On February 19, 1945, as part of their island-hopping strategy to defeat Japan, the United States invaded Iwo Jima. Iwo Jima was originally not a target, but the relatively quick fall of the Philippines left the Americans with a longer-than-expected lull prior to the planned invasion of Okinawa. Iwo Jima is located half-way between Japan and the Mariana Islands, where American long-range bombers were based, and was used by the Japanese as an early warning station, radioing warnings of incoming American bombers to the Japanese homeland.