The battle of Iwo Jima would rage on for another 22 days, claiming eleven thousand more American casualties and the lives of virtually the entire Japanese garrison. This was a colossal fight between two well-armed, veteran forces--the biggest and bloodiest battle in the history of the United States Marine Corps. From the 4th of March on, however, the leaders of both sides entertained no doubts as to the ultimate outcome. _Assault Preparations_ Iwo Jima was one of those rare amphibious landings where the assault troops could clearly see the value of the objective. They were the first ground units to approach within a thousand miles of the Japanese homeland, and they were participating directly in the support of the strategic bombing campaign. The latter element represented a new wrinkle on an old theme. For 40 years the U.S. Marines had been developing the capability for seizing advanced naval bases in support of the fleet. Increasingly in the Pacific War--and most especially at Saipan, Tinian, and now Iwo Jima--they were seizing advanced airbases to further the strategic bombing of the Japanese home islands. American servicemen had awaited the coming of the B-29s for years. The “very-long-range” bombers, which had become operational too late for the European War, had been striking mainland Japan since November 1944. Results proved disappointing. The problem stemmed not from the pilots or planes but rather from a vexing little spit of volcanic rock lying halfway along the direct path from Saipan to Tokyo--Iwo Jima. Iwo’s radar gave the Japanese defense authorities two hours advance notice of every B-29 strike. Japanese fighters based on Iwo swarmed up to harass the unescorted Superforts going in and especially coming home, picking off those bombers crippled by antiaircraft (AA) fire. As a result, the B-29s had to fly higher, along circuitous routes, with a reduced payload. At the same time, enemy bombers based on Iwo often raided B-29 bases in the Marianas, causing some damage. The Joint Chiefs of Staff decided Iwo Jima must be captured and a U.S. airbase built there. This would eliminate Japanese bombing raids and the early warning interceptions, provide fighter escorts throughout the most dangerous portion of the long B-29 missions, and enable greater payloads at longer ranges. Iwo Jima in American hands would also provide a welcome emergency field for crippled B-29s returning from Tokyo. It would also protect the flank of the pending invasion of Okinawa. In October 1944 the Joint Chiefs directed Fleet Admiral Chester W. Nimitz, CinCPac, to seize and develop Iwo Jima within the ensuing three months. This launched Operation Detachment.