In the realm of Chanoyu, it is necessary to heat water to make the tea. According to tradition, water is heated in a kama, 釜, kettle. Originally, the kama was part of a portable hearth called a fu-ro, 風炉, wind-hearth. In time, the kama was taken from the furo bowl, and used with a hearth sunk in the floor, called an i-ro-ri, 囲炉裏, enclose-hearth-inner. The word irori is abbreviated to ro, 炉. The furo can be used throughout the year, but if a ro is available, it is used in the cold half of the year, from November through April. The fu-ro, 風炉, wind-hearth, is used from...