A sunken hearth. A square box installed into the floor of a tea ceremony room to make a charcoal fire. The standard size ro for kyōma datami 京間畳, the common size *tatami 畳 used in Kyoto and vicinity, is about 44 cm square, and about 39 cm square for inaka datami 田舎畳, also called edodatami 江戸畳, the common size tatami used in the Kantō 関東 region. The larger ro is the most frequently used. The ro is constructed with a firebox *rodan 炉壇, set into the floor, and then framed around the edges of the tatami. The firebox is filled with ashes and a little stand, gotoku 五徳 is set on top of them. Another method of heating the kettle is to hang it from a chain or extended pot-hook from a leech nail attached to the ceiling. The sunken hearth is used only in winter and spring. During the summer and fall, the ro is closed up during formal changing of the straw mats, with either a mat the size of the sunken hearth or a wooden cover. There are eight traditional locations *hachiro 八炉, for positioning the sunken hearth. A round fireplace *ganro 丸炉, is provided in the waiting room machiaishitsu 待合室, and in the tea ceremony room kitchen *mizuya 水屋.
