This chapter looks at Japan’s East Asian policy in the postwar period historically and thematically. It is, of course, not a comprehensive account of Japanese foreign policy, as such a task would require more than a whole book. The aim of the chapter is to set the background for the arguments of the book introduced in the previous chapter. By looking at what Japan has actually done in its relations with East Asian countries, it considers how and why Japan has increasingly become more willing to take the initiative in the region and how it has pursued its policy objectives under the domestic, regional and international constraints imposed on it. Equally, this chapter shows that Japan has expanded the range of its initiatives, from the economic to the political area. This examination, in turn, will lead to an evaluation of how independent Japan’s East Asian policy has been, particularly in connection with its US relations, the considerations Japanese policymaking agents have taken into account in deciding the country’s foreign policy, how much the importance of East Asian countries in Japanese foreign policymaking has risen during the postwar period and what are the regional consequences of those changes in Japanese policy.