Koreans have a long history of creating innovative, functional, practical, and completely unique teaware. Korea created works and utensils independent of China and Japan, a lot of teaware that comes from Korea are truly Korean inventions and served a functional as well as an ascetic purpose. This was also true for the devices created for bringing the water to a boil.
Throughout Korea's history braziers were commonly made of stone, iron, or silver and usually sat atop three legs. Sometimes a kettle was just hung over hot coals, but most likely some kind of device was used for boiling the kettle. With the invasion of Korea by Japan in the early 1900s, Japanese style iron brazers became the dominant style in most tea circles. Even today this influence can sometimes be seen in the Korean tea rooms.