The United States decided to invade Okinawa in the fall of 1944 following the seizure of Peleliu and the Philippine landings. The planned invasion of Formosa was cancelled after General Simon Bolivar Buckner objected. Buckner argued that the Japanese army on it was “much too strong to be attacked by the forces by American Forces then available in the Pacific.” The strategic rationale behind the decision to invade Okinawa included Okinawa’s proximity to Japan as a staging base for a future invasion of the Japanese mainland.  Likewise taking the island would severe Japan’s lines of communication and commerce with Southeast Asia and to serve as base for strategic bombers. Planning began in October 1944 and the detailed plan for OPERATION ICEBERG was issued 9 February 1945. The campaign was not planned in isolation but “was bound up strategically with the operations against Luzon and Iwo Jima; they were all calculated to maintain unremitting pressure against Japan and to effect the attrition of its military forces.”

The War Department insisted that Lieutenant General Simon Bolivar Buckner command the newly formed 10th US Army. Buckner was chosen to command based on his taking of the Aleutians, displacing the veteran Marine Holland M. Smith. One critical history noted that “compared to his subordinates, Buckner was hardly fit to command a corps, let alone a field army.”

The 10th Army consisted of the 3rd Amphibious Corps (1st, 2nd and 6th Marine Divisions) under Major General Roy Geiger and the XXIV Army Corps (7th, 27th, 77th and 96th Divisions) under Major General John Hodge.2nd Marine Division was designated as a diversionary force, and the 77th Division was assigned to take the nearby island of Kerama Retto prior to the landings to provide the Navy a safe anchorage and as an artillery platform to shell Okinawa. The 27th Division was in corps reserve.  All were veteran units and had it was believed they would be “more than enough to overwhelm the estimated 70,000 Japanese on Okinawa.” However, much of XXIV Corps had only been engaged in hard combat on Leyte and was not relieved of their duties on Leyte on 1 March 1945.  This provided these units with no time to rest and refit. More importantly badly needed troop replacements had been diverted to Europe due to the crisis in infantry strength there during the battle of the Bulge. The operation was very large and “mounted on a scale that matched the previous year’s Allied landing in Normandy”...(see more at: http://padresteve.com/2009/11/03/okinawa-gottdammerung-in-the-pacific/)