The Battle of Okinawa was the last major battle of the Pacific War during World War 2.
Okinawa - a large Japanese island located about 400 mi (640 km) south of mainland Japan - was of interest for the Americans because it was to be used as an air base and staging area for a probable invasion of the Japanese mainland.
The Imperial Japanese Navy was no longer a force able to prevent an invasion. Nevertheless, a task force of Japanese surface ships led by Yamato - the heaviest battleship ever built - had a rather suicidal attempt to oppose, but the American air supremacy did not give them even the chance to reach the Okinawa waters. The Japanese Air Force, relying on inexperienced pilots and outnumbered, attacked the invasion fleet using an unprecedented number of kamikaze pilots, but managed to sink only small vessels.
The invasion began on April 1, 1945, when U.S. forces landed on the Okinawa's west coast and, facing a relatively weak opposition, the 6th Marine Division started an offensive towards the north of the island.
The Japanese forces withdrew into the Motobu Peninsula - a mountainous area with ravines - where their resistance intensified, but nonetheless, in about three weeks the northern area of Okinawa was secured by the Marines.
The conquest of the south of the island proved to be a different story. There, the Japanese defense relied on a fortified line located in front of Shuri town, beside which there was an old castle.
Despite the Japanese tenacity, the 7th and 96th divisions of the U.S. Army succeeded in the first week of the offensive to conquer two outposts of the line, known as Cactus Ridge and The Pinnacle.
The Americans had approached Shuri, but the initial attempts to overcome the Japanese opposition at Kakazu Ridge did not succeed. The fighting for the fortified caves, where the Japanese were defending, resulted in many casualties on both sides. Even the bombardments of an unprecedented intensity in the Pacific War could not annihilate the defenders in such positions.
Encouraged by their lasting until then, the Japanese launched several counteroffensives, repelled after close combat by the Americans who benefited from a superior firepower.
In May 1945, the U.S. military captured two critical positions flanking Shuri: Conical Hill in the east and Sugar Loaf Hill in the west. The monsoon rains had hampered much the conditions on the battlefield but, despite this, on 29 May, the 1st Marine Division finally captured the Shuri Castle .
Towards the end of June, the Americans overcame completely the Japanese defense in the south of the island, many Japanese soldiers preferring to commit suicide according to their code of honor than to be captured.
The victory had been achieved, but again, as in the Battle of Iwo Jima, at a great cost in terms of human lives, including a high number of post-traumatic stress disorder (PTSD) cases among the soldiers who survived.