In Japan, all large capacity fossil-fuel power plants are supercritical units and a steam condition of 246 kgf/cm²G, 538/566°C lias been adopted. Through extensive development work, the design and material technologies for steam turbines with a 593C steam temperature have been established, and the steam condition of 246 kgf/cm²G, 538/593°C was applied to the 700 MW steam turbine of Hekinan No. 3 Unit, Chubu Electric Power Co., Inc. for the first time in Japan. This unit has been operating successfully since it started commercial operation in April, 1993. Mitsubishi Heavy Industries, Ltd. (MHI) designed 1,000 MW turbines with a steam condition of 600°C class main and reheat steam temperature for the first time in Japan, even though in the world, applying the latest technologies developed for 600°C class application.