As tensions between China and Japan increase, including over the disputed islands in the East China Sea, Japan has adopted under Prime Minister Abe a new security posture. This involves, internally, adapting Japan’s constitutional position on defence and, externally, building stronger international relationships in the Asia-Pacific region and more widely. This book presents a comprehensive analysis of these developments. It shows how trust and co-operation with the United States, the only partner with which Japan has a formal alliance, is being rebuilt, discusses how other relationships, both on security and on wider issues, are being formed, in the region and with European countries and the EU, with the relationships with India and Australia being of particular importance, and concludes by assessing the likely impact on the region of Japan’s changing posture and new relationships.