Japan and the Republic of Korea (ROK) are said to have been in a “quasialliance” since the Cold War period, drawing closer at times during doubts over U.S. security commitment to Asia. In recent years, however, this status quo appears to have changed. Despite anxieties of U.S. retrenchment, the relations between the two states have hit an all-time low because of arguments over how the history of Japanese imperialism should be remembered, and they show no signs of improving. Does this mean that the quasi-alliance has ended? This article examines this question, and concludes that the quasi-alliance between Japan and South Korea has broken down because of escalating arguments over the “history issue.” Japan-ROK bilateral relations are dogged by misunderstandings of each other, and that this is needlessly distancing the two states from one another. The termination of the Japan-ROK quasi-alliance because of the “history issue” is, on balance, a negative development for the security of the Asia-Pacific and a demonstration of short-term political judgement. If the two states are serious about resolving this deadlock, both need to overcome mutual stereotypes that are “taken for granted.”