Japan’s Constitution stipulates the renunciation of war and forbids using force to settle international disputes. This radical shift has been led by Fumio Kishida, the prime minister, whose constituency is Hiroshima, the atomic-bombed city symbolizing Japan’s postwar pacifism. This book is about Hiroshima’s local nuclear politics and popular consciousness about pacifism. Based on published and unpublished local documents and participant observation, it describes how postwar global and national power has formulated local politics and discusses the impact of local struggles on national and global politics. The key concept is “imaginary”. Institutionalized imaginary effectively channels people’s suppressed desires and emotions into coordinated action in the society. The current political crossroad of Hiroshima and Japan is interpreted as a terrain constructed over the last half century by three paradoxically coexisting and competing pacifist imaginaries, namely constitutional, anti-nuclear, and nuclear pacifism. They were, however, significantly destabilized by the Fukushima nuclear disaster and a newly invented “proactive pacifism”. This book is an essential reading for scholars and students interested in Japanese postwar history and nuclear issues in general.