Boiling Hot Water for Tea

 Kettles for Chanoyu, the Way of Tea
In the Japanese Way of Tea, iron kettles are used to boil water for preparing the tea. In Japan, the history of iron kettle casting using sand molds can be traced back to the Heian and Kamakura periods. 
Iron Casting
Japan has had an active and time-honored history of iron casting, which has not been limited to producing kettles for the Way of Tea, but was also used in making a greater variety of items than one could imagine, from swords and cooking pots to hoes and innumerable others items. In the past, the iron used was called wazuku and was composed of “sand iron” or satetsu. This satetsu was quarried from the mountains and refined through smelting by craftsmen known as murage.
Chanoyu Kettle-Producing Regions
Historically, the areas best known for production of iron kettles for chanoyu were Ashiyazu in Chikuzen Province (now the town of Ashiya in Onga county, Fukuoka Prefecture), and Tenmyō in Sanonosho, Shimotsuke Province (now Inufushicho in Sano city, Tochigi Prefecture). However, over time, new production regions were born as craftsmen migrated to other areas (such as large cities or emerging new towns) following the work with the changing of the times.
 What is wazuku?
Wazuku is the term for a grade of iron (sometimes called “pig iron”) refined by using traditional Japanese smelting methods to extract magnetite iron from sand that is quarried from the mountainsides. From the Momoyama period to around the Meiji period, cooking pots, water kettles, spouted kettles, and other forms were all produced either by iron casters or by blacksmiths. From the Meiji period onward, exchange with foreign cultures blossomed and with it yozuku, which was made from imported iron and steel, was also introduced to Japan. Compared to yozuku, using wazuku was more labor intensive and allowed for only limited volume, making it poorly suited for mass-production. As high-volume production became more and more necessary due to modernization, the use of wazuku gradually disappeared. 
Resistant to rust, wazuku iron becomes more beautiful the more it is used. Exposed to the harsh elements, the beauty of the iron lanterns that hang at Haruna Shrine in Gunma Prefecture has remained unchanged for almost 660 years. The fact that Ashiya and Tenmyo kettles are still beloved by tea practitioners today is also due entirely to the rust-resistant feature of wazuku. 
The Nagano Family
Nagano Tetsushi I (Living National Treasure, 1900–1977) spent almost twenty years reviving the craft of chanoyu kettle-making using wazuku iron. At present, the technique has been passed down to Nagano Tetsushi II (1941–) and Nagano Arata (1973–), who continue to produce work by the mold casting and melting furnace method today at a studio in Okegawa city in Saitama Prefecture.
 Making a Kettle for Chanoyu  
If you break down the process of producing a kettle into precise detail, it can easily involve more than 100 individual steps and is an undertaking that requires time and patience. 

A mold is made using fine river sand. First, a wood shell is secured in a frame and the outer surface of the kettle is formed in the mixture of water and sand.

Once the outer surface is created, then intricate designs are added. The photograph shows sand being formed to the inside of the mold. When iron is poured into the mold, the raised areas of sand create concave patterns on the surface, in this case resulting in a design of mountains. This stage is called nurikomi and was used in kettle production even as early as the Muromachi period (1336–1573).

Prototypes of the kantsuki kettle ring lugs are also covered in the sand and soil mixture to create molds of the kantsuki, which are then impressed into the kettle mold.

When the outer mold and inner mold are ready, it is time for the casting step. Molten iron heated to 1400°C is poured into the mold.

After the casting is complete and has slowly cooled by annealing, the work is removed from the mold and trimmed. Then, it is washed with water to oxidize the inner and outer surface.

The two kettles seen here are different shapes, but the one on the left also shows the kettle before it has been oxidized and the one on the right has been finished with oxidization. The special characteristic of wazuku iron is that once the surface is coated with an oxidization layer, the internal body of the iron can last an extremely long time without rusting. 
Once the surface has sufficiently oxidized, it is stabilized by applying a coating of lacquer. Finally, once the kettle is actually filled with water and placed on the fire and delicious hot water has been boiled in it, then the process is complete. 
Kyoto Women's University, Lifestyle Design Laboratory
Credits: Story

Information and images provided by:

Text and direction by:
Nagano Arata

English translation:
Maiko Behr

Exhibition created by:
Sugishima Tsubasa, Kyoto Women's University

Project Directors:
Maezaki Shinya, Kyoto Women's University
Yamamoto Masako, Ritsumeikan University

Credits: All media
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