ABSTRACT
Over the last two decades, the China factor played only a marginal role in the Japan-South Korea security cooperation; in recent years, it has been widely accepted that the China's strategic influence would become more crucial not only for the resolution of the impasse over the Korean Peninsula but also for many strategic issues in Northeast Asia. The Japan-US-South Korea security cooperation historically has been focused on dealing with the North Korea's nuclear and the missile threats. Since the 1990s, many scholars have recognized and discussed the China factor as the nexus between the US-South Korea alliance and the US-Japan alliance as well as the Japan-South Korea security cooperation. The most important implication, which may be rather general, of Japan-US- Australian security cooperation for Japan-US-South Korea security cooperation is that bilateralism in trilateralism is indispensable. Japan, the United States, and Australia have conducted several joint military exercises since 2007.
