The Japanese economy underwent a fundamental transition from a liberal economy to a developmental state system during World War II, and despite efforts by the American occupation forces to dismantle them after 1945, these elements of the wartime economic system remained in place. Through an historical institutionalist lens, this book examines the reasons why the key features of the Japanese developmental state, such as pilot agencies and industrial associations, continued to play key roles in the post-war Japanese economy. Further, it locates the fundamental roots of the developmental state system in wartime Manchuria and thus highlights how decisions made in the context of war continued to influence the direction of the Japanese economy over the following decades. Analysing the institutional origin and evolutionary path of developmental state system, The Evolution of the Japanese Developmental State extends existing scholarship on the institutions that were at the heart of the developmental state system by focusing on not just why they were important, but also how and why they were originally built. Based on extensive archival research in both Japan and the USA, including Japanese language collections not widely known in the West, it will be of great interest to students and scholars of political science, economic history, economics and Asian studies.