Northern Territories Day is observed in Japan every February 7. This day commemorates the Northern Territories dispute, also known as the Kuril Islands dispute, between Japan and Russia, which has its origins in the Treaty of Commerce and Navigation signed on February 7, 1855. According to this treaty, the border was established between the islands of Etorofu and Uruppu, with the islands to the south belonging to Japan and those to the north to Russia. The dispute intensified after World War II, when the USSR invaded the Kurile Islands, and following the dissolution of the Soviet Union, Russia maintained control over the archipelago. The islands in question—Iturup, Kunashir, Shikotan, and Habomai—are referred to as the Northern Territories by Japan. The observance is marked by demonstrations organized by far-right political groups, which complicate diplomatic relations between Russia and Japan.