The 1943 plan for the defensive perimeter around the Japanese Home Islands stopped at Saipan in the Marianas. Prime Minister Hideki Tojo, who had been leading the cabinet since 1941, was optimistic in his hopes for a successful defense of the island.
30,000 soldiers held Saipan. The civilian population was indoctrinated that the Americans would rape the women, kill the children and leave no one alive. The Japanese defensive tactics called for heated defense as soon as the lading started. Vice Admiral Chuichi Nagumo, the hero of Pearl Harbor and the loser at Midway, was placed in command.
The United States Marines were under fire as soon as the landings started on June 15, 1944. 2,000 Marines were casualties, but 20,000 were ashore by nightfall. In a running fight, the battle for Saipan was over by June 20. Except for a group of caves, the island was in Allied hands. Saipan was declared secure on June 22.
But on the night of July 7, 3,000 Japanese charged in the largest Gyokusai (suicide charge) of the war. Stunned, the Americans fell back, but quickly recovered and wiped out the Japanese in an all-night fight. Nagumo and his staff committed suicide before giving the order to advance.
All but 1,000 of the Japanese military units were dead, along with 22,000 civilians. The soldiers had pushed or pulled many over cliffs, but most had committed suicide by jumping themselves or by holding onto grenades in the caves. American casualties numbered 16,525.
Tojo was stunned by the fall of Saipan. His government fell; much of the optimism for a negotiated armistice was gone. Most who had the whole picture of Japan’s war efforts realized that the war was lost; it was only a matter of time before the Japanese Home Islands came under direct attack.