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-to-military contacts will have a lasting impact on bilateral security relations.