Part VI: Iwo Jima
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Chapter 1: Background to DETACHMENT1
The autumn of 1944 saw the Allies poised for a major thrust both in Europe and in the Pacific. On the European Continent, the Allies had liberated almost all of France and stood ready to advance into Germany; in fact, the German western border and the heavily fortified Siegfried Line had already been breached; on the Eastern Front, the Russians had recaptured almost all Russian territory, had driven deep into the Balkans, and were engaged in cutting off sizable German forces in the Baltic countries after an advance into East Prussia. It was evident that Germany, now fighting by herself, having been abandoned by nearly all of her former allies, could stave off the collapse of the Third Reich for only a limited time.
In the Pacific Theater, the year of 1944 had gone badly for the Japanese also. Starting with the American offensive against the Gilberts in November 1943, the inexorable advance across the Pacific had taken American forces 3,000 miles westward by the end of the year. The conquest of Saipan, more than any other reverse, had brought home to Japanese leaders the realization that there no longer was any chance of a Japanese victory. Loss of the Marianas, accompanied by the Battle of the Philippine Sea which all but destroyed Japanese naval aviation, left the Japanese home islands open to American attack. Capture of Peleliu and Ulithi protected the American right flank for a thrust into the Philippines. By late October 1944, American forces had not only gained a foothold on Leyte, but had also inflicted disastrous punishment on the Imperial Navy during the Battle for Leyte Gulf.
The beginning of 1945 saw American forces in possession of most of Leyte and with a solid foothold on Luzon. The enemy naval forces, rendered largely impotent by the reverses they had suffered during the previous year, were no longer able to interfere successfully with American operations in the Philippines, whose liberation had become merely a matter of time.
The Allied advance by early 1945 had carried friendly forces deep into enemy territory in a line extending from an area east of the Kurile Islands southward and westward to a point separating the Mariana and Volcano Islands,
thence westward to the Philippines, where the line turned to the southeast and continued southwestward towards New Guinea and Australia (see Map I, Map Section) . Even though many thousands of enemy troops remained on bypassed islands such as New Britain, Kavieng, Wake, Marcus, and Yap, these erstwhile Japanese strongholds had been so effectively isolated and neutralized by American air power and submarines that they remained merely a nuisance. With the capture of the Mariana Islands during the summer of 1944, the United States had obtained a strongpoint from which the further assaults towards the Japanese home islands could be launched. As an added steppingstone towards the ultimate invasion of Japan, an advance from the Marianas to the Ryukyus appeared logical. It was also considered necessary to secure a foothold in the Nanpo Shoto. The island finally selected for invasion within the Nanpo Shoto was barely more than a speck of dust and volcanic ashes in the Pacific. Little known to the outside world until 1945, its name was destined soon to be on the lips of thousands of men and women throughout the free world and Japan. That island was Iwo Jima.
History and Importance of the Bonin Islands2
From the entrance to Tokyo Bay, a chain of islands, known as the Nanpo Shoto, extends southward for about 750 miles to within 300 miles of the Mariana Islands. The Nanpo Shoto consists of three major groups of islands: the Izut Shoto, the Bonin Islands, also known as the Ogasawara Gunto, and the Volcano Islands, known to the Japanese as the Kazan Retto. Among the latter group of islands lies Iwo Jima, located about 670 miles south of Tokyo, 700 miles north of Guam and nearly halfway between Tokyo and Saipan.
Iwo Jima, translated into English, means Sulfur Island, named for the sulfur deposits that extend to the very surface of the island. Iwo’s shape has alternately been compared to that of a pork chop, a dripping ice-cream cone, or an elongated sea shell of the type commonly found on ocean beaches of the mid-Atlantic and southern United States. From northeast to southwest, the island measures less than five miles across; the width varies from approximately two and a half miles in the northern part to only one-half mile in the southern portion. Altogether, Iwo Jima occupies less than eight square miles.
There was little about Iwo Jima or the remainder of the Volcano–Bonin Islands to make them attractive to foreigners in search of areas that could be colonized. In the mid-Sixteenth Century a Spanish navigator sighted the Volcano Islands but thereafter Europeans paid little attention to them. As the century drew to a close, a Japanese explorer discovered
the Bonin Islands and found them to be uninhabited. They remained this way until the early part of the Nineteenth Century, when an assortment of British and American whaling captains sailed into the waters surrounding the islands. A group of colonists, consisting of Englishmen, Portuguese, Italians, Hawaiians, and an American named Nathaniel Savory, who hailed from New England, set out from Hawaii and settled on Chichi Jima under British sponsorship.
In 1853, Commodore Matthew Perry stopped at Chichi Jima and, impressed by the possible use of the island as a coaling station for U.S. Navy vessels, urged the government to purchase a strip of land on the island on which warehouses could be erected. Congress at the time showed little interest in such a venture, and in the end the project was abandoned.
While none of the European powers showed any interest in the largely barren and forbidding island of Iwo Jima, the Japanese had different ideas. Shortly after Perry’s visit to Japan in 1853, the Japanese sent officials and colonists to the Volcano-Bonins. Eight years later, Japan laid formal claim to these islands. By 1891, following increased colonization, all of the islands in the Nanpo Shoto had come under the direct jurisdiction of the Tokyo Prefecture and thus became an integral part of the Japanese homeland. A ban on foreign settlement all but stamped out outside influence in the islands with only one exception: on Chichi Jima, the descendants of Nathaniel Savory and his group still celebrated Washington’s Birthday and the Fourth of July; on these occasions they proudly displayed Old Glory, an act hardly in keeping with Japanese policy.3
By 1943, Japanese colonization of Iwo Jima had resulted in the settlement of almost 1,100 Japanese civilians on the island. Most of these Japanese were either employed at a sugar mill located in the northeastern portion of the island or a sulfur mine and refinery located in the same general area. The inhabitants of Iwo Jima lived in five villages or settlements scattered over the northern half of the island. The northernmost of these was Kita, located in the north central part of Iwo. The village of Nishi was situated in the northwestern part of the island, while Motoyama, the largest built-up area on Iwo, was located in close proximity to the sulfur mine and refinery. The remaining two villages, Higashi and Minami, were located in the northeastern part of the island. (See Map 24).
Only the northern part of Iwo Jima had soil permitting some gardening. Vegetables, sugar cane, and dry grains were raised for local consumption. Rice and all other manufactured consumer items had to be obtained from Japan proper. The inhabitants of Iwo were able to supplement their diet through fishing. In this connection it must be pointed out that one of the most serious impediments to large-scale settlement of the island was the total absence of any source of fresh water, such as a lake or a river. Since the island also lacked wells, water had to be obtained
Map 24: Iwo Jima (Sulfur Island)
exclusively from rain carefully collected in concrete cisterns. At times, Iwo Jima was supplied with potable water by tankers. Some effort was also made to augment precious water supplies through the distillation of sea water.
While the northern part of the island was hardly designed to become a tourist attraction, the southern half of Iwo Jima was ugly beyond description. Near the narrow southern tip of Iwo, dominating the entire island, stands Mount Suribachi, an extinct volcano, which rises to an elevation of about 550 feet. To the north of Suribachi, inland from the beaches, the ground terraces successively upward to form a broad tableland occupying most of the central section of the island. The area between the northern base of Suribachi and the dome-shaped northern plateau is covered by a deep layer of black, volcanic ash so soft and so much subject to drifting that even walking becomes a problem. Wheeled vehicles cannot negotiate such ground; tracked vehicles can move across it only with difficulty.
The northern plateau consists of several elevations; the highest of these is Hill 382, located just east of Motoyama Airfield No. 2, halfway between Motoyama and Minami; two other hills reach a height of 362 feet. Much of this terrain consists of rough and rocky ground, interspersed with deep gorges and high ridges. Sulfur vapor permeates the entire area with a characteristic smell of rotten eggs. The ground itself is hot in this part of the island; the veils of vapor only serve to accentuate the impression of a ghostly landscape.
The beaches of Iwo Jima from Kitano Point, the northernmost tip of the island, to Tachiiwa Point, two miles to the southeast, are steep and narrow with many rocky shoals offshore. They border terrain that rises sharply towards the northern plateau. Rough and broken ground is typical of all beaches on northern Iwo Jima, in numerous instances with cliffs that drop off sharply towards the water’s edge. Beaches along the southwestern and southeastern shores of the island vary in depth from 150 to 500 feet and generally are free from rocks offshore. The terrain would be level, rising gradually towards the interior, if it were not for the existence of sand terraces created by the action of waves. These terraces, which differ in height and width, are undergoing a constant change depending on the surf and winds. Surf conditions at Iwo are unfavorable, even under normal conditions. The island does not possess any anchorage or other inlets to protect ships from the fury of the sea. Steep beaches bring breakers close to the shore, where they can mete out severe punishment to small craft that are inward bound or beached. Winds hitting the shore from the sea serve to increase the fury of the waves.
The climate of Iwo Jima is subtropical with a cool season extending from December through April and a warm season from May through November. Temperatures are moderate, with an average ranging between 63 and 70 degrees during the cool period and 73 through 80 degrees during spring, summer, and autumn. Annual rainfall averages 60 inches, with February the driest month and May the wettest.
The desolation of the island is further accentuated by the sparse vegetation.
A few coarse grasses and gnarled trees are engaged in a perennial struggle for survival. An officer in the Imperial Japanese Army, formerly stationed on Iwo, has described it as an “island of sulfur, no water, no sparrow, and no swallow.”4 The only living thing on Iwo, aside from the Japanese, was a bird resembling the American rail, a wading bird related to the cranes, but of medium size.
The above description of Iwo Jima, hardly complimentary in essence, may easily give rise to the question how an island of such poor proportions could assume the strategic importance that both the Japanese and Americans placed on it by the summer of 1944. At least one American, speaking to a Navy Chaplain, expressed the sentiment that “after God got through making the world, he must’ve took all the dirty ash and rubble left over and made Iwo Jima.”5 Yet the island was destined to witness one of the epic amphibious assaults of World War II, followed by a month-long running battle that cost the assault force heavily in men and equipment and at the same time resulted in the complete destruction of the enemy garrison. The factors that made this otherwise worthless pile of rock and black sand such Smith a prize to friend and enemy alike, require a detailed explanation. Only then can the struggle between 23,000 Japanese and an assault force initially of 60,000 men, combatting each other at closest quarters on this inhospitable island, be readily understood.
Japanese Defensive Preparations In the Bonin-Volcano Islands6
Japanese military interest in the Volcano-Bonin Islands first arose in 1914, coincident to the outbreak of World War I. Even though the Japanese home islands were never threatened during that war, which Japan entered on the side of the Allies, a few defenses were prepared on Chichi Jima, an island in the Bonin-Volcano Group about 175 miles north-northeast of Iwo Jima. On 10 August 1920, the Chichi Jima Branch, Army Fortification Department, was formally established, followed by the construction of fortifications beginning in June 1921. As a result of the Naval Arms Limitation Agreement, concluded on 6 February 1922, work on the fortifications was halted.7 Since all of the action had occurred elsewhere, the Japanese garrison on Chichi Jima led a peaceful existence and never fired a shot in anger.
During the postwar period and
throughout the twenties and thirties, the status of Chichi Jima did not undergo any appreciable change. Though a small garrison remained on the island, no additional installations were constructed. On Iwo Jima, the presence of any military installation was even less conspicuous, though by 1937 a wooden sign had been erected by the Imperial Navy, bearing a legend in both Japanese and English, clearly cautioning the careless trespasser from recording or photographing such installations as he might encounter on the island.
At the time of the Japanese attack on Pearl Harbor an Army force of about 3,700-3,800 men garrisoned Chichi Jima. In addition, about 1,200 naval personnel manned the Chichi Jima Naval Base, a small seaplane base, the radio and weather station, and various gunboat, subchaser, and minesweeping units.8 On Iwo Jima, the Imperial Navy had constructed an airfield about 2,000 yards northeast of Mount Suribachi. Initially stationed on this field were 1,500 naval aviation personnel and 20 aircraft.9
In the wake of the American seizure of the Marshalls and devastating air attacks against Truk in the Carolines during February 1944, the Japanese military leadership was forced to conduct an agonizing reappraisal of the military situation. All indications pointed to an American drive towards the Marianas and Carolines. To counter such a move, it became necessary to establish an inner line of defense extending generally northward from the Carolines to the Marianas, and from thence to the Volcano-Bonin Islands. In March 1944, the Thirty-First Army, commanded by General Hideyoshi Obata, was activated for the purpose of garrisoning this inner line. The commander of the Chichi Jima garrison was placed nominally in command of Army and Navy units in the Volcano-Bonin Islands.
Following the American seizure of most of the Marshalls, both Army and Navy reinforcements were sent to Iwo Jima. Five hundred men from the naval base at Yokosuka and an additional 500 from Chichi Jima reached Iwo during March and April 1944. At the same time, with the arrival of reinforcements from Chichi Jima and the home islands, the Army garrison on Iwo Jima had reached a strength of over 5,000 men, equipped with 13 artillery pieces, 200 light and heavy machine guns, and 4,552 rifles.10 In addition, the defense boasted 14 120-mm coast artillery guns, 12 heavy antiaircraft guns, and 30 25-mm dual-mount antiaircraft guns.11
The loss of the Marianas during the summer of 1944 greatly increased the importance of the Volcano-Bonins for the Japanese, who were fully cognizant
that the loss of these islands would facilitate American air raids against the home islands. Such raids, beyond any doubt, would raise havoc with the entire Japanese war production program, and deal a severe blow to civilian morale.
Final Japanese plans for the defense of the Volcano-Bonins were overshadowed by the fact that the Imperial Navy had already lost most of its naval strength and no longer constituted a major factor in frustrating possible American landings. Moreover, aircraft losses throughout 1944 had been so heavy that, even if war production was not materially slowed by American air attacks, combined Japanese air strength was not expected to increase to 3,000 aircraft until March or April of 1945. Even then, these planes could not be used from bases in the home islands against Iwo Jima because their range did not exceed 550 miles; besides, all available aircraft had to be hoarded for possible use on Formosa and adjacent islands where land bases were available in close proximity.12
In a postwar study, Japanese staff officers described the strategy applied in the defense of Iwo Jima in the following terms:–
In the light of the above situation, seeing that it was impossible to conduct our air, sea, and ground operations on Iwo Island toward ultimate victory, it was decided that in order to gain time necessary for the preparation of the Homeland defense, our forces should rely solely upon the established defensive equipment in that area, checking the enemy by delaying tactics. Even the suicidal attacks by small groups of our Army and Navy airplanes, the surprise attacks by our submarines, and the actions of parachute units, although effective, could be regarded only as a strategical ruse on our part. It was a most depressing thought that we had no available means left for the exploitation of the strategical opportunities which might from time to time occur in the course of these operations.13
Even before the fall of Saipan in June 1944, Japanese planners knew that Iwo Jima would have to be reinforced materially if it were to the held for any length of time, and preparations were made to send sizable numbers of men and quantities of matériel to that island. In late May, Lieutenant General Tadamichi Kuribayashi was summoned to the office of the Prime Minister, General Hideki Tojo, who informed the general that he had been chosen to defend Iwo Jima to the last. Kuribayashi was further apprised of the importance of this assignment when Tojo pointed out that the eyes of the entire nation were focused on the defense of Iwo. Fully aware of the implications of the task entrusted to him, the general accepted. By 8 June, Kuribayashi was on his way to his toughest and final assignment, determined to convert Iwo Jima into an invincible fortress that would withstand any type of attack from any quarter.
The Japanese could hardly have selected an individual better qualified to lead the defense of Iwo Jima. As a member of a Samurai family, the 54-year-old Kuribayashi already had a distinguished military career behind him at the time he received the Iwo assignment.
In the 30 years in which he had served the Empire, the general had seen much of the world. During the late twenties, as a captain, Kuribayashi had spent two years in the United States performing attaché duties. In the course of his travels in America, he gained a keen appreciation of American economic power, as expressed in a letter to his wife:–
The United States is the last country in the world that Japan should fight. Its industrial potentiality is huge and fabulous, and the people are energetic and versatile. One must never underestimate the American’s fighting ability.14
Following his travels in the New World, Kuribayashi served in the Japanese cavalry. In August 1936, as a lieutenant colonel, he commanded a cavalry regiment. For the next two years, by then a colonel, he served in the Ministry of War. In 1940, he was promoted to brigadier general and given command of a cavalry brigade. Following the Pearl Harbor attack, he participated in the occupation of Hong Kong as chief of staff of the Twenty-Third Army. In 1943, General Kuribayashi, by then a major general, was recalled to Tokyo, where he commanded the Imperial Guards until his appointment as commander of the Iwo Jima Garrison.15
General Kuribayashi arrived on Iwo Jima between 8 and 10 June. As a result, he was on the island when TG 58.1 and TG 58.4, consisting of seven aircraft carriers under the command of Rear Admiral Joseph J. Clark, unleashed their first strike against the Bonins, which resulted in the destruction of 10 Japanese fighters in the air and a possible 70 planes on the ground in two days of operations. In addition, 21 seaplanes were destroyed on Chichi Jima. On 24 June 1944, the American carriers under Admiral Clark again struck at Iwo. This time, 80 Japanese fighters rose to challenge the intruders. When the smoke of battle over Iwo cleared nearly half of the Japanese fighters had been destroyed. One of the Japanese fighter pilots who survived the fierce dogfights over Iwo Jima that day commented:–
The loss of forty planes and pilots in a single action staggered me. Equally disturbing was the sight of our inexperienced pilots falling in flames, one after the other, as the Hellcats blasted our outmoded Zeros from the Sky. How much like Lae the battle had been! Except that now the obsolescent planes were Zeros, and the inexperienced pilots were Japanese. The war had run full circle.16
The loss of the 40 sorely needed fighters on 24 June was not the only disaster that befell Rear Admiral Teiichi Matsunaga, commanding the Japanese naval forces on Iwo. Not one of 20 torpedo bombers he sent out against the American carriers returned to the island. A third wave of 41 aircraft dispatched against the task force not only failed to inflict any damage on the carriers, but in the process nearly half of the Japanese planes were shot out of the sky.
On the evening of 2 July, Japanese radio monitors on Iwo Jima noted a sudden increase in their adversary’s
radio traffic. Though the Japanese were unable to decipher the code, the strength of the signals indicated to experienced monitors that an American force was in fairly close proximity to Iwo Jima. Early the following morning, American carrier-based aircraft once again raided the island. While the 40 Japanese fighters remaining on Iwo took to the air to intercept the attacking American planes and soon became engaged in heavy dogfights, a squadron of bombers pounced on the island and bombed the airstrip in five waves. Not a single fighter opposed them, since all of the Zeros had been diverted by the American fighters. At the end of the day it became apparent that once again the Japanese had lost half of their remaining fighters, which left only 20 of the original 80. The air battle over Iwo continued on 4 July. At the end of the day, only nine Zeros, most of them badly damaged, returned to Iwo. This left Japanese aviation on the island with nine damaged fighters and eight torpedo bombers which had somehow escaped the holocaust in their revetments.
On the following day, this remnant of Japanese naval aviation on Iwo was dispatched on a final mission: to seek out the American naval task force and destroy as many carriers as possible. The fighter pilots were admonished to stay with the eight torpedo bombers and avoid combat with intercepting American fighters at all costs. It was made clear to both fighter and bomber pilots that they were engaged in a one-way mission from which they were not expected to return. When the attack force approached Admiral Clark’s carriers it proved no match for the intercepting fighters. The slow, sluggish Japanese bombers, heavily loaded with their torpedoes, were shot down one after the other by the attacking Hellcats. One of the few Japanese pilots to survive this action reported that in less than a minute seven of the bombers had been destroyed by American fighters. Late on 5 July, four dispirited Japanese fighter pilots and one bomber pilot returned to Iwo.
In addition to the annihilation of virtually all Iwo-based aircraft, another ordeal was in store for the Japanese garrison. On the day following the unsuccessful bombing mission, a U.S. naval force boldly appeared within sight of the island and subjected the Japanese to a naval bombardment from point-blank range. What it felt like to be on the receiving end of such a bombardment has been recorded by one of the Japanese:–
For two days we cowered like rats, trying to dig ourselves deeper into the acrid volcanic dust and ash of Iwo Jima. Never have I felt so helpless, so puny, as I did during those two days. There was nothing we could do, there was no way in which we could strike back. The men screamed and cursed and shouted, they shook their fists and swore revenge, and too many of them fell to the ground, their threats choking on the blood which bubbled through great gashes in their throats. Virtually every last structure on Iwo Jima was torn to splintered wreckage. Not a building stood. Not a tent escaped. Not even the most dismal shack remained standing. Everything was blown to bits. The four fighter planes which had returned from our last sortie were smashed by shells into flaming pieces of junk.17
For several days the survivors of the bombardment remained in a state of shock from their ordeal and frantic calls for reinforcements went out in view of what appeared to be an imminent invasion of the Island. When several Japanese transport ships appeared on the horizon, the garrison rejoiced, only to fall into deeper gloom and frustration when American submarines torpedoed these ships before their very eyes. Lookouts posted atop Mount Suribachi scanned the ocean for signs of the approaching invasion fleet, and false alarms were frequent.
Much to the surprise of the Japanese garrison on Iwo, an American invasion of the island did not materialize during the summer of 1944. There was little doubt that in time the Americans would be compelled to attack the island. General Kuribayashi, who had personally witnessed Admiral Clark’s second air strike against Iwo, as well as the naval bombardment in early July, was more determined than ever to exact the heaviest possible price for Iwo when the invaders came. Without naval and air support, it was a foregone conclusion that Iwo could not hold out indefinitely against an invader possessing both naval and air supremacy.
As a first step in readying Iwo for a prolonged defense, the island commander ordered the evacuation of all civilians from the island. This was accomplished by late July. Next came an overall plan for defense of the island. Lieutenant General Hideyoshi Obata, Commanding General of the Thirty-First Army, early in 1944 had been responsible for the defense of Iwo prior to his return to the Marianas. At the time, faithful to the doctrine that an invasion had to be met practically at the water’s edge, Obata had ordered the emplacement of artillery and the construction of pillboxes near the beaches. General Kuribayashi had different ideas. Instead of a futile effort to hold the beaches, he planned to defend the latter with a sprinkling of automatic weapons and infantry. Artillery, mortars, and rockets would be emplaced on the foot and slopes of Mount Suribachi, as well as in the high ground to the north of Chidori airfield.
A prolonged defense of the island required the preparation of an extensive system of caves and tunnels, for the naval bombardment had clearly shown that surface installations could not withstand extensive shelling. To this end, mining engineers were dispatched from Japan to draw blueprints for projected underground fortifications that would consist of elaborate tunnels at varying levels to assure good ventilation and minimize the effect of bombs or shells exploding near the entrances or exits.
At the same time, reinforcements were gradually beginning to reach the island. As commander of the 109th Infantry Division, General Kuribayashi decided first of all to shift the 2nd Independent Mixed Brigade, consisting of about 5,000 men under Major General Kotau Osuga, from Chichi to Iwo. With the fall of Saipan, 2,700 men of the 145th Infantry Regiment, commanded by Colonel Masuo Ikeda, were diverted to Iwo. These reinforcements, who reached the island during July and August 1944, brought the strength of the garrison up to approximately 12,700
men. Next came 1,233 members of the 204th Naval Construction Battalion, who quickly set to work constructing concrete pillboxes and other fortifications.
On 10 August, Rear Admiral Toshinosuka Ichimaru reached Iwo, shortly followed by 2,216 naval personnel, including naval aviators and ground Crews.18 The admiral, a renowned Japanese aviator, had been crippled in an airplane crash in the mid-twenties and, ever since the outbreak of the war, had chafed under repeated rear echelon assignments. More than pleased with finally having been granted a combat assignment, Ichimaru penned a poem which began:
Grateful to his Majesty for giving me
A chance to fight on the foremost front.
I depart with buoyant heart,
Filled with joy and exultation.19
Next to arrive on Iwo were artillery units and five antitank battalions. Even though numerous supply ships on route to Iwo Jima were sunk by American submarines and aircraft, substantial quantities of matériel did reach Iwo during the summer and autumn of 1944. By the end of the year, General Kuribayashi had available to him 361 artillery pieces of 75-mm or larger caliber, a dozen 320-mm mortars, 65 medium (150-mm) and light (81-mm) mortars, 33 naval guns 80-mm or larger, and 94 antiaircraft guns 75-mm or larger. In addition to this formidable array of large caliber guns, the Iwo defenses could boast of more than 200 20-mm and 25-mm antiaircraft guns and 69 37-mm and 47-mm antitank guns. The fire power of the artillery was further supplemented with a variety of rockets varying from an eight-inch type that weighed 200 pounds and could travel between 2,000-3,000 yards, to a giant 550-pound projectile that had a range of more than 7,500 yards.20 Altogether, 70 rocket guns and their crews reached Iwo Jima. As a result of American attacks against Japanese shipping, a number of artillery pieces were lost. Others reached Iwo, but their crews, traveling on other ships, drowned en route. In several instances, guns and crews arrived intact, only to discover that vital optical sights, shipped on other vessels, had been lost. Large shipments of barbed wire, essential for the defense of Iwo, never reached the island; the ships carrying this vital commodity were sunk en route.
In order to further strengthen the Iwo defenses, the 26th Tank Regiment, which had been stationed at Pusan, Korea after extended service in Manchuria, received orders for Iwo. The officer commanding this regiment was Lieutenant Colonel Baron Takeichi Nishi. Like Kuribayashi, he was a cavalryman, had travelled extensively abroad, and in the 1932 Olympics at Los Angeles had won a gold medal in the equestrian competitions. The regiment, consisting of 600 men and 28 tanks, sailed from Japan in mid-July on board
the Nisshu Maru. As the ship, sailing in a convoy, approached Chichi Jima on 18 July 1944, it was torpedoed by an American submarine, the USS Cobia. Even though only two members of the 26th Tank Regiment failed to survive the sinking, all of the regiment’s 28 tanks went to the bottom of the sea. It would be December before these tanks could be replaced, but 22 finally reached Iwo Jima. Initially, Colonel Nishi had planned to employ his armor as a type of “roving fire brigade,” to be committed at focal points of combat. The rugged terrain precluded such employment and in the end, under the colonel’s watchful eyes, the tanks were deployed in static positions. They were either buried or their turrets were dismounted and so skillfully emplaced in the rocky ground that they were practically invisible from the air or from the ground.
For the remainder of 1944, the construction of fortifications on Iwo also went into high gear. The Japanese were quick to discover that the black volcanic ash that existed in abundance all over the island could be converted into concrete of superior quality when mixed with cement. Pillboxes near the beaches north of Mount Suribachi were constructed of reinforced concrete, many of them with walls four feet thick. At the same time, an elaborate system of caves, concrete blockhouses, and pillboxes was established. One of the results of American air attacks and naval bombardment in the early summer of 1944 had been to drive the Japanese so deep underground that eventually their defenses became virtually immune to air or naval bombardment.
While the Japanese on Peleliu Island in the Western Carolines, also awaiting American invasion, had turned the improvement of natural caves into an art, the defenders of Iwo literally developed it into a science. Because of the importance of the underground positions, 25 percent of the garrison was detailed to tunneling. Positions constructed underground ranged in size from small caves for a few men to several underground chambers capable of holding 300 or 400 men. In order to prevent personnel from becoming trapped in any one excavation, the subterranean installations were provided with multiple entrances and exits, as well as stairways and interconnecting passageways. Special attention had to be paid to providing adequate ventilation, since sulfur fumes were present in many of the underground installations. Fortunately for the Japanese, most of the volcanic stone on Iwo was so soft that it could be cut with hand tools.
General Kuribayashi established his command post in the northern part of the island, about 500 yards northeast of Kita village and south of Kitano Point. This installation, 75 feet underground, consisted of caves of varying sizes, connected by 500 feet of tunnels. Here the island commander had his own war-room in one of three small concrete enclosed chambers; the two similar rooms were used by the staff. A communications blockhouse protruded above the ground level. This structure was 150 feet long, 70 feet wide; the roof had a thickness of 10 feet with walls five feet wide. The blockhouse was manned by 70 radio operators who worked in shifts. Farther south on Hill 382, the second
highest elevation on the island, the Japanese constructed a radio and weather station. Nearby, on an elevation just southeast of the station, an enormously large blockhouse was constructed which served as the headquarters of Colonel Chosaku Kaido, who commanded all artillery on Iwo Jima. Other hills in the northern portion of the island were tunneled out, All of these major excavations featured multiple entrances and exits and were virtually invulnerable to damage from artillery or aerial bombardment. Typical of the thoroughness employed in the construction of subterranean defenses was the main communications center south of Kita village, which was so spacious that it contained a chamber 150 feet long and 70 feet wide. This giant structure was similar in construction and thickness of walls and ceilings to General Kuribayashi’s command post. A 500-foot-long tunnel 75 feet below the ground led into this vast subterranean chamber.21
Perhaps the most ambitious construction project to get under way was the creation of an underground passageway designed to link all major defense installations on the island. As projected, this passageway was to have attained a total length of almost 17 miles. Had it been completed, it would have linked the formidable underground installations in the northern portion of Iwo Jima with the southern part of the island, where the northern slope of Mount Suribachi alone harbored several thousand yards of tunnels.22 By the time the Marines landed on Iwo Jima, more than 11 miles of tunnels had been completed.23
A supreme effort was required of the Japanese personnel engaged in the underground construction work. Aside from the heavy physical labor, the men were exposed to heat varying from 90 to 120 degrees Fahrenheit, as well as sulfur fumes that forced them to wear gas masks. In numerous instances a work detail had to be relieved after only five minutes. When renewed American air attacks struck the island on 8 December 1944 and thereafter became a daily occurrence until the actual invasion of the island, a large number of men had to be diverted to repairing the damaged airfields.
While Iwo Jima was being converted into a major fortress with all possible speed, General Kuribayashi formulated his final plans for the defense of the island. This plan, which constituted a radical departure from the defensive tactics used by the Japanese earlier in the war, provided for the following major points:–
a. In order to prevent disclosing their positions to the Americans, Japanese artillery was to remain silent during the expected prelanding bombardment. No fire would be directed against the American naval vessels.
b. Upon landing on Iwo Jima, the Americans were not to encounter any opposition on the beaches.
c. Once the Americans had advanced about 500 yards inland, they were to be taken under the concentrated fire of automatic weapons stationed in the vicinity of Motoyama airfield to the north,
as well as automatic weapons and artillery emplaced both on the high ground to the north of the landing beaches and Mount Suribachi to the south.
d. After inflicting maximum possible casualties and damage on the landing force, the artillery was to displace northward from the high ground near the Chidori airfield.
In this connection, Kuribayashi stressed once again that he planned to conduct an elastic defense designed to wear down the invasion force. Such prolonged resistance naturally required the defending force to stockpile rations and ammunition. To this end the island commander accumulated a food reserve to last for two and a half months, ever mindful of the fact that the trickle of supplies that was reaching Iwo Jima during the latter part of 1944 would cease altogether once the island was surrounded by a hostile naval force.
Opposition to General Kuribayashi’s unorthodox defense plan, which reflected changes in earlier Japanese military doctrine, was not long in developing. It must be noted that the defensive form of combat in itself was distasteful to the Japanese, who early in the war had been loath to admit to themselves that the Imperial Army would ever be forced to engage in this form of combat. In fact, “so pronounced was their dislike for the defensive that tactical problems illustrating this type of combat were extremely rare.”24 According to standard Japanese doctrine, the object of the defensive was to inflict on the superior hostile forces such losses by firepower—disposed appropriately on the terrain and behind man-made works—that the initial disparity of forces became equalized to the point of eventually permitting the defense force to go over to the offensive.
As far as the objective in defending Iwo Jima was concerned, General Kuribayashi’s plan adhered closely to the prevalent doctrine. It was the manner of execution that aroused the displeasure of some of his subordinates, for during the period following the American capture of Guadalcanal and up until the end of the fighting on Saipan, it had become almost standard procedure for the Japanese to defend the beaches in an attempt to drive the invader back into the sea. Once the position of the defending force on an island had become untenable, a brave banzai charge, in which the defenders sought victory in death, usually terminated all organized resistance. Kuribayashi’s intent of conserving his manpower and not staking all on a defense of the beaches or futile banzai charges was the epitome of the revised Japanese doctrine, already employed at Biak in the Southwest Pacific, to some extent in the Palaus, and very extensively on Luzon in the Philippines.
The most vociferous opposition to General Kuribayashi’s plan of defense, strangely enough, came from his own chief of staff, Colonel Shizuichi Hori, a former instructor at the Japanese Military Academy. The latter was strongly supported by General Osuga, commander of the 2nd Independent Mixed Brigade. In an unusual display of solidarity between Army and Navy, Captain Samaji Inouye, commanding the Naval Guard Force, sided with the two
Army dissidents. According to one source who was stationed on Iwo during the summer of 1944:–
Arguments raged in July, August, and September. Arguments were not confined to Iwo command alone, but taken to Tokyo’s Army and Navy staffs. In August Tokyo asked Nazi German General Staff’s opinion. Germany replied that waterfront repulse was unfeasible under overwhelming American shelling and bombings according to German experience. It was not that German reply was the decisive factor. But anyway, supporters of the waterfront idea gradually dwindled. Kuribayashi made some compromise and the hot arguments ended in September.25
Finally, in December 1944, General Kuribayashi decided to restore unity to his command. He dismissed Colonel Hori as chief of staff of the 109th Division and replaced him with Colonel Tadashi Takaishi. General Osuga, commander of the 2nd Independent Brigade, was succeeded by Major General Sadasue Senda, an experienced artilleryman who had seen combat in Manchuria and China. Altogether, a total of 18 officers were replaced.
During the final months of preparing Iwo Jima for the defense, General Kuribayashi saw to it that the strenuous work of building fortifications did not interfere with the training of units. As an initial step towards obtaining more time for training, he ordered work on the northernmost airfield on the island halted. In an operations order issued in early December, the island commander set 11 February 1945 as the target date for completion of defensive preparations and specified that personnel were to spend 70 percent of their time in training and 30 percent in construction work.
Despite intermittent harassment by American submarines and aircraft, additional personnel continued to arrive on Iwo until February 1945. By that time General Kuribayashi had under his command a force totaling between 21,000 and 23,000 men, including both Army and Navy units.26
General Kuribayashi made several changes in his basic defense plan in the months preceding the American invasion of Iwo Jima. The final stratagem, which became effective in January 1945, called for the creation of strong, mutually supporting positions which were to be defended to the death. Neither large scale counterattacks, withdrawals, nor banzai charges were contemplated. The southern portion of Iwo in the proximity of Mount Suribachi was organized into a semi-independent defense sector. Fortifications included casemated coast artillery and automatic weapons in mutually supporting pillboxes. The narrow isthmus to the north of Suribachi was to be defended by a small infantry force. On the other hand,
this entire area was exposed to the fire of artillery, rocket launchers, and mortars emplaced on Suribachi to the south and the high ground to the north.
A main line of defense, consisting of mutually supporting positions in depth, extended from the northwestern part of the island to the southeast, along a general line from the cliffs to the northwest, across Motoyama Airfield No. 2 to Minami village. From there it continued eastward to the shoreline just south of Tachiiwa Point. (See Map 25). The entire line of defense was dotted with pillboxes, bunkers, and blockhouses. Colonel Nishi’s immobilized tanks, carefully dug in and camouflaged, further reinforced this fortified area, whose strength was supplemented by the broken terrain. A second line of defense extended from a few hundred yards south of Kitano Point at the very northern tip of Iwo across the still uncompleted Airfield No. 3, to Motoyama village, and then to the area between Tachiiwa Point and the East Boat Basin. This second line contained fewer man-made fortifications, but the Japanese took maximum advantage of natural caves and other terrain features.
As an additional means of protecting the two completed airfields on Iwo from direct assault, the Japanese constructed a number of antitank ditches near the fields and mined all natural routes of approach. When, on 2 January, more than a dozen B-24 bombers raided Airfield No. 1 and inflicted heavy damage, Kuribayashi diverted more than 600 men, 11 trucks, and 2 bulldozers for immediate repairs. As a result, the airfield again became operational after only 12 hours. Eventually, 2,000 men were assigned the job of filling the bomb craters with as many as 50 men detailed to each bomb crater. The end of 1944 saw American B-24 bombers over Iwo Jima almost every night while U.S. Navy carriers and cruisers frequently sortied into the Bonins. On 8 December, American aircraft dropped more than 800 tons of bombs on Iwo Jima, which shook the Japanese up but did very little real damage to the island defenses. Even though frequent air raids interfered with the Japanese defensive preparations and robbed the garrison of much badly needed sleep, progress of the work was not materially slowed.
Despite the air raids, which became a daily occurrence in December, and increasing isolation from the homeland, morale remained high among members of the Iwo garrison. Japanese national holidays, such as the birthday of Emperor Meiji on 11 February, were celebrated with rice cake and an extra ration of sake. At the same time, the Iwo Jima defenders, gathered in small groups near their battle stations, listened to a Tokyo broadcast in which a song, especially dedicated to the defense of Iwo, was released to the public. Many of the men wore white headbands, similar to the ones worn by kamikaze pilots, to demonstrate their determination to die in defense of the island. Inside the pillboxes, for all to see and burn into their minds, were copies of the “Courageous Battle Vow, “ which pledged all to dedicate themselves to the defense of Iwo, and to fight to the last with any and all weapons at hand. The pledge appropriately ended with the following words:
Map No. 25: Japanese Defense Sectors
Each man will make it his duty to kill ten of the enemy before dying. Until we are destroyed to the last man, we shall harass the enemy by guerrilla tactics.27
As early as 5 January 1945, Admiral Ichimaru conducted a briefing of naval personnel at his command post in which he informed them of the destruction of the Japanese Fleet at Leyte, loss of the Philippines, and the expectation that Iwo would shortly be invaded. Exactly one month later, Japanese radio operators on Iwo reported to the island commander that code signals of American aircraft had undergone an ominous change. On the 13th, a Japanese naval patrol plane spotted 170 American ships moving northwestward from Saipan. All Japanese troops in the Benin Islands were alerted and occupied their battle positions. On Iwo Jima, preparations for the pending battle had been completed, and the defenders were ready.