Iwo Jima 1945 Read online

  3. It would contribute to the destruction of Japanese naval and air power.

  4. It would pave the way for the eventual invasion of Japan.

  Planning for the invasion of Iwo Jima could now begin in earnest.

  Iwo Jima was in the Nanpo Shoto Islands, south of Japan. It was also halfway between the airbases in the Marianas Islands and Tokyo.

  Airbases on the Marianas become operational in November 1944 and B-29 bombers immediately began bombing mainland Japan, in particular the capital, Tokyo. News of the raids gave the American people and servicemen a morale boost but plane and crew losses were high, far too high. If a plane was damaged by enemy action over Japan or suffered a malfunction, the crew had to ditch in the Pacific Ocean where their chances of being rescued were zero. Although the raids had to continue, the US Air Force was desperate for a staging airfield along the flight route, and Iwo Jima was the place. Not only could fighter squadrons join the bombers en route to Tokyo, crippled bombers could land on it.

  Operational Planning

  Planning for Iwo Jima continued throughout October but by mid-November it was clear that the timetable of operations had to be changed. The interval between the invasion of Luzon on 20 December and Iwo Jima on 20 January did not give time to switch shipping from one area to the other. Admiral Nimitz recommended delaying the attack on Iwo Jima (Operation Detachment) to 3 February while the invasion of Okinawa (Operation Iceberg) was rescheduled for 15 March.

  The campaign to clear Leyte in the Philippines was also taking far longer than expected owing to the arrival of two new Japanese divisions on the island and the atrocious weather. General Douglas MacArthur, Supreme Commander of the Southwest Pacific Area, had to postpone the assault on Luzon to 9 January 1945, in turn delaying the invasion of Iwo Jima. At the beginning of December Admiral Nimitz recommended delaying Operations Detachment and Iceberg to 19 February and 1 April 1945 respectively; the Joint Chiefs agreed.

  Troops and equipment come ashore on Luzon Island, the largest of the Philippine Islands. (NARA-111-SC-200008)

  Planning Operation Detachment

  Admiral Nimitz’s staff published a preliminary report of the invasion of Iwo Jima on 7 October so planning could begin. Operation Detachment’s objectives were to extend US armed forces control over the Western Pacific while maintaining military pressure against Japan. The capture of the island and its airbases were also outlined as part of the overall strategy for the defeat of Japan. Admiral Nimitz’s directive also specified the four commanders for the operation:

  1 Operation: Commander Admiral Raymond A. Spruance, USN.

  2 Joint Expeditionary Force: Commander Vice Admiral Richmond Kelly Turner, USN.

  3 Joint Expeditionary Force Second in Command: Rear Admiral Harry W. Hill, USN.

  4 Expeditionary Troops Commander: Lieutenant General Holland M. Smith, USMC.

  General Smith received Admiral Nimitz’s directive on 9 October and his staff immediately set to work planning the invasion. Fifth Fleet and V Amphibious Corps had cooperated before during the capture of the Gilberts, the Marshalls and the Marianas, and all levels of staff were used to working together. Responsibilities were distributed as follows:

  Commanding General, Pacific Ocean Areas Responsible for coordinating all aspects of the Pacific war; land, sea and air.

  Commanding General, Army Air Forces, Pacific Ocean Areas Responsible for the long range bombing campaigns, either to support invasions or against the Japanese homeland.

  Commander Fifth Fleet Coordinate naval gunfire support before the invasion, during the landing and during the battle.

  Commander Amphibious Forces, Pacific Organise the transfer of troops, vehicles and equipment to the island during the landing and the battle.

  Commander Service Force, Pacific Organise the delivery of supplies and ammunition to the beachhead.

  Commander Air Force, Pacific Organise bombing raids by land-based planes, particularly before the invasion.

  Major General Harry Schmidt, commander of V Amphibious Corps, was in turn appointed Commanding General of the Landing Force. Schmidt’s staff were responsible for preparing the Marine aspect of invasion, knowing that they had the Headquarters, Fleet Marine Force, Pacific, at their disposal.

  3rd, 4th and 5th Marine Divisions had been assigned as V Amphibious Corps’ Landing Force. 3rd Division had just captured Guam and it was resting and refitting on the island. 4th Division had just taken Saipan and Tinian and it was resting and refitting at its base on Maui in the Hawaiian Islands. Iwo Jima would be 5th Division’s first battle but many combat-experienced troops had been transferred to it to help it complete training on Hawaii Island.

  V Amphibious Corps Headquarters moved to Pearl Harbor on Oahu Island, in the Hawaii chain on 13 October 1944 to facilitate planning, and six days later Schmidt issued an outline plan. The following day, General Holland Smith, the Commanding General of Fleet Marine Force, Pacific, issued troop assignments to General Schmidt.

  As the various staffs worked together to finalise the planning for the invasion of Iwo Jima, Schimdt’s original plan evolved to accommodate information gathered from aerial intelligence reports. The various headquarters published their final drafts for Operation Detachment on the following dates:

  25 November Commander-in-Chief, US Pacific Fleet and Pacific Ocean Areas, Operation Plan No. 11-44

  23 December V Amphibious Corps, Operation Plan No. 3-44

  27 December Joint Expeditionary Force, Operation Plan No. A25-44

  31 December Fifth Fleet, Operation Plan No. 13-44

  By the time Admiral Spruance assumed command of all forces assigned to Central Pacific Task Force on 26 January 1945, all elements of Operation Plan 11-44 were being developed.

  As V Amphibious Corps made its final preparations for Iwo Jima, Sixth Army was advancing across Luzon. Huge plumes of smoke rise above Manila’s docks as the battle for the city begins. (NARA-111-SC-200052)

  THE ARMIES

  Commanders

  General Holland Smith

  General Smith, or ‘Howling Mad’ as he was known, was Commander of the Amphibious Force, Atlantic Fleet, in December 1941 and responsible for training several divisions in amphibious landings. He transferred to command the Amphibious Corps, Pacific Fleet, in August 1942. The organisation was later known as V Amphibious Corps and it moved to Pearl Harbor in September 1943 to begin planning for the Gilberts campaign. Smith was still in command when it was renamed Fleet Marine Force, Pacific, in August 1944.

  Major General Harry Schmidt

  Schmidt was Assistant to the Commandant of the Marine Corps from January 1942 to August 1943. He then commanded 4th Marine Division during the capture of Roi-Namur in the Battle of Kwajalein and in the invasion of Saipan. In July 1944, he took command of V Amphibious Corps and led it through the invasion and capture of Tinian Island.

  General Tadamichi Kuribayashi

  In December 1941, Kuribayashi was appointed Chief of Staff of the Japanese 23rd Army in time for the invasion of Hong Kong. He was promoted to lieutenant general as commander of the 2nd Imperial Guards Division, a training division, in 1943. On 27 May 1944, he transferred to the 109th Division and two weeks later was ordered to defend Iwo Jima in the Bonin Islands chain believing that ‘Japan has started a war with a formidable enemy and we must brace ourselves accordingly.’

  Kuribayashi arrived on the island on 19 June 1944, having had an audience with Emperor Hirohito. After surveying the island’s defences he set about planning new ones inland, eventually connecting the 5000 caves with 11 miles of tunnels. He believed that ‘America’s productive powers are beyond our imagination’ and wanted to turn Iwo Jima into a fortress. He realised he could not hold Iwo Jima forever but was prepared to fight a battle of attrition. He expected to die and on 5 September he wrote to his wife: ‘It must be destiny that we as a family must face this. Please accept this and stand tall with the children at your side. I will be with you always.’

  US Marin
es

  Weapons

  The Marine wore the 1941 pattern utility uniform, a simple loose-cut two-piece uniform made of sage green cotton herringbone twill. It was called either utilities or dungarees but never fatigues, the US Army word for uniform. The jacket had three flapless pockets while the trousers had four; the arrangement depended on which manufacturer made them. The M1 steel helmet was covered with a camouflage cloth which had a reversible brown/green coloration. The later version had slits for foliage, something that was not needed on Iwo Jima. Leggings were worn over the boots but they were often discarded because they could be difficult to put on and were uncomfortable to wear.

  A US Marine carried his equipment and personal belongings in a three-part olive drab M-1941 Haversack that could be arranged in five different ways: light marching, marching, field marching, transport and field transport. The upper section carried the rations, poncho and clothes needed in combat while the lower section contained extra shoes and utilities. The exterior of the upper pack had loops and tabs for attaching a bayonet, shovel, extra canteen and first-aid pouch; a bedroll could be folded around the top. The belt suspenders completed the haversack. The harsh Pacific environment quickly faded and then rotted the uniform and equipment.

  Officers were issued with either Colt M1911 or M1917 .45 calibre revolvers. The rank and file Marines were armed with the M1 Garand, which had a high rate of fire thanks to its gas operated rotating bolt system. The semi-automatic rifle fired .30–60 Springfield ammunition from the 8-round internal magazine and could also fire fragmentation, anti-tank and smoke grenades using a spigot attachment and special ammunition. The shorter M1 Carbine was issued to officers, NCOs and other specialists who benefited from carrying this shorter, compact weapon; it fired a 7.62mm round from a 15- or 30-round box.

  The M1A1/M1928 Thompson submachine gun could fire over 600 .45 ACP rounds a minute from 20- or 30-round stick magazines and they were often issued to scouts, NCOs and patrol leaders. Delays in production meant that only a limited number of M3 submachine guns, or ‘Grease Guns’ were available. Some men were issued with the Winchester M12 Trench Gun, a six-round pump action shot gun for close quarter combat. The MkII Fragmentation grenade and smoke and white phosphorous variants were used in great numbers in the close-quarter fighting, while the Ka-Bar knife could be used in a tight corner.

  The M1918 Browning Automatic Rifle, or BAR, had a high rate of fire and the .30 rounds it fired from a round box magazine had a high stopping power. It could be mounted on a bipod for increased accuracy and the trigger man could choose either automatic or semi-automatic fire. The M1917 Browning machine gun was a heavy, tripod-mounted weapon and its four-man crew used it in a semi-static role. It was water cooled and the belt-fed mechanism could fire up 600 .30 rounds a minute. The M1919 Browning Machine Gun was an air-cooled tripod-mounted weapon with a crew of two; it also had a maximum rate of fire of 600 rounds a minute.

  The M2-2 flamethrower was an excellent weapon for clearing pillboxes. It could fire a single ten-second burst or five two-second bursts of burning fuel from its two back-pack style canisters. Typically, each squad had one and the while one man operated the trigger, the other operated the valves. The Japanese feared the flamethrower and snipers kept a look out for the distinctive profile of the fuel tanks or for a bright burst of flame so they could engage the team. While there were few Japanese tanks to engage on Iwo Jima, the M1A1 bazooka was another useful weapon for engaging emplacements; it had a two-man crew, one man to fire and one to load.

  Kit

  The 75mm pack howitzer was a versatile weapon known as the ‘Little Dynamite’, which could be manhandled into areas that heavier artillery could not reach. It could be used to carry out direct firing against bunkers up to a range of around 500 metres or for indirect fire against targets up to 9000 metres away. The Marine division artillery battalions were equipped with the M2A1 (M101A1) 105mm Howitzer, which was capable of firing high explosive rounds to a range of 11,200 metres. The Corps artillery battalions had the M114 155mm Howitzer, capable of firing to a range of 14,600 metres.

  The Marine tank battalions were equipped with Sherman M4A3 (medium) tanks armed with the 75mm M3/L40 gun, which could fire armour piercing or high explosive rounds, and one .05 calibre and two .03-6 calibre Browning machine guns. They weighed 30.3 tonnes and had 53mm of armour at the front, 63mm at the side and 40mm at the back; they rarely reached their top speed of 30mph on Iwo Jima. Sherman tanks mounting flamethrowers were particularly effective and burning fuel could be fired approximately 91 metres; each tank carried 300 gallons of fuel, which gave 150 seconds of flames. The tanks’ air intakes and exhausts were modified with chimneys so they could drive off the landing ships and through shallow water onto the beach. M3 Gun Motor Carriages were half tracks, mounting a 75mm gun, and they were used as mobile anti-tank guns to attack emplacements.

  Everything had to be brought to Iwo Jima by sea and the huge logistics operation involved a wide range of ships and landing craft. The Landing Ship, Tank (LST) was 106 metres long, 16.8 metres wide and could either carry ten tanks and fifteen vehicles or 160 officers and men; it had a crew of 104. The Landing Ship, Medium (LSM) was 62 metres long, 10 metres wide and could either carry five tanks, six LVTs (amphibious armoured carriers), nine DUKWs (amphibious trucks) or 54 officers and men; it had a crew of 58.

  A Landing Ship Tank delivers Sherman tanks to the shore. Some bogged down in the soft sand, a few hit mines and others were hit by Japanese artillery; the few lucky survivors were welcomed by the Marines. The air and exhaust intakes which allowed tanks to beach in shallow water can be seen. (NARA-127-GW-109825)

  The Landing Vehicle Tracked (LVT(A)-1), was an armoured amphibious vehicle used to ferry men from the Landing Ships to the shore. The ‘amtrack’ as it was widely known was 7.95 metres long, 3.25 metres wide and could carry 18 men or 2000kg of supplies; it had a three man crew. The LVT(A)-4 variant mounted a turret with a 75mm Howitzer. The DUKW was a six-wheeled drive amphibious truck used to ferry artillery from the Landing Ships to the shore. It was widely known as the ‘duck’, and was 9.4 metres long, 2.5 metres wide and could carry 2.3 tonnes or 12 men; it only had one crewman. Once ashore, ammunition and supplies were taken inland by the Clever-Brooks amphibian trailer, which could carry a 3.5-ton load, or the M-29C Light cargo carrier (Weasel), which hauled a half-ton load.

  An amtrack crew get their final instructions from one of the control boats supervising 4th Division’s assembly area before heading towards the beach. (NARA-127-GW-110134)

  Tactics

  The Marines were virtually always on the offensive and the fighting tended to follow a steady pattern. The Japanese would watch and wait in their camouflaged bunkers and caves until the Marines were fixed firmly in their sights. After everyone went to ground, spotters would locate the Japanese position while armoured dozers cut a road forward so the tanks could move into position, guided by the Marines. While the flame tanks sprayed the area with burning liquid, the Shermans fired 75mm rounds and their machine guns at the bunker aperture or cave mouth. Flamethrowers and tank flamethrowers were found to be the best weapons for clearing the Japanese out of their bunkers and caves.

  Once the bunker was temporarily silenced, the assault team rushed forward to make sure no one was left alive inside. The Marines could then renew their advance but they had to be wary of Japanese soldiers opening fire from a new, hidden position. Demolition teams had to check the area, searching the caves and pillboxes for signs of life; they rarely saw any. Progress was slow and dangerous and advances were often measured in metres.

  The engineers landed alongside the assault troops and they had to carry out a variety of perilous tasks. They had to use flamethrowers and explosives to blast open or seal pillboxes and caves. They also had to probe for mines in the volcanic ash or use explosives to carve routes through the rock for tanks. 5th Engineer Battalion described two methods of advancing through a minefield when tanks were not available:

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bsp; Mines had to be removed by hand, under fire; or equipment had to be run into the minefield until it was blown up, then removed and the process repeated until a path through the minefield was opened. The former method was slow, tedious, and exposed highly trained specialists to high casualties. The latter method was slow, and costly in armoured dozers and tanks.

  The artillery found it difficult to locate and then silence Japanese mortar, artillery and rocket batteries. Corps and division observation and intelligence officers pooled their information with aerial observers for the best results. The Japanese made excellent use of the rough terrain and camouflage to hide their weapons and they held their fire until they would have the maximum impact on the Marines’ advance, usually when they were in an exposed position. The Regimental headquarters then had to quickly establish where the Japanese guns were, either from the men on the ground or from the observer planes circling overhead. The information had to be transmitted to the artillery batteries or fleet ships so that counter battery fire could be arranged as quickly as possible. It meant that the men on the ground often had to wait hours under fire until the Japanese guns were silenced.

  An Intelligence Officer with 4th Marine Division makes it clear that combined arms attacks were the only way to advance. He also shows how the Japanese often withdrew to a new position when the Marines were closing in:

  Our Battalion CO has coordinated his direct support weapons and delivers a concentration of rockets, mortars and artillery. Our tanks then push in, supported by infantry. When the hot spot is overrun we find a handful of dead Japs and few if any enemy weapons. While this is happening, the enemy has repeated the process and another sector of our advance is engaged in a vicious fire fight, and the cycle continues.