This study is a review and analysis of the Japanese government's 2014 Strategic Energy Plan (SEP). As the first plan to be issued after the Fukushima disaster of March 2011, the 2014 plan incorporates policies that represent the most comprehensive and systematic changes ever proposed for Japan's energy system. The study reviews the key elements of the plan, employing a framework that explains the nature and magnitude of the changes planned for Japan's energy system and related institutions. The analysis demonstrates that the shock of the triple disaster opened up a window of opportunity in Japan's policy environment for a fundamental change in Japan's energy policy, allowing for major reforms to the energy industrial structure and energy institutions. A unique aspect of this study is that it draws upon in-person interviews conducted with key government officials who were directly involved in the formulation of the SEP, providing new insights into Japan's energy policy planning process and the drivers behind the planned reforms. Given the nature and magnitude of the potential changes implied in the SEP, this paper concludes that the 2014 SEP is best understood as a comprehensive blueprint towards a major planned transition of the Japanese energy system.