Kettle for boiling water.
Originally, the furo-kama combination (kirikake-furo) was like a stove as the kettle fit directly on top of the furo. This style is still used for its one-piece ease and formal feeling. With the development of Tea came a diversification of kettle size and form based on the change from metal to clay furo, and the addition of a tripod to make it all functional. When the hearth-ro was redesigned for Tea during Sen Rikyu's period, we have a reduction of the huge kitchen irori and a standardization of size, with further variety of shape and surface decoration of kettles as well.
As the aesthetic of Wabi cha gained both in popularity and in numbers of participants, masters strove to make Tea into something reflecting themselves more closely. Since the older kettles were scarce and represented an "old-fashioned" Karamono-based aesthetic, Teamasters took it upon themselves to have kettles fitting their taste made in Kyoto, where most of them lived or orbited the center of power, Nobunaga and later Hideyoshi and Rikyu. The kettles made in Kyoto constitued a whole new category, known as Kyogama.
Kyogama still embody the gentle elegance of Kyoto culture as well as its daring flair. Rikyu commissioned many kettles which have become classic archetypes. Among them are shapes called Amidado, Shiribari, Mozuya, Unryu, etc. Later Teamasters have all tried their hands at kettle design, and the variety is huge. There are at least 50 classic shapes and hundreds of master's designs. There are at least 7 types of mouth designs, 6 types of bottoms and 7 of lids, and 5 different ways to attach the Kan, kettle rings. Surface textures and designs of the lugs or kansuki are practically infinite.
Clean kama and return it to ro or furo to dry; be sure to pour kama water into the chakindarai.
First using the hishaku, ladle most of the hot water out of kama and both： a, on to the surface of the kama and b, into the chakindarai (being sure the chakindarai is free to use). This washes the impurities off the kama and helps cool it while giving it a deeper patina.
To get the last of the water out of the kama, use two towels, zokin preferred, to hold the kama by its sides and pour the remaining water into the chakindarai. DO NOT USE THE KAN TO DO THIS !
Put kama onto the kamasue upside down and, using the kiriwara, a tough-bristled brush, and ladlesful of hot water, scrub just the bottom of the kama with a circular motion. Be certain not to scrub above the cast mark around the edge of the kettle.
When done, turn the kama back upright and, if there is water still left in the kama, use a fukin to pat, not wipe the interior moisture out. On tall kettles, be sure the shoulders inside are patted dry.
Return kama to the ro or furo with the kan. DO NOT USE A TOWEL