Part 1
Iwo Jima
Chapter I
Decisions, Plans and Preparations1
October 1944--February 1945It was a long, hard pull for the Navy across the Pacific to within striking distance of Japan; but, by the time Saipan in the Marianas had been conquered (August 1944) and the major part of Luzon liberated (February 1945), two practicable routes were open to the ultimate objective--the Nanpo Shoto and the Nansei Shoto island chains. The first, better known to Americans and Europeans as the Bonins2, begin not far off Tokyo Bay and continues southerly for some 700 miles to Minami Shima, which is 290 miles northwest of the northernmost Marianas, and 615 miles north of Saipan. Most of these islands are tiny volcanic cones, too small for an airfield. But Chichi Jima and Iwo Jima had distinct possibilities. 1. The Bonins and Ryukyus in Pacific Strategy
The other island chain, the Nansei Shoto (better known to Americans and Europeans as the Ryukyus), forms a great arc some 600 miles long, from Honshu, southernmost of the Japanese home islands,
to Formosa, making the eastern border of the East China Sea. This chain contains five or six islands suitable for air bases, the best and largest being Okinawa.The spokesmen for taking Luzon (led by General MacArthur) and for taking Formosa (led by Admiral King) had held long discussions at Cincpac headquarters, at San Francisco, and with the Joint Chiefs of Staff at Washington. The Luzonites won because the Army estimated that securing Formosa would require nine combat divisions and more service troops than were likely to be available before the surrender of Germany. This was practically decided at the San Francisco Conference of 29 September--1 October 1944, between Admirals King, Nimitz and Spruance and Generals Harmon and Buckner. Admiral Nimitz there submitted a carefully written memorandum, which not only urged that Luzon be the target but gave his opinion as to what should follow. He recommended a staggered, two-pronged advance, as follows. The first--target date 20 January 1945--should thrust "up the ladder of the Bonins" to Chichi Jima or Iwo Jima; the second--target date 1 March--along the arc of the Ryukyus to one or more positions such as Okinawa or Amami O Shima. The purpose of the one would be to obtain emergency landing facilities for Saipan-based B-29s and a base for their fighter escorts in bombing Japan proper; and of the other, to secure and develop a sound air and naval base for the invasion of the Japanese home islands.
Admiral Spruance, who seems to have been the first high-ranking naval officer to appreciate the possibilities of Okinawa, observed with pleasure at San Francisco that Admiral King, who hitherto had been insistent on taking Formosa, had been reluctantly won over by Admiral Nimitz's logic. At this point in the discussion King turned to Spruance and remarked, "Haven't you something to say? I understand that Okinawa is your baby." To which Spruance, a man of deep thought but few words, replied that Nimitz had put the case so well that he had nothing to add.
From San Francisco Admiral King brought the word to the Joint Chiefs of Staff, who on 3 October issued the directive to General
MacArthur and Admiral Nimitz, in pursuance of which the operations described in this volume were carried out: --
- General MacArthur will seize and occupy Luzon, target date 20 December, and provide support for subsequent occupation of the Ryukyus by Admiral Nimitz's forces.
- Admiral Nimitz, after providing covering and support forces for the liberation of Luzon, will occupy one or more positions in the Bonins-Volcano Group, target date 20 January 1945, and one or more positions in the Ryukyus, target date 1 March 1945.
- Both C. in C.'s will arrange for coordination of forces and resources between themselves and with the Commanding Generals of XX Army Air Force,3 and of the China-Burma-India area.
So there it was, on the line. The eastern (Iwo Jima) operation was placed first after Luzon because it was expected to be easier that the western (Okinawa) one. It was never anticipated that the same troops would be used for both operations, but the same Pacific Fleet would have to cover and support both, while the Seventh Fleet and Amphibious Force were engaged in covering and liberating the Southern Philippines, as described in our previous volume. It was necessary that Fast Carrier Forces (TF 38 or 58) be detached from supporting these Philippines operations in time to cover both the Bonins and the Ryukyus invasions.
2. Planning for Iwo Jima
Planning for Invasion
Left to right: Rear Admiral W.H.P. Blandy, Rear Admiral Harry W. Hill, Lieutenant General H.M. Smith USMC, Vice Admiral Richmond K. TurnerPostponing consideration of the Okinawa plans to Part II, we shall explain why Iwo Jima of glorious though gory memory was chosen as the Bonins objective. The only alternative was the more northerly and larger Chichi Jima, which had a good protected harbor, Port Lloyd. But that island is too rugged for quick airfield
construction, and air reconnaissance showed that it was more heavily fortified than Iwo.The Bonin Islands might have been an American possession if President Franklin Pierce's administration had backed up Commodore Matthew Calbraith Perry. Chichi Jima was first settled from Honolulu in 1830 by two New Englanders--Aldin B. Chapin and Nathaniel Savory--a Genoese, and 25 Hawaiians, who made a living raising provisions for sale to passing whalers. Commodore Perry called at Port Lloyd on 14 June 1853, next day purchased for fifty dollars a plot of land on the harbor, stocked it with cattle brought over in U.S.S. Susquehanna, set up a local government under Savory, promulgated a code of laws, and took possession for the United States. He intended to make Chichi Jima a provisioning stations for the United States Navy and American mail steamers. But this action was repudiated by the Pierce administration in Washington. Thus, in 1861 Japan was able to annex the Bonin Islands without opposition. The government did not disturb the American colony, and serious colonization of the group by Japanese did not start until 1887.4
Iwo Jima, central island of the Volcano group, had great value as a strategic outpost, but for nothing else. Situated in lat. 24° 45' N, long. 141° 20 E, shaped like a bloated pear or a lopsided pork chop, Iwo is only 41/2 miles long and 21/2 miles wide. The volcanic crater of Mount Suribachi, 550 feet above sea level, at the stem of the pear, remained inactive during World War II, but numerous jets of steam and sulphur all over the island suggested that an eruption might take place at any moment. The northern part of the island is a plateau with rocky and inaccessible shores, but beaches extended from the base of Mount Suribachi for more than two miles north and east. These beaches, the land between them, and a good part of the terrain are deeply covered with brown volcanic ash and black cinders which look like sand, but are so much lighter than sand that walking is difficult and running impossible. Marston mat had to be laid to accommodate wheeled and even tracked
vehicles. Up to 1944 the island was inhabited by about 1100 Japanese civilians who raised sugar and pineapples, extracted sulphur and ran a crude sugar mill; but all were evacuated before this operation began.The unique importance of Iwo Jima for warlike purposes was derived from its location and topography. It lies almost midway between Honshu and the Marianas, 625 miles north of Saipan and 660 miles south of Tokyo. The Japanese constructed two airfields on the island, and a third had been started. On 14 July 1944 General "Hap" Arnold, head of the Army Air Forces, recommended to the Joint Planners that Iwo be seized to provide for emergency landings of the B-29 Superforts, and to base P-51 fighter planes to escort them in raids on Tokyo. The Joint Planners agreed, provided that the seizure of Iwo would not interfere with other and more important operations.5
As soon as the 3 October 1944 directive arrived at Cincpac headquarters, Admiral Nimitz's staff planners, presided over by Rear Admiral Forrest Sherman, moved fast. On 7 October they produced a staff study which became the basis for the plan and outlined the Iwo operation very much as it was carried out.6
Admiral Raymond A. Spruance, Commander Fifth Fleet, had the over-all command at Iwo Jima. Under him Vice Admiral Richmond K. Turner commanded the Joint Expeditionary Force (TF 51). As this was to be a Marine Corps landing, Lieutenant General Holland M. Smith USMC was made Commander Expeditionary Troops (TF 56), which consisted of the V Amphibious Corps, Major General Harry Schmidt USMC. Also under Turner were Rear Admiral Harry W. Hill, Commander Attack Force (TF 53), and Rear Admiral W.H.P. Blandy, Commander Amphibious Support Force (TF 52). Also in support of the operation were Vice Admiral Marc A. Mitscher's Fast Carrier Force (TF 58), an expanded Logistic Support Group commanded by Rear Admiral Donald B.
Beary, and a Search and Reconnaissance Group (TG 50.5) under Commodore Dixwell Ketcham.The landing force, the V 'Phib Corps, comprised the 3rd Marine Division (Major General Graves B. Erskine USMC), which had recently liberated Guam; the 4th Marine Division (Major General Clifton B. Cates USMC), then at Maui; and the new 5th Marine Division (Major General Keller E. Rockey USMC), then on the island of Hawaii. General Schmidt's headquarters were on Guam, but to plan for Iwo he moved to Pearl Harbor on 13 October. When General MacArthur was persuaded to postpone the Lingayen landings to 9 January, the two operations coming up were postponed for a full month--Iwo Jima to 19 February, and Okinawa to 1 April 1945.
There also had to be keen planning on the logistics end.7 In operations for the liberation of the Philippines, a seagoing logistics group was set up in order to bring oil, replacement planes, spare parts and fleet tugs to the fast carrier forces at sea. This procedure proved so successful that the group was now enlarged and extended by adding ammunition ships and other auxiliaries, redesignating the group Service Squadron 6, and placing it under the command of Rear Admiral Beaty, who had been head of Training Command Atlantic Fleet at Norfolk.8 Detroit, one of the old light cruisers, was allotted to him as flagship. The Iwo operation, comparatively short, gave the new method of issue and transfer a good tryout. Twenty-seven fleet oilers were employed. Between 8 February and 5 March 1945 they delivered at sea 2,787,000 barrels of fuel oil (1,702,000 of them to Fast Carrier Force), 7,126,000 gallons of aviation gas (3,378,000 to the fast carriers), and 105,000 barrels of diesel oil. Ulithi, the headquarters of Commodore Carter's Servron 10, was the terminus of merchant tankers that supplied fleet oilers or floating storage.
Shasta and Wrangell on 19 February made the first successful
experiment in alongside transfer of ammunition at sea.9 Three escort carriers, recently modified to carry replacement planes, and two of the older CVEs operated with oiler groups. By 1 March they had delivered 254 new planes and 65 pilots and crewmen to fleet, light and escort carriers. Virgo, fitted as a mobile general stores ship, made the first successful experiment in transferring by line packages of dry stores, small stores and clothing.A valuable innovation was the conversion of two LSTs to be mother ships to landing craft.10 Each had bunks, cooking and mess facilities for 40 officers and 300 men, 20 reefer boxes carrying 160,000 rations of fresh and frozen provisions, space for the same number of dry rations, and large evaporators, Now, at last, boat crews, left on the beach when transports retired for the night, had a chance for a shower bath, a hot meal and a "sack". During the first two weeks of the Iwo operation these mother ships also refueled and watered 54 small vessels such as PCEs and LCTs, and reprovisioned an additional 76.
The Army Air Force setup in the Pacific was modified in August 1944 when Lieutenant General Millard F. Harmon assumed command of the newly formed Army Air Forces, Pacific Ocean Areas. General Harmon was also deputy commander to "Hap" Arnold of XX Air Force, which included the B-29s operating from Chinese bases, and of XXI Bomber Command of B-29s in the Marianas. In December 1944, Admiral Nimitz named him Commander Strategic Air Force, Pacific Ocean Areas, with control over all land-based aviation in the Pacific. 3. Air Bombing and Naval Bombardment11
As air bases became available in the Marianas the VII Army Air Force (Major General Willis H. Hale) began to subject Iwo Jima to one of the longest sustained air bombardments of the war. This air force, widely scattered on the Pacific, was mainly engaged in keeping bypassed islands neutralized. Truk was the main target, but others--such as Ponape, Wotje, Marcus and Wake--were given attention from time to time. As new bases in the Marianas were developed, General Hale's fighters and bombers moved forward to attack the Bonins chain. On 10 August the first B-24s based on Saipan bombed Iwo Jima. Thereafter that island and others nearby were hit whenever the weather permitted. There were 10 such raids on the island in August, 22 in September, and 16 in October. Most of them were aimed at cratering the airfields, but some were anti-shipping strikes on harbors in Chichi Jima and Haha Jima. These were laid on to oblige the Navy, which was concerned over the extensive reinforcement of Iwo Jima that was being staged through Port Lloyd and other island harbors. General Hale protested that his B-24 pilots were not trained for anti-shipping attacks, but not until the B-29s began operating from Saipan were these strikes called off.The first B-29 from the United States landed on Saipan on 12 October, and by the end of November there were enough to launch the first strike against Japan.12 Before that happened the Japanese, realizing what they were in for, counterattacked the Saipan fields twice, and ineffectively; but after the first B-29 raid against the Japanese homeland, on 24 November, they hit back hard. Early on the 27th, as the Superforts were loading bombs for a second strike, two twin-engined Japanese bombers came in low, destroyed on B-29 and damaged eleven others. Around noon the same day 10 to 15 single-engined fighters evaded the radar screen, destroyed three more B-29s and severely damaged two. These raids, which continued intermittently until 2 January, succeeded in damaging six and destroying eleven B-29s.
Since the loss of a B-29 was serious, strenuous efforts were made
to intercept or stop these raids. Vice Admiral John H. Hoover, Commander Forward Area, stationed two destroyers 100 miles northwest of Saipan as early warning pickets. They detected some raids, but not all. Since it was rightly suspected that the Japanese bombers staged through Iwo Jima, Admiral Nimitz gave that island top priority on 24 November. He ordered the curtailment of VII A.A.F. strikes on bypassed islands and shipping in order to concentrate a joint aerial bombing and naval bombardment on Iwo, 8 December.A fighter sweep by 28 P-38s opened the attack at 0945; 62 B-29s bombed at 1100 and 102 B-24s at noon; Crudiv 5 (Rear Admiral Allan E. Smith), comprising heavy cruisers Chester, Pensecola and Salt Lake City with six destroyers, arrived off Iwo at 1330 and opened bombardment at 1347. "Hoke" Smith approached the island from the west, rounded Mount Suribachi and then reversed track in a half-circle. Unfortunately the sky was so heavily overcast as to force the planes to bomb by radar and to hamper ships' spotting. Surface visibility was good enough to enable the island to be well covered by a naval bombardment, which lasted for 70 minutes and expended 1500 rounds of 8-inch and 5334 rounds of 5-inch shell. The bombers dropped 814 tons of bombs. Photographs, taken three days later, showed that both airfields on Iwo were wholly or in part operational, but no more enemy air raids hit the Marianas until Christmas Day.
The job of keeping Iwo airfields neutralized was now turned over to B-24s of VII A.A.F. Between 8 December 1944 and 15 February 1945 they flew at least one strike daily over the island. The day before Christmas, Rear Admiral Smith's heavy cruisers, together with five destroyers, delivered a second bombardment, coordinated with a B-24 strike. This strike was slightly more eventful than the initial one in December, but even less effective. The bombardment, which expended 1500 rounds of 8-inch, provoked return fire from a 6-inch coast defense battery (designated "Kitty" on the target maps) in the northeast part of the island, but "Kitty's" claws managed to strike no closer than 200 yards. As proof of the slight damage
inflicted by this bombardment, the Japanese were able to pay a vicious return visit to Saipan on Christmas Eve, a raid of 25 planes which destroyed one B-29 and damaged three more beyond repair.Crudiv 5 returned 27 December for a repeat performance, lighter than the others; and a fourth bombardment was set up for 5 January 1945. While fighter planes and B-24s hit Iwo Jima the same cruisers and six destroyers bombarded Chichi Jima, 145 northward, and the slightly nearer Haha Jima. Their hope was to catch a convoy bringing Japanese supplies to these islands, whence they were forwarded to Iwo by small craft at night. Destroyer Fanning, steaming ahead of the group as radar picket, encountered at 0206 a surface target, later identified as LSV-102, which she sank. At 0700 Admiral Smith's group opened a one hour and 49 minutes' bombardment of Chichi Jima. During it, destroyer David W. Taylor suffered an underwater explosion, probably from a mine, which flooded her forward magazine. The Haha Jima bombardment by Salt Lake City and two destroyers lasted for an hour. Crudiv 5 then pounded Iwo Jima for another hour and three quarters. The reply was negligible, and a few aircraft which made passes at the cruisers were easily driven off.
The next bombardment came on 25 January, following a three-hour forenoon bombing by VII A.A.F. B-24s, escorted by P-38s. Rear Admiral Oscar C. Badger was now O.T.C., wearing his flag in battleship Indiana, and he brought along two more destroyers as well as Crudiv 5. The bombardment opened at 1400 and lasted for two hours. Indiana planted 203 rounds of 16-inch on the island and Crudiv 5 added 1354 rounds of 8-inch.
Beginning the last day of January, and for two weeks, VII A.A.F. bombed the island night and day. The Superforts also got in a few licks on 24 and 29 January and 12 February, adding 367 tons of bombs to the impressive total that hit, or at least were aimed at, the island.13
Probably no island in World War II received as much preliminary
pounding as did Iwo Jima. For ten weeks, until 16 February when the intensive pre-landing bombardment began, the island was hit by land-based aircraft almost every day, and the total tonnage of bombs dropped was not far from 6800.14 In addition, 203 rounds of 16-inch, 6472 rounds of 8-inch and 15.251 rounds of 5-inch shell were fired in the five naval bombardments. Under ordinary circumstances, so heavy and prolonged a bombardment would have been more than sufficient to pulverize everything on an island of that size. Yet the Japanese restored the airfields on Iwo Jima to operation a few hours after each attack, and continued to fortify the island.Staff planners and Admiral Nimitz himself anticipated no unusual difficulty in taking Iwo Jima. Pacific Fleet technique for wresting islands from the enemy had been worked out as the result of abundant experience at Tarawa, Kwajalein, Eniwetok, Saipan, Guam and Peleliu. Yet when the Marines landed on the island 19 February, after three more days of intensive bombardment, expecting to secure it in a few days, they were forced to fight for it bitterly almost yard by yard over a period of one month and to lose 6137 of their number. How that could happen becomes apparent when we examine the Japanese defense system on Iwo Jima.
Until after the American seizure of the Marshall Islands in February 1944, Iwo Jima was simply a whistle stop on the air line from Japan to the Marianas and Carolines. Chichi Jima had been a small naval base since 1914, and most of the Japanese armed forces in the Nanpo Shoto were there; Iwo Jima had only a single airstrip capable of accommodating about 20 planes and a garrison of about 1500 men. After losing the Marshalls, Imperial General Headquarters 4. Japanese Preparations15
realized that the Marianas and Carolines were threatened and began to strengthen their next line of defense. In March 1944 the build-up of Iwo began in earnest. By the end of May there were over 5000 Army troops with artillery and machine guns, and a Navy guard force with a dozen coast defense guns of 120-mm caliber and upward, 12 heavy antiaircraft guns and thirty 25-mm twin-mount antiaircraft guns, manned by about 2000 men. The naval commander on the island was an airman, Rear Admiral Toshinosuke Ichimaru. By D-day the total strength of the island garrison was about 21,000 officers and men.When the Americans invaded Saipan in June, Imperial General Headquarters placed the defense of the Volcano group directly under Tokyo, organized the 109th Infantry Division, and sent it to Iwo under the command of Lieutenant General Tadamichi Kuribayashi. Tokyo strategists correctly estimated that Iwo Jima would be the choice for an Allied landing and they set about to make it impregnable. Thanks to the energy and skill of General Kuribayashi, they almost did.
Troops originally intended to reinforce the Marianas were now diverted to Iwo Jima. Because the island had no harbor, and attack by United States submarines was feared, reinforcements were unloaded at Chichi Jima, whence they were sent on to Iwo by small craft. This procedure did not save them from loss. On 18 July 1944, for example, U.S. submarine Cobia sank Nisshu Maru, transporting a tank regiment from Japan to Iwo, about 180 miles northwest of Chichi. Most of the troops were rescued by 28 tanks were lost. In six months, the Japanese lost about 1500 men en route to Iwo by surface and submarine attacks on their vessels.
Occasional sinkings of transports did little to check the build-up. Now relieved of arming Marianas and Marshalls, Japan had plenty of steel, concrete and other material to spare. Keen-eyed aerial photo interpreters working for Admiral Turner watched prepared positions on Iwo grow in strength and intensity from day to day. Owing to cliffs on the bulgy northeastern part of the pear-shaped island, the only places possible to land on were the beaches north and
east of Mount Suribachi, between which lay No. 1 Motoyama airfield with No. 2 not far north. General Kuribayashi figured out that the beaches and No. 1 airfield would be untenable in face of the naval and air strength which probably would be applied against them, and so decided to concentrate his defenses in and about Mount Suribachi in the south, and on the plateau around Motoyama village on the bulge. His naval advisers, on the other hand, insisted that the attack must be stopped at the water's edge. A compromise was made whereby the Navy constructed a series of pillboxes and strongpoints covering the beaches, and Kuribayashi assigned the troops to man them. Thus, Iwo had the benefit of the older technique for repelling an amphibious attack ("annihilate it at the water's edge") plus the new technique, tried at Peleliu, Leyte and Lingayen, of a desperate defense in depth.The Japanese naval coast defense guns of 120-mm (4.7 inch) and 155-mm (6-inch) caliber were so sited as to enfilade the beaches and approaches to them in a narrow arc of fire. Casemated behind four to six feet of concrete, they were so located as to have maximum protection from naval gunfire. Behind the beaches on both sides was a system of concrete pillboxes so placed as to be mutually supporting. Large concrete blockhouses were also built in this part of the island. Antiaircraft guns were placed in pits so that a direct hit was required to knock them out. A system of tunnels connected the various positions, in each of which a deep cave shelter was provided for the troops.
On the slopes of Mount Suribachi was a labyrinth of dug-in gun positions for coast defense artillery, mortars and machine guns. These were accompanied by elaborate cave and tunnel systems providing living quarters and storage space for servicing the weapons. From the volcano's rim, everything that went on at both sets of beaches, or on most of the island, could be observed.
General Kuribayashi's one main line of defense crossed the island between Nos. 1 and 2 airfields, taking full advantage of the terrain features. Here was a network of dug-in positions for artillery, mortars, machine guns and infantry weapons. These were in a system
of caves connected by underground tunnels. A second line of defense ran between No. 2 airfield and the central Motoyama sector. Accurate range and firing data were provided at each weapon position, so that high accuracy could be obtained with minimum exposure. But the main feature of the bulbous part of the island was an intricate network of caves and excavated rooms, all connected by deep tunnels. In some places there were five levels of these caves, and few were less than thirty feet underground. One cave might have several entrances, and most served the double purpose of protection to men and a position for weapons. A mortar could be set up at a cave or tunnel mouth, fired and then withdrawn. Even tanks were emplaced in pits or narrow ravines with only the turret exposed. Added to the natural strength of the underground system was the use of camouflage with materials blending into the surrounding terrain and vegetation. Many of these positions were so cleverly prepared that they were not spotted until they opened fire, or the protective camouflage was blown away by our gunfire. Later, when the Marines were fighting ashore, a camouflaged rifle pit or machine-gun position might be exposed only when the troops were taken under fire from the rear.All this followed the battle plan drawn up by General Kuribayashi in September 1944. He was to "transform the central island into a fortress". When the landings took place, the garrison must aim at "gradual depletion of enemy attack forces, and, even if the situation gets out of hand, defend a corner of the island to the death". "All forces will prevent losses during enemy bombing and shelling by dispersing, concealing and camouflaging personnel, weapons and materiel". The password for this operation meant "desperation", or "desperate battle".
Following the successful Allied landings on Luzon in January 1945 the Japanese high command was forced to take a new look at the strategic situation. In an atmosphere of pessimism and mutual suspicion it was difficult to reach any but the most general agreements on policy. But the need was urgent, and on 20 January 1945
an "Outline of Army and Navy Operations" was promulgated.16 This new policy predicted that the final battle of the war would be fought in Japan itself. The outline attempted to provide a strategic defense in depth by prescribing an inner defense line running from the Bonins through Formosa to the coast of China and southern Korea. Key strongpoints to be developed on this defense perimeter were Iwo Jima, Okinawa, Formosa, the Shanghai area and the South Korea coast. China and Southeast Asia were classed as secondary theaters. When United States forces, the principal enemy, penetrated this inner defense perimeter, an intense war of attrition was to be waged against them in order to reduce their preponderance, shatter their morale and delay the invasion of the home islands. Air forces were to exert themselves fully over the perimeter defense zone, but air strength in general was to be conserved until a landing was under way, then concentrate on the invasion fleet, with emphasis on the use of the Kamikaze Corps. The planes themselves were to be concentrated in Kyushu, the Ryukyus, Formosa and Eastern China. Ground forces were to hold out as long as possible without reinforcement.General Kuribayashi did his best to implement this directive, and his best was very good indeed. During the long series of air attacks and bombardments the garrison holed up, then came out to repair damage. Reinforcements and new guns and materiel were brought in at night and improvement of all defenses continued. If, as the Japanese expected, the assault could have been made shortly after the Marianas were secured in the fall of 1944, the island would have been ill prepared to meet it, but the postponement to February 1945 gave Kuribayashi his opportunity to sell the island at the highest price. Subsequent complaints by General Holland Smith and others about the amount and quality of naval bombardment and air bombing were completely off the beam: Iwo's defenses were of a nature that neither could possibly neutralize them. The only way to knock out most of the positions was for ships to close to point-blank
range, 2000 yards or less, and blast them out. This could not be done until the attack force was ashore, and one knew the location of the strongpoints.Intelligence of Japanese defense through aerial photographs was helped by submarine Spearfish, which snooped Iwo in early December and took photographs of the beaches through her periscope. The nature of the soil was correctly estimated, and the number defensive positions seen was not far short of the truth. But she could not spot the caves and tunnels, and nobody in Marine headquarters seems to have put together the experience at Biak and Peleliu to anticipate the new Japanese tactics of defense in depth, which were to cost the Marine Corps dear.
The Japanese Navy's only contribution to the defense of Iwo Jima was in the form of submarines bearing the human torpedoes that they called kaiten, but the initial success of this gimmick, sinking a fleet oiler in Ulithi lagoon on 20 November, was not repeated.17 A kaiten unit composed of I-370, I-368 and I-44 sailed for Iwo Jima 22-23 February 1945. The first-named ran afoul of destroyer escort Finnegan (Lieutenant Commander H. Huffman USNR), escorting a convoy from Iwo Jima to Saipan, on 26 February. She made a surface radar contact distant seven miles at 0555, sound contact at 0630, delivered three depth-charge and hedgehog attacks and hung on until 1034 when a very deep underwater explosion was heard and debris with Japanese markings rose to the surface. That marked the end of I-370.
Before the Iwo operation began, escort carriers Anzio (Captain G.C. Montgomery) and Tulagi (Captain J.C. Cronin) were made nuclei of hunter-killer antisubmarine units. A fighter plane from Anzio, flying a ten-mile-square search in the early hours of 26 February, at the request of destroyer Bennion, which had made and lost contact, sighted RO-43 (not a kaiten submarine) and destroyed it west of Chichi Jima by a depth-bomb drop from 150 feet. Next day Tulagi sent planes after two submarines reported to be southeast of Iwo Jima but apparently missed them; Anzio planes, however,
flew a repeat performance on the 27th and sank I-368, a few miles west of Iwo Jima.18I-44 reached Iwo waters, but was kept down by destroyers for over 48 hours, almost suffocating the crew, and then returned to base. Vice Admiral S. Miwa, commanding Sixth Fleet (the submarines), was furious, and relieved the skipper of his command. A second kaiten unit of I-36 and I-58 (the boat that later sank Indianapolis) was then formed, and departed Kure 1 March. The first had to turn back shortly after its sortie, and I-58, after a frustrating cruise around Iwo, constantly harassed by antisubmarine craft, was recalled on 9 March.19
Table of Contents ** Next Chapter (2)
1. This subject is also covered to some extent in Vols. XII Chap. I and XIII Chap. I. To the sources mentioned there add J.A. Isely and P.A. Crowl The U.S. Marines and Amphibious War (1951) chap. x, Lt. Col. Whitman S. Bartley USMC Iwo Jima: Amphibious Epic, published by Marine Corps Historical Branch 1954. In addition the writer discussed the strategic questions affecting the operations in this volume with Rear Admiral Forrest Sherman in May 1945, and profited by a perusal of his personal compilation, "Future Operations Recommendations to Cominch". Footnotes
2. The Bonin Islands (Ogasawara Gunto to the Japanese) properly are the central group of Nanpo Shoto comprising Muko, Chichi, and Haha. The southern group, which includes Iwo Jima, is called the Volcano Islands, but Bonins is often used for the entire chain. Jima or Shima means an island, Shoto an archipelago, Gunto an island group.
3. XX A.A.F. included XX Bomber Command in China and XXI Bomber Command in Marianas.
4. Lionel B. Cholmondeley History of the Bonin Islands (London 1915).
6. Cincpac-Cincpoa "Joint Staff Study DETACHMENT" 7 Oct. 1944. Operation DETACHMENT was the code name for the capture of Iwo, but it was little used.
7. Worrall R. Carter Beans, Bullets, and Black Oil (1953) chap. xxii; Conservron 6 (Rear Adm. Beary) "Logistic Analysis Iwo Operaton" 8 Mar. 1956. For Leyte logistics see Vol. XII Chap. V.
8. For brief biography see Vol. X 47n.
9. Serpens, a Coast Guard-manned cargo ship of Servron 8 refitted as ammunition carrier, blew up in Lunga Roads, Guadalcanal, on 29 Jan. 1945 with the loss of all hands but three.
10. Commo. Carter (p. 290) credits this type to "Admiral Turner's ingenuity and initiative".
11. Comcrudiv 5 (Rear Adm. Allan E. Smith) Action Reports of 17 Dec. 1944 and 21 Jan. 1945; Craven & Cate V chap. xix.
12. For description of the Superfortress, see Vol. XIII 162.
13. "Analysis of Air Operations Pacific Ocean Areas and B-29 Operatons:, Nov.-Dec. 1944.
14. Comairpac "Analysis of Air Operations--Iwo Jima" 21 June 1945.
15. Cincpac-Cincpoa Bulletin No. 136-145 Defense Installations on Iwo Jima 10 June 1945, Bartley Iwo Jima, MacArthur Historical Report II.
16. MacArthur Historical Report II 542 ff.
17. See Vol. XII 51.
18. CTG 52.2 (Rear Adm Durgin) Action Report of 21 April 1945, Enclosure A, p. 8.
19. M. Hashimoto Sunk (1954) pp. 139-143.
