evidence: Although all three disputes are labeled as "territorial issues," each one has a fundamentally different character from a legal, political, historical, and practical point of view. I define the Northern Territories as not a territorial issue but a historical memory issue for Japan. The four islands became Japanese territory due to the 1855 Treaty of Shimoda between the Tokugawa Shogunate and Tsarist Russia. Since then the islands’ ownership was never disputed by any country until they came under Russian occupation as the result of an attack that began on August 9, 1945, just six days before Japan surrendered. These islands subsequently became a symbol of the pain that Japan experienced from the Soviet Union during the concluding period of World War II. [...] Because of the psychological anguish regarding Russia that has gripped Japan since the summer of 1945, the Northern Territories have always been put at the center of Japan’s negotiations with the Soviet Union and its modern-day counterpart. Japan relinquished the Kuril Islands in the San Francisco Peace Treaty (1951), but since the Soviet Union did not sign that treaty, the issue was reexamined in the 1955–56 peace treaty negotiations between the two countries. The Japan–Soviet Union Joint Declaration of 1956 included the partial solution of agreeing on the transfer of the two smaller islands, Habomai and Shikotan, after the conclusion of the peace treaty, but the fate of the two larger islands, Kunashiri and Etorofu, was under a complete deadlock.