Saipan, capture of

Saipan, capture of. One of the most critical battles of the Pacific war, the seizure of this Pacific island by US forces caused the fall of the Japanese prime minister, General Tōjō. Its capture brought Japan within range of US B29 bombers (see strategic air offensive, 3).

One of the Mariana Islands and a Japanese mandate, Saipan was a vital Japanese administrative base. At 22 km. (14 mi.) long it was large enough to be defended in depth and high ground allowed the defenders to bombard the western landing beaches. These were protected by reefs, a way through which had to be blasted by underwater demolition teams (seefrogmen) before the 2nd and 4th US Marine Divisions of Lt-General Holland Smith's 77,000-strong 5th Amphibious Corps landed on 15 June 1944. Because of an inadequate pre-landing bombardment, the 32,000 troops of Lt-General Saito Yoshitsugu's Thirty-First Army caused 4,000 marine casualties in the first 48 hours, even though Saito had been expecting the landings elsewhere. He expected, too, to hold the marines in their beachhead, and that they and their transports would be destroyed by the approaching Japanese Mobile Fleet. When neither happened—the Mobile Fleet was defeated in the Philippine Sea battle—he could only withdraw to the island's centre and fight a delaying action. But his men fought so fiercely that the three days allotted to the island's capture became three weeks.

A crucial objective in the south, Aslito airfield, was overrun on 18 June, but when the marines swung northwards Saito's defensive line, which included the rugged terrain around Mount Tapotchau, proved difficult to penetrate. In the centre the newly committed 27th Infantry Division was forced to attack his most heavily defended area, which included a densely wooded escarpment soon known as Purple Heart Ridge (see decorations), and when it failed to make any progress the division's commander was relieved.

Helped by accurate naval fire, which was able to find Japanese defensive positions among the valleys, the advance was soon resumed, but the Japanese continued to fight tenaciously and on the night of 6/7 July they launched the war's largest banzai charge. By some accounts more than 4,300 Japanese bodies were buried afterwards, and though this defeat heralded the end of all organized resistance small groups continued to hold out for a long time. On 9 July, the day the fighting officially ended, many Japanese soldiers, and civilians faithful to the Japanese cause, jumped from Marpi Point.