Security relations between Japan and its East Asia neighbors have been complicated for decades. Entering the third decade of the 21st century, Japan will have to face new security challenges posed by COVID-19 and manage its current relations with the United States, China and South Korea. Mitigating local and global security threats will be one of the most critical challenges for the future. This book focuses on internal and external factors that are influencing current Japanese security policy and analyses the security issues from numerous perspectives, including social issues and their effect on security policies, bilateral relations between Japan and its partners in Asia, and the significance of the U.S.-Japan Alliance.