The 4th Marine Division first saw action in February 1944 when it and the U.S. Army’s 7th Infantry Division assaulted the Kwajalein Islands, the command center of the Marshall Islands group. It was also a key U.S. strategic objective because Kwajalein was the site of major Japanese airfields and it would supply the U.S. fleets with good anchorages within 1,000 miles of the Japanese Fleet Headquarters at Truk Island.
Alarmed at the speed with which the Marshall Islands fell to the American Forces, in March 1944 the Imperial Headquarters began transferring additional infantry divisions from Manchuria and Japan to the Mariana Islands to from an absolute defense line. By June 1944 there were over 60,000 Japanese troops entrenched in the Marianas, with Saipan being the most heavily defended island.
The Mariana Islands of the Central Pacific played a pivotal role in the United States northwest advance towards Japan because the larger Mariana islands of Guam, Saipan and Tinian offered bases from which B-29 Superfortresses could bomb Japan.
Saipan, an island roughly 14 miles long and 6-1/2 miles wide was the most heavily defended island of the Mariana Group. The 2nd and 4th Marine Divisions stormed ashore at Saipan, with the 27th Infantry Division initially held in reserve. Deadly Japanese artillery, mortar and heavy machinegun fire caused over 2,000 casualties on the first day. Suffering extremely high casualties, the Marines and Army units later joined up to attack a major Japanese inland stronghold.
The battles waged on relentlessly for 4 weeks as the Marines faced the largest enemy tank assaults of the Pacific War and fanatical suicide counter-attacks. Egged on by Japanese soldiers, thousands of civilians killed themselves by jumping off cliffs to the rocks and pounding ocean below.
Iwo Jima, a small volcanic island of little more than 8 square miles, was supremely important with its strategic location half way between Tokyo and Saipan. For the American forces, capturing Iwo’s 3 airfields reduced the distance for B-29 bombers to reach Tokyo from 1,400 miles flying out of Tinian to only 660 miles from Iwo.
Nearly 23,000 Japanese manned the most elaborate fortified defenses of World War Two, including over 600 gun emplacements and pillboxes, countless connected cave defenses and deep shelters. In the end, the Marines turned the battle into a literal blood bath for the Japanese with only 216 Japanese troops surviving. In addition to the 22,000 Japanese killed, the Marines suffered 25,000 total causalities of Killed, Wounded and Missing. Imagine such carnage in only 8 square miles.
A Special introductory commentary is provided by historian and CIB Media president Frank R. Cambria, Captain, US Army.
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