This paper presents an outline of the series of HDR/HWR projects conducted by Tohoku University since 1983, starting with the Gamma-project, which was followed by the HWR, Fractal and MTC projects. The final goal of these projects is to establish/develop the design methodology for engineered geothermal reservoirs. A brief review of each project is also presented, with emphasis upon the progress of the main research topics, such as monitoring of reservoirs by active/passive acoustic techniques, rock mass properties, in situ stress, modeling and simulation and water/rock chemical interaction.