This chapter explores Japan's climate policies from its decision to host the international climate negotiations in 1997, which led to the eventual formation of the Kyoto Protocol, through to Japan's formulation of its nationally determined contribution for the Paris Agreement. As the host of the climate conference at which the Kyoto Protocol was reached, Japan has been a relatively strong supporter of global action on climate change. Japan's relatively ambitious climate policy goals before the Fukushima nuclear accident were strongly supportive of the nuclear industry. Nuclear energy was marketed as a clean, low carbon energy. At the time of the Fukushima nuclear accident, Japan obtained over a quarter of its electricity from nuclear energy. Japan became the world's third largest producer of nuclear energy after the United States and France, as well as a major exporter of nuclear technology. This nuclear position would change dramatically as a result of the Fukushima nuclear crisis.