The Battle of Okinawa was the Marine Corps’ final battle of World War II. For three months, the U.S. Tenth Army, including the Marines of III Amphibious Corps, fought a grueling and bloody struggle to seize the largest island of the Ryukyus chain. Allied planners anticipated this battle would be the opening phase of the greater struggle for the Japanese home islands. Using Okinawa as a base, they planned to launch Operation Downfall—the invasion of Japan and the endgame of World War II Dropping atomic bombs on Hiroshima and Nagasaki shortly after the fall of Okinawa ultimately precluded the need to invade the home islands. On 15 August 1945, Japan announced that it would surrender to the Allied powers. However, the fact that Okinawa did not become the base from which the Allies would launch the final invasion of Japan does not diminish its significance. The almost fanatical defense of the island by Japanese forces and the bloody toll their efforts exacted played an important role in convincing American planners to seek means other than an invasion to force Japan’s surrender. The fall of the island also helped to further isolate Japan, cutting off its supply routes with the rest of its empire and enabling the United States to more effectively blockade the home islands. The battle proved to be the last opposed amphibious assault of World War II and the end of the grand drive across the Pacific that began with the landings on Guadalcanal in August 1942. Over the course of three years, the Allies had conducted a two-pronged assault to retake the territories seized by Japan in 1941–42 and breach Japan’s inner defenses. The first, led by General of the Army Douglas MacArthur, advanced from the Solomon Islands across New Guinea and into the Philippines (refer to map on page 5). The second, commanded by Fleet Admiral Chester W. Nimitz, moved across the Central Pacific Ocean, beginning with the Gilberts in November 1943, advancing to the Marshalls in early 1944, and culminating with the seizure of the Marianas and liberation of Guam in the summer of that year. In the course of this twin advance, the Japanese fortresses at Truk and Rabaul had been isolated, its lines of communications with its territories in Southeast Asia severed, and the home islands subjected to an unremitting bombing campaign launched from bases in the Marianas. Yet the Japanese showed no sign of surrendering. Indeed, in the fall of 1944, they demonstrated an even greater determination not to give up ground and capitulate. The 1st Marine Division’s (1st MarDiv) fight for the island of Peleliu left the veteran division a bloodied shell. Beginning with the Philippines campaign, Japanese aircraft began suicide kamikaze strikes against U.S. Navy ships. These defensive tactics also inflicted significant casualties during the Battle of Iwo Jima, the only battle of the Pacific war where American casualties exceeded those of the Japanese. There was a cold logic to Japan’s change in tactics. Its efforts to stem the Allied assault across the Pacific had led to egregious, irreparable losses of personnel, ships, and equipment. The Imperial Japanese Navy was a shell of its former self, its carrier air arm virtually annihilated during the Marianas campaign. Unable to match the United States’ industrial strength and the overwhelming power of the U.S. Marine Corps, Army, Army Air Corps, and Navy, the Japanese sought to wage a war of attrition. By choosing a deliberate defense that would inflict as many casualties upon the Allied forces as possible, the Japanese hoped that they would be convinced that a negotiated truce would be preferable to the high costs that would result during an invasion of the Japanese home islands. Therefore, the Japanese defenders would fight to the death with their mission being to make the Allies pay the highest price possible in Allied blood.