S9 (history of psychological factors): With China's rapid economic take-off, China has gradually become the driving force of economic development in East Asia, some Koreans believe that China's economic and political status of the upgrade will lead to restored ancient Chinese domination of Asia 'tributary system.' model, over dependence on China will lead Korea to be absorbed into the 'China Economic Circle', became a vassal of the Chinese economy. Therefore, this kind of psychological factors also become an FTA between the two barriers.