Northeast Asian countries compete against one another in order to procure natural resources from abroad. Moreover, competition surrounding energy-related technologies is getting overheated in this region. It would be worth paying attention to energy competition between South Korea and Japan, so we can better understand energy security in Northeast Asia by comparing South Korea’s and Japan’s energy strategies. This paper examines how important coal is in the two countries’ economies and why coal has become so important . It also analyzes the similarities and differences of their coal policies, especially focusing on policy trends and prospects related to Clean Coal Technology. This paper will warn of another hot competition among the countries in this region and suggest multilateral cooperation.