Kama (釜) is a Japanese term meaning metal pot or kettle. The specific term for a kama used in Japanese tea ceremony is chagama (茶釜, "tea kettle"). Kama are made of cast iron, and are used to heat the water used to make tea.
In the tea room, the kama is either heated over a portable brazier (furo) or in a sunken hearth (ro) built into the floor of the tea room, depending on the season.
Kama are often round or cylindrical, and have a lug on each side, for inserting metal handles called kan. These are used to carry the kama and/or hang it over the ro. Otherwise, or when using a brazier, a tripod may be used to support the kettle over the heat source. There are also brazier sets in which the kama is designed to be used without a tripod. Kama (釜) is a Japanese term meaning metal pot or kettle. The specific term for a kama used in Japanese tea ceremony is chagama (茶釜, "tea kettle"). Kama are made of cast iron or copper and are used to heat the water used to make tea. In the tea room, the Kama is either heated over a portable brazier (furo) or in a sunken hearth (ro) built into the floor of the tea room, depending on the season. Kamas are often round or cylindric Ro (sunken hearth): This hearth is used during autumn and winter seasons when it is cold. In the Tatami flooring a hole is created to put the kama in. The Kama being surrounded by a box-like frame will warm up faster and stay warm longer; moreover, it provides an image of warmth during the colder seasons. In case of the Ro, incense used is Neriko which are tiny kneaded balls from mixed woods, spices, and herbs, instead of Kouboku aromafrom tic wood. The preparation ritual will be slightly different from the Furo procedure in spring and summer but the basics are the same.al, and have a lug on each side, for inserting metal handles called kan. These are used to carry the kama and/or hang it over the ro. Otherwise, or when using a brazier, a tripod may be used to support the kettle over the heat source (Sen, 1979, p. 22). There is also brazier sets in which the kama is designed to be used without a tripod. A portable brazier used in the spring and summer seasons. Furo have a variety of shapes and the earliest ones were made of bronze but later iron and clay braziers became common. The unglazed clay Furo coated with black lacquer was preferred for formal use. It was placed on a lacquered board to prevent heat damage. The iron type was set on a paving tile. On the edge of a Furo a fire window or cut-out opening provided the necessary draft to keep the Sumi burning properly. A bed of ashes Hai was laid inside the Furo and the Sumi placed on top was lighted. The Kama was then set directly on the bronze or iron brazier, but a trivet was used for a clay brazier. Kama for portable ranges is slightly smaller than those used for fixed hearths Ro (Sen, 1979, p. 22).
Reference
1. Sen, Soshitsu. The Japanese Way of Tea, New York/Tokyo: Weatherhill, 1979.pg 22