Southeast Asia is the region where Japan has been most deeply engaged in the postwar era. Japan has provided over half of its official development assistance (ODA) to the region, accounting in 1960 to 2011 for 34.9 percent of ODA from the world to today’s ten Association of Southeast Nations (ASEAN) countries. The amounts and categories of assistance to these countries (as of Japan’s fiscal year 2011) was $153.72 billion in loans, $16.50 billion in grants, $1.44 billion in technical cooperation, $168,905 for accepted trainees, $47,857 for dispatched experts, and $5,358 for overseas Japanese volunteers.1 In net disbursements of ODA, Japan is in fifth place among the Organisation for Economic Co-Operation and Development-Development Assistance Committee (OECD-DAC) member countries today. In gross disbursements, however, Japan ranks second only to the United States. Southeast Asia still occupies a major part of Japan’s ODA, and the country is rediscovering ASEAN and its member countries as important partners in promoting Japan’s economic, political, and security interests in a changing Asia-Pacific region. Prime Minister Abe’s visits to all ASEAN member countries within a year of his second inauguration demonstrated the emerging recognition of the region’s increased importance for Japan’s engagement in international affairs.