General Subjects Section, Academic Department, Infantry School, Fort Benning (Georgia)
Beachhead Operations of the 3rd Battalion, 381st Infantry Regiment, 96th Infantry Division in the assault of Okinawa, April 1-4, 1945, Ryukyus Operation. Capt Arsene P. Bonifas
(Personal Experience of a Battalion S-3
Prelude – Doc Snafu
The Allied Forces in the Pacific before the Ryukyus Campaign: April 1945
By April 1945, the war in the Pacific Theater of Operations had reached a critical juncture. The Allied forces, led primarily by the United States, had achieved significant victories against the Japanese Empire, steadily advancing through the vast archipelagos of the Pacific. Yet, the fight was far from over. With the planned invasion of the Ryukyu Islands, particularly Okinawa, the Allies faced one of their most daunting challenges. The situation in the Pacific at this time reflected both the fruits of earlier successes and the formidable obstacles that lay ahead. Understanding the strategic, logistical, and operational context of this moment illuminates the complexity of the campaign and its significance in the broader war effort.
Strategic Position of the Allies
By early 1945, the Allied strategy in the Pacific was centered on bringing the war to Japan‘s doorstep. This plan followed the island-hopping strategy, which involved bypassing heavily fortified Japanese positions to capture strategically important islands. These captured islands were then used as bases for airfields, supply depots, and staging areas for further advances. The capture of the Mariana Islands in mid-1944, including Saipan, Tinian, and Guam, had been a decisive step in this strategy. From these islands, the Allies were able to launch long-range bombing raids on Japan’s home islands using the new B-29 Super Fortresses. The subsequent seizure of Iwo Jima in March 1945 further strengthened this position, providing a forward base for emergency landings and fighter escorts for bombers heading to Japan. However, the next step, the Ryukyus Campaign presented unique challenges. Okinawa, the largest of the Ryukyu Islands, was only 350 miles from Kyushu, the southernmost of Japan’s home islands. Its capture was deemed essential for staging a full-scale invasion of Japan (Operation Downfall), which was tentatively planned for later in 1945.
The Japanese Defensive Strategy
While the Allies had gained momentum, Japan remained determined to resist at all costs. The Japanese High Command had shifted its strategy to focus on inflicting maximum casualties on the Allies in hopes of forcing a negotiated peace. Recognizing the strategic importance of Okinawa, Japan committed extensive resources to its defense. Unlike previous battles, where Japanese forces often fought to delay Allied advances, Okinawa was intended to be a final, decisive defensive stand. The Japanese strategy on Okinawa, known as ‘Ketsu-Go’, prioritized a layered defense. The island’s rugged terrain, characterized by ridges, caves, and fortified positions, was transformed into an intricate network of defensive lines. The Japanese 32nd Army, commanded by Lt Gen Mitsuru Ushijima, prepared to exploit these natural features to delay and bleed the Allied forces. Kamikaze attacks, which had been introduced in the Philippines Campaign, were also expanded to target Allied naval forces during the Okinawa Invasion. The use of suicide aircraft and boats underscored Japan’s willingness to resort to desperate measures to defend the home islands.
Allied Preparations for the Ryukyus Campaign
The Allies, under the overall command of Gen Douglas MacArthur in the Southwest Pacific and Adm Chester W. Nimitz in the Central Pacific, approached the Ryukyus Campaign with caution and meticulous planning. The invasion of Okinawa, code-named Operation Iceberg, was the largest amphibious assault in the Pacific Theater and required an unprecedented level of coordination between the US Army, Navy, and Marine Corps. The US 10-A, commanded by Lt Gen Simon Bolivar Buckner Jr, was assigned to lead the ground assault. This force consisted of approximately 180.000 troops, including divisions from both the Army and the Marine Corps. The naval support for the operation was equally massive. The Fifth Fleet, under Adm Raymond Spruance, assembled over 1200 ships, including battleships, aircraft carriers, cruisers, and destroyers. This formidable armada provided pre-invasion bombardment, air cover, and logistical support. The Allied air forces also played a critical role in softening Japanese defenses and isolating Okinawa. Prior to the invasion, US bombers and fighters launched extensive raids on the Ryukyu Islands and surrounding areas. The objective was to destroy Japanese airfields, disrupt supply lines, and weaken defensive positions. Additionally, the Allies conducted psychological operations, including leaflet drops, to undermine Japanese morale and encourage surrender.
Logistical Challenges
The scale of the Ryukyus Campaign presented significant logistical challenges for the Allies. Supplying such a large force across the vast distances of the Pacific required careful planning and coordination. By 1945, the US had developed an efficient supply chain, supported by an extensive network of bases stretching from Hawaii to the Marianas. However, Okinawa’s proximity to Japan and the threat posed by kamikaze attacks made supply operations particularly perilous. The Allies also had to contend with adverse weather conditions in the Pacific. Typhoons and rough seas could disrupt naval operations and delay the transport of troops and equipment. The risk of disease, particularly malaria, further complicated the campaign. To mitigate these risks, the Allies invested heavily in medical support, including field hospitals and preventive measures.
Morale and Psychological Factors
The morale of Allied forces in the Pacific was a complex mix of determination, exhaustion, and apprehension. By April 1945, many soldiers, sailors, and airmen had been fighting for years and were weary from the relentless pace of the war. The ferocity of battles such as Iwo Jima and the Philippines had left a deep impression on the troops, highlighting the high cost of fighting against a determined enemy. Nevertheless, there was a sense of optimism among the Allies. The victories of 1944 and early 1945 demonstrated the effectiveness of their strategy and the superiority of their resources. The knowledge that Japan’s industrial capacity and naval power were severely diminished bolstered confidence. However, the prospect of a protracted and bloody campaign on Okinawa tempered this optimism. Soldiers were acutely aware of the difficulties of amphibious assaults and the resilience of Japanese defenders.
Broader Implications of the Ryukyus Campaign
The Ryukyus Campaign was not only significant for its immediate military objectives but also for its broader implications for the Pacific War. By April 1945, the Allies were preparing for the endgame. The fall of Okinawa would provide a critical base for launching Operation Downfall, which envisioned a two-phase invasion of Japan. Okinawa would serve as a staging area for troops and supplies, as well as a base for air and naval operations against Japan’s home islands. Moreover, the campaign’s outcome would influence the political and strategic calculations surrounding the use of the atomic bomb. The anticipated high casualties of an invasion of Japan underscored the need for alternative means to end the war. Thus, the Ryukyus Campaign was not only a test of Allied military strength but also a harbinger of the decisions that would shape the postwar world.
Conclusion
As the Allied forces prepared for the Ryukyus Campaign in April 1945, they stood on the cusp of both triumph and tragedy. The victories of the previous years had brought them within striking distance of Japan, yet the battles that lay ahead promised to be among the most brutal of the war. The invasion of Okinawa would test the resolve, coordination, and ingenuity of the Allied forces, while Japan’s fierce resistance would foreshadow the challenges of bringing the Pacific War to a decisive close. The situation in the Pacific at this time reflected the broader dynamics of World War II: the relentless advance of Allied forces against a determined Axis power, the interplay of strategy and logistics in a global conflict, and the human cost of war. The Ryukyus Campaign would prove to be a pivotal chapter in this epic struggle, shaping the final stages of the war and the future of the Pacific region.
Introduction – Capt Arsene P. Bonifas
This document covers the operations of the 3rd Battalion, 381st Infantry Regiment, in the assault of Okinawa (Ryukyus Campaign) during the period April 1 – April 4, 1945. To orient the reader with events in the Pacific leading up to the actual invasion it will be necessary to discuss the incidents preceding this major operation. The battle for the Philippine Islands began on October 20, 1944, when the newly organized XXIV Corps comprising the 96th Infantry Division and 7th Infantry Division under command of Gen John R. Hodge, and the X Corps composed of the veteran 1st Cavalry Division and the 34th Infantry Division invaded Leyte (Philippine Islands).
On January 9, 1945, the Sixth Army invaded Luzon (Philippine Islands) and by March 4, 1945, Manila was completely in American hands. The conquest of the Philippine Islands was only partially completed when the first penetration of the inner defenses of the Japanese empire took place with the invasion of Iwo Jima by the veteran 4th and 5th Marine Divisions on March 18, 1945.
The war in the Pacific was progressing very rapidly and the anticipated end of the war in Europe would release large forces for redeployment to the Pacific Theater. The capture of the Marianas and Philippine Islands placed us some 1300 miles from the Japanese Homeland and the capture of Iwo Jima had advanced the line to within 640 miles of Tokyo. The next problem confronting the Allies was to secure a position in the Nansei Shoto Chain which extends from Kyushu down to Japanese held Formosa prior to the invasion of the homeland.
Okinawa, the principal island in the Ryukyus Chain and only 350 miles from the island of Kyushu was selected as the final target prior to the invasion of the Japanese Homeland. Okinawa, an island approximately 67 miles long and varying in width from 3 to 10 miles, is surrounded by a coral reef extending 300 to 1000 yards off shore and a seawall ranging in height from 3 to 10 feet. The reef and seawall greatly increased the hazards of an amphibious operation. The northern area is generally rugged, mountainous, wooded, undeveloped and of little military importance, while the southern area consists mostly of rolling country, broken by numerous escarpments. The southern area contains the greater number of the towns, roads and communication centers. Practically all of the 430.000 inhabitants live in the southern portion and Naha, the capital city, had a prewar population of about 65.000.
Okinawa is located in the temperate zone and has a relatively high and equable temperature throughout the year. The Hyukyus Chain is in the typhoon region where three to six typhoons may be expected to strike yearly. April 1, 1945, was selected as the target date for Operation Iceberg considering this time of the year would be most favorable for military operations. The island became a prefecture of Japan in 1879 and Americans were excluded by the Japanese thereby greatly hampering our intelligence efforts.
The well trained and disciplined Japanese 32nd Army defended Okinawa, Lt Gen Mitsuru Ushijima was placed in command August 1944 and had under his command 56.000 to 58.000 combat troops; major units consisted of the 62nd Division from China, 34th Division from the Kwantung Army in Manchuria, 44th Independent Mixed Brigade, 27th Tank Regiment and the 1st Artillery Mortar Regiment. It was estimated his forces would be considerably strengthened by the conscription of natives for service units and use in the front lines when necessary. The Japanese 9th Division was shifted from Okinawa to Formosa in December 1944 in anticipation of an attack on this island. The invasion of Okinawa and outlying islands was necessary for the following reasons: (a) primarily to establish air bases from which to attack the main island of Japan to secure sea approaches and to secure airfields for our land based fighters to caver the invasion of Japan; (b) to support operations along the coast of China; (c) to sever the Japanese air and sea communications between the empire and territory gained by conquest; (d) to acquire bases for future operations and continuous, pressure against the enemy.
To accomplish this objective the necessary task of gaining control of the air and sea fundamentally fell to the navy. Lt Gen Simon B. Buckner Jr, was selected as the Commanding General of the new US Tenth Army, activated for this important operation. Three Marine Infantry Divisions and four Army Infantry Divisions were alerted and eventually took part in the capture of Okinawa. The plan for the landings envisaged the following: (1) Kerama Islands to be assaulted beginning L minus 6 to secure an anchorage and naval base; (2) The Keise Islands to be captured on L minus 1 to enable Corps long range artillery to be landed and support the main landings on April 1; (3) tenth Army to land on L Day April 1, 1945, on Hagushi beaches with two corps abreast, III Amphibious Corps on the left (north) and the XXIV Corps on the right, (south).
Gen Buckner was given the following mission: ‘Assist in the capture, occupation, defense and development of Okinawa Island and establishment of control of the sea and air in the Nansei Shoto Area (Ryukyus) with the eventual aim of extending control of the Nansei Shoto by capturing, defending and developing additional positions’.
General Situation
Gen Mitsuru Ushijima, the Commanding General of the Japanese 32nd Army, sent his Chief of Staff, Gen 0ho to Tokyo in Jan 1945 to obtain the strategic plan to be used in case of attempted landings on Okinawa. He was told not to oppose the landings since the Kamikaze Corps and suicide boats would destroy the US Navy and leave the American forces stranded to be annihilated. Meanwhile, Gen Ushijima continued the improvement of numerous field fortifications and the organization of students attending the university in Naha into guerrilla units.
Gen Simon B. Buckner had been placed in command of all Expeditionary Troops. Adm Chester W. Nimitz was in command of the US Pacific Fleet and Joint Expeditionary Forces by VAdm Richmond K. Turner. Adm Nimitz envisioned the overall strategy would consist of isolating the Okinawa Area by long range air and naval striking units and the destruction of the enemy by joint operations of all naval and ground forces.
Task Force 58 commanded by VAdm Marc Mitscher began an attack on the Japanese Homeland in March and continued attacks on Kyushu, Honshu, Shikoku and the great Jap naval bases of Kobe and Kure until March 23, 1945. The Fifth Air Force, operating from Luzon; struck Formosa daily from March 18 to March 25. The XXI Bomber Command hit the industrial cities of Honshu from the Marianas. The Japanese were beginning to feel the full might of our navy and army air force. The Japanese high command wondered where we would strike next.
The 77th Infantry Division was given the mission of landing and capturing the Kerama Retto group prior to L Day. The Keise Islands were to toe captured on L minus 1. The III Amphibious Corps, commanded by Gen Roy S. Geiger, was to land on Hagushi beaches on the Tenth Army left flank (north) with the 1st and 6th Marine Divisions in assault with the mission of driving to the east coast and turning north to seize the Ishikawa Isthumus to prevent the arrival of reinforcements from the north.
The XXIV Corps, commanded by Gen John R. Hodge, was to land with the 7th and 96th Infantry Divisions in assault, 96th Infantry Division on the right (south) to split the island as rapidly as possible and turn their drive to the south. The strategy was to divide the Japanese 32nd Army thereby making their annihilation much easier. The 3rd Marine Division was to execute a feint on the southeastern tip of Okinawa on L Day and L plus 1. The 27th Infantry Division, floating reserve prepared for employment anywhere in the zone of the Tenth Army. 7th, 77th and 96th Infantry Divisions were engaged in combat in Leyte (Philippine Islands), until February 10, 1945, and came under the Tenth Army during the period February 10 to February 22. Training was almost negligible since the units were scattered and had to construct their own camps. Some training in breeching and scaling seawalls was conducted.
