On 19 February 1945 U.S. Marines stormed ashore on Iwo Jima, a small volcanic island half way between the Mariana Islands and Japan. These landings opened more than a month of extremely bloody ground fighting between three Marine divisions and more than 20,000 Japanese defenders. By late March 1945, when the Marines were relieved by a U.S. Army garrison, over six thousand Americans had been killed, along with about ninety percent of the Japanese. However, by then the island was already a refuge for U.S. bombers, with more facilities being actively developed.
The mid-1944 conquest of the Marianas, providing base sites for a strategic bombing campaign against the Japanese home islands, made Iwo Jima an invasion target. The attack decision was formalized early in October 1944, by which time the U.S. Army Air Force was frequently bombing the island. These raids, supplemented by periodic warship gunfire attacks, became daily occurances later in the year, after the B-29 bombers began hitting Japan and Iwo Jima had been used to stage several destructive air raids against the B-29s' own bases. The Japanese, clearly understanding the importance of the place, had been fortifying it since March 1944. After the Marianas fell, they greatly expanded this work, which was not seriously hindered by the air and sea bombardment. By early 1945, it was obvious that capturing Iwo Jima, though essential, would be very costly.
The Iwo Jima invasion began on 16 February 1945, when a formidible U.S. Navy armada started three days of pre-landing preparations. As minesweepers and underwater demolition teams cleared the nearby waters, warships and aircraft methodically tried to destroy the island's defenses. However, given the abundance of well-concealed strongpoints and deeply buried underground facilities, this was not nearly enough. Thus, when the Marines landed, they confronted intense opposing fire from the landing area and from flanking positions on Mount Suribachi in the south and the rugged terrain of northern Iwo Jima. Securing Mount Suribachi and the rest of southern Iwo Jima required more than four days of intense combat. Another week's bloodshed brought the Marines into the middle of the desperately defended north, where the bitter fight to eliminate organized Japanese resistance took nearly four additional weeks.
For the U.S. Marines, Iwo Jima was the most difficult of World War II's many tough fights. It remains an enduring demonstration of the essential role of infantry when ground must be captured, even when seemingly overwhelming air and sea power is present. The abundant heroism of the attackers was recognized by the award of no fewer than twenty-seven Medals of Honor, more than half given posthumously. In American hands, Iwo Jima soon became an important base for the air campaign that ended with Japan's August 1945 capitulation, thus justifying the blood spilled to take it. Had the war continued, its role would have been even more critical.