In this chapter I review the Japanese government’s strategy towards managing security of energy supplies, and the implications of this strategy for regional cooperation and competition. I focus in particular on how the government’s approach to Northeast Asian energy security is influenced by the weak commercial position of Japanese firms in international markets, and by the structure of the fuel markets within which they compete. I make two arguments. First, the supply-side approach taken by the Japanese government towards risk management in the energy sector has focused on diversifying the fuels and locations from which fuels are imported, and on strengthening the competitive position of domestic firms in international fuel markets. Second, the implications of its approach for the likelihood of regional cooperation and competition are conditioned by the structure of the private markets for fuels. In particular, while often overlooked, I argue that the private regime governing trade and investment in oil and gas enables a significant degree of cooperation between Japan, China, South Korea, Russia, and other countries, even as the Japanese government maintains parochial elements in its strategy towards managing perceived risks associated with fuel imports.