Yokotsuka Yutaka grew up hearing the sound of furnaces and mingling with the foundrymen working at his grandfather’s factory in Komatsugawa on the eastern edges of Tokyo. “I naturally thought that I’d grow up, graduate from school, and succeed my family business. I had no doubts,” he says in looking back at his life.
After over 40 years spent at the foundry, this quiet and unpresuming maker now dedicates his time to the making of Japanese water kettles or tetsubin using age-old traditional methods.
Tetsubin is a Japanese cast iron kettle used for boiling water. It became a popular household utensil during the late Edo period in the 18th century when leaf tea or sencha became available for mass consumption.
Although many similar utensils for boiling water with spouts and handles are found around the world, surprisingly water kettles made of cast iron were historically only made in Japan. The California Academy of Sciences has studied the tetsubin and although it says that the exact origins of the tetsubin are unclear, its genesis may stem from the widely held belief among tea enthusiasts that water boiled in an iron kettle tastes better than water boiled in any other material.
In formal tea ceremonies, the water is boiled in a cast iron pot without the spout and is scooped out with a bamboo ladle. Many practitioners of formal tea agree that the water boiled in cast iron makes the best tasting tea.
While I will leave it to the scientists to provide the scientific rationale as to why this may be the case, the tetsubin, the smaller, portable and more convenient utensil for boiling water for tea, quickly became the affordable luxury for people in the late Edo period. Tetsubin on top of burning charcoal heaters or hibachi became very fashionable to share tea and keep warm with family and friends, even if it was for the purpose of making cheaper and more common leaf tea.
The production of tetsubin peaked in the early 20th century when they were made in foundries all over Japan. But as national development turned towards militarization in the 1930s, the supply of iron for non-military needs became tight. Concurrently, as charcoal heating of the homes was replaced by kerosene, gas and electricity, the demand for tetsubin steadily dropped. Nowadays tetsubin making is mostly carried out in Iwate, which is where most ironware is produced in Japan.
A good quality tetsubin is light-weight with crisp motifs and unobtrusive exterior. They also have well-balanced spouts that pour water without dribbling. Its handle is hollow and forged from a sheet of iron which stays cool even when the kettle is heated. Apart from the handle forged by a fellow metal smith, Yokotsuka-san makes the rest of the kettle himself.
Traditional tetsubin-making involves four separate molds. There are two molds for the exterior and interior of the body, a mold for the spout, and a mold for the lid and its knob. Yokotsuka-san only uses the external mold once because re-using the mold, which is made from sand, makes the design of the kettle less crisp.
The pouring of molten iron is the most difficult part of the tetsubin-making process. The temperature of the iron and the speed of pouring all affect the end result. Yokotsuka-san admits that because the wall of the tetsubin is so thin, mistakes are not rare.
After they are cast, each tetsubin is baked in charcoal. This is a traditional method to reduce the initial rusting of the interior until a mineral layer is formed through repeated use. The exterior is coated with an iron mordant base and urushi lacquer.
Yokotuska-san is as firm and iron-willed as his creations in maintaining the legacy of tetsubin-making in Tokyo. “The foundries closed in Tokyo, and casting work of crafts became moribund in Japan. So I feel a great purpose in making tetsubin using the traditional techniques here in Tokyo”, Yokotsuka-san explains. He hopes to keep the fires of Tokyo’s forgotten foundry history burning, and dreams that one day he will be able to pass the knowledge on to the next generation.