This book offers the first systematic and comprehensive analysis of the Japanese debate on the nation’s Southeast Asia policy from 1938–1941 and 1952–1960. In a detailed discourse analysis, it compares competing arguments offered by business circles, the military, the political and diplomatic elites, and intellectuals on Japan’s regional strategy. This book advances the field of the history of Japan’s diplomatic thought, not only by addressing the issue of continuity and change in the discourse on Japan’s relations with South East Asia, but also by demonstrating how this debate served to explore more fundamental questions about Japan’s identity, its relations with Western nations and its stance on Asian solidarity. Heiko Lang (PhD) completed his doctoral studies at the Universities of Tokyo and Munich and is currently teaching international relations at Hosei University, Tokyo.