Iwo Jima 1945 Read online

  This flamethrower team is making sure that no one is left alive; two men cover the bunker with their rifles while a third squirts burning fuel into the aperture. (NARA-127-GW-111008)

  The Japanese were masters of infiltration at night and towards the end of each day every commander had to assess his unit’s progress. If necessary, some were ordered to withdraw to ‘tie in’ their flanks and form a solid defensive front. Marines would dig in for the night, set up their support weapons, establish communications and post lookouts. They would then have to keep watch all night, raising the alarm if anything suspicious was seen.

  The Japanese

  The Japanese soldier wore the Type 98 pattern yellowish-khaki, or mustard, two part uniform which faded in the tropical climate. He had a wool uniform for winter and a cotton one for summer; he could wear a khaki cotton shirt in warm conditions. The long trousers or pantaloons were secured over the ankle boots with spiral wound woollen puttees and tapes.

  Officers had to buy their own uniforms so style and quality varied and colours ranged from tan to dark green. A Type 3 officer’s uniform was introduced in 1943 in various shades of green and it was a cheap cut of material with cuff insignia. Jackets could be worn over a white or light green shirt, and the uniform was completed with a black or green tie.

  Most officers and men wore cloth field caps with a leather or cloth peak and they came in various shades of green ranging from grey-green to a dark green. Some wore the Type 92 dome helmet but it was made of poor quality steel and was little use against shrapnel; others wore the Type 92 cork version tropical helmet.

  Officers bought their own revolvers and while some had the woefully inadequate old Type 26 double action revolver, some had the newer Type 4 or Type 14 recoil spring action revolvers. The Type 94 was a lightweight recoil operated, locked breech action weapon. Many officers bought Western revolvers due to the unreliability of the Japanese models. Officers were also armed with the Shin Gunto, or New Army Sword, which was both a badge of rank and a weapon.

  The Japanese soldier was armed with the Type 99 Short Rifle, a bolt action weapon which fired a 7.7mm Arisaka cartridge from a 5-round internal magazine. The Type 2 rifle grenade launcher was attached to the rifle and a blank cartridge or wooden bullet propelled the 30mm or 40mm rounds. Many soldiers used the Type 99 sniper version to good effect in Iwo Jima’s rough terrain. They also carried the Type 99 hand grenade or the Type 4 Ceramic grenade. The ceramic version had a porcelain or terracotta body and they had been introduced because the Japanese armaments industry could not produce enough steel grenades.

  A few soldiers might have been armed with submachine guns but production was limited and few were available. The Type 100/40 could fire 450 8mm Nambu rounds a minute but it had a complicated design and often jammed. The Type 100/44 was a modified version that had resolved many of the problems and it could fire 800 rounds a minute.

  The Type 96 light machine gun could fire 700 7.7mm Arisaka rounds a minute. It was an air-cooled, gas-operated machine gun and was fed by a 30-round top mounted curved box magazine. The Type 92 heavy machine gun could fire a 7.7mm round up to 400 rounds a minute but it used a strip cartridge rather than a belt system and had a tendency to jam. This heavy weapon was tripod mounted and the three-man team usually operated it from a fixed position. The lighter Type 1 heavy machine gun had been introduced in 1941 but it too was usually fired from fixed positions.

  Japanese soldiers often used the Type 89 grenade launcher and although it was called the knee launcher by the Marines, it was a mortar type weapon with short tube supported on a rod and base. The operator held it against the ground and dropped the grenade down the tube and the timer was designed to explode the grenade above the ground. It was conveniently portable, easily concealed, had a rapid rate of fire and could be fired out of caves or slit trenches. The Type 97 81mm mortar had a range of 2800 metres while the modified Type 99 had the recoil mechanism removed to make it lighter. Type 94 90mm and Type 96 150mm mortars had a range of 4000 metres and both had Type 97 versions, again with the recoil mechanism removed to make them lighter. They were often used in fixed positions on Iwo Jima, as were a range of mortars over 150mm calibre. Although the Japanese Army had a small number of flamethrowers, they were rarely used in the defensive role.

  Kit

  The Japanese deployed a number of different artillery pieces and while the Type 94 75mm mountain gun could be broken down and carried as a pack artillery piece, the Type 95 75mm Field Gun needed towing. The Type 92 100mm cannon and Type 4 150mm howitzer would have been virtually immobile during the battle. There were a variety of fortress cannons and howitzers deployed in bunkers and fortified caves along the coast, the majority overlooking the landing beaches.

  Both the Type 97 Chi-Ha tank armed with a 47mm gun and the Type 95 Ha-Go armed with a 37mm gun, were deployed on Iwo Jima. Both types were small and only had thin armour no more than 25mm thick. They were no match for the Marines’ Shermans and they were often half buried or hidden in gullies in the hope that they could shoot at close range.

  The 26th Tank Regiment was sailing from Japan to Iwo Jima in July 1944 when its convoy was intercepted. On 18 July the Nisshu Maru was torpedoed near Chichi Jima by the American submarine, USS Cobia, and while only two of the 600 crew members were drowned, all 28 tanks were lost. It was December before 22 replacement tanks arrived.

  Tactics

  Japanese tactics changed as the battle progressed. Before the invasion, General Kuribayashi focused his attentions on driving the Marines off the island. Previous experience had shown that the US Navy and Air Force could devastate fortifications along the beach. Instead positions covering the beach would be camouflaged and remain silent until the waves of assault troops were ashore. They would open fire as soon as the Marines moved off the beach.

  Japanese tanks were designed to operate in jungle areas and were much smaller and lighter than their American counterparts. This crew had hidden their machine out of sight ready to catch the advancing Marines in the flank. (NARA-127-GW-143230)

  While no beach or underwater obstacles were used, the beach area was protected by mines and anti-tank ditches. Dozens of camouflaged bunkers, pill boxes and spider holes, all linked by trenches or tunnels, covered the approach to Airfield 1. Heavier artillery pieces, field guns and mortars were positioned on the slopes of Mount Suribachi and the Quarry, overlooking the flanks of the beach. They could either fire at the troops as they moved inland or at the landing craft while they unloaded troops and equipment along the shoreline. Kuribayashi was hoping that the devastating crossfire from hidden positions would force the Marines to evacuate the beachhead before nightfall.

  However, V Amphibious Corps was able to secure a beachhead and force its way inland. They found that the Japanese were dug in everywhere, having spent months building and camouflaging their defensive positions. Each one had been carefully positioned to cover likely avenues of advance and provide interlocking fields of fire.

  The Marines needed to use every trick in the book to outwit their cunning enemy. Here they are trying to fool a sniper into giving his position away by raising a helmet on a rifle. (NARA-127-GW-113649)

  The Japanese soldiers hid underground during barrages and airstrikes and dragged their support weapons to the surface as soon as they ended, ready to engage the advancing Marines. They wanted to draw the Marines in and engage them in close combat, so that they could not use their heavy support weapons or call down artillery or air strikes. It meant that ground had to be captured in close combat with the aid of tanks, flamethrowers and demolitions. Many Japanese positions only fell after vicious hand-to-hand fighting. When weapons became clogged with volcanic ash soldiers resorted to fighting with rifle butts, knives, hand grenades, picks and entrenching tools.

  If the Japanese were trapped, they refused to surrender, choosing to fight to the death or commit suicide. It meant that the Marines suffered heavy casualties in the deadly war of attrition. Often the Japanese soldier
would evacuate his position at the last moment, withdrawing along tunnels or caves to a new hiding place. 4th Division’s Intelligence Officer summarised the hit and run tactics used by the Japanese:

  The enemy remains below ground in his maze of communicating tunnels throughout our preliminary artillery fires. When the fire ceases he pushes Observation Posts out of entrances not demolished by our fires. Then choosing a suitable exit he moves as many men and weapons to the surface as he can, depending on the cover and concealment of that area, often as close as 75 yards from our front. As our troops advance toward this point he delivers all the fire at his disposal, rifle, machine-gun, and mortar. When he has inflicted sufficient casualties to pin down our advance he then withdraws through his underground tunnels most of his forces, possibly leaving a few machine gunners and mortars.

  Sometimes the Marines worked all day long, destroying pillboxes and caves, with hardly a shot being fired; then the Japanese emerged after dark to attack.

  To begin with the Japanese artillery and heavy mortars were dug in and camouflaged while their crews selected and calculated the ranges to likely targets. With the Marines controlling the air, it was important only to fire when necessary because a lack of transport meant it was often impossible to move a heavy weapon to a new position. Once a battery position had been spotted, it was targeted until destroyed by air strikes, naval bombardments and artillery fire. The amount of Japanese artillery fire rapidly reduced during the final stages of the battle as the Marines pushed the infantry back, capturing key observation points and battery positions.

  The few Japanese tanks on the island were generally kept hidden and deployed in a semi-static role. Once they had stopped an attack, they would move to a new hidden position. Meanwhile, the Japanese soldier had to be proactive to stop tanks getting close to their emplacements, particularly the hated flame tanks. They used antitank mines and ditches to stop tanks or force them to drive in front of an anti-tank position. Close-quarter attack units also crept up on a tank and then jumped out to place charges in its tracks or against weak side or rear armour. The tactic was suicidal but acceptable to the Banzai mentality of the Japanese soldier. These close-quarter attack units were also used to infiltrate the Marine lines so that they could attack command posts, communications installations or artillery positions.

  THE DAYS BEFORE THE ASSAULT

  There was a large beach on both sides of the long southern neck of the island but the American planners advised landing only on the southeast side. Prevailing northerly or north westerly winds generated rough surf on the southwest beaches, creating dangerous conditions for landing craft and amphibious vehicles. On 8 January 1945 V Amphibious Corps revised its assessment and believed that landing craft could transfer unloading operations to the southwest beaches if the wind changed direction.

  The plan was for 4th and 5th Divisions to land side-by-side on the southeast beaches, with 26th Marines waiting offshore as the Landing Force reserve. 3rd Division had been slated as Expeditionary Corps reserve and it would wait off Iwo Jima’s coast until ordered ashore. While the divisions had their own organic artillery, limited space on the beachhead meant that 1st Provisional Field Artillery Group would be limited to two battalions of 155mm howitzers. V Amphibious Corps would have to rely on close air support and naval gunfire to compensate for the lack of heavy artillery. 138th Anti-aircraft Artillery Group would land as soon as possible to provide protection for the beachhead.

  The Invasion Plans

  Major General Keller E. Rockey’s 5th Division would land on the southern section of the beach, codenamed Green and Red. Colonel Harry B. Liversedge’s 28th Marines would land on the left on Green 1 Beach, advance across the narrow neck of the island and then turn southwest to cut Mount Suribachi off from the rest of the island. Colonel Thomas A. Wornham’s 27th Marines would land on the right, on Red 1 and Red 2 Beaches, cross to the opposite shore and then advance northeast along the west side of Airfield 1. 1/26th and 3rd/28th Marines would be released from the division reserve when required and land on Red or Green Beaches. Colonel Chester B. Graham’s 26th Marines would be ordered forward from corps reserve when necessary. Colonel Louis G. DeHaven’s 14th Marines were the division artillery and gun crews would occupy designated battery positions as soon as they were captured.

  Major General Clifton B. Cates’ 4th Division would land on the northern section of the beach, codenamed Yellow and Blue Beaches. Colonel Walter W. Wensinger’s 23rd Marines would land on Yellow 1 and Yellow 2 Beaches and advance across the west half of Airfield 1 before turning northeast towards Airfield 2. Colonel John R. Lanigan’s 25th Marines would land on Blue 1 Beach and clear the rest of Airfield 1, Blue 2 Beach and the Quarry. Colonel Walter I. Jordan’s 24th Marines would be called forward from 4th Division reserve when necessary and land either on Blue or Yellow Beach. Colonel James D. Waller’s 13th Marines were the division artillery and gun crews would occupy designated battery positions as soon as they were captured, like the 14th.

  Major General Graves B. Erskine’s 3rd Division was due to be released from Expeditionary Troops Reserve on or after D-plus-1. 9th Marines would land on Yellow Beach while 21st Marines would land on Red Beach.

  Aerial reconnaissance showed that the Japanese defences covering the beach had been considerably strengthened over the winter, resulting in last minute changes to the landing plans. General Schmidt wanted to extend the three-day naval bombardment based on previous bad experiences. General Smith also wanted 5th Marine Division to take Mount Suribachi quickly and 26th Marines was transferred from corps to divisional reserve while one battalion was assigned to 5th Division ready to go ashore if necessary. One of 3rd Marine Division’s RCTs took 26th Marines’ place in corps reserve.

  The plan was for 68 LVT(A)4s (amtracks) armed with 75mm howitzers to hit the shoreline at H-Hour and drive up onto the first terrace of the beach ready to give covering fire while waves of LVTs delivered the Marines to the shore. 4th and 5th Tank Battalions would wait offshore in Landing Ships until called forward, to avoid congestion on the beach. A similar plan to land on the western beaches was prepared in case the wind changed direction. A small island off the west coast called Kangoku Rock would be also be checked out and used as an artillery site if suitable.

  This aerial view over the south tip of the island, looking from the west, shows how V Amphibious Corps had to develop both beaches. The area between was crammed with all manner of headquarters, logistics units, stores and medical facilities. (NARA-111-SC-206876)

  MARINE COMBAT ORGANISATION

  The acronym RCT is an American military term for the Regimental Combat Team. On Iwo Jima a Combat Team was composed of a Marine regiment and all the attached combat and support units, including tanks platoons, specialist engineers, logistics units and medical facilities. While the Regiment was responsible for carrying out the divisional orders in its sector, the attached units could be transferred between regiments at short notice.

  Gathering Intelligence

  A lot of intelligence about Iwo Jima was already available when V Amphibious Corps began planning for Operation Detachment. Data had been gathered for air strikes by carrier planes in June and July 1944 and it was used to prepare preliminary situation maps and beach studies; however, more detailed information was needed. Documents captured on Saipan in June 1944 gave General Schmidt’s staff an idea of the Japanese Order of Battle on Iwo Jima. However, additional troops had been moved onto the island ready to repel the invasion and V Amphibious Corps intelligence section had to collect new information.

  A total of 371 aerial photography sorties were flown over Iwo Jima during the weeks that followed and they charted the progress of the Japanese defences as well as the damage done by bombing. The staffs of the Amphibious Forces, Pacific, and the Fleet Marine Force, Pacific, produced a Joint Situation Map on 6 December 1944 and at the end of January 1945 their photo interpretation officers met on Guam to collate information. A few days later they produced the ‘Joint Enemy
Installation Map’, identifying all known Japanese positions on the island.

  The Navy also wanted to know more about Iwo Jima, and the submarine Spearfish had been observing the coast since early December 1944. The commander spied on the island and took photos of the shoreline, concluding that while tractors could cross the beach, wheeled vehicles would struggle to get off it. He also noted gasoline drums had been half buried close to the waterline, ready to be set on fire as soon as the Marines stepped ashore.

  The overall conclusion was that the Japanese had nine battalions deployed in extensive field works across the island. Major General Osuka had divided his defences into four sectors, with one infantry battalion manning each sector; a fifth battalion was deployed around the coast. The expectation was that the remaining four battalions would be held in reserve ready to counterattack. If the counterattack failed the survivors would probably fall back to the high ground at the northeast end of the island and fight to the last man.

  JAPANESE DEPLOYMENT

  Mount Suribachi Sector 312th Independent Infantry Battalion

  Southern Sector 309th Independent Infantry Battalion

  Western Sector 311th Independent Infantry Battalion, 1st Company 26th Tank Regiment

  Eastern Sector 314th Independent Infantry Battalion, 3rd Company 26th Tank Regiment

  Northern Sector 3rd Battalion, 17th Independent Mixed Regiment, 2nd Company 26th Tank Regiment