A Study on the Change of Interdependence and Relationship between South Korea, North Korea, the United States and China: Focusing on Strategic Triangle Relations

The purpose of this article is to examine the meaning of the change in U.S.-China-South-North Korea relations as a key actor in Northeast Asia. In addition, a strategic triangle structure is formed and used as an explanatory body. Accordingly, the paper sets the following as the basic assumption. First, in international relations, equilateral triangles are the most ideal, but in the change of the friendly-hostile relationship between the two, triangles are difficult to maintain their ideal shape and inevitably undergo ‘shape changes’. Second, the change in shape of the triangle means the formation of a strategic environment. Third, the typical shape change of the strategic environment is an isosceles triangle, and countries located at the vertices of the isosceles triangle have vulnerabilities, and those countries attempt strategic responses to overcome vulnerabilities. This article understands that the recent change in the U.S.-China relationship to a strategic competition relationship is a strategic environment change that triggers a triangle change in shape for Korea. Accordingly, it raises the need to pay attention to changes in cooperative relations with China along with traditional friendly relations with the United States in the Korea-U.S.-China relationship. In addition, the strategic triangle is a global environmental change that can be used in appropriate educational programs to explain the patterns and dynamics of changes in relationships of international actors.