The sovereignty dispute in the East China Sea (ECS) includes the boundary of maritime areas and the ownership of the Diaoyutai Islands, which resulted in the complexity of problems solving in the ECS. Based on the sovereignty maintenance, energy exploitation, and sea power development, the People's Republic of China (PRC) must not give up strategic interests of the ECS. Japan announced the "nationalization" of the Diaoyutai Islands in September 2012 to impel the PRC to change its original strategy, to execute the sovereign means by routine navigation through the sea law enforcement departments, joint maritime exercise, and claiming the Air Defense Identification Zone (ADIZ) of the ECS and so forth. The PRC intended to gain substantial control over the area. This situation results in the conflicts between Japan and China in the ECS.