A glazed tile is a clay tile with a glaze applied to its surface. There are two methods of coloring roof tiles: smoked roof tiles, in which carbon molecules contained in fuel are adsorbed on the surface to produce a silver color; and glazed roof tiles, in which carbon molecules are adsorbed on the surface of the fuel to produce a silver color. These glazed tiles can be roughly divided into three types: salt glazed, high-fired, and low-fired. In salt glaze firing, salt is added in the late stages of firing to compound the sodium in the salt with the silicic acid in the substrate to form a glassy coating of sodium silicate, which is generally referred to as a red tile or salt ware tile. This process began in the early Meiji period (1868-1912) and is mainly produced in the Mikawa region of Aichi Prefecture. High-fired glazed tiles are mainly blackish brown or reddish brown, and are mainly produced in the San’in and Hokuriku regions, where cold resistance is required. Low-fired glazed tiles are generally referred to as glazed tiles or ceramic tiles, and are now being produced throughout Japan, mainly in the Mikawa region of Aichi Prefecture and the Awaji region of Hyogo Prefecture.
