What is a Noborigama kiln? A world of ceramics where no two pieces are ever the same, born from the flames and ash of firewood.
In the world of pottery, there are broadly two types of kilns: modern gas and electric kilns, and wood-fired kilns that have been passed down through the ages. Gas and electric kilns allow for precise temperature control, resulting in uniform and consistent firing. However, wood-fired kilns are different. The flames dance like living things, the ash swirls in the wind, and the expression of the vessels changes constantly within the kiln. The true pleasure of a wood-fired kiln lies in the accidental beauty that is born beyond the potter's intention, and the Noborigama (climbing kiln) is a prime example. Once the fire is lit, no one knows the final form until the moment the kiln is opened. This tension and mystery are the essence of wood-firing.
What is a Noborigama (climbing kiln)?
A multi-chamber structure utilizing a hillside
A Noborigama, or climbing kiln, is a kiln that utilizes the slope of a mountain, connecting multiple firing chambers (rooms) in a step-like arrangement. The lowest section has a firebox, where wood is burned, and the flames and hot air flow from there to the next chamber, and then to the next. At the very top is a chimney, through which the hot air flows in one direction, warming the entire kiln.
The greatest advantage of this structure is its high fuel efficiency. The heat from the wood burned in the lowest chamber is relayed to the chambers above, allowing a large space to be maintained at high temperatures with less fuel. Furthermore, since a large quantity of pottery can be fired in a single kiln firing, the historical form of "community kilns," where potters from a production area gather to fire a kiln together, was common.
Kilns vary in size, with most having 3 to 10 chambers, and some large Noborigama kilns exceeding 10 meters in length. The angle of the slope, the size of the chambers, and the position of the firebox differ subtly depending on the production area and pottery studio, which contributes to the individuality of the ceramics.
Today, due to safety management and fuel costs, the number of active Noborigama kilns has significantly decreased. However, in various production areas, some are still maintained and used to preserve tradition and culture, and many pottery enthusiasts visit these kiln firings.
History of the Noborigama, introduced from Korea
The origin of the Noborigama is in China, where it was developed in the 10th century and then spread throughout Asia. The technology of the Noborigama was introduced to Japan from the late 16th to the early 17th century. During this period, Korean potters who came to Japan brought advanced kiln technology to various parts of the country.
Before then, Japanese kilns were predominantly single-chamber "Anagama kilns" or flat kilns. The "Renboshiki Noborigama" (connected-chamber climbing kiln) introduced by Korean potters was a groundbreaking technology that enabled mass production and high-temperature firing by connecting multiple firing chambers. This technology first flourished in Arita (Saga Prefecture) and Hagi (Yamaguchi Prefecture) in Kyushu, and then spread throughout Japan.
Particularly in Arita, the Noborigama became the foundation for the industrialization of porcelain production. Arita-ware was mass-produced during the Edo period and boasted a quality and quantity that allowed it to be exported to Europe via the Dutch East India Company. The existence of efficient Noborigama kilns was behind this success.
On the other hand, in ancient kiln sites such as Bizen, Shigaraki, and Tanba, the transition from Anagama kilns to Noborigama kilns proceeded at different paces depending on the region. The characteristics of the local clay, the style of the pottery, and the temperament of the artisans also influenced the choice of kiln.
Differences from Anagama kilns
Structural comparison: single-chamber vs. multi-chamber
Anagama kilns and Noborigama kilns are both traditional wood-fired kilns, but their structures are fundamentally different.
An Anagama kiln is "single-chamber." It has one long firing space (tunnel-shaped), and the flames from the firebox at the front flow towards the back. Due to its simple structure, the movement of flames and ash directly affects the pottery. Temperatures and atmospheres (oxidation/reduction) vary greatly between the front and back, and top and bottom of the kiln, so the firing results change dramatically depending on where the piece is placed.
A Noborigama is "multi-chamber." Multiple firing chambers are connected, and additional wood is introduced from "side fireboxes" on the sides of each chamber to adjust the temperature. Within a single kiln, different temperature zones and atmospheres can be created for each chamber, making it possible to fire different types of vessels simultaneously.
An Anagama kiln is suitable for individual potters or small groups to create distinctive works, while a Noborigama is suitable for multiple pottery studios in a production area to cooperate in firing a large quantity. Nowadays, individual artists often have Anagama kilns, while Noborigama kilns are often maintained as communal kilns in production areas.
Pottery suitable for each kiln type
Since Anagama kilns are strongly influenced by flames and ash, they produce rich natural glazes, fire colors (hiiro), and scorch marks, creating diverse "landscapes" on the pottery. Many Bizen ware pieces are fired in Anagama kilns, and they develop rich expressions even without glaze. Each piece has a strong individuality, truly embodying "ichigo ichie" (one time, one meeting) pottery.
Noborigama kilns, with their large firing spaces and high degree of freedom in temperature control, can accommodate a wide range of ceramics, from porcelain to earthenware. Both delicate porcelain like Arita-ware and soft earthenware like Hagi-ware have a history of being fired in Noborigama kilns. However, some production areas and artists deliberately create works that enjoy the accidental flame effects of Noborigama kilns.
No two pieces of Japanese pottery are exactly alike, and encountering a work is a "once-in-a-lifetime" experience. For more on the charm of encountering Japanese pottery as a "once-in-a-lifetime" experience, please refer to the article below:
Wood-Firing Process: From Ignition to Kiln Opening
Kiln Loading (Arranging vessels on saggars and shelves)
Kiln firing begins with "kamadzume" (kiln loading). This is the process of carefully arranging vessels inside the kiln before firing.
Instead of simply placing vessels on shelves, they are either placed inside heat-resistant containers called "saya" (saggars) or arranged on "tanaita" (kiln shelves) and set inside the kiln. Saggars are used to protect the vessels from direct contact with ash and flames. On the other hand, some production areas and artists intentionally expose the vessels directly to flames and ash without using saggars to create rich "landscapes." Bizen ware is a prime example of this.
Kiln loading is not just about stacking. Where each piece is placed in the kiln determines the firing result. Potters read the flow of flames, temperature distribution, and ash dispersion patterns to position the vessels in the best possible locations. Experienced artisans are intimately familiar with the kiln's characteristics and possess the wisdom to know that "placing it here will likely produce this kind of landscape."
Kiln loading can take several days. For a large Noborigama kiln, it's a monumental task to load hundreds or even thousands of pieces at once. After loading, the kiln entrance is sealed with bricks in preparation for firing.
Ignition to Firing (1-2 weeks of management)
Once the kiln loading is complete, it's time for ignition. The process begins with "yonetsu" (preheating), where the entire kiln is slowly and gently warmed at a low temperature. Rapid temperature changes can cause cracks and breakage in the pottery, so the temperature is increased carefully.
Once the main firing begins, the kiln firing continues day and night. Wood-fired kilns require 24-hour management, with potters taking turns to tend the kiln. They adjust the amount and timing of wood fed into the kiln while monitoring the temperature, controlling the temperature and atmosphere (oxidation firing or reduction firing) inside the kiln.
Firing temperatures vary by type, but generally, earthenware is fired at 1,200-1,300 degrees Celsius, and porcelain at 1,300-1,400 degrees Celsius. However, in wood-fired kilns, experienced potters judge the firing results not only by temperature gauge readings but also by the color of the flames and the appearance of "test pieces" (trial firings) visible inside the kiln.
The kiln site at night is a fantastical scene. The glowing red firebox of the kiln in the darkness, the scattered sparks, the smell of smoke. The artisans silently chop wood and tend to the kiln. In that silence, thousands of years of pottery history are condensed.
In the case of a Noborigama, firing is completed sequentially from the lower chambers, and additional wood is gradually fed into the fireboxes of the upper chambers. One kiln firing can take several days, or even more than 10 days in some cases, and during that entire time, someone is always attending to the kiln.
Kiln Opening: Facing the results created by fire
Once firing is complete, it's time for "reikyaku" (cooling) the kiln. Immediately after firing, the inside of the kiln is over 1,000 degrees Celsius, so opening it too quickly would cause the pottery to crack from thermal shock. The kiln is allowed to cool slowly and naturally, waiting until the internal temperature has sufficiently dropped. Cooling can take several days.
Then comes the "kamadashi" (kiln opening). This is the most exciting moment for both potters and pottery enthusiasts. The sealed kiln entrance is opened, and each piece of pottery is taken out one by one.
Cheers erupt or quiet sighs escape with each piece removed. Some pieces show the intended "landscape," others display unexpected beauty, and unfortunately, some are cracked. Inside the kiln, the potter's intention and the whims of the fire combine to produce results that no one can predict.
It's no exaggeration when artists say they don't know the finished form of their work until the kiln is opened. Wood-firing is an act of co-creation between the potter and the fire.
Landscapes created by flame and ash
What makes wood-fired pieces special is the "keshiki" (landscape) that emerges, which cannot be replicated in gas or electric kilns. Keshiki is a pottery term referring to the natural patterns and changes that appear on the surface of a vessel during the firing process.
Ash Glaze (Haiyu) / Natural Glaze
Burning wood generates a large amount of ash. This ash, carried by the high-temperature flames, dances inside the kiln and settles on the surface of the pottery. At high temperatures, the ash melts and becomes vitreous, fusing with the surface of the vessel. This phenomenon is called "shizen'yu" (natural glaze) or "haiyu" (ash glaze).
Even without the potter intentionally applying glaze, the wood ash naturally acts as a glaze. The color variations are diverse, ranging from bluish, greenish, ocher, to brownish, depending on the amount and quality of the ash, the temperature, and the composition of the vessel's clay body. Even within the same kiln, entirely different expressions can emerge depending on where the vessel is placed.
In Shigaraki, Bizen, and Iga ware, for example, the beauty of this natural glaze is highly valued. The organic and complex expressions, distinct from the uniform beauty of artificially created glazes, are one of the greatest appeals of wood-fired works.
Fiery Red (Hiiro)
The color of the vessel changes significantly between areas directly hit by the flame and shadowed areas. Surfaces exposed to the flame take on a reddish hue, while unexposed surfaces may turn darker. This contrast in shades is called "hiiro" (fiery red).
Especially in Bizen ware, the hiro is beautiful, with a gradient from red to black creating a rich expression across the entire vessel. It's as if the history of dialogue with the fire is etched directly into each piece.
Hiiro is difficult to reproduce, and it's almost impossible to intentionally create the exact same landscape. That's why each piece becomes a unique entity, holding a special meaning as "my own vessel" for the user.
Scorching and Carbonization
Wood ash and charcoal can adhere to the pottery, creating black scorch marks. Also, if the kiln's atmosphere becomes reducing (low in oxygen), the surface of the pottery can carbonize and turn black. This is called "tanka" (carbonization).
While scorching and carbonization might seem like negative changes at first glance, they impart depth and strength to the pottery. The contrast between the black scorch marks and the earthy color of the clay body, and the matte black texture created by carbonization, are expressions that can absolutely never be achieved in a gas kiln.
Kiln Changes (Yohen)
"Yohen" refers to the general term for accidental changes that occur on the surface of a vessel due to unexpected movements of flames and ash. Literally, it means "changed within the kiln."
The expressions of yohen are diverse: traces where the glaze flowed in unexpected directions, complex patterns created by a large amount of ash accumulating only on specific parts, color changes born from temperature fluctuations, and so on.
Historically, in Japanese pottery, yohen pieces have been considered to possess special value. As "once-in-a-lifetime" landscapes created by nature, yohen vessels are highly prized in the world of tea ceremony. Yohen is a record of the moment when the potter's skill and nature's chance intersect.
Regions using Noborigama and Anagama kilns
Throughout Japan, there are regions that continue to uphold the tradition of wood-fired kilns. Each region produces unique ceramics that utilize local clay and techniques.
Bizen / Okayama Prefecture
One of Japan's Six Ancient Kilns, known for its "mugyu" (unglazed) pottery. Bizen ware is often fired in Anagama kilns, characterized by "landscapes" such as hiro (fire color), goma (sesame seed patterns), and botamochi (rice cake patterns) that emerge during long firing periods (1-2 weeks). The deep reddish-brown color, born from the chemical reaction between the iron in the clay and the flames, is a symbol of Bizen ware.
Shigaraki / Shiga Prefecture
Another of Japan's Six Ancient Kilns, known for its rough clay texture and the beauty of natural glaze. Both Noborigama and Anagama kilns are used, and the greenish-blue color of "haiyu" (ash glaze) created by melting wood ash is striking. In recent years, many distinctive contemporary artists have emerged, making it a region where tradition and innovation coexist.
Iga / Mie Prefecture
A pottery region near the Shiga-Mie border, similar to Shigaraki, characterized by powerful forms made with coarse clay and rich natural glazes. It has been cherished by tea masters as a tea ceremony pottery region since ancient times, producing ceramics that embody the aesthetics of "wabi."
Tanba / Hyogo Prefecture
One of Japan's Six Ancient Kilns, known as a Noborigama production area. Tanba ware fired in Noborigama kilns is characterized by its simple yet powerful expressions and the rich "landscapes" of natural glaze and hiro. Today, as a region actively preserving and utilizing Noborigama kilns, it is committed to passing on the wood-fired kiln culture.
Hagi / Yamaguchi Prefecture
A Hagi ware production area where the techniques introduced by Korean potters are still alive. Hagi ware fired in Noborigama kilns is characterized by its soft white to pinkish surface and distinctive crackle glaze (kannyu). It is particularly renowned as a tea bowl production area, praised by tea masters as "Ichiraku, Nihagi, Santaratsu" (First Raku, Second Hagi, Third Karatsu).
In these production areas, kiln firing events and kiln opening tours are held annually, offering opportunities to directly experience the process of wood-firing.
Where to see and buy wood-fired kiln works
Due to their nature, wood-fired kiln works are rarely mass-produced and displayed in stores. It is best to purchase them at individual exhibitions by artists and pottery studios, pottery fairs in production areas, specialized galleries, or nowadays, online, where you can learn about the story behind the work.
Pottery fairs in production areas
The "Bizen Ware Festival" is held annually in Bizen City, where many artists and pottery studios directly sell their works. Shigaraki has its "Pottery Fair," and Tanba has the "Tanba Ware Pottery Festival," among other large events held once or twice a year in each production area. These are special opportunities for pottery enthusiasts to choose works while talking directly with the artists.
Galleries and specialized pottery shops
In major cities like Tokyo, Kyoto, and Osaka, there are galleries specializing in wood-fired works. These feature carefully selected pieces by experienced buyers, allowing you to find unique, high-quality items.
Online platforms
In recent years, online platforms for purchasing Japanese ceramics have also become well-developed. Nokaze offers works by artists from various production areas such as Bizen, Shigaraki, Iga, and Hagi, allowing you to choose vessels along with the stories of the regions and the backgrounds of the artists. For those living far away or who have difficulty accessing specialized pottery shops, online platforms serve as an important gateway to discovering wood-fired ceramics.
→ Explore works at Nokaze
Frequently Asked Questions (FAQ) about Japanese Pottery Kilns
Q1. What is a Noborigama (climbing kiln)? How is it different from gas and electric kilns?
A Noborigama is a traditional wood-fired kiln that utilizes the slope of a mountain, connecting multiple firing chambers (rooms) in a step-like arrangement. Unlike modern gas and electric kilns, which allow for precise temperature control and uniform firing, the greatest appeal and characteristic of wood-fired kilns like the Noborigama is the creation of "accidental beauty (keshiki)" that is born beyond the potter's intention, due to the dancing flames and swirling ash.
Q2. What is the difference between a Noborigama and an Anagama kiln?
The biggest difference lies in the "chamber structure (single-chamber or multi-chamber)." An Anagama kiln has a single, long space (single-chamber), where the flames and ash directly affect the pottery, making it suitable for creating unique, "ichigo ichie" pieces with strong individuality.
On the other hand, a Noborigama consists of multiple connected chambers (multi-chamber), allowing for temperature and atmosphere adjustments in each chamber. This enables the efficient firing of various types of pottery simultaneously and in large quantities.
Q3. What do "keshiki" (landscape) and "yohen" (kiln changes) refer to in wood-fired pottery?
These are pottery terms that refer to the natural patterns and changes that appear on the surface of a vessel during the firing process. "Natural glaze (ash glaze)" occurs when wood ash melts into a vitreous state at extremely high temperatures. "Hiiro" (fire color) refers to the beautiful gradients created by direct flame contact. "Scorching and carbonization" are black marks and patterns caused by ash and charcoal adhering to the pottery. The general term for these unexpected, accidental changes is "yohen."
Q4: Where can I buy works fired in a Noborigama or other wood-fired kilns?
Since they cannot be mass-produced, it is rare to find them in general stores. You can primarily purchase them at "pottery fairs" held in production areas like Bizen, Shigaraki, and Tanba, at "specialized galleries" in urban areas, or through "online platforms (such as Nokaze)" that provide detailed information on the stories of the regions and the backgrounds of the artists.