Northeast Asia is one of the most important regions of the world both economically and in terms of its historical heritage. The region poses significant challenges for international law whilst international law can unleash cooperative endeavours which can place the region in a formidable location in the new multi-polar world order. This work sets out a contextual regional approach to international law focusing on the relations as between China, South Korea and Japan. In particular the author deliberates on the historical development of international law in the region, the relationship of international law with the Chinese, Korean and Japanese legal systems; historical disputes as between the three States; and the respective practices in the sphere of monetary and trade relations. This work will be of interest to international law scholars, practitioners and policy makers.