After the Japanese were forced into the defensive in the second half of 1942, the Americans were confronted with heavily fortified garrisons on small islands. They decided on a strategy of "island hopping", leaving the strongest garrisons alone, just cutting off their supply via naval blockades and bombardment, and securing bases of operation on the lightly defended islands instead. The most notable of these island battles was the Battle of Iwo Jima, where the American victory paved the way for the aerial bombing of the Japanese mainland, which culminated in the atomic bombings of Hiroshima and Nagasaki and the Bombing of Tokyo that forced Japan to surrender.