The "give back our islands" comment is a reference to an ongoing dispute between Japan and Russia over the four southernmost Kuril islands (northeast of Hokkaido). They were originally settled by Ainu people, and Japanese sovereignty over them was asserted in 1855. At the end of World War II, the Soviet Union annexed the islands, and they remained under Russian control when the USSR collapsed, but the Japanese government continues to claim them as rightful Japanese territory to this day.