Hydropower generation companies in Japan profit by using regional resources of river flows and topographical conditions in hilly/mountainous areas, which have economic development and population settlement disadvantages. The residents of those areas understandably demand that such companies share the benefits of hydropower generation with them. Against this background, an analysis is provided of the historical development of the conflicts and compromises among different stakeholders (who separately seek private, regional or national benefits) on the hydropower generation in Miyazaki Prefecture since the 1920's, with a focus on the prefecture-operated hydropower projects in the Omaru River basin.