Over the past half century, South Korea and Japan have established themselves as firm and reliable allies of the United States, contributing to peace and stability in the Asia-Pacific region. Japan has done much to aid South Korea economically, and South Korea, positioned on the front line of threats emanating from North Korea backed by China and the Soviet Union, has contributed to Japan's security. South Korea and Japan have also become economic powerhouses and models of free markets and international trade. As of 2013, Japan had the world's third-largest nominal gross domestic product (GDP) at $4.9 billion, and Korea ranked fourteenth at $1.3 billion. Bilateral human, economic, and cultural exchanges between Korea and Japan have increased significantly over the past fifty years. Korea and Japan traded $85 billion in goods in 2014, 385 times the figure from 1965. Approximately ten thousand visitors traveled between the two countries in 1965, whereas in 2014 the number was over five million. Moreover, since 1998, cultural exchange between South Korea and Japan has boomed. The "Korean wave" (or hallyu)—which describes the overseas popularity of Korean soap operas, songs, and movies—is widespread in Japan, and Japanese novels, manga, and anime are becoming popular in South Korea, especially among the younger generations.
Despite increasing cultural exchange and deepening economic interdependence between the two countries, serious disagreements remain. Instead of steady progress toward a better relationship, Korea-Japan relations have shown a pattern that begins with improved ties but is followed by serious deterioration. Historical and territorial controversies often cause these recurring conflicts. This cycle reflects the incomplete nature of the 1965 Treaty on Basic Relations, which did not fully resolve historical controversies and territorial disputes. Given the deteriorating security situation in East Asia and the emergence of an assertive China, the United States has an interest in repairing Korea-Japan relations.