For many decades, Northeast Asia has been a centre of significant interest and conflict among the great powers (i.e. United States, China, Russia, Japan). During the Cold War, the sense of East-West confrontation was extremely tangible in Northeast Asia. The end of the Korean War resulted in two contending camps. One was the triangular relationship among the Soviet Union, China, and North Korea, and the other was the triangular relationship between the US, Japan, and South Korea. In other words, the thirty-eighth parallel not only divided the Korean Peninsula, but also delineated the borders of international power politics in Northeast Asia. However, the deterioration of the relationship between China and the Soviet Union in the 1960s led to reconciliation in Sino-American relations in the 1970s. As a result, the bipolar structure of the Cold War in this region was transformed into a rather complex situation. Since the 1970s there have been six powers, divided in three sets of hostile bilateral relations: the antagonistic bilateral relations between the US and the Soviet Union, between China and the Soviet Union, and between North Korea and South Korea.