Assault Phase of the Iwo Jima Landings
The Landing Plan called for putting 9,000 men ashore in the first 45 minutes. The flag signal to "Land the Landing Force" was executed at 0615. At 0805 naval gunfire was lifted and 120 aircraft shot rockets and machine guns and dropped bombs on the beach area and its flanks. Napalm was used generously.
At 0825 the early landing waves were in position and at 0830 the first wave was directed to proceed to the beach. The Pre-Landing Gunfire Support Plan called for putting 8,000 shells on the beach while the troops were moving in from the Line of Departure. Fire was directed at the beach until 0857, when it shifted to the flanks and immediate rear.
The first assault wave hit the beach along the 3,000-yard front at almost exactly H-Hour, 0900, and moved ahead rapidly for the first 350 yards under the very real assistance of a rolling barrage of naval gunfire. The second wave was the initial troop wave.
As the Marine Commander reported: No anti-boat gunfire was reported by the initial waves. The Japanese gun, mortar, and small arms fire against the later waves of amtracs, and against the troops which landed from them was definitely light on the southern beaches until about H plus 30 minutes, by which time many lead vehicles were well off the beach.
Japanese gunfire picked up more quickly against the later waves headed for the northern beaches and by 0920 reports of heavy Japanese mortar fire against the right flank beaches were received.
Progress straight across the southern belt of the island was rapid and by 1030 Marines had reached the cliffs overlooking the western beaches of Iwo Jima and by 1130 these cliffs were in the possession of the Fifth Marine Division. Progress on the right flank was slower, much slower, as the Marines met gradually intensifying fire from the quarry and plateau area, from undestroyed pillboxes, and encountered land mines.
The tanks were called for, and by noon some reserve units were called in. Since these were embarked in LCVP's and LCM's real problems at the beach line soon developed. The amtracs had had their difficulties with the steep beach and the steep slopes of volcanic sand, but by and large they made it. When it came to the landing craft, the LCVP and the LCM, the amphibians ran into trouble because of the combination of steep beach gradients and the onshore swells. The craft grounded fair and square but the swells broached, and then swamped many, before they could be completely unloaded.
By nightfall, all assault elements of both divisions had been landed, plus other supporting elements to bring to 30,000 the total of troops landed in one day.
All the amphibians, whether on land or sea, and everyone else within sight of Mount Suribachi, received a tremendous lift when the spirited Marines of the 28th Regiment of the Fifth Marine Division raised the American flag on the summit of Mount Suribachi about 1035 on 23 February 1945.
Despite this favorable turn (which facilitated the full force of the Fifth Corps being used against the defensive positions to the north), the Japanese "fight unto death" tactics were aided by the rugged volcanic crags, steep defiles, and severe escarpments. The Marine advance was slow, but inexorable.
At 1800 on 16 March, Iwo Jima was declared secure.
Source: Photos from Naval
Historical Center/ National Archives & Records Administration