The 82-day battle lasted from April 1 until June 22, 1945.After a long campaign of island hopping, the Allies were planning to use Okinawa, a large island only 340 mi (550 km) away from mainland Japan, as a base for air operations for the planned invasion of the Japanese home islands.Their mission was to neutralize Japanese airfields in the Sakishima Islands and provide air cover against Japanese kamikaze attacks. The 9th Division was moved to Taiwan before the invasion, resulting in shuffling of Japanese defensive plans.Most of the air-to-air fighters and the small dive bombers and strike aircraft were US Navy carrier-based airplanes. Primary resistance was to be led in the south by Lieutenant General Mitsuru Ushijima, his chief of staff, Lieutenant General Isamu Chō and his chief of operations, Colonel Hiromichi Yahara.
Japanese air opposition had been relatively light during the first few days after the landings.
The 2nd Marine Division was an afloat reserve, and the 10th Army also controlled the 27th Infantry Division, earmarked as a garrison, and the 77th Infantry Divisions. Hiromichi Yahara The Japanese land campaign (mainly defensive) was conducted by the 67,000-strong (77,000 according to some sources) regular 32nd Army and some 9,000 Imperial Japanese Navy (IJN) troops at Oroku naval base (only a few hundred of whom had been trained and equipped for ground combat), supported by 39,000 drafted local Ryukyuan people (including 24,000 hastily drafted rear militia called Boeitai and 15,000 non-uniformed laborers).
It was planned that General Buckner would report to Turner until the amphibious phase was completed, after which he would report directly to Spruance. The Japanese had used kamikaze tactics since the Battle of Leyte Gulf, but for the first time, they became a major part of the defense.
They were named "Tekketsu Kinnōtai" (ja:鉄血勤皇隊, Iron and Blood Imperial Corps).
This mobilization was conducted by the ordinance of the Ministry of Army, not by law.