CSIS – Overshadowed by the invasion of Ukraine, Russia’s recent and rapid militarization of a group of islands claimed by Japan has flown largely under the radar. Taken by Russia at the end of World War Two, Kunashiri, Etorofu, Shikotan, and the Habomai islands of the Kuril Island chain, which Japan claims as its “Northern Territories,” have  complicated relations between the two states for decades.