South Korea and Japan had limited direct bilateral military ties during the Cold War though both were key allies of the United States in East Asia. With the end of the Cold War, however, South Korea and Japan started to engage in confidence and security building measures (CSBMs) as the U.S. military deployment in the region came into question. These measures were initiated as a response to uncertainties about each other's security policy in the post-Cold War environment. However, the sharp rise of the mutual North Korean threat in recent years has given the two countries a more compelling reason for the CSBMs. Nonetheless, it remains to be seen whether these bilateral military-tomilitary contacts will have a lasting impact on bilateral security relations.
In recent years, South Korea and Japan have significantly increased confidence and security building measures (CSBMs) between their respective armed forces. Although these measures were initiated as a response to uncertainties about each other's security policy in the post-Cold War environment, the sharp rise of the mutual North Korean threat has been the primary driver of the recent bilateral military contacts. Saddled with severe economic problems and bereft of reliable allies, North Korea has become even more militant and provocative than in the past, threatening to develop nuclear weapons and testing long-range ballistic missiles. This North Korean militancy has dampened the anxiety felt by South Korea and Japan about each other.
However, the suppression of this security anxiety may last only as long as the North Korean threat. In this context, the confidence building and security enhancing measures now underway may prove inadequate. To reduce the potentially dangerous uncertainty in the bilateral relationship, leaders in Seoul and Tokyo need to nurture a sense of security partnership in maintaining peace and stability in East Asia. Investing in more meaningful CSBMs now could make a difference in the future direction of bilateral security relations.
THE POST-COLD WAR STRATEGIC CONTEXT
Given their reputation for mutual disdain toward and distrust of each other, South Korea and Japan may have surprised many with their increased security cooperation in recent years. Indeed, there are very few studies on South Korea-Japan security relations in the post-Cold War period. Excellent empirical studies by Chong-Sik Lee (1985) and Brian Bridges (1993) are now dated. A more recent study by Victor D. Cha (1999) sheds some light on the subject; however, his theoretically sophisticated work still focuses mostly on the Cold War era to explain the dynamics of South Korea-Japan security cooperation in terms of the perceived level of U.S. military commitment to their respective security.' We focus our study on the post-Cold War era. Our analysis is guided by a "postclassical realist" view on international relations that emphasizes perceived threat and probability of conflicts as they affect the security calculations of Seoul and Tokyo:2
As even a casual observer of East Asian affairs would note, despite the fact that South Korea and Japan are allies of the United States, during the Cold War, neither country made much of an effort to promote direct bilateral security ties. The South Koreans, well-protected by the United States, harbored bitter memories of Japanese colonialism while the Japanese, also well-protected by the United States, were reluctant to get involved in other entangling commitments.' Although the end of the Cold War did not alter many South Koreans' negative perception of Japan and did not fundamentally transform Japan's circumspect attitude toward alliances, it did change the strategic calculation in Seoul and Tokyo.
With the collapse of the Soviet Union, it became quickly obvious to both South Korea and Japan that they could not take for granted the forward deployment of troops of their mutual ally, …