1945年二战结束时，日本和俄罗斯并未签署和平协议，这在很大程度上是因为两国对南千岛群岛针锋相对的领土要求，该地区在日本被称之为北方四岛。
When World War II ended in 1945, Japan and Russia did not sign a peace treaty, owing largely to their competing claims over the Southern Kuril Islands, known in Japan as the Northern Territories.