The Battle Of Okinawa
The OKKA would like to extend their thanks to the late Richard Pryce (former OKKA member) for producing this factual historical insight.
Operation Iceberg
The Capture of Okinawa
In the spring of 1944 there were no plans to seize Okinawa for the foreseeable future as the central Pacific drive gained momentum after the seizure of the Marshall Islands in the previous three months of that year. Throughout the spring and summer of 1944 the Army and Navy Staffs had been planning the invasion of Formosa (Taiwan) sometime in the spring of 1945. Operation Causeway as this operation was known envisaged an assault on Formosa after south west Pacific forces had established themselves in the central and southern Philippines late in the autumn 1944.
During the summer of 1944, with successful operations against Japanese positions throughout the Pacific the invasion of the Philippines began early at Leyte Gulf on 20th October 1944. General McArthur had sought thereafter to seize Luzon as the next phase of the Philippine operation and bypass Mindanao. These operations would now place American Air and Naval Forces astride the main Japanese supply routes from the south.
Admiral Chester Nimitz, Commander in Chief Pacific Ocean Area CINCPOA, reconsidered the Formosa plan after consultation with his Army and Navy Chiefs and Admiral Ernest J King, the Head of the US Navy and Chief of Naval Operations, who in turn discussed this with the Joint Chiefs of Staff in Washington. The outline of all the discussions was that American Forces would cancel the Causeway Operation and assemble plans to attack the Bonin Islands and the Ryukyus. The planned assaults were calculated to bring unremitting pressure against the Japanese by thrusting northward closer to Japans home islands.
As soon as the Leyte invasion had been agreed, the Joint Chiefs issued a directive on 3rd October 1944 for American Forces to capture islands in the Bonins (Iwo Jima) and The Ryukyus (Okinawa) to begin in March 1945. As the Iwo Jima Operation was to be an all Marine Corps and Navy Operation the planning for Okinawa began in Hawaii on the island of Oahu with the establishment of the US 10th Army in September 1944 under the command of General Simon Buckner.
The principle mission of seizing the objective was assigned to a huge joint Army Navy Task Force. This became known as Central Pacific Task Forces commanded by Admiral Raymond Spruence, the Commander of the US Navy Fifth Fleet. The joint expeditionary task forces would be commanded by Admiral Richmond Kelly Turner. General Simon Buckner’s 10th Army would be under Admiral Turner’s command for the assault phase as was the practice during all amphibious operations throughout the Pacific War.
| XXIV Corps. | III Amphibious Corps. |
| 7th Infantry Division | 1st Marine Division |
| 96th Infantry Division | 6th Marine Division |
| 2nd Marine Division | 27th Infantry Division |
| 77th Infantry Division | 81st Infantry Division |
| Plus Island Occupation Garrison | Tactical Airforces Ryukyus |
| Naval Forces Ryukyus |
Although the US 10th Army had not led a campaign in the war prior to the planned invasion of Okinawa, its constituent Divisions had all been battle tested in the Pacific in previous operations. A total of 183,000 Troops would be available for this operation along with all the support services.
The basic plan for the seizure of islands in the Ryukyus Group (Nansei Shoto) saw the operation in three phases. Firstly islands in the Keise Shima and Kerame group for the development of bases and landings on the southern part of Okinawa. Secondly the seizure of Le-Shima and the control of northern Okinawa and thirdly the capture of other islands in the Nansei Shoto group as required. The main assault on southern Okinawa was planned on the west coast just north and south of Hagushi. This was chosen for logistics fleet protection anchorage in the target area. As a result it was decided to capture the Kerama Islands west of Okinawa one week before the main assault. After the planning phase and assemblage of forces, the target date for the Landings was set for 1st April 1945.
The first landings in the Ryukyus took place on the Kerama Islands on the morning of 26th March 1945 by units of 77th Infantry Division. Five days later Fleet Marine Recon Force landed on Keise Shima, 11 miles southwest of Hagushi Beaches and only 8 miles from Naha the capital of Okinawa. These islets were seized in order to place heavy artillery on them as they could reach all of southern Okinawa and support the main landings. During the planning phase of the operation a complex plan saw events unfolding that would keep the Japanese under constant pressure from Airforces across the Pacific and China for the period up to April 1945.
Bombardment of Okinawa began on 25th March 1945 when ships of the bombardment force shelled the southeast coast. Meanwhile aircraft from Task Force 58, the Carrier Forces, struck the island with over 3,000 sorties prior to L-Day. At this time the U S Navy was now supported by a Task Force of the Royal Navy Commanded by Admiral H B Rawlings. The British Carrier Force struck the islands in the Sakishima group.
The task of defending Okinawa fell to the Japanese 32nd Army under the command of General Mitsuru Ushijima activated on 1st April 1944 one year prior to the invasion. Before then the island was poorly defended, but after the invasion of the Marianas in June 1944, large scale reinforcements were sent to the island during the summer and autumn of 1944. By the time the Americans invaded Okinawa the total strength of the army amounted to nearly 100,000 men including draftees and conscripts.
The initial plan for the Japanese defence rested on defeating the invasion at the water’s edge. In the early months of 1945 this was replaced by a plan for the 32nd Army to offer resistance around a central fortified position. As part of the defensive plan and the build up to an American Assault, a large portion of the Imperial Japanese Navy and the Kamikaze would try to weaken U S Naval Forces and Assault Forces supplies coming ashore.
Despite the hopes of the Japanese High Command their planning proceeded on the assumption that it was impossible to defeat the Americans, but to inflict a maximum number of casualties on the enemy and deny the use of the island for as long as possible. Therefore General Ushijima drew his forces around the hills of Shuri and the 32nd Army planned to defend only the southern third of Okinawa strongly. General Ushijima would not go to the enemy, but wait for them to come to him.
Dawn on Easter Sunday 1st April 1945 disclosed a Fleet of 1,300 Ships in the waters adjacent to Okinawa. The Landings were planned for 08.30hrs. As the Landing Forces approached the beaches they expected fire from the Japanese. There was hardly any fire from the shore. As the troops began to land at the beach there was only sporadic artillery and mortar rounds landing at the water’s edge. As the Naval bombardment moved inland the troops for the first time saw the nature of the land. In the background along the line of hills they could see the nature of the devastation of burning villages and towns.
After the first hour the III Amphibious Corps had landed the 1st Marine Division and the 6th Marine Division north of the Bishi River on the left flank. At the same time XXIV Corps had landed the 7th Infantry Division and the 96th Infantry Division on the right flank south of the Bishi River. Behind the first waves of soldiers came reinforcements and waves of tanks. The entire landings on Okinawa had taken place with incredible ease. After making sure the troops were not heading into a trap the soldiers and Marines began to move inland and up the hillsides behind the beaches.
After moving off the beaches their immediate objectives were the two airfields at Kadena and Yontan. Both fields were captured without opposition except for wrecked Japanese planes and supplies strewn about the fields. By nightfall some 60,000 men had landed including reserves, artillery and anti-aircraft guns. Kadena airfield was serviceable for emergency landings on the evening of the first day.
Around the hills of Shuri, the Japanese had a good observation of the Hagushi beaches, but were content to do nothing. As Lt-General Ushijima had planned they would allow the Japanese Airforce to mount their opposition in the air and not reveal his artillery defences to the American Bombardment Force.
Favoured by perfect weather and light resistance units of 7th Infantry Division pushed across the island and had reached the hills of Nakagusku Bay on 3rd April. On the left flank, although the Marines had more difficult problems with terrain and supplies the Island was now cut in two, the Japanese Forces in the north and south were now separated. On 4th April the XXIV Corps turned south and had taken Kuba. As the two Divisions moved into line abreast across the narrow waist of the island the real battle for Okinawa would then begin. Meanwhile as the Marines reached the east coast they moved into the Katchin Peninsula and the east coast roads to Hizaonna. The 6th Marines on the left, facing north, moved into the hills of Yontan-Zan northwest of the Hagushi Beaches and captured Nagahame against stiff resistance.
By now the tempo of Japanese air attacks began to increase over the next 4 days. On 6th April they mounted a 400 plane attack which inflicted damage to battleships and transports around the anchorage, a harbinger of things to come. On the following day the Imperial Japanese Navy left Japan with the Battleship Yamato, a light cruiser and 8 destroyers with the intention of attacking the landing forces west of Okinawa. Search planes from Task Force 58 discovered them and attacked with 386 Aircraft. Yamato and the light Cruiser as well as four of the destroyers were sunk for the loss of only ten planes to the Americans. Throughout April the Kamikaze struck against Task Force 58 sinking 20 Ships with 157 damaged. The losses to the Japanese during the same period amounted to 1,100 aircraft destroyed.
The next phase of the fighting on Okinawa will now only be outlined in sketch form. The fighting from the second week of April to the third week of June 1945 would be fiercest of the whole Pacific War. The breaking of the Shuri defence zone was complicated and a very bloody affair that would end in the slaughter of the entire Japanese garrison.
By now XXIV Corps was ready to make its advance towards the south on the 4th April. The Corps objective was the line of hills stretching from Urasoe Mura on the west coast to Ouki on the east Coast. Sweeping gains were made on the first day but thereafter increasing resistance indicated that the Americans had run into the outposts of the Shuri defensive system. By the 6th April the first of the infamous ridges such as “Cactus Ridge” in the west and “The Pinnacle” in the east were encountered. From now on the iron defence of Okinawa would be revealed. These first defences would take 3 weeks to overcome with terrible losses on both sides. On 13th April the Japanese attempted to counterattack but were crushed with heavy losses and ending in total failure.
In the north the Marines of III Amphibious Corps advanced towards the Motobu Peninsula on the 8th April. The main Japanese resistance was around the dominant height of Yae-Take. After 4 days of vigorous combat the defenders were eliminated with the loss of over 2,000 Men. The advance continued towards the north of the Island on 19th April with the Marines only encountering light resistance guerrilla tactics from irregular troops throughout the remainder of the month. As the last remaining actions of the Corps were being fought in the north of the island, plans were being drawn up to transfer the whole of the III Amphibious Corps to the south in order to bolster the attack of the XXIV Corps.
Because of the success of the northern phase of the Okinawa Operation, it was decided to merge phase 1 and 2 together and therefore Admiral Turner issued the attack order for the seizure of Le-Shima. The assault was to commence on 16th April with a minor landing on Minna Shima the day before. Nowhere else in the ICEBERG Campaign did the native Okinawans fight so hard and successfully as they did on Le-Shima, more than 1,500 men and women joined the garrison to defend their home island. During the six days of battle for Le-Shima the Americans killed 4,706 Japanese many of whom were civilians. American casualties amounted to 1,120 of which 172 were reported killed. It was during this battle that the famous US War Correspondent Ernie Pyle was killed on the 18th April.
Back in the south the plan for the attack on the Shuri Defence system envisaged an assault by XXIV Corps to begin on 18th April and break through the intricate defences towards the line Yonabaru on the eastern coast to Naha on the west. The plan called for the single largest air attack and artillery bombardment in the Pacific War. In spite of this the attack failed. Nowhere had any breakthrough been made. The Japanese had turned back the American attack. The centre of the Japanese defences was a location known as “Item Pocket”. This obstacle would take a week of hard fighting before it could be neutralized. On 24th April after many ridgeline battles the first line of the Shuri defence ring was broken.
On 24th April General Hodge ordered a renewed attack on the second line of the defences around Shuri to begin 26th April. The next infamous ridge line was “The Maeda Escarpment Barrier”. The fighting here and along the whole line was to last until 3rd May. The 77th Infantry Division suffered especially heavy casualties in the engagement and estimated that they had killed over 3,000 Japanese.
Meanwhile on the night of 2nd May General Ushijima called a meeting of his staff in the caverns 100ft below Shuri Castle to discuss strategy. The Japanese Army Commanders had been divided over this since before the American landings. Even now bitter argument still raged about how the Japanese were to continue the fight for Okinawa. After much argument General Ushijima decided to launch an all out attack on the centre of the American Lines beginning 4th May with supporting flank attacks from the sea landing behind the American lines. In support of the offensive a large Kamikaze air attack was planned for the night of 3/4th May. The assault began after dark on the night of 3rd May. The Kamikaze struck American shipping sinking two vessels and damaged four others. At the same time Japanese shipping engineer troops in small boats moved up the shoreline on both east and west of Okinawa to attempt landings behind the American lines. Both efforts were discovered and virtually the whole force was wiped out suffering between 500 to 800 losses the attempt was a complete fiasco. During the following two days and nights the Japanese fought to penetrate towards Tanabaru. The deepest penetration was up to a mile behind the Corps front line. On the following day with a counterattack from the west, the Americans retook the crest of Tanabaru Escarpment. The three day battle cost the Japanese 462 dead in this location alone. By midnight 5th May General Ushijima knew that the offensive had failed. From now on the remainder of the defence would be a war of attrition and the gloom that descended on the men of 32nd Army was one of ultimate defeat that was unavoidable and only a matter of time.
On 11th May the American offensive resumes with XXIV Corps consolidating their lines from Ouki in the east to Asa Kawa on the west coast. By now the full complement of III Amphibious Corps had moved to the south. The disposition saw the Marines on the right with XXIV Corps on the left. The plan of attack this time envisaged an envelopment of Shuri, which was expected to finally prise this defence from the Japanese. The attack though coordinated from the start soon broke down into a series of intense battles. By 21st May the Americans finally seized the anchor point of the defensive zone in the east. At “Conical Hill” the first chance at envelopment now beckoned. Meanwhile the Marines in the west over these 10 days fought some of their hardest battles of the Pacific War. At “Sugar Loaf Hill” the Japanese hung on tenaciously to deny the Marines a breakthrough. At the end of May though the Americans had penetrated to the inner defences of Shuri and opened up a corridor along the eastern shore, the main Japanese lines had only really received a few dents. By the last week of the month the rains had set in that would turn the ground into mud baths.
During the rainy period at the end of May, both flanks forged ahead of the centre. On the western side the 6th Marines gave up their fight to take “Sugar Loaf” and moved forward near the coast to cross the Asato River. On the night 23/24th May 5 LVT’s crossed the river and entered Naha without opposition. Most of Naha was taken the next day with Japanese resistance only being met towards the southeast. At the same time the 7th Infantry Division on the left pushing south to reach Naha-Yonabaru valley soon came to a standstill along a line of hills that the Japanese now sought to hold as the threat the Americans now presented to the entire Japanese defensive position from the rear.
The fall of Shuri began when General Ushijima realized that his position was gradually being unhinged from his flanks. On the evening 21st May he called a meeting of his commanders in the caverns below Shuri Castle. By now the Japanese had lost over half of their effective front line troops. After again heated argument it was decided that they would evacuate the positions around Shuri Heights by the end of the month and re deploy further south. On the evening 22/23rd May the evacuation began. This was not discovered until American Reconnaissance Aircraft spotted movement towards the south on 26th May. General Buckner ordered the 10th Army to maintain pressure on the Japanese as soon as it was discovered that the Japanese were on the move. By 29th May elements of 1st Marine Division entered the ruins of Shuri Castle and on the last day of the month linked up with units of 7th Infantry Division approaching from the southeast. American Forces were now south of the tough Shuri defensive system that had taken nearly two months to overcome. General Buckner declared now that the hard part was now over even though the Japanese had succeeded in pulling back their remaining forces. It would still be another three weeks of pursuit and hard fighting before organized resistance would end.
The final battle of Okinawa was about to begin. When it became apparent that the Japanese had escaped General Buckner revised 10th Army plans for the pursuit south. The advance set for 1st June the general attack would parallel the east and west coasts. On the eastern flank 7th Infantry Division ran into some stiff resistance around Chan, otherwise resistance was patchy and scattered. Soon they had turned east and occupied the rain soaked Chinan Peninsula, and by the afternoon 3rd June reached the south coast at Hyakuna. It now seemed to General Buckner that General Ushijima would now make his last stand at the southern tip of the Island at Yaeju-Dake.
Meanwhile III Amphibious Corps plan of attack in the west was to strike due south and cut off the Oroku Peninsula. At the same time a sea borne assault by 6th Marines would land on the northwest coast. The landings began 4th June and after a short while ran into a strong hill position known as “Hill 57”. This position was honeycombed with tunnels caves and passageways that would take the Marines ten days to clear. By 15th June the defenders of Oroku were finished. The survivors of the hill battle forced out of their positions ended their resistance at the base of Naha Inlet. Admiral Ota, the Okinawan Base Force Commander committed suicide. The 1st Marine Division had by now reached the western shore at Itoman.
The last Japanese defensive line fell along the Yaeju-Dake and Yuza-Dake hill mass in the central part of the island in the south. General Ushijima had arrived here around 4th June just ahead of the Americans. The positions of the assaulting forces now had the hill mass in the XXIV Corps area and towards the west the III Amphibious Corps moved up to Kunishi Ridge. By 11th June the Americans were ready for the final push of the campaign. From 6th June Army Divisions began to probe the eastern face of the Japanese positions with limited success. Flame Thrower Tanks now became the American solution to the Japanese Coral Caves and the battle raged with orange rods of flame, shells, rockets and bombs. In the centre 96th Infantry Division launched a night attack against the ridge between the two peaks of Yaeju-Dake and Yuza-Dake and established a toehold. The next day 12th June, by evening both divisions had forced the Japanese off most of the forward positions.
Meanwhile on the western side the Marines up against the “Kunishi Ridge” ran into stiff resistance. For 5 days the Japanese held off the Marines at the base of the ridge. Eventually with the aid of tanks and slackening resistance on 17th June they had reached the top, and the positions had been evacuated. As the “Kunishi Ridge” fell General Buckner on 15th June said that the campaign was down to the final kill. By now General Ushijima’s crack troops were rotting in the rubble of the Shuri battlefield.
After gaining the hills of Yaeju-Dake only a level plateau separated XXIV Corps from General Ushijima’s headquarters thought to be on the southern coral ledge at the tip of Okinawa. On the evening 17th June 10th Army could see the entire Japanese zone from their solid front lines across Okinawa. General Ushijima’s 32nd Army suddenly collapsed its discipline and morale finally broken after 8 days of defeat. On 18th June General Ushijima issued his last orders to 32nd Army. He ordered his remaining troops to the north of the island in order to wage guerrilla warfare after organized resistance had ended. While many did try to infiltrate to the north, most were determined to fight savagely to the end and take as many Americans as they could with them.
On 18th / 19th June 6th Marine Division in the west and 7th Infantry Division in the east began to encounter weak resistance as they advanced towards the south coast of the island. Only in the centre around “Medeera Pocket” did the Japanese show any organized fight which lasted until 21st June. Although the ratio of casualties now favoured the Americans, the Japanese had to be cleared from caves and crevices with great care as the front lines now disappeared. On the afternoon 18th June General Buckner visited a forward observation post of 2nd Marine Division at the southwest tip of Okinawa. While watching the progress of the fighting a Japanese artillery shell exploded above the observation post and General Buckner was struck by a fragment of coral in the chest which killed him. Major General Roy S Geiger assumed command of 10th Army.
Mass surrender of the Japanese did not begin until 10th Army crowded them to the water’s edge. As General Ushijima concluded the activities of 32nd Army within the cave system near Mabuni, American soldiers of 7th Infantry Division began to arrive at the entrance to the cave at the top. Japanese soldiers blasted the opening to seal themselves inside. General Ushijima radioed his last message to Tokyo on the evening 21st June. Realizing that they could hold out no longer, he and his chief of staff, General Cho, readied themselves for death. In the early hours of the following morning both men appear at the mouth of the cave facing the east, the time for the honoured rites of hara-kiri had arrived. A simultaneous shout and a flash of a sword followed by another and both men had nobly accomplished their last duty to their Emperor.
From 23rd June until the end of the month 10th Army began a thorough mop-up operation throughout the southern half of Okinawa to prevent any Japanese infiltrating towards the north. The operation was completed by 30th June and on 2nd July the Ryukyus campaign was declared ended.
The price paid for Okinawa was dear. Total American casualties amounted to 49,151, of which 12,520 were killed in all services. Ship losses were 36 sunk and 368 damaged and 763 aircraft lost. The Japanese losses were staggering. A total of 110,071 were killed including civilians. Added to this was 7,401 POW’s and over 7,830 aircraft destroyed. The operation exceeded all expectation with American forces now within 350 miles of Kyushu. With the atomic bombs of August 1945 followed by the Japanese surrender; this battle became the last one of World War II.
For further information of this battle, I would recommend the following books for a detailed analysis of the battle.
U S Army in WWII Okinawa The Last Battle by Appleman/Burns
History US Marine Corps in WWII Volume 5 Victory and Occupation by Shaw / Kane
The Quiet Warrior: Biography of Admiral Raymond A. Spruance (Classics of Naval Literature) by Thomas B. Buell
The Magnificent Mitscher Biography Admiral Marc Mitscher by T. Taylor.
These are but just a few. There are a lot of works dealing with this campaign that illustrate the hard battle that this was and the enormous loss of life that it entailed.