Island Battles of the Pacific

Iwo Jima

Chapter 1.  Background 

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. 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 Islands

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 Sulphur Island, named for the sulphur 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.

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 sulphur 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 sulphur mine and refinery. The remaining two villages, Higashi and Minami, were located in the northeastern part of the island.

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 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. Sulphur 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 sulphur, no water, no sparrow, and no swallow.” 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.” 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 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 Islands

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. 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. 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.

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. In addition, the defense boasted 14 120mm coast artillery guns, 12 heavy antiaircraft guns, and 30 25mm dual-mount antiaircraft guns.

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.

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.”

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 materiel 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 attache 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.”

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.

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 lwo 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.”