and here are a few photos of these.
This is what I call “White Raku” ie. with a boracic glaze that appears on a white surface. I remember that in this example at the time I applied a white slip over a clay that would otherwise appear rather pink.
On this bowl I applied a red clay slip to create an orangish underglaze. The brushwork was done with a chrome oxide and burnt umber applied with a wide brush.
This is a squared bowl with green chrome oxide brushwork and a little umber pigment.
This bowl is painted entirely with a red burning clay I derived from the Oklahoma side of the Red River. The boron glaze is allowed to melt to a degree that forms bubbles and craters, and the opacity is simply due to these tiny melts in the glaze.
This bowl has the same boracic clear glaze, but it is allowed to melt until it is smooth. If left in to kiln to a greater heat, the glaze can become extremely smooth and shiny. I always preferred to remove these from the kiln at just the point that the smallest bubbles begin to form. This lends an opacity and soft white tone. This bowl is thrown with porcelain clay. Porcelain clay, due to the large particle size, actually makes a useful Raku clay. It’s actually like a heavily grogged clay of small particles and resists thermal shock. BTW I was doing this back in the early 1970s. I may have been one of the first to surmise this result.
This is a bowl with an underglaze of another glaze with copper oxide. The kiln is run with a lot of extra carbon from combustion. This allows the copper to form some dark greens instead of metallic copper, which I find to be incompatible with tea aesthetics. There are little bits of copper metal in places about the rim, which I feel acts more as an accent than an overexpression that is often expected by the uninformed when folks use the word ‘Raku’.
