Seventy years have passed since the end of Japan’s colonization of Korea and the military occupation of Korea by the Soviet Union and the United States, which led to the establishment of two separate states, the Republic of Korea (ROK or South Korea) and the Democratic People’s Republic of Korea (DPRK or North Korea) in 1948. Japan normalized its diplomatic relations with South Korea in 1965. Since then, the two countries have collaborated at governmental, economic, cultural, academic, and individual levels, although they continue to disagree about the interpretation of Japan’s colonial rule of Korea. In contrast, Japan and North Korea have yet to normalize diplomatic relations, which deteriorated during the Cold War. Japan came to identify North Korea as the primary security threat to its national security after the Cold War because of North Korea’s nuclear and missile development. Japan now sees China as the most pressing threat to national security, but North Korea continues to be a priority. North Korea’s nuclear and missile development has hurt its relations with Japan and South Korea. South Korea still has a strong desire to improve inter-Korean relations and achieve Korean unification, but Japan has been reluctant to normalize its relations with North Korea.