Japan’s March 2011 triple disaster of earthquake, tsunami, and nuclear meltdown shattered the country’s nuclear-dependent energy policy. Questions about the long-term consequences of Fukushima still linger, but a political and economic re-evaluation of the costs and benefits of this high-risk technology is long overdue. Concerns about the future role of nuclear power are part of the larger international debate about energy security and climate change. Germany is frequently seen as leading the way toward a clean-energy future with its nuclear exit and renewables expansion, but both Japan and Germany have managed to maintain a secure energy supply with dramatically reduced—or even zero—nuclear power since 2011. A comparison of similarities and differences between Japan and Germany helps to explain each country’s responses to Fukushima and to draw out key lessons for future energy systems. Energy policies that scrutinize vested interests of the industry and allow for more decentralized energy systems, relying on more renewable energy sources and more programs for emissions reductions, are key in shaping the inevitable big shift.