As I described before, in the section on the history of Shigaraki Pottery,many works with natural and unsophisticated beauty (in Japanese we wouldspeak of these as "wabi and sabi"), were being produced in Anagamastyle kilns. Indeed the oldest style kiln in Japan is the Anagama. Howeverthere were many other kinds of kilns in Japan as well.
Interestingly, potters in Japan stopped building Anagamas in the early 17thcentury. They began, instead, to build Nobori-gama style kilns with manychambers. One of the reasons may have had to do with issues of productivity:a Noborigama style kiln could produce ten or twenty times as much potteryin a singe firing, as compared to the average Anagama.
A second reason may be tied to the relative predictability and consistencyof firing which Noborigama kilns produce. This predicability caused Noborigamasto be used in the production of glazed ware. In Shigaraki, for example,this trend led to the production of Namako-Yu glazed Hibachi (a charcoalbrazier). Indeed by the mid 1960's Shigaraki's production of Hibachi hadgrown until it was meeting fully 90% of Japan's Hibachi demand.
Such product demand led to increasingly larger Noborigama style kilns, andmore frequent firings. Business overhead expenses increased as productionincreased Heightened competition meant that a failed firing could lead aHibachi producer to bankruptcy. Certainly the Noborigama style kiln wasthe right kiln for the predictability and consistency needed for successin such a production environment.
But the building of Anagamas experienced a revival in Shigaraki in the 1960's.Mr. Michio Furutani and Mr. Yasuhisa Kouyama are credited with initiatingthis revival. Since that time, there has been an increase in the buildingand use of Anagamas. And I am happy to report that there are fifty-threeanagamas now being regularly fired in Shigaraki.
However, the resurgence in using Anagamas has not come easily. With mostall the energies of the previous 350 years directed toward building andfiring the Noborigama style kilns, there was much to relearn about Anagamas.It is said that every potter who has recently built an Anagama has had to"grope in the dark", and to study hard to determine how to bestfire these Anagamas.
Still, for those potters who have their eye set on the works of naturalash glazing, Anagamas are the choice. The relative safety and predictabilityof the Noborigama is inconsistent with the pursuit of natural ash glazing.
Every potter has their own kiln design and their own way of firing. However,I would like to describe my Anagama and the method of firing which I usefor making my works. Admittedly every firing happens under slightly differentcircumstances (for example the different combination of work for loading,the weather, the kind of firewood being used, and the circumstances of themoisture content in the ground under the kiln). But I would like to explain,in general principle, my kiln design and my approach to firing.
I have built eleven Anagamas since 1972. Each kiln has had a slightly differentdesign and construction. I am still firing four of these eleven kilns. Threeare in Shigaraki, Shiga in Japan, and the fourth is in Bloomsburg, Pennsylvania,in the United States.
Here is a general description of the Anagama kilns which I have in Shigaraki:all of my kilns are comprised of a single long chamber. The firebox andthe stacking space are together in that single chamber. The incline of theslope of the kiln is 10 centimeter to 30 cm. Approximately half the kilnis above ground level. The width of the stacking space is 165 cm, the depthis 250 cm, and height is 110 cm. The depth of the fire box is 90 cm. Thefire box does have a grate. (See the images of "Shiho Kanzaki's Anagama".)
I would like to explain how I go about firing my Anagama. As I mentionedbefore, the method of each individual firing must change according to theconditions described earlier. I have never used a pyrometer or cone. InsteadI rely on my experience and intuition. But in light of these things, I willtry to explain my firing process as fully as possible.
The firebox of my Anagama has a grate. So my kiln has two fire-mouths: oneis under the grate, and the other is above the grate. I can stroke firewoodinto the kiln through either the lower fire-mouth, or the upper one.
At the start of the firing, the chimney is wide open (undampered). I begin by lighting a small "campfire" outside of the kiln, near the lower fire-mouth. I continue the fire outside the kiln until the radiated heat begins to draw the smoke into the kiln. During this time there is a very small but gradual increase of the temperature inside the kiln.
Next I begin gradually stoking firewood through the lower fire-mouth (intothe lower fire box), being careful not to gain much temperature. I continuethis stoking pattern for about 12 hours until I reach 300 degrees centigrade.This stoking pattern stalls the temperature at 300 C. After confirming thatI have reached this point, I begin stoking the upper fire-mouth, controllingthe quantity of the firewood with care so that I do not increase the temperaturetoo rapidly. As point thit I partially close the lower fire mouth with bricksto create air ports. From this point on in the firing, I stoke only theupper fire box.
At approximately 30 hours into the firing, a reddish smoke is coming outof the spy hole. The temperature is nearing 800 C. in the kiln. After confirmingthe color of the smoke, I put a cover on the chimney leaving it approximatelyhalf open.
Of course the decisions about how the chimney is dampered, and the amountof air coming in the air ports determine the pace of the firing. It is difficultto describe exactly how all those decisions are made during the course ofthe firing. And of course, every firing is a little different in this regard.
Over the course of the next several days, the smoke coming out of the chimneyis black in color, and we can see the red color of the flame at night.
At five days into the firing the flame coming out of the spy hole is becominglonger, and is beginning to change to a whiter color. The flame from thechimney, at this stage, looks rather short and "pressed down".
I continue this pattern of stoking until about day seven or eight. At dayseven or eight, the coals in the firebox are beginning to build up. Thisbuild-up of coals and cinders causes the temperature to drop somewhat. Noticingthis, I decrease the amount of wood in each stoke.
At about day eight of the firing, the flames coming out of the chimney arequite tall and aggressive. The flames comingout of the chimney light up the area around the kiln at night. I continuethis stoking pattern into the tenth day of the firing. At day ten, the flamefrom the chimney is getting white in color, and I have to make a decisionabout when to end the firing.
All my work comes from the Anagama, using this method of firing.