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Toward A Vocabulary For Wood-Fired Effects

by Dick Lehman

Recently I had the good pleasure of working with Odin Maxwell and Shiori Noro, who were busy translating into English the fine Japanese text by Mr. Furutani Michio, entitled, Anagama: Building Kilns and Firing. As an active wood-firing potter, I had been asked to work alongside them as technical editor.

Furutani (along with Yasuhisa Kohyama and Shiho Kanzaki) was a pioneer in the revival and revitalization of the use of anagama kilns in Shigaraki, Japan, during the last 40 years. The book is pioneering, as well, in Japanese literature insofar as it seeks to provide an understandable and transparent “how-to” approach for building and firing anagama kilns. But it goes beyond being merely a “how-to” text in that it explores a variety of kiln designs, clay bodies, and firing approaches with an end toward explaining how wood-fired surface effects are achieved. And finally, Furutani seeks to help us understand a bit about his particular passion for these peculiar wood-fired surfaces, and how they are an expression of his own motivation, personal aesthetic and spirit………..and does so in a way that warmly includes stories, personal anecdotes and humor.

As a wood-firing potter, I found one particular aspect of this text most interesting and fascinating: it was the affirmation that there exists in the Japanese language a thoroughly-developed and specific vocabulary to describe the variety of surface effects which occur in wood-firing.

While this “glossary of terms”, might be used somewhat specifically or idiosyncratically by individual Japanese potters, the terms do have a more-universally-understood meaning and comprehension in Japanese culture and society. I made visits to Furutani’s studio (unfortunately Mr. Michio Furutani died rather suddenly in the year 2000, but I spoke to his wife and son, who continue the pottery studio and the traditions he established), to Shigaraki potter Mr. Shiho Kanzaki, and several other Japanese potters, asking about how these terms are defined. I discovered that there is general agreement about the meaning of these terms, and that there is a general expectation that these terms are at least loosely understood by the Japanese public.

Allow me to offer just a portion of this glossary of terms to illustrate their specificity, their interrelatedness, and the extent to which they seem to assume and underscore a certain visual literacy (with respect to wood-firing) within Japanese society:

* “Bi-doro: From the Portuguese “vitrol”, meaning “glass”. This refers to glossy streams of natural-ash-glaze (shizenyu) which terminate in a shiny bead of glass. They may flow over areas on which little or no natural-ash-glaze has developed. Sometimes, the streams of glaze may drip over areas where the underlying ash-glaze has a contrasting matte finish. It is important to note that (potters often would) not refer to streams of glaze with a matte texture as bi-doro. Instead, depending on the qualities of such a drip, (they) would have used the terms haikaburi, shizenyu, or youhen.

Haikaburi: Literally: “ash-covered”. In wood-fired kilns, wood ashes fall on the pottery during firing and melt into a natural ash glaze. Haikaburi is one type of natural-ash-glaze which has as its fundamental characteristic, a matte texture. This matte texture results when ash deposits which pile up on the pieces do not fully melt into a glossy surface. Haikaburi and shizenyu occupy different positions on the natural-ash-glaze continuum. Haikaburi is simply less melted. It may be helpful to imagine haikaburi as being the precursor to shizenyu (shizenyu being a type of natural-ash-glaze which has fully melted and begun to stream down the sides of pottery).

Hi-Iro: Literally: “firecolor”. It is commonly referred to as “flashing” in the West. Hi iro refers to changes in the color of the clay body itself due to the interaction between the flames and (the) minerals in the clay. Hi iro pottery does not have a buildup of ash glaze. In fact, if ash glaze does develop, the hi iro tends to be obliterated. (Potters develop) specialized kilns and firing techniques to attain hi iro effects.

Koge: Pots near the firebox may be covered with embers during the firing. Burying pots in embers causes cooler firing temperatures for those pots (or for the buried portions of those pots). When natural-ash-glaze is not allowed to develop on the pieces buried in embers, burial in embers causes the clay to develop dark charcoal-colored or pastel-hued qualities. On the other hand, if haikaburi or shizenyu is allowed to develop prior to burying the pieces in embers, and the firing temperature is sufficiently high, the buried portions of natural-ash-glaze will develop a coal encrusted surface. Note that a piece which is partially buried may exhibit koge on the buried portion and haikaburi or shizenyu (or both) on the exposed portion.

Shizenyu: Literally: “natural glaze”. In the case of wood-fired kilns, a natural-ash- glaze develops when ashes fall on the pottery and melt. Shizenyu usually develops in the hotter parts of the kiln and refers to natural-ash-glazes which are fully melted and glassy. Shizenyu and haikaburi occupy different points on the natural-ash continuum. Shizenyu is simply more melted, glossy, and shows more streaming than haikaburi.

Youhen: Literally: “kiln change”. This term refers to pieces which undergo unexpected changes in color and/or texture during the firing. Note that textural changes in natural-ash-glazes are almost always accompanied by color changes. This effect can be seen in the transition zones between shizenyu and haikaburi or haikaburi and koge.”

I was so impressed with this functional yet dynamic vocabulary that my first thought – upon the completion of my work as technical editor – was that we potters in the English-speaking world should develop a more-universally accepted/understood vocabulary of wood-fired surface effects. Currently we primarily use a descriptive vocabulary – without a generally-accepted or universally-understood set of terms for the range of firing effects that natural ash surfaces produce. We speak about “ash runs” and “drips” and “flashing”. But beyond that we have little in the way of universally-held terminology. I wondered aloud, to myself, if a set of more commonly-held terms might be an advantage.

After all, I reasoned, if this vocabulary was in common use among potters – and eventually in broader society – it would inevitably lead to an enhanced visual literacy…and in particular, an enhanced ceramic visual literacy. And it would be no cosmic leap-of-logic to conclude that with increased literacy there might be (at least on some level) growing appreciation. Such a deepening in comprehension and valuation might well lead to an amplified appetite for such works. And a larger market would have obvious benefits to wood-fire potters.

A greater public literacy would be a “bonus” to the obvious working benefits that would also accrue to and between potters, if this functioning vocabulary were in place. “Yes”, I thought, “a commonly-held functioning vocabulary of wood-fire surface effects would be a good thing here in the West.”

I have visited Japan often enough to know, first hand, that there is a genuine sense in which the general population, there, knows more about ceramics, when compared to our population here in the West. Certainly Japan’s additional 500-1000 years of high-fire ceramics history is not to be overlooked; nor are the effects of centuries of tea ceremony to be ignored as contributors to a general ceramic visual literacy in Japan.

But those things not withstanding, the differences between East and West are tangible: if we were to go into a random sushi bar in Japan and ask an arbitrary group of patrons for a definition of koge or hi iro, we might reasonably expect that someone in the crowd would be able to answer correctly.

Go into a random McDonalds here in the West and ask for a definition of “ash encrusted” – and unless one’s diction, enunciation and pronunciation are superb, one might be lucky to escape with simply a quizzical wince or a raised eyebrow. Dare to follow up with a question about “flashing” and well . . .

But as I thought more about developing a vocabulary of wood-fired surface effects, I began to have just the slightest doubt about the wisdom of doing so. It is not that I began to question the obvious benefits and dividends that such a vocabulary has already produced in Japanese language and culture. But I began to wonder if there might be, for us here in the West, some actual benefits from having had a deficient vocabulary…some ultimate betterment for not having developed or inherited a tradition-of-terms. My doubts began to creep in at exactly the place where I least expected them: they occurred as I began to carefully examine my own wood-fired pots.

“How could a single term,” I heard myself asking aloud, “ever capture the meaning of this kind of surface effect?” I was looking at the thickly-gouged foot ring on a wood-fired vase, fired for 15 days with Chinese Elm. The pot was made from a porcelain body that I had developed from domestic clays. The foot ring had collected a deep pool of natural ash glaze: the sides of the pot having sent cascading torrents of aquamarine glaciers sliding toward the foot’s collection pool, where it suddenly changed into piles of icy-white glass. In the apparently rapid reduction-cooling of this pot (which was located quite near the front of the kiln near the firebox) after the final large charge of Chinese Elm splits, the surface of the icy pool had cooled rapidly, had contracted, and had placed the depths of the still-molten glass under sufficient pressure that a large molten bubble ‘burped’ out of the pool’s depths. It, in turn, cooled quickly enough to remain a glassy, transparent globe, but not before managing to grow a few floating icy-white crystals which convincingly danced their geometry across the surface of the aquamarine bubble of glass. How can one word capture this? “How dare one term try?” I wondered.

I next examined the wrinkly flow of yellow and steely-gray natural-ash-glaze on a large tsubo form, that reminded me of the wrinkled skin on my aged grandmother’s forearm…arms we might all like to have, should we be lucky enough to live to such a ripe old age. As with the forearm, the skin of glaze had not suddenly, near the end of its life, gotten bigger so as to result in folds of unnecessary surface. No, this pot’s surface is more like Grandmother’s skin: what had been underneath that once-robust and supple surface had been reduced and diminished; there was less muscle and fat and general “tone” to support what had earlier been “just the right amount” of skin. The same was true with this natural glaze surface.

When we speak, as potters, of “reduction”, we are usually thinking about it more as a chemical than a physical occurrence. But here “reduction” has taken on a momentum and physicality that we seldom see: this pot was, moments before the final stoke, full-fat and supple with glassy runs and drips. But by being so close to the firebox and so affected by the final giant stoke of fuel, this glaze lost the very “stuff” of itself: the fire was so ferociously oxygen-hungry that it ripped oxygen molecules from the molten natural-ash glass, even as the surface was cooling and contracting. The actual physical substance of the sub-surface glass – its real physical content – was REDUCED, leaving the “skin” to ‘hang saggy on the bones’ over what previously had been lush, thick flowing torrents of snail’s pace ash. Now that’s reduction! How can a single term gather up all this meaning?

Or how can one simply describe a ‘current’ of flowing natural-ash hare’s fur in hues of copper and caramel and blue-gray and olive-celadon…a current which has been interrupted and overtaken by a strong glassy flow the color of honey…only to find in the middle of that, a section of ‘too-fast-accumulation-of-ash’ which has produced matted surfaces in taupe, peach, and gun-metal blue, surrounded by crystals the color of springtime dandelions? (See image #3.)

How might I ever communicate to you, with a single word, a surface the color of a winter river? What terminology can describe a surface on which ten days of Cottonwood ash has produced an ‘ice-jam’ of descending natural-ash crystals that has backed-up and built-up like the ice-dams against bridge abutments, or the piles of ice-shelves along the wind-blown shore of Lake Michigan?

Is there a single term for a natural-ash-glaze surface which captures the color of summer…a color which might be described as yellow, and golden, and buttery, and primrose, and saffron, and daffodil, and topaz, and banana, and canary, and citron, and ocherous, and blond, and amber, and orange – all at the same time – and yet be punctuated with ‘pitting’ the color of storm-cloud-gray?

What words will amply describe a shizenyu which is the color of Spring flowers: colors we don’t normally associate with “natural” in “natural-ash-glaze”; colors invading a soft pastel range that, if seen at all, we tend to identify with coal-buried surfaces.

How might I describe the surface of an upside-down-fired porcelain bowl, where caramel flashing, and baby-blue-and cobalt-blue hare’s fur mingle with golden, bronze-studded crystals – all in the space of half an inch?

And what about pots that break the rules? What about surfaces where thick ash accumulations (haikaburi and shizenyu, bordering on bi-doro) mingle with flashing (hi-iro): atmospheres and effects which generally do not belong together on the same pot; rich blue-blacks and apple-greens and battle-ship-grays and banana-yellows surrounding intense orange flashing with taupe-brown freckles.

And the next pots only made the consideration of a definable vocabulary more difficult for me: how might I describe a surface where potassium-rich, matte-white flowing drips converge with a salt-glaze-like pitted surface in runny colors of blue-gray and green and brown and copper? (See image #9.); or surfaces which resemble the topographical residue of prehistoric volcanic remainders? (See image #10.); or colors and surfaces usually associated with copper-matte raku stain results?

And finally, what kind of vocabulary might serve us if we diverge from a strictly-held value of “all-natural-ash-glaze-surfaces”? How will we describe those pots whose surfaces have applied glazes, and THEN have been fired for 15 days with wood? Can we possibly generate terms for surfaces where crusty dry-drooling moonscapes collide with smooth-flowing watery drips…generating “dragon-fly-eye” droplets which include both the watery and the crusty? (See image #12.); how do we speak about surfaces where cascading crystals surround both glossy and armadillo-skinned drips? (See image #13.); and where do we reach for terms to describe glazed and wood-fired surfaces which go beyond all our previous expectations and experiences?

What I saw in these pots caused me to question the idea of developing a glossary of wood-fire terms. I began to better-appreciate the advantages of a “descriptive vocabulary”. Despite my own assessment of their projected benefits, I am not yet ready for a set of single terms to try to capture these complex surfaces. I am concluding that for now, I want many words with which to describe each of these surfaces: multiple words and references, and similes and metaphors, and rich colorful imagery – not simply a glossary of single terms. I want a descriptive vocabulary that, while describing the surface effects, might provide as much information as possible about the materials used, the kiln design, and the firing approach.

I am concluding that perhaps now is not the time to generate a contemporary (Western) glossary of terms for natural-ash wood-fired surface effects. But I am not concluding that, having had an (earlier) established vocabulary, we would be less well-off now. And I am not ready to speculate on what might have happened if we had somehow inherited a tradition of terminology from some earlier generation.

But what I am ready to speculate is this: just possibly, NOT having had a traditional vocabulary may have been an unanticipated benefit to the development of wood-fired surfaces here in the West. Perhaps by not having had a “Tradition”, we have been inclined to approach this wood-fire process with fewer limitations and greater freedom than we might otherwise have been: freedom to experiment with a wide variety of clay materials, kiln designs, fuels, firing approaches, and pottery forms. And this freedom may have led to the resulting expansive nature of the natural-ash surface results that are being discovered: surface results which may go beyond shizenyu, haikaburi and hi iro.

So, should we forever foreclose on the idea of developing a contemporary vocabulary of natural-ash wood-fired surface effects? Of course not. And it would be unrealistic to think that we will wait until we have another several hundred years of experience under our belts before we begin utilizing a more-universally-accepted vocabulary. As we gain more experience with wood-firing, we will be developing a functional vocabulary…..it is inevitable. But it is my hope that as we develop this vocabulary, we might “hold it lightly”, making it an expansive and not a restrictive vocabulary.

In the meantime, I think we will be well-served to continue to investigate with as many methods and firing approaches and kiln designs and clay bodies and fuel choices as our imaginations allow…and then to use as many words as are necessary to comprehensively describe the resulting rich and remarkable surfaces.

* Thanks to Odin Maxwell and Shiori Noro for the use of this portion of a developing glossary which is to accompany the translation of Furutani’s book.

Dick Lehman is a full-time studio potter, working in Goshen, Indiana, USA, and a frequent contributor to Ceramics Monthly Magazine.

This article is reprinted with expressed permission from the March 2004 issue of Ceramics Monthly Magazine, PO Box 6102, Westerville OH 43086-6102, USA; www.ceramicsmonthly.org

Dick Lehman
Copyright January 2003
All rights reserved