Page 713

Chapter 12: Summary1

The battle of Iwo Jima requires a detailed analysis because it was unique in certain respects. First, it featured the employment of three Marine divisions (less one regiment) under a single tactical Marine command, the largest body of Marines committed to combat in one operation during World War II. Secondly, enemy resistance under General Kuribayashi was such that American casualties sustained in this operation exceeded those of the Japanese. Out of the savage struggle for eight square miles of inhospitable island emerged convincing re-affirmation of the fact that once air and naval superiority had been gained over and around an objective, Marines could make a landing, gain a foothold, and extend it until the enemy was driven into a severely restricted area. There, he could be annihilated, regardless of the size and number of his guns or the quality of his defense. The then Secretary of the Navy, James V. Forrestal, gave voice to his “tremendous admiration and reverence for the guy who walks up beaches and takes enemy positions with a rifle and grenades or his bare hands.”2 Yet it would be folly to assume that sheer courage alone, even when coupled with material superiority, was the decisive factor that led to certain, if bloody, victory. Even Admiral Spruance’s statement, that “in view of the character of the defenses and the stubborn resistance encountered, it is fortunate that less seasoned or less resolute troops were not committed,”3 only touches on one important facet within the overall picture.

The reason Marines were able to prevail against a firmly entrenched enemy, who knew in advance of the impending attack, can be found in detailed and meticulous planning. The plans for the Iwo Jima operation possibly were the most far-reaching for any operation in the Pacific area up to this time in World War II. Preparations extended not only to American bases in the Marianas, the Marshalls, and the Hawaiian Islands but all the way back to the mainland of the United States, “from whence came hundreds of new ships to transport the troops to the

Page 714

objective. Most of these ships were under construction less than six months before the target day, and some of the smaller ones existed at that time only in blueprint form.”4 In fact, with one exception, the transports carrying the 4th and 5th Marine Divisions to the objective were either under construction or being commissioned as late as 31 October 1944.5 It is typical of the long-range planning preceding Operation DETACHMENT that many of the participating vessels had to be transferred from the European Theater to the Pacific prior to the invasion.

At Iwo Jima, as in similar operations, two command ships were employed so that, in the event one command ship became a casualty, the commander aboard the other could take over. In this case Admiral Turner, as Expeditionary Force Commander, was embarked in a command ship with General Holland Smith as Expeditionary Troops Commander, while Admiral Harry Hill, as Attack Force Commander and General Schmidt, as Landing Force Commander, were embarked in the other command ship. The VAC chief of staff was to comment on the command relationships at Iwo Jima in these terms:–

The Navy was of course in command afloat. The Landing Force Commander assumed command ashore after setting up a command post there. General Holland Smith could have assumed command ashore by setting up a headquarters ashore. He did not do so, nor to the best of my knowledge did he ever issue any command to the troops ashore. In fact, he had only a skeleton staff, and as he remarked to General Schmidt the only reason he went on the expedition was in case something happened to General Schmidt.6

When Admiral Nimitz coined his phrase about the uncommon valor displayed by Americans who served on Iwo Jima, he was referring not only to the Marines who did the lion’s share of the fighting, but also to personnel of the U.S. Army and Navy, on the ground, at sea, and in the air, who supported them. According to one historical evaluation:–

Without supplies and medical care the assault would have ground to a halt, and without close air, naval gunfire, and artillery support, there would have been no neutralization to permit the tank-infantry demolition teams to advance.7

Based on sound doctrine, training, and experience, the participating services and arms developed excellent teamwork that could not have been surpassed. In view of the depth and extent of the Japanese defenses, naval gunfire had only a limited effect. Long and medium range bombardment accomplished little, and even area fire failed to do much” damage to underground enemy defenses. Following the operation, Admiral Blandy was to make this comment in dealing with the preliminary bombardment:–

It was not until fire support ships, their spotting planes, and the support aircraft had worked at the objective for two days, had become familiar with the location and appearance of the defenses, and had accurately attacked them with close-range gunfire and low-altitude air strikes, that. substantial results were achieved.8

Page 715

This statement leads directly into the only deep-seated controversy to develop from the Iwo Jima operation, that of the duration of the naval gunfire support.9 This dispute still simmers more than 25 years after the event, and it appears doubtful that it will ever be completely resolved to the satisfaction of all concerned. The issues in this case are clear:–

Previous amphibious assaults had amply demonstrated that against such defenses only deliberate, short-range destructive fire would be effective. And both Marine and Navy commanders knew that even under the most favorable conditions this method of bombardment was extremely time consuming.10

Then, as now, the lines in the naval gunfire controversy were clearly drawn, and little room remained for compromise. Most of the Marines who fought on Iwo Jima give credit to the high degree of precision which naval gunfire had reached since the early operations of world war II, but at the same time firmly agree with one former Marine participant who commented that “undoubtedly, longer bombardment before D-Day would have materially shortened the battle and saved many lives.”11

It would serve no useful purpose at this time to rekindle the barely submerged passions that have occasionally popped to the surface regarding this subject. Even minute inspection of all available data does not lead to concrete and infallible conclusions that would stand up to prolonged investigation. Thus the controversy simply becomes one of the vantage point occupied by each of the participants at the time of the operation. To a Marine who went ashore on D-Day or later and saw the carnage wrought by the Japanese shore guns among his comrades, it becomes inconceivable that, regardless of time limits and restrictions on ammunition expenditure, more was not done to assure that enemy shore defenses were knocked out prior to the landings. This feeling is born of a mixture of anger and frustration, known only to those who have been exposed to superior enemy firepower for any length of time, bereft of the possibility to reply at once and in kind. Little has yet been devised to relieve the initial feeling of helplessness experienced by the rifleman who hits a hostile beach under the muzzle of still functioning enemy guns.

From the Navy’s vantage point, the situation was slightly different. In the first place, the Iwo Jima operation had been tightly wedged in a time frame between the invasion of Luzon and the coming assault on Okinawa. Under such pressure, perhaps the best that could be achieved was neutralization, not destruction of the enemy artillery as

Page 716

desired by the Marines, The naval viewpoint is summed up in this statement:–

There is no reason to believe that ten or even thirty days of naval and air pounding would have had much more effect on the defenses than the bombardment that was delivered. The defenses were such, by and large, that the only way they could be taken out was the way they were taken out, by Marine Corps infantry and demolitions. ... Aerial bombardment and naval gunfire simply could not reach underground into the maze of caves and tunnels, yet these had to be cleared or sealed shut before the island could be secured as an air base on the Bonins’ road to Tokyo.12

This line of reasoning carries little weight with Marines who faced the maze of virtually untouched pillboxes and covered emplacements between the Southern and Central Airfields and those to the east and west of the latter. These defenses were situated in more or less open terrain that was largely accessible to direct fire at relatively short ranges from vessels standing offshore. It required the herculean efforts of men in eight days of costly fighting to reduce these fortifications. in the words of General Harry Schmidt: “With additional time available for pre-D-Day firing naval guns might have accomplished much in this area to facilitate its capture.”13 The Navy has contended that:–

... heavy ammunition replenishment at sea had not been service tested and the bombarding ships were far from a supply base and could not carry enough ammunition for the prolonged bombardment desired by the Marines.14

Neither the validity of this contention nor the flow of time itself have done much to cool the passions of Marines who underwent the trial by “fire and steel” on Iwo Jima. There simply appears to be no way to equate the feelings of men who have watched their comrades and friends torn apart by enemy weapons with the cold realities of logistics, statistics, and strategy. Thus, for the purposes of this history, the controversy must remain unsolved.

Let it be said for the record that, once the Marines had gone ashore, naval gunfire was furnished to the satisfaction of the landing force. In this connection, the positive must be accentuated. One account summed up the quality of naval gunfire support in these words:–

The cooperation of these vessels, from the largest battleship to the small, specialized gunboats, was excellent. The nature of the terrain continued to limit their effectiveness, however, and in most instances only neutralization was obtained. Supporting ships and craft were quick to observe enemy activity and take it under fire after first checking with units ashore to determine that the shelling would not endanger friendly troops.15

General Kuribayashi himself unwittingly paid tribute to the accuracy of American naval gunfire support when he passed word to his superiors that the power of bombardment from ships required reevaluation:–

The beach positions we made on this island by using many materials, days and great efforts, were destroyed within three days so that they were nearly unable to be used again. ... Power of the American warships and aircraft makes every landing operation possible to whatever beachhead they like,

Page 717

and preventing them from landing means nothing but great damages.16

The same factors that limited the success of naval gunfire also proved a hindrance to the effectiveness of the preinvasion air bombardment. The bombing of Iwo Jima and adjacent islands over a period of several months by high-altitude B-24 bombers based in the Marianas had prevented the Japanese from enjoying the unrestricted use of the two airfields on Iwo Jima. On the other hand, the increasingly heavy air raids did much to drive the enemy underground. In evaluating the results of this extensive bombing, Air Force historians themselves conclude that, despite “the heavy going over the island had received, weather conditions and the topography of Iwo Jima had rendered the results much less decisive than had been expected.”17

While bombers of the Seventh Air Force had concentrated mostly on the destruction or neutralization of the operational airfields in the Bonins, Admiral Durgin’s carrier pilots assaulted those defenses that would interfere with the amphibious assault and the subsequent push inland. Deficiencies in the armament of the support aircraft and the small size of the bombs they carried severely limited the effectiveness of these attacks. Even when a target had been pinpointed, the bombs proved too small to smash buried blockhouses. The use of napalm, which was badly needed to strip enemy positions on Iwo Jima of their natural cover, also proved disappointing when, in numerous instances, the liquid failed to ignite.

On D minus 1, as the weather cleared and the carrier pilots hail become familiar with the terrain and the targets on the island, more was accomplished than during the two preceding days. Japanese defenses on the slopes of Mount Suribachi and emplacements above the East Boat Basin proved to be particularly attractive targets for the Navy flyers, who not only bombed these targets but also strafed them with 5-inch rockets. The latter were effective due to their accuracy but lacked the destructive power required against the formidable enemy fortifications. In evaluating the effectiveness of these air strikes, the advance commander of the air support control units only allowed that they “conceivably weakened the areas commanding the landing beaches.”18

Greatly contrasting with the inconclusive results obtained from the above air strikes was the support furnished by the pilots of Task Force 58 on D-Day. The Marine and Navy flyers, whose heroic efforts were clearly visible to Navy personnel and Marines about to hit the Iwo Jima beaches, drew vociferous praise. As long as Vice Admiral Mitscher’s carriers remained at Iwo, the carrier squadrons were able to furnish all the ground support requested, but on D plus 4, when the large carriers departed, a shortage of aircraft quickly developed. Planes needed for ground support had to be diverted to such other duties as antisubmarine patrols, strikes against other islands in the Bonins, and sea rescue operations.

As a rule, response of aviation to requests from ground units was quick,

Page 718

though on many occasions more than an hour elapsed before the supporting aircraft appeared on the scene. Even then, the normally overcrowded Support Air Request Net proved to be the weak link in obtaining air strikes without undue loss of time. It is ironic that Iwo Jima Marines were denied the close support that was to become the trademark of Marine aviation, while Army troops in the Philippines at this time were reaping the benefits from exactly that type of support furnished by Marine dive bombers.19 As in other campaigns, each echelon intervening between the ground unit requesting air strikes and the pilots furnishing the support resulted in loss of time and attendant confusion. Once again, the crux of the matter was control of support aircraft by the ground units, something that higher headquarters were still most reluctant to grant. At the conclusion of operations in the Marshalls and the Marianas:–

Marine commanders pressed hard for increased use of Marine air in close support. They wanted pilots, planes, and a control system oriented to ground needs and quickly responsive to strike requests. The winds of change were in the air in the summer of 1944 and refinements in close support techniques were coming. Operations later in the year saw planes bombing and strafing closer to frontline positions and evidenced a steady increase in the employment of Marine squadrons in this task as well as in air-to-air operations.20

In the case of Iwo Jima, it is significant that all three participating Marine divisions unanimously recommended that in future operations, the air liaison parties be given more direct control over aircraft during close support missions.21 The start made in this direction during 1944 proved to be only the first step in an uphill and time-consuming struggle, some of which still had not been resolved at the time of the Korean War.

Throughout the Iwo operation, air observers played an important role. Fighter-type aircraft, flown by especially trained pilots of VOC-1, augmented the float planes normally used to spot naval gunfire. On an improvised basis, Marine artillery and tactical observers operated from carrier-based torpedo bombers until the small observation planes of the VMO squadrons had gone ashore, In spite of the difficulties, the latter held their own. One historical account was to sum up their performance this way:–

Like other Marines on Iwo, the VMO squadrons had to prove they could take it. The little planes and their pilots and ground crews were subjected to everything from kamikazes to artillery fire to faulty launching gear, and all of these took their toll.22

Aside from difficulties encountered with the overcrowded Support Air Request Net, communications on and around Iwo Jima functioned exceedingly well. The multiplicity of wire and radio nets complicated the situation, and there were instances of enemy jamming and interference between sets. The performance of communications personnel

Page 719

was rated as excellent. Wire was widely used and with good effect. Radio bridged the gap where wire could not be employed. It was a far cry from the unsatisfactory radio equipment that had been employed in the early operations in the Pacific, notably at Tarawa. The short distances involved at Iwo Jima, as well as the very slow rate of advance, eased the burden of maintaining and expanding communications: there never was any serious breakdown. As in previous operations, the Navajo talkers performed an outstanding service, and their employment contributed materially to the effective and speedy transmittal of urgent classified radio traffic without danger of enemy interception.23

Contributing to the overall success of the Iwo Jima operation was close coordination between the supporting arms. The systems of coordination used at the headquarters of the three divisions were similar, though General Erskine’s division maintained an installation known as the “supporting arms tent,” whose organization and functions have been described in these words:–

The basic method of coordination between supporting arms was to achieve close personal liaison on all levels. Targets were freely interchanged according to the method of attack best suited, and, whenever operations were in progress or prospect, the artillery, naval gunfire, and air officers were together or readily accessible to each other by wire. Plans for scheduled fires or pre-King-Hour preparations were habitually prepared jointly, and so presented to the G-3, Chief of staff, and the Commanding General. Much of the success achieved may be traced to the separate maintenance of a “supporting arms tent,” so-called, adjacent to the G-3 Section. In this center, wire communications converged from the division switchboard, from the similar 5th Amphibious Corps establishment, from the division artillery fire direction center, and from the naval gunfire and air radio centrals. It was thus possible to establish any sort of communications necessary, and to plan without interruption, while being within a few steps of the G-3 Section.24

Throughout the operation, close liaison was maintained between the corps artillery, air, and naval gunfire officers and the Commander, Landing Force Air Support Control Unit, in the Joint Operations Rooms on board the USS Auburn and subsequently through facilities of the supporting arms tent at VAC headquarters ashore.25

The performance of the shore based artillery at Iwo Jima deserves special mention. Standard tactics, vindicated in previous operations, were employed. It quickly became evident, though, that the 75-mm and the 105-mm howitzers of the division artillery battalions were far from adequate for the destruction of the type of emplacements encountered on the island. In fact, the 155-mm guns and howitzers of the corps artillery frequently had to score up to a dozen hits in one place before they caused major damage to some of the strongest enemy installations.26 In performing its mission, artillery was further handicapped by limited observation, which often prevented forward observers from seeing more than 200 yards ahead. As a result, great dependence was placed on aerial spotting, particularly for counter-battery

Page 720

and destruction fire. Despite such limitations, officers and men of the corps and division artillery carried out their mission in an exemplary fashion.

From 23 February to 1 March, the VAC artillery fired its maximum number of missions, most of them counterbattery. During the first four days in March, normal missions were fired, but the amount of ammunition expended had to be reduced since expenditure exceeded the inflow. After a breather on 5 March, when no preparations were fired, both the corps and division artillery made a maximum effort on the following day. On 6 March, a heavy time-on-target preparation was fired in which 11 division and corps artillery battalions participated. Despite the higher expenditure of ammunition, amounting to 2,500 rounds for the corps and 20,000 rounds of 75-mm and 105-mm for the division artillery, this massive concentration had no decisive effect.

In discussing the performance of the artillery during the Iwo Jima operation, General Schmidt underscored another aspect:–

A feature of the employment of artillery in the Iwo Jima operation not noted in the report was that the bulk of the artillery ashore was sited around Airfield No. 1. During the greater portion of the time artillery was firing continuously (approximately 450,000 rounds fired during operation) at the same time Airfield No. 1 was being used for aircraft operation to capacity. This was also true even after Airfield No. 2 began operating. It is considered remarkable that no friendly planes were hit and that aircraft operations were not impeded by our artillery or vice versa. The method of control employed for the protection of planes taking off or landing was simply to have an individual of the firing unit placed to observe whether any aircraft were in the line of fire and to give warning if that were the case.27

Engineer support to VAC during Operation DETACHMENT was generally excellent. The task of constructing and maintaining roads in the VAC area was assigned to the 2nd Separate Engineer Battalion, which also accomplished the preliminary work in restoring the Southern Airfield. It was the work carried out by this unit that enabled small observation aircraft to operate from this airfield by D plus 7. The further completion of additional strips on this airfield was the shared accomplishment of these Marine engineers and the 62nd Naval Construction Battalion.

In addition to executing their important task of constructing roads, operating water points, and erecting various buildings and supply dumps, Marine engineers also had a combat mission to perform. The latter was the responsibility of the division engineers who cleared mines, dozed trails that enabled tanks to approach the front lines, and performed such other jobs as were designed to help the infantry advance over treacherous terrain. Much of this work was carried out under direct enemy observation and fire. Engineers, individually or in small groups, joined the infantry in demolishing the numerous enemy caves and strongpoints. For the hard-toiling engineers, there were only two bright sides to the operation: the sand-clay fill obtained from quarries on the island made excellent road

Page 721

construction material; and “engineer operations were further facilitated in that no bridges were required.”28

The employment of amphibious vehicles on Iwo Jima featured a greater variety than had been previously used, including armored amphibian tractors, amphibian trucks, and sea-going jeeps. First to hit the beach were the LVT(A)s of the 2nd Armored Amphibian Battalion, equipped with one 75-mm howitzer, one .50 caliber machine gun mounted in the turret ring, one .30 caliber machine gun mounted in front of the assistant driver, and one .30 caliber machine gun mounted in front of the howitzer loader. Once within effective range of the beaches, the LVT(A)s were to open fire with all weapons. After going ashore, these vehicles were to move about 50 yards inland and protect the following assault waves by firing on targets to their front and flanks.

Almost immediately, the steep terraces and the composition of the beaches caused the vehicles to bog down. A few made it across the first terrace only to become stalled on the second. While neither the LVT(A)s nor the following LVTs containing the assault troops drew voluminous enemy fire, progress of the LVTs upon reaching the beaches also was stymied by the loose volcanic ash and the steep terraces. Since in many instances the beach was very narrow and the surf broke very close to the steep ledge, many LVTs swamped. Some of the vehicles were thrown broadside on the beach where sand and salt water filled them.

It soon became apparent that the volcanic cinders and sand would not support wheeled vehicles. Only the LVTs, caterpillar tractors, and other tracked vehicles had a chance of making it inland across this treacherous ground. As emphasized in one report: “Supplies and equipment were hauled from ships directly to the front lines, and had it not been for LVTs the troops ashore could not have been supplied during the early stages of the landing.”29 Because of their importance to the logistics effort, it became necessary to use these vehicles around the clock during the early phase of the operation.

One of the new types of equipment to be used by all three Marine divisions during the Iwo operation was the 3½-ton Cleaver-Brooks trailer, employed to haul cargo and medical supplies. Major difficulty was encountered in launching these amphibious trailers in the rough seas and getting them across the steep terraces. LVTs were generally able to bring the trailers ashore, but attempts to have the DUKWs perform this service resulted in the loss of both the trailer and DUKW. While comments on both the LVT and DUKWs were generally favorable, VAC concluded: “The amphibian trailers did not prove to be of any particular or specific help during the operation.”30

The amphibian truck, the DUKW, had the primary mission of bringing the division artillery ashore on D-Day. Personnel to operate these vehicles was furnished both by the Marine Corps and the U.S. Army. The difficulty in landing

Page 722

the artillery resulted from the high surf and the tactical situation ashore. While some of the DUKWs landed without difficulty, others were swamped after exhausting their limited fuel supply or developing mechanical problems. Others that were overloaded, sank almost immediately after disembarking from the LSTs. Many of the DUKWs ran afoul of the steep beaches and broached when the front wheels dug down into the sand or volcanic ash and could not get sufficient traction to pull the vehicles forward. Following the initial landings, DUKWs hauled supplies, especially ammunition, evacuated the wounded, and performed mail and messenger runs.

Another amphibious vehicle that proved its worth during the Iwo operation was a light cargo carrier, dubbed the “weasel.” This tracked carrier had been issued to the three Marine divisions participating in DETACHMENT in November 1944. At Iwo Jima, the Weasels hauled light supplies, evacuated the wounded, and were used to string telephone lines. Their versatility in overcoming loose sand and the steep terrain made them the ideal all-purpose vehicle, and they were soon pressed into service as messenger or command cars or for the purpose of hauling trailers and small artillery pieces over terrain that wheeled vehicles could not negotiate. In addition to their versatility, the Weasels offered a poor target for the enemy because of their speed and low silhouette. The only difficulty encountered with these vehicles was at sea, where the high swells occasionally proved more than they could handle. It is interesting to note that a total of 133 DUKWs were destroyed during the Iwo Jima operation, amounting to 53 percent of those employed; only 9 Weasels were lost in combat, accounting for 13 percent of the number that were disembarked. The remaining 61 vehicles remained in operating condition until the Marines left Iwo Jima.31

One of the most successfully handled, yet difficult aspects of the Iwo Jima operation pertained to the treatment and evacuation of the wounded. The bitterness of the fighting, from the first to the last day of battle, coupled with the large number of men simultaneously locked in combat, placed an extremely heavy burden on the medical units, both ashore and afloat. During the initial days of the operation, doctors and corpsmen alike occupied a precarious foothold on beaches that were exposed to enemy fire of all calibers. As often as not, the medical personnel ashore became casualties themselves, especially the corpsmen attached to the combat units or the beach evacuation stations. It was not a rare occurrence for corpsmen to be hit as they carried litters with wounded to the rear or cared for the wounded at the evacuation stations. Casualties among medical officers and corpsmen were correspondingly high: 738, among them 197 killed.32

In order to take care of the Iwo Jima casualties, medical plans had been drawn up well in advance of the operation. As a result, during the first nine days of the battle, once a casualty had arrived

Page 723

at one of the evacuation stations, he could expect prompt evacuation to one of the hospital LSTs that were lying 2,000 yards offshore. These LSTs acted as collection centers from which the casualties were forwarded to APAs and hospital ships. Initially, the transport of casualties from the beaches to the hospital LSTs was handled by landing craft, LVTs, and DUKWs. However, increasingly rough surf eventually prevented the use of small landing craft, and amphibious vehicles were employed exclusively. The DUKWs, in particular, proved useful because they handled well in the surf and alongside the big ships, and patients were more comfortable inside the DUKWs than inside the wet, bouncing LVTs.33

In addition to the hospital ships Bountiful, Samaritan, and Solace, and the hospital transport Pinkney, the LSV Ozark was pressed into service as an auxiliary hospital ship. Together with transports that were leaving the combat area, these ships evacuated 13,737 casualties.34 An additional 2,449 men were airlifted to the Marianas.

Because of the small size of Iwo Jima, distances from the front lines to battalion aid stations were invariably short. Nevertheless, the difficult terrain and constant exposure to enemy fire made even such short distances extremely hazardous both for corpsmen and patients alike. At first, LVTs and Weasels were widely used in order to bring casualties to the beaches; during the latter phase of the operation when roads had been constructed that were passable for wheeled vehicles, jeeps oftentimes carried casualties to the rear.

The availability of whole blood to treat the victims of extensive loss of blood and shock undoubtedly saved many lives. Such transfusions of whole blood had not been used in any previous Central Pacific campaigns. Landing force medical facilities alone used more than 5,000 pints. By D plus 25, 12,600 pints had been used, nearly one pint for every patient evacuated.35 Once the situation on the beaches had stabilized, hospital tents went up wherever a place for them could be found, and as electric power became available, the shore based hospitals were able to operate around the clock. In evaluating the efficiency of the medical care provided at Iwo Jima, VAC was to report:–

The medical service for the Iwo Jima operation approached nearer the ideal than during any previous operations in the Central Pacific Area, and it is firmly believed that the casualties received the maximum medical care possible commensurate with the military situation.36

One of the most difficult problems that had to be overcome during Operation DETACHMENT was that of supplying the landing force. Heavy surf, the deep volcanic ash, the enemy’s complete coverage of the beaches with artillery, mortars, and small arms fire, and congestion at the beaches all combined to increase the complexity of logistics. Only the abandonment of carefully laid plans and timely improvisation saved the day, making possible an uninterrupted flow of supplies to the frontline units that kept the operation going.

Page 724

Iwo Jima provided a testing ground for the vehicles that shuttled back and forth through the heavy surf in an attempt to land badly needed cargo when and where required. Beyond that, it became a proving ground for men of the beach and shore parties, the frequently unpublicized and unsung heroes of the battle of logistics. Previously, little had been done to provide these parties with proper training, experience, and continuity of function. The force that went ashore on Iwo Jima included beefed-up pioneer battalions, which were further reinforced with men from the replacement drafts and division headquarters personnel, as well as U.S. Army port troops.

Taken as a whole, this conglomeration of units performed well in a situation which was considerably more complex than had been envisioned in the planning for the invasion. It had not been intended to bring any of these men, except for advance elements, ashore until the beaches were reasonably secure. Yet circumstances dictated a departure from previous plans and more than 10,000 of these service troops were landed on D-Day. Once ashore, under the most difficult circumstances, these men performed splendidly, though their presence added to the congestion and increased the number of casualties.

As it turned out, between 60 and 70 percent of the supplies unceremoniously dumped on the beaches were salvaged and either moved inland or incorporated into the hastily established beach dumps set up by forward elements of the division shore parties which went ashore with the fifth and sixth assault waves. These advance elements carried out their mission in an exemplary fashion despite the most adverse conditions imposed by the terrain and the heavy enemy fire. The casualties among these units were correspondingly heavy, some of them being reduced to half strength.

In order to keep the logistics effort from foundering in the deep volcanic ash, Marston matting and armored bulldozers had to be pressed into service. Once again, the American penchant for improvisation proved to be a decisive factor in getting troops and supplies off the crowded beaches. Marston matting was of tremendous value in serving as the only usable roadways over which vehicles could move inland during the initial phase of the assault. The armored bulldozer was employed on the beaches to level sand terraces and cut routes inland. Their steel plates protected both driver and engine from enemy fire. On northern Iwo, these machines and their drivers performed an equally important service in clearing roads into previously impassable terrain under fire.

The movement of supplies across the beaches was in no small way facilitated by the presence of Navy cranes, as well as other equipment designed to expedite the unloading of the cargo vessels. In this connection, the expertise of TF 53 and its commander proved invaluable. In line with his extensive logistical experience, Admiral Hill was keenly aware of the requirements that had to be met and had at an early time recommended that ample cargo handling equipment be available for Operation DETACHMENT.37 Despite all preparations, the

Page 725

tactical situation prevailing on Iwo Jima on D-Day caused the beaches to become so congested that on the following day underwater demolition teams had to be employed to assist in clearing lanes through the wreckage for incoming vessels.

It needs to be emphasized that, all difficulties to the contrary, no acute supply shortages developed for the assault troops, though in the days following the landings units were living from hand to mouth. Such shortages as did develop involved 60-mm mortar illumination shells, grenades, cylinders for charging flamethrowers, and ordnance spare parts. As an expedient, these items were flown to Iwo Jima from Saipan, the first extensive use of air supply by the Marines.38

The timing of the logistics support at Iwo Jima, an extremely important factor in an amphibious operation, proved to be well conceived and executed. Liaison teams from the 8th Field Depot, which constituted the VAC shore party, accompanied the 4th and 5th Marine Divisions ashore. As of 22 February, units of the field depot came ashore and rendered valuable service in assisting the divisional shore parties. Two days later, when VAC assumed control ashore, the field depot took over and the unloading continued without interruption. At this time, the beaches were still under enemy fire, which caused temporary work stoppages but proved unable to interfere seriously with the unloading. On D plus 6, 25 February, general unloading got under way. The opening of the western beaches to small landing craft on 2 March removed the entire unloading operation from the threat posed by variable weather conditions. Henceforth, the menace of heavy surf pounding the eastern side of the island could be overcome by switching shipping to the western beaches.

In evaluating the overall success of the logistics effort at Iwo Jima, it appears appropriate to comment:–

... the wonder is not that things were confused but that the vast quantities of supplies actually crossed the beaches so quickly. Expertly handled ship-to-shore communications and a high degree of coordination between Navy and Marine logistical control personnel afloat and ashore did much to overcome the difficulties inherent in the situation.39

The official VAC report dealing with Operation DETACHMENT echoes this sentiment and, speaking of the adversities facing the Marines that went ashore on Iwo Jima, concludes:–

The fact that these factors failed to impose any limitations on the conduct of operations reflects the highest credit on all concerned. Without the tireless support through unprecedented difficulties rendered by the expeditionary force and the supply agencies of the landing force, the sustained assault of the Corps would have been impossible.40

Finally, a word about the tactics employed on Iwo Jima both by the assault force and the defending Japanese. The small size of the island permitted little or no maneuverability to either force, and once the first Marines had

Page 726

gone ashore, the fighting that was to typify the entire operation was dictated by General Kuribayashi, whose defensive organization “was the most intelligent and complete one yet encountered.”41 Basically, the Japanese conducted a position defense which was effective, intense, and notable for its economy of forces. There was no employment of mobile reserves, nor was there a withdrawal through a series of defensive lines. All precautions had been taken to assure that enemy troops were not exposed to the American supporting arms. General Kuribayashi’s defense was simple; it was this very simplicity that made it so effective.

The enemy plan was based on the concept that a maximum number of weapons of all calibers were to fire more or less continuously from well-concealed and -protected positions until they were destroyed. Almost from the beginning of the operation the American supporting arms were handicapped by the geographical limitations of the island, the character of the terrain, and the strength of the enemy defenses. The heavier Japanese installations, in particular, often proved impervious to field artillery of light and medium calibers and required the destructive power of main battery naval gunfire. During the latter phase of the fighting, the proximity of the Marines to enemy positions frequently denied them the benefit of adequate heavy fires or bombardment.

Even though few underwater obstacles interfered with the Iwo Jima landings, the minefield ashore were the strongest yet encountered in the Pacific Theater, indicative of the progress made by the Japanese in this sphere of defensive warfare. The operation also saw the first use of antipersonnel mines by the Japanese in the Central Pacific.42

The Japanese made more widespread use of rockets than in earlier operations, though on Iwo Jima their effect was limited. Some of the rocket launchers were installed in locations from where they could be fired at certain areas. Movable rocket launchers were kept in caves, moved outside and fired, then pulled back into the caves. During the early phase of the Iwo Jima operation, the Japanese fired large rockets towards the northern slope of Mount Suribachi. However, due to the inaccuracy of this fire, the missiles went beyond the mountain and finally fell into the sea. If anything, these large weapons were well adapted for harassing fire, but their accuracy was doubtful.

In contrast to the relative inefficiency of the enemy rockets, the Japanese artillery performed better than had been anticipated by the invasion force. Coordination, volume, and accuracy of the enemy artillery fire, especially during the days immediately following the invasion, initially made it appear as if the Japanese were massing their fire, thus taking a page out of the book dealing with American artillery doctrine. It was subsequently determined that prior to the American landings, the enemy had

Page 727

registered his artillery on critical terrain features against which he massed his fire, rather than relying on current observation.

General Kuribayashi’s use of mortars was exceptionally skillful and very effective. In fact, it was this weapon, and the large number used, that inflicted more casualties on the Marines than any other support weapon. During the latter part of the campaign, the Japanese apparently suffered a shortage of mortar ammunition which restricted their choice of targets to Marine weapons, vehicles, and large groups of personnel. As with rocket launchers, the Japanese skillfully hid their mortars, either emplacing them on reverse slopes or moving them out of caves to fire, and quickly moving them back under cover.

Among the weapons Marines encountered on Iwo Jima for the first time were the 320-mm spigot type mortar, new types of mobile rocket launchers and rockets, and 90-mm and 120-mm howitzers.

The landing force also made use of several innovations, sometimes on an experimental basis. Thus the rolling barrage, dating back to World War I, found renewed use during the operation. Generally, this type of artillery support proved successful, though the troops often did not advance as rapidly as expected. This required continuous modification of the barrage schedule resulting in repeating fires in certain blocks and delaying the lifting of fires from others.43 With respect to the utilization of mortars, in accordance with recommendations following operations in the Marianas, an effort was made to develop a craft mounting the 4.2-inch chemical mortar. As a result, three 4.2s were mounted on an LCI and successfully employed on D-Day and thereafter.

The effectiveness of the enemy mortar fire gave rise to the recommendation that a larger mortar be adopted, and that possibly a 120-mm mortar battalion be added to each division. Marines who had been on the receiving end of enemy 47-mm gunfire felt that a 57-mm gun should be substituted for their own 37-mm piece. Similarly, a tank with thicker armor and heavier armament than the Sherman would have facilitated operations on Iwo Jima. A great majority of the Shermans were equipped with small flamethrowers that proved their worth by squirting fire through one or two of their machine gun ports, but a tank capable of shooting a flame for about 100 yards from a turret- mounted tube proved the most efficient. In order to deceive the Japanese, who tended to concentrate their fire against any type of flamethrower, these tubes outwardly were exact replicas of the 75-mm gun.

In his letter to President Roosevelt, Rear Admiral Ichimaru somewhat contemptuously referred to American material superiority as opposed to Japanese fighting spirit.44 While there can be no doubt that such material superiority did in fact exist, it is equally

Page 728

clear that other important factors were at work which the Japanese admiral pointedly ignored. Not least among these were the outstanding leadership and discipline of the men who came to take Iwo Jima or die in the attempt; the physical stamina and mental power of endurance of these men, both tempered in months or years of thorough training; and the intangible, indefinable something known as esprit de corps or morale, that induces men to give their last in a common cause.

Without all of the above qualities, the individual Marine could not have gone on to victory on Iwo Jima, a battle that has been linked to “throwing human flesh against reinforced concrete.”45 For the men of the landing force that assaulted and captured one of the strongest enemy bastions in the Pacific, the operation was the supreme test. Judging by the performance of these men and the results attained, the inevitable conclusion can be drawn that a heavily defended objective can be seized by such a force regardless of its size, the difficulty of its terrain, and the degree of man-made defensive perfection. An amphibious assault against such an objective will be successful if it can be isolated by surface and air superiority and prepared by naval bombardment and bombing.