Clay Culture: Chinese Fast Firing

Chinese fast firing was established long before it migrated to Japan becoming raku, which was later adapted to a Western raku technique in the US and Europe.

I was stunned to learn that what closely resembles our Western raku technique has been practiced in China for over 1000 years. While teaching at the Nanjing University of the Arts in Nanjing, China, in 2011, I sat down with Lu Bin, head of the ceramics department, and his wife Li, also a ceramics professor, to watch his film, “The Ethnic Potters of Southwest China,” which he produced in 2009. The first half of the film concentrated on forming. The second half turned to the region’s kilns and firing processes. One kiln type he termed the Wok Cover Kiln is used for fast firing and has been for over 1000 years in Guizhou, Hebei, Henan, Sichuan, Shanxi, and Shandong provinces.

As I watched a man pull a glowing orange pot from the kiln and put it into a container with sawdust, I turned to Bin in shock, “But that’s raku! We think of raku as a 16th-century Japanese technique!” “Yes, I know,” Lu said. Lu, very knowledgeable in ceramic world history, knew Paul Soldner had popularized the Japanese technique in the US in the 1960s. Soldner had added post-fire reduction to liven up his pots’ surface. Once introduced, potters everywhere began experimenting with the technique. It was immediate, dramatic, and visually seductive. As it swept across the US and beyond, it was automatically referred to as raku.

1 Flame shooting from the reduction pit lid while wet cinders are shoveled onto the flame breaching the edges.

2 The still smoldering reduction pit with surrounding moat prepared to hold water. Several pots are warmed up on top of the pit lid.

The term became synonymous with fast firing regardless of origin, fuel source, or post-fire reduction. The name raku has emerged as a 440-year-old example of branding. We’ve been using it the same as we use the brand names Kleenex and Xerox—it’s still common to hear the word Kleenex used when referring to a tissue.

The village in Lu’s film, Zhijin, is in Guizhou Province. It’s part of an expansive, mountainous, coal-bearing region and an abundant source of anthracite coal. With this dense, high-carbon, low-emissions type of coal, it makes sense that this region developed fast firing (kuai huo) and formulated a clay body that includes a percentage of powdered coal.

Fast Firing First Hand

I returned to China in 2018, wanting to see the process firsthand. My translator, Xu Huaming, and guide, Lu Kui, joined me in the village of Gu Cheng in Ying Jing County, Sichuan Province, to observe this living museum in action.

We reached a wide open firing area in the center of the largest factory. This and most areas were covered with fiberglass roofing to protect the work and workers from the annual rainfall total of 67 inches of rain occurring 213 days a year.

Two bare-chested men, perfectly cast as Sumo pot wrestlers, were emptying one of two reduction pits. Each pit was six feet deep, two feet wide, and lined with bricks. The kiln chamber, once exposed, was a foot deep and six feet in diameter, with a three-foot-high, wok-shaped cover made of clay smeared around bent metal rods.

3 Loading warmed pots onto clay chucks for the next firing. A layer of coal has already been spread onto chamber’s floor.

4 The wok cover is cantilevered into alignment with the sunken kiln base as the worker on the left bends to turn on the forced air.

After one worker hosed water into a moat encircling the now empty reduction pit, each man slung a strap around his neck to secure a heavy, heat-resistant apron providing protection from shoulder to ankle. A wicker hat with a sweeping long brim and an attached wet towel shielded the men’s heads and faces. Geared up, they were prepared to face the blast of 2192°F (1200°C) from the kiln chamber.

The two men stood suspended with honed intuition, waiting for the perfect atmospheric color in the kiln. Then BOOM, the action began! In synchronization, one worker turned off the kiln’s forced air supply while the other tossed two gallons of sawdust into the open pit. He then pulled the cement counter balance as the wok cover  over the kiln chamber lifted, exposing the radiating heat. Using eight-foot-long hooked rods, they began lifting and swinging glowing pots into the reduction pit. The air filled with sparks and dense smoke as a second large scoop of sawdust was added. Once the kiln chamber was emptied, the worker who had added the sawdust slid a thin metal disk over the reduction pit, causing a three-foot flame to roar out, grasping for oxygen, from a center hole.

5 The forced air machine can be seen in the foreground. Clay smeared onto a metal rod dome forms the kiln’s wok cover.

6 Radiating glow from pots being immediately transported from the kiln chamber.

I tried to be patient while Huaming translated; however, what we were seeing was so unusual yet so familiar at the same time. The glaze-less surfaces of the pots that had been pulled from the reduction pit were glistening silver, sandpaper textured, and immediately captivating. There were distinct variations in silvery buildup due to disparity in heat and reduction. The clay body is a mixture of the local low-fire white clay and yellow kaolin from the mountains that is then combined equally with powdered coal and stored for six months. Lu Bin explained that each village had their own variation. For example, Zhijin’s clay mixture was only 25% raw coal. All combinations, though, result in low shrinkage and thermally retentive, porous vessels.

Beginning the cycle again, one worker scattered about four gallons of coal onto the kiln floor, then the other set out thick, residue-encrusted clay chucks to stack the next 46 preheated pots. Once loaded, one worker lowered the wok-covered lid and the other switched on the air blower, instantly reigniting the coal to reach temperature in an hour. The cycle typically repeated ten times a day. At this point in the firing, they had 30 minutes until the second reduction pit needed to be cleared.

7 As the cement cantilever is raised, the kiln’s wok cover is lowered next to the chamber. Casseroles line the back wall glowing orange from the kiln’s reflection while warming.

8 Maneuvering 2192°F (1200°C) pots into the reduction pit. A second load of sawdust waits in foreground.

With their short break on lounge chairs over, one worker removed the metal disc covering the reduction chamber and they began fishing out finished vessels from the pit. Some pots were fused together or stuck on their chuck. A woman separated the ware using a hatchet, then tied the handles of eight pots together, easily relaying them to a waiting 40-foot truck. The pots are then sold at local markets for cooking herbal medicines. The buyer will then seal the vessel’s open pores left by the burned coal by boiling a batch of sticky rice in the pot.

Research and History

Once I began researching the history of fast firing, it didn’t take long to become tangled in information about raku’s origin and elusive documentation for fast fire in China. Daniela Xu and Lu Bin were essential resources for providing and interpreting information.

Firing fast, using coal as fuel and in the clay mixture, originally migrated south from Mongolia. Similar pots have even been discovered in the Qin Dynasty (221–206 BCE) tombs and with the Terra Cotta Warriors. However, what most resembles our Western practice began in Ping Ding County, Shanxi Province, at least 1000 years ago according to Lu Bin.

9 Still hot pots being pulled from the second reduction pit.

10 Spouted jugs, also for cooking herbal medicines, packed in straw ready to be transported to market. Apparent are variations in silvery residue.

The Raku Museum in Japan cites that the father of Tanaka Chōjirō, the first Raku master, originated from China. Although his ceramic practice was different, he may have guided his son in alternative practices he was acquainted with from China.

Now aware of the dimensions of fast firing, I wrestle with the name raku as a universal label although it’s firmly embedded in the ceramic medium’s vernacular. Should we attempt to demonstrate unbiased accuracy and refer generally to it as Fast Fire regardless of post reduction? Maybe we should name each style, such as Japanese fast fire for the ware not produced by the Raku family? Or, Western fast fire, although it bears more resemblance to the Chinese style? Or, shall we carry on unfolding new territory through experimentation and our irresistible intrigue with what we’ve globally come to call raku?

11 A hatchet is used to separate pots and chuck in the right pot’s opening that fused together during firing.

the author Coreen Abbott has an MFA in ceramic sculpture from the San Francisco Art Institute. She has been adjunct lecturer at UC Berkeley, California; Nanjing University of the Arts, China; Jingdezhen Ceramics Institute, China; as well as teaching and living in Faenza, Italy. She has been a professional artist since 1976 and lives in San Francisco. To learn more, visit www.coreenabbott.com and Facebook at CoreenAbbottCeramics.

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