Lit. "lapis lazuli tile." A tile to which a blue glaze ruriyū 瑠璃釉 has been applied. The glaze is made from feldspar chōseki 長石 to which a small quantity of cobalt oxide kobaruto sankabutsu コバルト酸化物 is added, turning the glaze blue or greenish blue. Since this glaze has insufficient viscosity, it must either be applied in several layers or an adhesive substance must be added to produce a rich depth of color. Glazed tiles were not used extensively in Japan. They were far more popular in China and the Korean peninsula. Examples: a pair of blue-green tiles found at Kyōōgokokuji 教王護国寺 (Tōji 東寺) first half of the Heian period. Both are pendant *gatō 瓦当 tiles placed along the edge of the eaves. It is doubtful that the entire roof was covered with glazed tiles. It is generally believed that they were used only along the eave-ends.