Operation Iceberg: The Assault on Okinawa - The Last Battle of World War II (Part 2) April - June 1945

The Opening Shots
The Americans Move
The Assault Goes In
The Advance Gets Underway: L+1 to L+3
A General Advance: L+4 to L+17
IIIAC Moves North
The Ie Shima Landings
The Main Assault on the Shuri Defences: 19 April (L+18)
The Japanese Strike Back
The Assault on the Shuri Defences and the Battle for Sugar Loaf Hill
The Americans Push South
Ushijima Makes A Last Stand
Bibliography and Further Reading

The Opening Shots

New Mexico class battleship bombardments Okinawa
New Mexico class battleship bombardments Okinawa
The Second World War first reached Okinawa on 29 September 1944 when B29s bombed the airfields and reconnaissance was conducted to photograph as many of the islands as possible. An attack by carrier aircraft quickly followed on 10 October, which was intended to cover the approaching invasion of Leyte - the Japanese referring to this as the air battle of Formosa and lost some 500 aircraft and thirty-six ships in three days. The islands were hit again on 3 and 10 January, both by the Fast Carrier Force (TF 38), and again on 1 and 31 March, by the newly re-designated Fast Carrier Force (now TF 58) after it had hit targets in the Tokyo area. While American patrols effectively isolated the Ryukyus from Formosa and Japan, B29s continued to pound the airfields in-between attacks on Japan itself. By the end of March there were almost no operational aircraft left on Okinawa and many of the cities and towns (including Naha and Shuri) were badly damaged or destroyed. On 24 March five battleships (16in guns) and eleven destroyers shelled targets on Okinawa and between 26 and 31 March the British Carrier Force attacked Sakishima Gunto to neutralise the airfields there.

The Japanese, expecting an attack on Formosa or Okinawa at any time, alerted the air force to implement Ten-Go on 25 March but massive B29 raids on the Kyushu airfields badly disrupted preparations and it was not launched until the 6 April, five days after the assault on Okinawa began. The Mine Flotilla (TG 52.2) started clearing the approaches to Okinawa on 22 March (discovering six minefields and destroying some 257 mines) while on 25 March the Gunfire and Covering Force (TF 54) moved into position with nine battleships (3 x 16in, 5 x 14in and 1 x 12in guns), 10 cruisers (7 x 8in and 3 x 6in guns), thirty-two destroyers and escorts, as well as 177 gunboats. A massive amount of ordnance was fired in the seven days leading up to L-Day (as an example, some 37,000 rounds of 5in, 33,000 rounds of 4.5in and 22,000 4in rockets were fired) as well as 3,100 air strikes conducted on beach and in-shore targets. While this had little direct impact on the Japanese defenders it certainly kept their heads down as they refused to respond to the onslaught.

The Americans Move

US 77th Division on Geruma Shima
US 77th Division on Geruma Shima
Kerama Retto is a group of islands and islets about fifteen miles west from Okinawa, and although unsuitable for the construction of airfields, can provide an excellent anchorage for over seventy large ships and eventually became the fleet's rearming, refuelling and repair base. While the proposal to capture the islands was initially resisted due to the fear of air attack, it was realised that such a base was a necessity given the experience at Iwo Jima. The 77th Infantry Division (Western Island Attack Group) swept through the Keramas from the west on 26 March (L-6) and five of the division's infantry battalions - 1st Battalion, 305th Infantry Regiment (1/305), 3/305, 1/306, 2/306 & 2/307 - met little resistance as they secured the islands by 29 March with four of the islands had just under a thousand IJN troops on them. Japanese losses amounted to 530 dead and 121 taken prisoner while American losses amounted to 31 dead and 81 wounded. Around 1,200 civilians were interred with another 150 committing suicide. 350 suicide boats were captured. The remaining IJN troops were left undisturbed on Tokashiki under a gentlemen's agreement and surrendered after VJ Day. The 77th Infantry Division re-embarked on 30 March leaving the 2/305 behind for security, while a provisional infantry battalion formed from the 870th Anti Aircraft Battalion on relieved this on 23 May. The fleet base and a seaplane base were operational before the islands were finally secured.

Keise Shima (eleven miles southwest of the Hagushi Beaches) was secured by an unopposed landing of the 2/306 on 31 March. This was followed by 420th Field Artillery Group with the 531st and 532nd Field Artillery Battalions (155mm guns) to support the assault forces on L-Day and throughout southern Okinawa.

Underwater demolition teams (UDT) undertook reconnaissance sweeps of the Hagushi Beaches on 29 March, while spotter aircraft flying over Okinawa reported no human activity, the island seeming deserted. Then, on 30 March, UDTs 4, 7, 11, 16, 17 and 21 swam towards the beaches and started to clear anti-boat obstacles from mid-morning. By this time, the assault force was assembling a little to the west of Okinawa and the carrier Force took position some fifty miles to the east. The 2nd Marine Division, who were the demonstration force, embarked on 31 March and arrived off the southeastern Minatogawa Beaches in the early morning, which the Japanese considered to be the most likely landing spot, a ruse that had been reinforced by the operation of minesweepers and UDTs since 29 March.

The Assault Goes In

US Landing Craft at Okinawa
US Landing Craft at Okinawa
Admiral Kelly Turner gave the order to "Land the Landing Force" at 04.06, 1 April 1945 - Easter Sunday and April Fool's Day. The pre-invasion bombardment started at 05.30 and as the sun rose at 06.21 the soldiers and marines who would shortly be landing on it, saw Okinawa Gunto for the first time. Gradually, the amtracs formed into groups and started to circle, awaiting the order to head towards the beach. Carriers planes and gunboats bombarded the beaches and as the control craft pennants came down, an eight-mile line of amtracs began their 4,000 yard dash to the beach. At the same time, the 2nd Marine Division began their feint and ironically suffered the first casualties as kamikazes slammed into a transport and LST (Landing Ship, Tank or Troops) - apart from these air attacks the demonstration prompted no other Japanese reaction. Ushijima had few troops near the Hagushi Beaches anyway and the remainder were positioned exactly where he wanted them. The assault force churned their way past the Battleship USS Tennessee and formed into the regimental assault waves of two battalions abreast in eight waves:
Flamethrower Tank of 6th Marine Division, Okinawa
Flamethrower Tank of 6th Marine Division, Okinawa
There was only sporadic mortar and shellfire as the assault troops landed - resistance from the 1st Specially Established Regiment was light as it had only rudimentary training and few heavy weapons. Okinawa was not to be a repeat of Peleliu, Tarawa or Iwo Jima with the assault waves meeting fierce and coordinated resistance upon landing. Some 50,000 American troops landed in the first hour and the larger landing ships started to deliver heavy weapons and armoured vehicles at 14.00. By nightfall another 10,000 troops had come ashore and a 15,000-yard beachhead had been established with 6th Marine Division on the left, then 1st Marine Division, then 7th Infantry Division and 96th Infantry Division on the right. A 600-yard gap existed between XXIV Corps and IIIAC but this was closed on L+1. The first day saw the 4th Marines on the edge of the Yontan Airfield and 17th Infantry on the perimeter of Kadena. It also saw twenty-eight dead, twenty-seven missing and 104 wounded for the opening day of Operation Iceberg.

The Advance Gets Underway: L+1 to L+3

On the morning of L+1, 2nd Marine Division conducted another feint off the southeast beaches, which again achieved very little. Both Kadena and Yontan airfields quickly fell into Allied hands with Kadena being useable for emergency landings by the end of the day and Yontan being useable by the end of L+2. Neither airfield had been destroyed by the Japanese and the main bridge across the Bishi Gawa had been captured intact. The weather remained good for the next couple of days and so the Americans continued their rapid advance with the 6th Marine Division moving north and securing the Ishikawa Isthmus by the 4 April. The 1st Marine and 7th Infantry Divisions advanced eastwards and reached the east coast by the end of 3 April whereupon the 96th Infantry Division wheeled south, the Marines set about securing the Katchin Peninsula and 7th Infantry Division started to move south also. By the end of 4 April (L+3) all the units were in position across the Chatan Isthmus, exactly where they had expected to be in after two weeks of heavy fighting. Meanwhile the build-up continued and more support troops came ashore - the fleet dispersed as best it could but more and more ships gradually fell victim to the increasing air attacks. Hundreds of civilians were rounded up and interrogated with the picture of a general Japanese withdrawal to the south emerging.

The weather however, turned sour on 4 April and in many instances forced unloading to stop. The rain turned the dust tracks into quagmires and forced the construction of new roads between the rainstorms. The US engineers began to replace the weak native stone bridges with steel Bailey bridges and the coastal highway was renamed 'US1'. Marine fighter squadrons began to fly into Yontan on 4 April and into Kadena two days later.

A General Advance: L+4 to L+17

The Tenth Army's eastern flank was secured by 3/105 of the 27th Infantry Division who, between 6 and 11 April, swept the Eastern Islands northeast of the Katchin Peninsula in the Chimu Wan. They were supported by Fleet Marine Force Pacific's (FMFPac) Amphibious Recon Battalion, UDT 7 and Army amtrac units with the remainder of the 105th Infantry remaining as a floating reserve aboard the Eastern Islands Attack and Fire Support Group (TG 51.19). Most of the islands were undefended except for Tsugen Shima, which was defended by 1st Battery, 7th Heavy Artillery Regiment. The Japanese lost 243 men killed while thirty escaped, and the Americans lost fourteen dead.

The Americans could only guess at the intentions of the Japanese as aerial reconnaissance showed little movement in the south of the island (the Japanese tended to stay underground during the day), some wondering if the enemy had evacuated elsewhere, had been drawn to the southeast by the demonstrations or was waiting to counterattack. General Hodge ordered the 7th and 96th Infantry Divisions to advance south, while the Japanese waited for the main American attack. The Japanese plan was to use the 62nd Division to hold the main defence line, while the 24th Division and 44th IMB were to stay in reserve in case of additional American landings in the south. The 62nd Division held excellent positions in commanding terrain with the 63rd Brigade on the right flank and 64th Brigade on the left in deeply echeloned positions. It had a clear line of sight right across the XXIV Corps area and its artillery could fire on the Hagushi Beaches and Nakagusuku Wan.

The two American divisions pushed through the outlying positions as they moved cautiously south, and then suddenly met very strong resistance around Cactus, Kiyaniku and Tombstone Ridges (while the Americans tended to use Japanese names when such terrain features were identified on a map, if such terrain was unnamed, it would be given a nickname or a name after a nearby village). A key terrain feature, called 'The Pinnacle' was captured by the 184th Infantry after a tough battle on 6 April (L+5) and was thought to be the spot where Commander Perry raised the American flag in 1853. The 63rd Brigade managed to put up enough resistance to halt the advance from 6 to 8 April. The covering force had done its job well, having slowed the Americans for some eight days and inflicted over 1,500 casualties, but at a cost of over 4,500 killed. The outer Shuri defences had now been discovered and the Americans could only assume that even tougher fighting lay ahead.

The reinforced 63rd Brigade still manned much of the Kakazu Ridge that ran northwest to southeast to the northeast of Kakazu village. The 383rd Infantry (96th Inf Div) assaulted the ridge on 9 April and were repulsed several times. They finally captured it on 12 April at a cost of 451 killed, while the 63rd Brigade lost 5,750. During these battles, the 7th Infantry Division to the east made little progress due to the rough terrain and the strong resistance. Despite the fact that 7th Infantry Division's front was only one-third of the entire XXIV Corps' front, the terrain forced narrow frontages which the Japanese exploited and the almost non-existent road network hampered the logistic effort. The Tenth Army's floating reserve, 2nd Marine Division, left for Saipan on 11 April. Although slated to land Kikai off Amami O Shima in July, the landing never took place.

Some of the more aggressive Japanese commanders wanted to conduct a counterattack but Colonel Yahara held them at bay by pointing out that even if the counterattack was successful, any force would be exposed to the full weight of American firepower once they reached the plains. With the Americans becoming stalled on the outer Shuri defences however, Lt General Ushijima gave in to the idea and the 22nd Infantry (24th Div) was moved north from the Okoru Peninsula to attack through the 63rd Brigade's line in the east. Elements of the 63rd Brigade, along with the 272nd Independent Infantry Battalion (the 62nd Division reserve) would attack in the west. The counterattack was launched at 19.00, 12 April with a 30-minute barrage to cover the attack. The attack was far too weak and not well enough co-ordinated to have any serious impact, as many commanders, realising its folly, held back their troops. The 22nd Infantry was unfamiliar with the rough terrain in front of the 7th Infantry Division and the attack foundered, but the 96th Infantry Division faced a determined and well-planned attack from the 272nd IIB, which caused the 381st Infantry a difficult time. The battle lasted until the night of the 13 / 14 April and delayed the American push by three days but cost the Japanese several hundred dead. XXIV Corps continued its slow push south as it prepared to assault the main Shuri defences. The 13 April saw the death of President Franklin D Roosevelt, which stunned the American forces.

IIIAC Moves North

While XXIV Corps pushed slowly south, IIIAC fought an altogether different battle in the north. The 1st Marine Division defended Yontan Airfield, the landing beaches, and also cleared the remainder of the island behind XXIV Corps. The 6th Marine Division secured the Ishikawa Isthmus (with the 22nd Marines) and pushed north with the 29th Marines (to the west) and 4th Marines (to the east), supported by tanks and artillery. The terrain was very rugged and had dense vegetation but also limited roads, which made movement difficult.

As the Marines moved north, it gradually became clear that the Japanese had concentrated on the Motobu Peninsula in the northwest and so the 29th Marines moved in that direction while the 4th and 22nd Marines cleared the few pockets of resistance and secured the 29th's rear areas. As the 29th moved towards the peninsula, resistance gradually increased. The Japanese were in fact concentrated in a redoubt built on the 1,200-foot high Yae Take (Mount) that measured 6 miles by 8 miles. The difficult terrain made it almost impossible to use armour and was ideally suited to the heavily armed 'Udo Force' (some 1,500 men) that had been detached from the 44th IMB. The Marines attacked the position in earnest on 14 April and the battle lasted for four days. Some 700 enemy dead were counted, but many managed to either escape to the south or to conduct a lengthy guerrilla war in the north. This was conducted through countless small-scale skirmishes, hit-and-run raids, ambushes and sniping. Added to the Japanese troops, many Okinawan (due to Japanese propaganda) irregulars fought (trained by veterans from China) alongside them and conducted sabotage. The battles even drew in the 7th Marines as they tried to secure the Ishikawa Isthmus. Eventually, the 27th Infantry Division relieved the 6th Marine Division in the north on 4 May. The 6th had suffered some 1,837 casualties. The 27th gradually cleared the north during May and early June, fighting a ten-day battle on Onna Take (1,000-ft high), and declared the north secure by 4 August.

The Ie Shima Landings

The landing on Ie Shima (occasionally known as Ie Jima) was codenamed Indispensable. The island itself is around 5.6 km (3.5 miles) off the western end of the Motobu Peninsula and some 32km (20 miles) north of the Hagushi Beaches. It measures some 9km (5.5 miles) long and 4.5km (2.75 miles) wide and is surrounded by a coral reef. The north and northwestern coasts have cliffs up to 30m high and a large number of caves, while the southern coast has beaches that range from 9 to 35 metres in depth and 125 to 900 metres in length (that are separated by low cliffs). The ground moves inland at a gentle slope away from the beaches, up to a plateau that averages around 50m above sea level. The road network was well developed, but mostly unsurfaced, while the terrain was generally of cultivated farmland with areas of trees, scrub and low grasses. In the east, the Iegusugu Pinnacle (a cone-shaped limestone peak) rises to a height of 185m (600 ft) and was covered with scrub and trees, as well as being honeycombed with caves and tunnels. The Japanese naturally reinforced these and constructed a multitude of pillboxes, bunkers and blockhouses. To the south of 'The Pinnacle' was Ie Town (most of the buildings being of stone construction and substantially fortified) and to the west in the centre of the island were three airstrips between 6 and 7,000 feet in length, in the shape of 'XI'. The Igawa Unit of 3,000 troops defended the island along with some 1,500 armed civilians.

Minna Shima, an islet that lay some 6.4km (4 miles) south of Ie, was captured by elements of the Fleet Marine Force Pacific Reconnaissance Battalion on 12 / 13 April. This was followed by the deployment of three battalions of artillery (305, 306 and 902 FA) onto the islet on 15 April. The 77th Infantry Division was moved some 480km (300 miles) and assaulted Ie Shima on the morning of the 16 April (W Day), fully supported by naval gunfire and artillery firing from the Motobu Peninsula. The 306th Infantry landed on Beach Green T-1 at 07.58 (S Hour), which lay to the southwest, while the 305th Infantry (minus 2nd Battalion) landed on Red T-1 and Red T-2. As before, there was very little resistance as the infantry regiments swept across the island capturing the airfields and heading towards Ie Town and 'The Pinnacle'. Resistance started to mount considerably as the Americans approached the town and the 307th Infantry (minus 1st Battalion) was landed, along with part of the 706th Tank Battalion on Red T-3. By the 18 April, American forces were closing in from the north, south and west but accusations had already started to fly over the time being taken to accomplish the mission. The attack on the town initially foundered with heavy resistance being encountered in the town centre and the administrative area (called Government House Hill), as well as high ground on he edge of town (called Bloody Ridge). The town was eventually cleared by the 20 April and the assault on 'The Pinnacle' started in earnest. Fighting continued for several days and resistance did not finally cease until 26 April. The Japanese lost some 4,700, including most of the 1,500 militia and around one-third of the remaining civilians on the island died. The Americans suffered 1,118 casualties (218 killed). Tragically, Ernie Pyle, the very popular war correspondent for Scripps-Howard, was killed on 18 April by machinegun fire. The 77th Infantry Division was to later erect a monument over his grave in the division cemetery. The 77th was moved to Okinawa between the 25 and 28 April, leaving behind the 1/305 to continue mopping up operations. The 1/305 were themselves relieved by the 1/106 on 6 May. The 2/305 occupied the island of Zamami Shima. The entire population of Ie Shima was removed from the island so as not to interfere with the construction work on the airfields. They were returned after the war's end.

The Main Assault on the Shuri Defences: 19 April (L+18)

By now, XXIV Corps was facing the main cross-island defensive line (the Shuri defences) situated on a series of steep ridges and escarpments to the north of Shuri itself. To the west was the 27th Infantry Division, the 96th lay in the centre and the 7th was deployed in the east. Little movement had taken place since 14 April as the Americans prepared for their main offensive. The Japanese 62nd Division still defended the entire front with its 64th Brigade entrenched in the centre and the west, while the 63rd Brigade was fortified in the east, mainly along the Urasoe-Mura and Tanabaru Escarpments. The 44th IMB was to the rear, around Shuri.

The 27th Infantry Division made a preliminary attack on the night of the 18 April as bridges were secretly built across the Machinato Inlet that separated Uchitomari and Machinato on the west coast. The 106th Infantry managed to secure a valuable foothold on the very northwest end of the Urasoe-Mura Escarpment and cleared Machinato Village with a bold night attack. The main attack was launched at 06.40 on 19 April after a opening barrage by twenty-seven artillery battalions with naval gunfire and aircraft attacked the Japanese rear area. The 7th Infantry Division attacked in the direction of Skyline Ridge that anchored the eastern end of the Japanese defence lines but made little progress against strong resistance. The 96th Infantry Division met equally determined resistance as it attacked between the Tombstone and Nishibaru Ridges and suffered the same lack of success. The 27th continued to hold its ground on the south side of the Machinato Inlet and made some gains along the Urasoe-Mura Escarpment but failed in its assault on Kakazu Ridge when the 193rd Tank Battalion became separated from the 1/105 resulting in the loss of some 22 tanks.

The next week saw the three divisions struggle against well-entrenched opposition with no unit advancing more than 1.188km (1,300 yards). The 27th Infantry Division to the west was hung up on the north side of Gusukuma towards the coast and on the northwest end of the Urasoe-Mura Escarpment further inland, along with the 96th. Kakazu,, as well as the Nishibaru and Tanabaru Ridges had eventually been taken but the Japanese 22nd Infantry was still holding up the 7th Infantry Division to the east. The Americans assembled the Bradford Task Force, formed from all the reserve components they could scrap together, and supported by armour it assaulted the Kakazu Pocket on 24 April, only to find the Japanese had abandoned it. While it diverted important assets away from the frontline, the Japanese also lost their one outstanding opportunity to launch a counterattack as the Americans had no reserve left - all had been committed to operations.

By the end of April, most units had made some progress with the 7th Infantry Division advancing on its inland flank to the Kochi Ridge but was held up once again by the Japanese 22nd Infantry. The 96th was still moving forward slowly against the Japanese 32nd Infantry on the Urasoe-Mura Escarpment, as was the 27th. By this time the three divisions were exhausted and well-below strength. It was proposed to land the 77th Infantry Division on the southwest coast north of Minatogawa to force the Japanese to pull troops out of the main Shuri defences but General Buckner rejected the idea as he considered the risk to a single division that far behind enemy lines too great especially with the added logistics burden and the requirement for ships to protect the anchorage. Instead, the 1st Marine Division was attached to XXIV Corps on 30 April relieving the 27th Infantry Division on the western flank, while the 77th relieved the 96th, despite being three battalions down on occupation duty. The effort to push south continued until the 3 May when the Japanese attempted their most determined counterattack.

The Japanese Strike Back

As they became increasingly frustrated at the prolonged defensive battle, many Japanese commanders clamoured (again) for a counterattack to halt the American's slow but steady advance. Colonel Yahara (Operations Officer, 32nd Army) once again warned of the folly of such an attack but the Chief of Staff, Major General Cho, succeeded in pushing for just such an attack. The Japanese attacked on the night of 3 May with the main effort coming from the 24th Division as it attacked in the centre and the east. While penetrations were made in several places, the attack never really threatened the American position on Okinawa and the attack was eventually repulsed, despite the Japanese supporting it with landings on the coast to the rear of the frontline. The Japanese lost some 7,000 men out of the remaining 76,000, while the Americans suffered only some 700 casualties. The Japanese rebuilt their units, mainly using rear area service troops and prepared for a battle of attrition to the end. The 62nd Division, reduced to about one-third strength, defended the western third of the line, while the 24th Division (now at about two-thirds strength) defended the rest. The 44th IMB (at around 80 percent strength) supported the 62nd Division. Japanese artillery had been reduced to about half-strength and is ammunition expenditure substantially curtailed.

Meanwhile, TF 51 (Joint Expeditionary Force) had been not only been providing close air support to the forces ashore, but also combat air patrols to guard against air attack and kamikazes, reconnaissance, anti-submarine patrols, as well as vital logistic and medical support. The first two weeks also saw TF 57 (British Carrier Force) in action off Saishima Gunto in order to neutralise the airfields on the island. The fast carriers of the Third and Fifth Fleets also attacked airfields on mainland China, Formosa, throughout the Ryukyus and on Kyushu. The Kamikaze (or Special Attack) idea of intentional suicide attacks on Allied ships by volunteers was first seen in the Philippines and while attacks were conducted sporadically in those early days, by the time of Okinawa it had become a well-developed operation, that of Ten-Go. The 1st Special Attack Force consisted of over 1,800 aircraft from the combined 5th and 6th Air Armies on Kyushu and Formosa, under Admiral Soemu Toyoda. The first big raid during Operation Iceberg was conducted on the 6 and 7th April with a 355 plane strike where the US Navy lost six ships with another 21 damaged and over 500 casualties. The Japanese lost almost 400 aircraft. The raids continued unabated through April with a total of fourteen American ships being sunk, ninety being damaged compared to 1 sunk and forty-seven damaged for conventional air attacks. The Japanese lost almost 1,100 aircraft and raids continued through May (being heavier towards the end of the month) with the Japanese concentrating not only on the picket ships, transports and carriers in the fleet but the airfields as well. The final attacks occurred on the 21 - 22 June. In all the Japanese committed some 1,900 aircraft and sunk some twenty-six US ships and damaged 225 using Kamikazes and sunk 1 ship and damaged 61 with conventional attacks.

In a desperate attempt to disrupt the American operation, the Japanese despatched the Yamato on 6 April on what was, in effect, its own kamikaze mission. The super battleship was to beach itself on Okinawa just south of the landing beaches and then bombard the American forces ashore and the transports. The ships only had enough fuel to make a one-way trip. The Yamato was accompanied by the cruiser Yahagi and eight destroyers on its Ten-Ichi (Heaven Number One) operation. They sortied from Tokuyama Naval Base on southwest Honshu led by Vice Admiral Seiichi Ito. The force was detected by a US submarine soon after it had reached the open sea but contact was lost as night fell. US carrier planes found the force the next morning (7 April) and aircraft from TF 58 attacked at noon. The Yamato (ten torpedo and five bomb hits), Yahagi (seven torpedo and twelve bomb hits) and four destroyers were sunk. The battleship went down with 2,487 crew. The remaining destroyers limped back to port.

The Assault on the Shuri Defences and the Battle for Sugar Loaf Hill

The IIIAC resumed control of the 1st Marine Division on 7 May, which was on the western flank of the American line. As they pushed south, the island naturally widened and so it became necessary to insert a fourth division in the line. The 6th Marine Division was assigned a sector and moved the 22nd Marines into the very western end of the line, to the 1st Marine Division's right. The 77th Infantry Division received the understrength 305th Infantry and the rested 96th Infantry Division relieved the 7th Infantry Division on 8 May (the surrender of Nazi Germany was announced that day). The Tenth Army renewed its offensive on 11 May with the 6th Marine, 1st Marine, 77th Infantry and 96th Infantry Divisions in line from west to east.

Limestone Hill on Okinawa
Limestone Hill on Okinawa
Each division had its objective. The 96th Infantry Division would attack Conical Hill, the 77th Infantry Division would go for Shuri Castle, the 1st Marine Division would strike for the Dakeshi-Wana-Wana complex guarding Shuri itself and the 6th Marine Division would assault Sugar Loaf Hill. The objectives facing the Marines were probably the toughest with Sugar Loaf probably the defensive equal of anything found on Iwo Jima. It was actually a complex of three hills, with Sugar Loaf being a oblong ridge about fifty feet high and protected on its flanks by The Horseshoe and the Half Moon, with smaller emplacements in front of it on Charlie Ridge, Charlie Hill, Hill 3 and Hill 1 (running east to west). The Japanese units defending Sugar Loaf and the area around it consisted of: the 2nd and 3rd Battalions, 15th IMR; 44th IMB; 2nd Battalion, 223rd Special Guard Force (IJN); a 75mm AA gun battery from the 81st Field AAA Battalion; along with elements of the 103rd Machine Cannon Battalion and 7th Anti-Tank Battalion.

Initial progress was slow but steady, although the two divisions in the centre did not penetrate as much as those on the flanks. The 6th Marine Division then became entangled on the Japanese defensive bastion of Sugar Loaf Hill, while the other divisions battled for stoutly defended ridges and hills. The 6th Marine Division's 22nd and 29th Marines finally reached the main defensive position on 14 May after crossing the Ada River and clearing a number of the outlying positions. The first attack on it was driven back, despite being supported by tanks but the second, made by the 2nd Btn, 22nd Marines just before dusk managed to reach the base of the hill. After being reinforced and resupplied they continued up the hill, led by Major Courtney and dug in under the protection of artillery fire. The Marines held their positions (thanks in no small part by one particular Marine, Corporal Rusty Golar) under enemy fire and counterattacks until well into the next day, but finally under heavy pressure they had to withdraw. The positions on Sugar Loaf held against continued Marine assaults, preceded by thunderous artillery barrages, until 18 May when a flanking manoeuvre brought the breakthrough that was needed. A small, almost imperceptible depression had been observed running north to south between the Half Moon and Sugar Loaf and Marines who had accidentally wandered into it had been subjected to a much smaller amount of enemy fire than in other places around Sugar Loaf. General Shepherd who had come up to the front decided to move the 29th Marines through the depression with two battalions striking at Half Moon Hill and then hold to support a third battalion which would attack Sugar Loaf's left flank. The two battalions hit the Half Moon and dug in to support the third battalion. Four times they went up, four times they were repulsed. On the 18 May though, the Marines managed to take the hill by moving round three tanks into positions where they could fire on the Japanese defenders when they emerged from their caves to occupy the defensive positions on the crest. The tanks decimated all who showed themselves and the Marines moved forward to occupy the crest and then advance down the reverse slope. It took the 4th Marines another four days however to clear the complex entirely. The 6th Marine Division suffered some 2,662 casualties in the battle for Sugar Loaf Hill, with another 1,289 suffering combat fatigue. Their next target would be Naha.

1st Marine Division at Naha, Okinawa
1st Marine Division
at Naha, Okinawa
Meanwhile, to the east of the 6th Marine Division, the 1st Marine Division was pushing towards Dakeshi Ridge, Dakeshi Town, Wana Ridge and Wana Draw, while its ultimate objective was Shuri Heights. Its regiments leapfrogged their way forward and were exposed to fire from their left flank and front almost all the way. The division took both Dakeshi Ridge and Town after a three-day seesaw battle that saw the Americans moving forward by day and the Japanese counterattacking by night. Sometimes the daytime would see a fresh attack to recover ground lost during the night. In many instances platoons would take a position at the cost of three-quarters of their strength and then try and hang onto it grimly with the survivors. On 14 May, the 1st Marine Division entered the Wana Draw, which was formed from the reverse slope of Wana Ridge on its left and the forward slope of another ridge to its right. The fighting for the Draw was bitter but the Marines struggled forward and continued to draw closer to Shuri.

The 77th Infantry Division took on the Chocolate Drop - Wart Hill - Flattop Hill complex in the centre of the island, with Shuri Castle as their ultimate objective. This forbidding position was almost as formidable as Sugar Loaf Hill and bristled with machineguns, mortars and 47mm antitank guns. While many Army units expressed a dislike of working with the leathernecks (and the feeling was just as strong the other way), the 77th believed they had earned a form of respect from the Marines, having worked well with them on Guam. Indeed, the Statue of Liberty Division "admired them and had great respect for the way they handled themselves so professionally. We were more than glad to have had them on Guam. On the other hand, they equally respected us for the support and cooperation they received from us." (Astor, 1995, p. 420) The Marines even called the Statue of Liberty Division the '77th Marines' - an honour indeed. After several days of hard fighting, where many companies were reduced in strength by up to 85 percent, the 77th Infantry Division finally took the Chocolate Drop and Wart Hill. The next target was to be Ishimmi Ridge, the position guarding the immediate access to Shuri.

The 96th Infantry Division was driving against Conical Hill, as well as Dick Hill, just to the east of Flattop. Strong resistance was not only stalling their own advance but that of the 77th Infantry Division as well. On 17 May a platoon entered a road cut between Dick and Flattop Hills to clear an enemy minefield. They used bayonets to detonate the mines, a tactic that cost some nineteen casualties, but in the process sealed off five caves full of Japanese. At this point, Lt Colonel Cyril Sterner, in command of 2/382, realised that this road was the key to the Japanese position. Sterner ordered forward some seven tons of bangalore torpedoes that were laid in the ruts on either side of the road and detonated, thus clearing the mines. Tanks were now able to get to the rear of Dick and Flattop Hills and help the Americans turn the flanks of the Japanese positions. By 21 May, Dick and Flattop were also in American hands. Conical Hill however was the key to the eastern flank of Ushijima's defences and its capture would unmask Yonabaru, the eastern terminus of the Naha - Yonabaru highway which might enable the XXIV Corps to effect a double envelopment in conjunction with the Marines of IIIAC to trap Ushijima's forces before he could withdraw them properly. Its importance meant that General Hodge assigned its capture to his best regimental commander, Colonel Eddy May and the 382nd Infantry. That very importance was not lost on General Ushijima either, who assigned over 1,000 of his best troops to its defence. The attack was preceded by an intense barrage from both artillery and tanks. The 2nd Battalion (Colonel Edward Stare) moved out to begin the attack, but one of the two companies that were to start the assault was delayed in reaching its jump off point. The two lead platoons of the company that was ready to go, waited for the other company but eventually the two commanders, Technical Sergeants Guy Dale and Dennis Doniphan, started up Conical Hill on their own initiative. Meeting little resistance, they reached a point just below the peak and dug in, without suffering a single casualty. Somehow the Americans had caught the Japanese unawares, but that did not last long. Lt Colonel Kensuke Udo quickly organised a counterattack which failed to dislodge the Americans, who were initially reinforced with the rest of F Company, led by Lt O'Neill, and then by a second company (E) led by Captain Stanley Sutten and finally by G Company. Over the next three days they desperately fought of determined Japanese counterattacks in a bitter battle for Conical's forward slope. Finally though, the battalion was relieved by 1/381 under Lt Colonel Daniel Nolan who themselves attacked onto Sugar Hill, thus sealing the fate of Conical Hill.

As the Americans pushed south, the 7th Infantry Division, having been previously relieved by the 96th re-entered the lines on 19 May at the extreme eastern end of the US line and attacked towards Yonabaru. The division quickly took the town and seemed to completely take the Japanese by surprise, as the infantry were unsupported. The 184th Infantry tore a huge gap in the Japanese lines, which the 32nd Infantry could exploit. The weather however deemed to take a hand and the heavy rains that started on 22 May significantly hampered the division's progress and the attack effectively came to a halt on 26 May. The breakthrough, stalled though it was, was to cause Ushijima to reconsider his position.

The Americans Push South

Street fighting at Naha, Okinawa
While there had been rain earlier in the campaign, the heavy rains started to fall on 22 May which would substantially slow the pace of the advance for the Americans as low ground flooded, small streams and rivers overflowed their banks, gullies and ravines turned into thigh high seas of mud and the already overstretched roads became impassable in many spots. Finally, on the 29 May, the 22nd Marines took Naha, while the 5th Marines (1st Marine Division), seeing that the area between themselves and Shuri Castle was in fact quite lightly defended, took advantage and sent an element up to take the castle, despite it being in the 77th Infantry Division's sector, much to the Army's exasperation. Once up there they saw the final elements of the 24th Division withdrawing to the south and called up whatever air and fire support they could. While this accounted for a few hundred Japanese, the vast majority had withdrawn safely. To the east, the Army units that had at last broke through the weakening Japanese defence line ran into a number of Japanese units on the move that created a melee of intermingled Japanese and American units.

This was because Ushijima had received communication from Lt General Miyazaki Suichi at Imperial General Headquarters in Tokyo that there was little chance of a reinforcement or resupply effort from the home islands to help Okinawa. Ushijima now had three options. The first was to gather all his remaining forces at the Shuri line and hold it in a last stand. The second was to retreat to the Chinen Peninsula while the third was to retreat to the Kiyan Peninsula. Recognising that the main Shuri defence line was beginning to buckle, Ushijima rejected the first option as it would, more than likely, result in a rapid defeat and would shorten the time available to those preparing the defence of the home islands. He rejected the second option because the Chinen Peninsula had not been sufficiently prepared for a defensive stand. He therefore chose the third option as the 24th Division had already prepared the Kiyan Peninsula and a large amount of supplies and ammunition existed there to make a last stand. Ushijima therefore initiated a complex scheme of withdrawal for the units holding the line. Under cover of the heavy rain, the 62nd Division withdrew through the 44th IMB on 25 May and then attacked elements of XXIV Corps to the east to create the illusion that the Japanese units that were on the move were massing for a counterattack, something the Americans readily accepted as they assumed the Japanese would hold the Shuri defence line at all costs. They then established a defence line just to the rear of the Shuri line. The 24th Division then withdrew on 29 May to form a new line south of Itoman on the west coast and the 44th IMB then withdrew on 31 May to form a line from the 24th Division to the east coast. The 62nd Division then conducted a fighting withdrawal through the new lines between the 30 May and 4 June. The Imperial Japanese Naval Base Force on the Oroku Peninsula misinterpreted its order and withdrew too early on 28 May. Dissatisfied with their positions they immediately returned to their base to die defending it rather than fight alongside the Imperial Japanese Army. Many wounded were left behind to form a skeleton defensive force with the rearguards and the 32nd Army HQ left its tunnel complex beneath Shuri Castle on 27 May, establishing a temporary command post at Tsukazan the next day and moved to a new command post o Hill 89 near Manubi on the south coast the day after that.

On 24 May, Japanese paratroopers of the 1st Raiding Brigade attempted an airlanding raid on Yontan airfield from Japan. Only one of the transports managed to land, but the Japanese within it managed to destroy or damage two fuel dumps and a number of fighter aircraft. Meanwhile the US forces had continued to advance south. The 6th Marine Division found itself blocked by Naha Harbor and so conducted a shore-to-shore amphibious assault on 4 June from the west coast north of Naha into Naha Harbor to flank the IJN positions on the Oroku Peninsula. The 4th Marines landed on Beaches Red 1 and 2 south of Naha at 06.00 to be followed by the 29th Marines. The two-regiment operation has not been given much attention but it was larger than many earlier operations and was the last opposed amphibious assault of World War II. At this point the 2nd Marine Division's 8th Marines returned to Okinawa from Saipan on 30 May. The 2nd and 3rd Battalions landed on Iheya Jima on 3 June and the 1st Battalion on Aguni Shima on 9 June. The 7th Infantry Division had pushed south to the Chinen Peninsula by 3 June and the 96th Infantry and 1st Marine Divisions steadily advanced in the centre as the 6th Marine Division cleared the Oroku Peninsula.

Ushijima Makes A Last Stand

By 11 June, the remains of the 32nd Army had been pushed to the southern end of the island, although substantial pockets remained in the American rear areas. Ushijima now intended to hold a line running from just south of Itoman in the west, through the Yuze-Dake and Yaeju-Dake ridgelines to just south of Minatoga on the east coast, a defence line about 5 miles long. The 8th Marines landed at Naha on 15 June and were attached to the 1st Marine Division to help with the final push. At this point, the assaulting divisions sectors had narrowed that only three to five of the freshest battalions were required in the line. The Americans gradually moved south, with the 7th Infantry Division overrunning a pocket of 44th IMB troops on Hill 115 southwest of Nakaza on 17 June. The 96th Infantry Division was pinched out of the line on 20 June to deal with a large pocket of Japanese 24th Division troops near Medeera and Makabe. This would not be completed until 22 June. As the 6th Marine Division continued to clear the west coast and the Oroku Peninsula, the 1st Marine Division cleared the final pocket of 62nd Division troops near the southern end of the island on the Kiyamu-Gusuku Ridge. The 7th Infantry Division meanwhile, closed in on the headquarters of the 32nd Army, defended by the survivors of the 24th Division on a coastal ridge, Hill 89. At 17.00, on 21 June 1945, Okinawa Gunto was declared secure, although numerous pockets of resistance remained, which would take many days to subdue. At 03.40 on 22 June 1945, Lt General Ushijima and Major General Cho committed ritual suicide outside their cave on the southern side of Hill 89. There was an equally tragic ending for the American commander. Lt General Simon B Buckner died from shrapnel wounds on the 18 June while observing the fighting from a forward observation post in the 1st Marine Division area after a Japanese shell had exploded nearby. Major General Roy Geiger was appointed Commander, Tenth Army by Admiral Nimitz, the only Marine officer to command a field army, and was promoted to Lt General the next day. A mere five days later, Geiger was relieved by Lt General Joseph W Stilwell ('Vinegar Joe').

As a final move, the Fleet Marine Force Pacific, Amphibious Reconnaissance Battalion secured Kume Shima, some 55 miles west of Okinawa between 26 and 30 June 1945 to establish a radar base and fighter direction centre. The battalion met no resistance from the 50-man garrison until after the landing.


The armed forces of the United States and Japan had met in a battle that had lasted eighty-two days where little quarter was granted and proved what had been known to both sides, that the one side who was to be victorious, would have to completely eliminate the other. Both sides used their resources, whether abundant or not, to utmost of their ability to gain whatever tactical advantage they could. Okinawa provided a glimpse of what might have happened if the United States had invaded the Japanese Home Islands in Operation Downfall.

It was only the much larger and longer Philippine Campaign that saw higher casualties than Okinawa. The United States suffered over 51,000 casualties with the US Marine Corps suffering 2,938 killed and missing, 16,017 wounded. The Army suffered 4,675 killed and missing, with 18,099 wounded, while the Navy suffered its highest casualty rate of the war, with 4,900 dead and missing, and another 4,800 wounded. The United States lost 763 aircraft and suffered 36 ships being sunk and another 368 damaged, with 43 being so badly damaged they were scrapped. The British Carrier Force (TF 57) suffered four ships damaged, 98 aircraft lost, 62 personnel killed and 82 wounded. Over 100,000 Japanese troops and Okinawa militia (Boeitai) fought on Okinawa, although precise estimates of their casualties are difficult due to the duration of the fighting, the inflated accounts of enemy numbers of dead, the imprecise estimate as to the numbers of enemy involved and the nature of the combat on the island. The US estimated some 142,000 of the enemy were killed but this is more than the total that was on Okinawa. Some 7,400 combatants were taken prisoner during the campaign, as were some 3,400 unarmed labourers. Large numbers of troops surrendered after the end of hostilities. Approximately 10,000 IJA and IJN personnel survived the battle, as did approximately 8,000 militia. The Japanese lost 7,830 aircraft, some 4,600 Kamikaze crew died alongside many hundreds of other pilots, 16 warships were sunk and four damaged while the IJN lost over 3,650 personnel in the Yamato's sortie. Over 122,000 of Okinawa's population had been killed and a culture shattered due to the fighting.

Two white painted G4M1 'Betty' bombers with green crosses instead of Rising Suns arrived from Tokyo on 19 August with the Japanese surrender delegation. They were then flown to Manila in American aircraft and returned the next day. Due to a mix up the planes were not refuelled properly and one of them cashed just off the coast of Japan on its return trip, but the delegates were rescued and delivered the terms of unconditional surrender to the Emperor on time.

Large numbers of Japanese troops were killed in post-operation 'mopping up' and many more prisoners were taken, eventually rising to some 16,350 by the end of November 1945. On 16 August, Japan announced its decision to surrender and Japanese forces still holding out in the Kerama Retto were among the first to surrender after this announcement on 29 August. On 7 September 1945 (five days after VJ Day), the Ryukyu Islands were formerly surrendered to Lt General Stilwell by Vice Admiral Tadao Kato and Lt General Toshiro Nomi (both having been stationed on Sakishima Gunto) - there were still some 105,000 IJA and IJN personnel throughout the Ryukyu Island chain.

The United States now possessed a base just over 500km (320 miles) southwest of Kyushu. A colossal construction project began utilising some 87,000 construction troops from the US Army, Navy and Royal Engineers to build some 22 airfields to accommodate the Eighth Air Force deploying from Europe, as well as Marine and Navy air units while Navy and Marine airfields were established at Awase and Chimu on Okinawa and Plub Field on Ie Shima. Naval Operating Base, Okinawa was established at Baten Ko on the southern end of Buckner Bay (the renamed Nakagusuku Wan) to control the port facilities at Naha, Chimu Wan, Nago Wan and Katchin Hanto. The island gradually developed into a major staging base for the Army and Marine units that were slated to participate in the invasion of Japan. Two extremely powerful typhoons in September and October caused serious damage and the relocation of a number of port facilities. The main naval base was moved from Baten Ko to the southeast end of the Katchin Peninsula to what was, and is, still known as White Beach.

The deployment and use of the atomic bombs made the continued build up on Okinawa for Operation Downfall unnecessary but the Korean (1950 - 53) and Vietnam (1965 - 73) Wars made Okinawa an important logistics base for the US Army and operating base for the US Navy well into the 1970s. The US Air Force continued to maintain a major base at Kadena Airfield after its formation in 1947 and B29 bombers flew missions against North Korea while B52 bombers flew to Vietnam while strategic reconnaissance aircraft operated from Okinawa against targets all over Asia. After the war, the military administration of Okinawa initially fell to the navy but was handed over to the US Army on 1 July 1946. As time went on, more and more responsibility for Okinawan affairs was handed over to the Okinawan people as their government developed. There were a number of violent demonstrations in the early 1970s as students and left wing extremists protested not only against the war in Vietnam but also desired that Okinawa be returned to Japanese control and US forces be evicted from the island despite the fact that they provided about 70 percent of the island's income. On 15 May 1972, Okinawa was formerly returned to Japanese sovereignty and Buckner Bay reverted to its former name of Nakagusuku Wan. US military bases however, would be allowed to remain and some of them are shared with the Japanese Self-Defence Force.

There are several points that should be noted when looking at the Battle for Okinawa:

  1. The United States expected the enemy to vigorously defend the Hagushi landing beaches on the western coast and then concentrate rapidly for a counterattack. To this end a lot of effort was put into suppressing beach defences with some 44,825 shells, 33,000 rockets and 22,500 mortar shells, as well as having 500 carrier planes bomb and strafe the beaches and the area immediately behind them. When the assault forces landed they faced only light resistance and suffered only 55 killed and 104 wounded on the first day. They made the mistake of assuming that the enemy had learnt nothing from his experiences earlier in the war, while in fact the enemy was now intent on conducting a skilful defence in depth designed to minimise his exposure to the overwhelming combat support deployed by the United States. Instead he used tactics first used successfully at Peleliu, refined at Iwo Jima and used it to perfection on an island large enough to make it even more effective. The Japanese had been expecting a landing at the Hagushi Beaches and possibly one at Minatoga as well (where in fact the 2nd Marine Division had been demonstrating) and therefore deployed their forces in a central defensive line running across the island through Shuri Castle. While there was some hope that the war of attrition combined with conventional and suicide air and sea attacks might produce victory, as a minimum they hoped that a prolonged battle might inflict such enormous casualties that it might dissuade the Americans from invading the homeland.
  2. The selection of the Hagushi Beaches for the landing site of the assault proved to be the correct choice, rather than dividing the assault between there and the Minatoga Beaches as the Tenth Army was able to put its entire force ashore with minimal loss and disruption and to quickly capture the airfields at Kadena and Yontan, so almost immediately beginning their return to operation.
  3. As the Marines cleared the northern stretches of Okinawa, including the Motobu Peninsula, they faced the difficulty of keeping themselves supplied in a campaign of manoeuvre on a large land mass, rather than the positional warfare they had conducted on relatively small islands in the Pacific. Marine divisions had little organic transport at this point and while Major General Meritt A Edson, Chief of Staff, Fleet Marine Force Pacific had actually tried to rectify this in preparation for operations such as Okinawa, the Headquarters of the US Marine Corps had actually reduced the number of transport units in the search for manpower to form the 6th Marine Division. With the diversion of trucks from carrying supplies to that of carrying infantry to aid in a rapid advance, the logistics situation rapidly deteriorated. Lt Col Victor H Krulak soon found himself bemoaning "the pitiful amount of transport we have." (Hoffman, 1995, p. 67) The heavy rains in late May made much of the terrain impassable for vehicles and so the only way to move supplies around was by foot. Amtracs and DUKWs could ferry supplies along the coast but once again, Marine units suffered due to their lack of transportation assets and some units began to run out of food and water but the creation of Marine air delivery units which dropped supplies to the frontline.
  4. The Japanese amassed the largest amount of large calibre artillery for any island battle on Okinawa. They had almost 300 pieces of 70mm or bigger, over 125 dual-purpose antiaircraft guns and cannons, over 80 antitank guns and hundreds of mortars, including twenty-four 320mm models. Many of the larger pieces were mounted on rails so they could be quickly moved into and out of caves which were themselves well-camouflaged and protected against attack. As on Iwo Jima, the Japanese fought mainly from caves and tunnel systems which were very difficult to detect, often surrounded by minefields and concentrated on the reverse slopes of hills.
  5. The Japanese showed initiative and flexibility in using their defensive stance to best advantage. A common tactic that took advantage of this was shown in an early American attack on Kakazu Ridge when the leading elements of an infantry regiment took the front slopes and crest of the ridge in a predawn attack without artillery preparation. The Japanese responded by firing preregistered artillery and mortar attacks and grazing machinegun fire that prevented reinforcements from crossing the open ground between the original positions and the ridge. The enemy then launched numerous small counterattacks from the caves on the reverse slope, all supported by mortar fire. After sustaining heavy casualties and running out of ammunition, the US forces withdrew under cover of a smoke barrage to their original positions, suffering 326 killed for no gain.
  6. While the Japanese made a mistake in conducting the May counterattack, the attack was not the usual banzai charge but a co-ordinated and well-supported conventional assault that attempted to utilise predawn amphibious shore-to-shore landings around the flanks of the American lines. Having become used to the Japanese using small-scale counterattacks, the assault caught the Tenth Army by surprise but in a position to react and defend against the assault. If the attacks had been conducted but a few days earlier, the situation may well have been very different.
  7. The Lt General Buckner and his staff misread the intention of the Japanese at the end of May. Lt General Ushijima realised that as he had committed almost all his trained reserves into attempting the 4 May counterattack or rebuilding the units in the frontline, if the Americans continued to make inroads into his positions his main position around Shuri would be in danger of encirclement. He therefore decided to withdraw and form a new defensive line to the south in the Kiyan Peninsula in order to prolong the battle and extract the most attrition. The orderly withdrawal began on the 22 May and was complete by early June. A skeleton force still manned the Shuri defences keeping Tenth Army at bay and poor weather hampered aerial reconnaissance, although there were a number of sightings of enemy troops movements and artillery and air support did engage one column of several thousand Japanese who were making a rare daylight movement. The US command were convinced that this was either a rotation of units out of the frontline (something the Americans did on a common basis) or a build up for a counterattack.
  8. Several times, Buckner (backed by Nimitz) refused to sanction the employment of US forces in another amphibious assault to outflank the Shuri Line, after looking at the possibility in detail, primarily before 22 April. This was despite the support given to such an idea by the CO of the 77th Infantry Division (Bruce), the Operations Officer and CO of the XXIV Corps (Guerard & Hodge) and finally the Commandant of the Marine Corps. Buckner offered several reasons, both tactical and logistical, for this stance, including (counter-arguments included in brackets):
The points above help to illustrate these lessons:

The difficulty of reading enemy intentions.Both sides were surprised by the actions of the other. The Americans were surprised by the Japanese decision not to defend the Hagushi Beaches or the airfields in central Okinawa, the absence of banzai attacks, by the sudden switch to an offensive strategy in early May and by the decision to withdraw from the Shuri Line. Equally, the Japanese were often perplexed by American decisions. They expected a landing at Hagushi but the well-executed feints off Minatoga kept them in the dark about US intentions there. In almost every situation where the US conducted night attacks, they literally found the Japanese sleeping in their caves, one such operation netting an advance of some 2,000 yards on 22 May - the Japanese being confident that the Americans would not attack at night without an artillery barrage or across muddy terrain that would impede the movement of tanks. On both sides, estimates of enemy intent was based partly on habit and when either side did something different, the other was surprised. In fact, establishing such habits seemed to pave the way for something that could take advantage of the surprise created. Okinawa shows the difficulty of establishing what your enemy intends to do, even though one side had complete aerial control over the battlefield, a situation that seems reminiscent of recent conflicts.

The limits of massed firepower. Tenth Army was supported by numerous battleships, cruisers, aircraft and the equivalent of forty-four artillery battalions. The Navy fired over half-a-million shells of 5in calibre or greater, while the ground forces fired over 1.8 million shells (not including mortar rounds) at Japanese targets. In the end, a large proportion of defenders died from direct fire or close range weapons such as tanks, flamethrowers, grenades and satchel charges. Stand-off precision weapons are now increasingly available but are correspondingly expensive - a way must be found of producing these more cheaply as their value lies not only in their accuracy and lethality but the impact they can make on the logistics burden for expeditionary operations.

The limits of target acquisition. While it is true that target acquisition has made great strides since World War 2, in a situation such as Okinawa, the enemy was well-concealed and the weather generally poor and so it will still take someone on the ground to spy out which targets are worth hitting. In many cases, US ground forces made extensive use of patrols to search for enemy strongpoints, but the Japanese rarely fired on small numbers of troops and often battalions and regiments took heavy casualties in areas that the small patrols had moved through untouched. Future conflicts might well be better fought with smaller forces better able to direct such precision firepower. Casualty percentages may still remain high when fighting a well-concealed, determined and fortified enemy, but at least the actual numbers may be lower.

The use of lower tech equipment. The kamikaze campaign saw the use of the Baka bomb that was a small, piloted, rocket-boosted glider carrying a ton of explosives and could reach a speed of up to 500mph. In many respects it was better than the modern generation of cruise missiles as it had a thinking pilot behind the controls. The Japanese also occasionally used old wooden biplanes when they started to run short of modern aircraft. They actually proved relatively immune to the then current antiaircraft fire which had shells fused to explode when they neared metal objects. The Japanese proved that old or low-tech equipment combined with some ingenuity could go a long way.

The casualty rates in the supporting fleet. The devastation inflicted on the fleet at Okinawa should encourage the development of systems such as the V-22 Osprey that would allow the fleet to remain at a greater distance from the objective and decrease its vulnerability.

Joint operations in an amphibious operation. Okinawa represented the height of joint operations during World War 2. A Navy admiral was theatre commander, another was commander of the joint air, sea, land task force. An Army general commanded the landing force of two corps, one each from the Army and Marines. He had a deputy from both the Army and Marines and predetermined that a Marine general should succeed him if he was incapacitated or killed. The Tenth Army staff contained a large number of Marine and Navy officers, and a Marine commanded the landing force's organic air support that contained almost equal numbers of Marine and Army Air force components. Artillery battalions operated interchangeably and massed fires wherever they were required and by whoever required them. An Army general commanded the base force development of soldiers, sailors and Marines (and even Royal Engineers) that provided logistics support to the Tenth Army and that built the air and naval bases required for the invasion of Japan. Not long after the end of the battle for Okinawa and World War 2, the American leadership entered a bitter debate on how defence should be organised for future conflicts. The result was the Department of Defense and a trend towards greater centralisation. Okinawa holds an important lesson for today's commanders in that there were strong, independent services that learned to work together well through a system that coordinated their activities but maintained a healthy spirit of competition that fostered innovation and encouraged performance. The only negative aspect of the move towards greater 'jointness' in operations has been the Marine Corps anxiety over its institutional survival. Since 1946 there has been a pressure from some quarters to strip the US Marine Corps of the equipment that is duplicated in the other services. It is important to remember that the Marines remain the premier sea-based air-ground expeditionary force to conduct amphibious operations, as it is what a force trains, exercises and does that counts, not what it is equipped with.

Bibliography and Further Reading

Alexander, Joseph H. Storm Landings, Naval Institute Press, Annapolis, MD, 1997. A detailed account of the major amphibious assaults of the Pacific War. cover cover cover

Alexander, Col Joseph H. USMC (Ret). The Final Campaign: Marines in the Victory on Okinawa Marines in World War II Commemorative Series, Marine Corps Historical Centre, Washington DC, 1996. cover cover cover

Appleman, Roy E. Okinawa, Konecky & Konecky Military Books, 1994. cover cover cover

Astor, Gerald. Operation Iceberg, Dell Publishing, New York, 1998. cover cover cover

Iwo Jima and Okinawa , Black, Wallace B. , Prentice Hall, London, 1993 cover cover cover

Feifer, George, The Battle of Okinawa: The Blood and the Bomb, Lyons Press, 2001. cover cover cover

Foster, Simon, Okinawa 1945 , Cassell Military, London, 1999. cover cover cover

Hallas, James H., The Devil's Anvil: The Assault on Peleliu , Praeger Publishing, 1994 cover cover cover

Huber, Thomas M., Japan's Battle of Okinawa, April - June 1945 , Leavenworth Papers No. 18, Combat Studies Institute, US Army Command and Staff College, Fort Leavenworth, Kansas, 1990. cover cover cover

Leckie, Robert, Okinawa: The Last Battle of World War Two , Penguin Books, New York, 1996. cover cover cover

World War II , Matanle, Ivor, Godalming, 1995 (Second Edition). cover cover cover

Great Battles of World War II , Macdonald, John, Guild Publishing (BCA), London, 1986.
cover cover cover

Rottman, Gordon L. Okinawa, 1945, Osprey Publishing, Oxford, 2002, Campaign Series No. 96. cover cover cover

Eagle Against The Sun, Spector, Ronald, Cassell Military, London, 2001. cover cover cover

A World at Arms : A Global History of World War II , Weinberg, Gerhard L, Cambridge University Press, 1994 cover cover cover

Yahara, Colonel Hiromichi. The Battle for Okinawa, John Wiley & Sons, London, 1997. cover cover cover

World War II , Young, Brigadier Peter. (Ed), Orbis Publishing, London, 1978. cover cover cover
Articles Alexander, Col Joseph H. USMC (Ret). 'Okinawa: The Final Beachhead' in US Naval Institute Proceedings, April 1995, pp. 78 - 81.
Donahoe, Patrick J. 'Flamethrower tanks on Okinawa' in Armor, January - February 1994, pp. 6 - 10.
Falk, Col Stanley L. AUS (Ret). 'The Assault on Okinawa' in Army, June 1995, pp. 46 - 51.
Hanson, Maj Steven M. 'The Battle for Okinawa' in Marine Corps Gazette, June 2000, pp. 47 - 53.
Hoffman, Maj Jon T. USMCR. 'The Legacy and Lessons of Okinawa' in Marine Corps Gazette, April 1995, pp. 64 - 71.
Leonard, Charles, J. 'Okinawa' in After the Battle, No. 43, London, 1984, pp. 1 - 25.
Mayo, Col Robert S. USMCR (Ret). 'With Marine Engineers on Okinawa' in Marine Corps Gazette, April 1997, pp. 62 - 70.
Rottman, Gordon L. 'Japanese Suicide Boats at Okinawa, 1945' in the Osprey Military Journal, Volume 4, Issue 1, pp. 51 - 57.
Stevenson, Matthew. 'War's End on Okinawa: In Search of Captain Robert Fowler' in The Journal of Military History, No. 67, April 2003, pp. 517 - 528.


'Okinawa: The Last Battle', Appleman, Roy E., Burns, James N., Gugeler, Russell A. and Stevens, originally published in 1948 by the United States Army's Center for Military History in Washington DC. It is now available online at the Center's website. Active as of 20th December 2002.
'Battle of Okinawa' Webpage , part of the GlobalSecurity.Org Website. Active as of 20th December 2002.
Fisch, Jr., Arnold G. 'Ryukyus', originally published by the US Army (originally part of The US Army Campaigns of World War II series). Active as of 12th February 2002.
'Welcome to Marine Corps History' Webpage , part of the official US Marine Corps Website. Active as of 25th November 2001.
World War II - Okinawa
How to cite this article: Antill, P. (23 May 2003), Operation Iceberg: The Assault on Okinawa - The Last Battle of World War II (Part 2) April - June 1945, http://www.historyofwar.org/articles/battles_okinawa2.html
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