According to the mass media, Japanese nationalism is on the rise. Tokyo's stance on national security is becoming uncharacteristically assertive. This book explores the prospect of Japan's remilitarization and challenges the preconceived approaches taken by existing theories on Japan's national security. The book examines Japan's pacifism since the Second World War, developments in Japanese military build-up since the late 1960s, and Japan's responses to the conflicts in Afghanistan and Iraq. Controversies between realism and social constructivism continue to dominate Japan's national security debates, but neither is fully able to make pointed predictions. This study, in bridging the gap between these two rigid approaches, provides an understanding of this vital aspect of Japanese national security.