This book examines the complex and connected past, present, and future of Northeast India and Japan. It looks at the intricate political geography and ethnolinguistic diversity of India’s Northeast, and its historical and strategic relationship with Japan. From the theatre of the Second World War to a potential economic corridor to the Indo-Pacific, the Northeast, which shares a border with China, Nepal, Bangladesh, Bhutan and Myanmar, has emerged as an area of central importance in India–Japan relations. The book highlights the importance of connectivity and cooperation in the North Eastern Region, for sustainable growth, better accessibility, and quality of life. The chapters in the volume look at shared economic, socio-political, and environmental concerns of the two countries as well as the shared legacies between Japan and the Northeast through stories, collective memories and memorials about World War II, and research. They also explore the strategic implications of China’s One Belt One Road initiative in the region and for India–Japan relations, India’s Act-East policy, provincial politics and ethnic conflicts, and the challenges for sustainable development and greater cooperation for the two countries. With contributions from both Indian and Japanese academics, this book will be a key resource on understanding Asian politics. It will be of great interest to scholars and researchers of politics and international relations, strategic studies, development studies, and Asian studies.