The Korean Diaspora in Japan is a legacy of Japan's colonization of Korea in the first half of the 20th century and has always been the largest group of foreign residents in an otherwise ethnically homogenous Japan. A major issue is the role that Koreans in Japan play in supporting North Korea. Although a very small segment of the population, Koreans affiliated with the organization known as Chosen Soren have figured prominently in the triangular relationship between Japan, North Korea, and South Korea over the past 50 years. During the Cold War, Chosen Soren activities in support of North Korea severely strained Japan-South Korea relations that were already plagued by lingering animosity from the colonial period. For many years, Chosen Soren was the conduit through which Japan and North Korea attempted to expand trade and eventually establish formal diplomatic ties. However, Japan-North Korea relations have deteriorated in the post-Cold War era due to North Korea's growing military threat to Japan, and most recently, North Korea's admission that it had been systematically kidnapping Japanese citizens. Studying the history of Chosen Soren will result in a better understanding of the complexities underlying Japan's current foreign policy toward North Korea.