The twentieth century has been called a century of war. Wars and colonization leave deep chasms between countries. In the case of Japan, these frictions have manifested themselves as historical issues. The history since World War II has also been a history of trying to overcome the hostility surrounding these issues. Since the end of the war there have been various attempts at reconciliation, and indeed, periods in which Japan has enjoyed good relations with China and also with South Korea. Despite that, historical issues have overheated in the twenty-first century, and their effects may extend beyond Japan's relations with China and South Korea to impact its relations with the United States, Southeast Asia, and Europe. --