Anagama: The traditional kiln of Japanese ceramics
The Anagama kiln is an ancient Japanese ceramic technique, consisting of a long, tunnel-structured, wood-fired kiln embedded in hillsides for optimal temperature control. Its continuous firing and the formation of suspended ash creates natural glazes and unique textures in the ceramics, making each piece distinctively varied and artistic.
The origin of the Anagama kiln
The Anagama kiln, originally from 5th century Japan, is a relic that has transcended borders and eras. It actually dates back thousands of years, as it emerged as an adaptation of the “dragon” kiln from China, arrived in Japan through Korea, thanks to trade and cultural exchanges, evolving in its technique and form.
Its distinctive design, an elongated cavity and tunnel shape, is embedded in hillsides, taking advantage of the natural slope for efficient heat distribution. This unique design allows the furnace to resemble a fire-breathing dragon, maintaining a high temperature for several days.
It is characterized by having no physical separation between the combustion chamber and the firing chamber. Wood firing produces a high temperature and creates a unique glaze on each piece. Its use requires time, effort and knowledge. It is a highly valued firing technique today.
A Dance with Fire: The Anagama Technique
What makes ceramics fired in this type of kiln special is not only its aesthetic aspect, but also the artistic and intuitive process involved in its creation. The key lies in the wood used as fuel, which, as it burns, deposits ash on the pieces, generating natural glazes and unique patterns. This interaction between wood, ash and clay gives life to works where each one tells its own story of fire and artisanal dedication.
The Fire Process: Stages of the Anagama Enchantment
- Preparation: Cleaning and necessary repairs.
- Ceramic Preparation: Pieces usually pre-fired to resist the intense Anagama process.
- Furnace Charging: Strategic placement of the pieces, essential for the final effects.
- Furnace Sealing: Vital air flow control.
- Ignition: Gradual and controlled heating.
- Fire Maintenance: Addition of wood to maintain temperature and ash effects.
- Cooling: This process, as crucial as heating, can take several days.
- Kiln Discharge: Exciting moment where unique results are revealed.
- Cleaning and Finishing: Final touches before exhibition or use.
1: Door approximately 75 cm wide.
2: Firebox.
3: Stacking platform made of silica sand. Here the unfired pieces are placed.
4: Two dampers, one for firing and the second for closing the chimney hermetically.
5: Flue.
6: Fireplace 3 meters high.
7: Cast arc, made of heat-resistant (castable) cement.
Image/ See page for author, CC BY-SA 3.0 http://creativecommons.org/licenses/by-sa/3.0/, via Wikimedia Commons
Anagama Kiln Characteristics
Wood firing process
Firing in the Anagama kiln with wood is essential to achieve unique ceramic pieces. During the process, a large amount of wood is used, which produces intense combustion and generates high temperatures in excess of 760º C/1400º F. The wood burns and the resulting ash is drawn through the chamber into the chimney. This ash is deposited on the ceramic pieces, creating a unique glaze on each one.
Effect of ash on the ceramic pieces
The presence of ash in this Japanese kiln has a significant impact on the final result of the ceramic pieces. The chemical composition of the ash, combined with the high temperatures, results in complex chemical reactions on the surface of the pieces. This process generates vitrification effects, creating glazes with unique colors and textures on each piece, which give a distinctive stamp to ceramics fired in such a kiln.
Use and maintenance of the Anagama furnace
Its use and maintenance require a series of special considerations that differentiate it from other types of kilns. Below, we will explore the fundamental differences, firewood supply and maintenance, as well as temperature control and care of parts.
Differences with other types of kilns
The Anagama kiln is distinguished from more modern ones, such as gas or electric kilns, by its method of cooking with wood. This ancestral technique involves the constant use of firewood to maintain a constant high temperature. Unlike gas or electric kilns that are more efficient in terms of temperature control, this ancient kiln used in Japanese pottery requires continuous dedication.
Firewood supply and maintenance
The supply of firewood in the Anagama is essential to maintain an adequate temperature during firing. A constant supply of dry and properly cut wood is necessary to ensure proper operation of the kiln. In addition, caution should be taken when introducing the wood into the kiln, avoiding extinguishing the fire and ensuring proper combustion. Kiln maintenance also involves periodic cleaning of the ashes and checking for possible wear and tear on the structural parts.
Temperature control and parts care
Careful control of temperatures is crucial to achieve the desired results when firing ceramic pieces in the Anagama kiln. The pottery artist must constantly monitor the temperatures inside the kiln to avoid damage to the pieces and to ensure a uniform firing. In addition, special attention must be paid to the gradual cooling of the structure to avoid sudden temperature changes and possible cracks in the ceramic pieces.
Cover image: KAMUI
Ruins in Seto City, Aichi Prefecture, Japan. Minamiyama is known for the ruins of its Anagama kilns, which date back to the Heian period and were used until the Kamakura period.
