Kuril Islands dispute

The Kuril Islands dispute concerns the sovereignty of four islands at the southern end of the Kuril chain: Iturup (Etorofu), Kunashir (Kunashiri), Shikotan, and the Habomai islets. Japan refers to them as the Northern Territories (Hoppō Ryōdo); Russia administers them as part of Sakhalin Oblast. The dispute has prevented Russia and Japan from concluding a formal peace treaty ending World War II.

Soviet forces occupied the islands in late August and early September 1945, shortly after the USSR's entry into the Pacific War. Japan renounced claims to "the Kuril Islands" in the 1951 San Francisco Peace Treaty, but the Soviet Union did not sign that treaty, and Tokyo has consistently argued that the four disputed islands are not part of the Kuril chain referenced in the treaty and are instead an extension of Hokkaido.

The 1956 Soviet–Japanese Joint Declaration restored diplomatic relations and committed Moscow to transferring Shikotan and the Habomais to Japan after a peace treaty was signed — a formula both sides have invoked but interpreted differently ever since. Subsequent negotiations, including the 1993 Tokyo Declaration and the 2001 Irkutsk Statement, reaffirmed the territorial issue as unresolved.

Talks intensified under Prime Minister Shinzō Abe and President Vladimir Putin, who met more than two dozen times between 2012 and 2020, exploring joint economic activities on the islands. Progress collapsed after Russia amended its constitution in 2020 to prohibit the alienation of territory, and Japan's sanctions following Russia's 2022 invasion of Ukraine prompted Moscow to suspend peace treaty negotiations in March 2022.

The islands have strategic value: they control access between the Sea of Okhotsk and the Pacific, host Russian military deployments including coastal missile systems, and lie within rich fishing grounds. Roughly 17,000 Russian civilians currently live on the islands; the pre-1945 Japanese population was expelled by 1949.