OPPOSITE US marines pass a dead Japanese soldier on Okinawa; a handful of the third of a million men who fought in the battle. RIGHT A captured Japanese AA gun in Okinawa following the battle.

The Fighting Forces of Okinawa

Alexander Izza reviews the strategy, tactics, weapons, and morale of the opposing forces in the culminating land battle of the Pacific War.


If we are to understand the forces at play in the Battle of Okinawa, it first needs to be put in the context of the Pacific War as a whole.

US grand strategy in the Pacific revolved around using their powerful fleet of aircraft carriers and battleships to launch attacks against key strategic positions within Japan’s Pacific Empire, known as the ‘Greater East Asia Prosperity Sphere’. The aim here was ‘unremitting pressure’ against the Japanese military, grinding down their forces and eventually forcing them to surrender.

From late 1944, US military planners added the mass bombing of Japanese cities as part of this campaign. Military technology such as B-29 bombers, M47 oil gel bombs, and M69 gelled-gasoline (napalm) enabled the US to unleash unprecedented devastation against Japan.

One bombing raid against Tokyo on the night of 9 March 1945 created a colossal firestorm that swept the city, killing upwards of 100,000 people; some historians even suggest the casualties may have been much higher.

OPPOSITE US marines pass a dead Japanese soldier on Okinawa; a handful of the third of a million men who fought in the battle. RIGHT A captured Japanese AA gun in Okinawa following the battle.
US marines pass a dead Japanese soldier on Okinawa; a handful of the third of a million men who fought in the battle. A captured Japanese AA gun in Okinawa following the battle.

This ‘bombardment’ element sat alongside the ‘blockade’ of Japanese access to its empire. By early 1945, important victories on islands across the Pacific including Guadalcanal, Peleliu, and Iwo Jima had left Japan hemmed in and essentially cut off from its conquered territories in South-east Asia – denying them crucial resources to fuel their war machine.

From the Japanese perspective, the situation in the Pacific was dire. Defeats by the US were compounded by the emergence of a new enemy in 1945. In April, the Russians notified the Japanese that they would allow the 1941 Neutrality Act to expire and would join the fight against them.

Nevertheless, surrender was not countenanced by Tokyo, despite the pleading of several notable diplomats in Europe to consider the option. The Prime Minister, Admiral Susuki Kantaro, was committed to a plan of exacting a terrible toll from the advancing US forces, convincing them to not invade the homeland and forcing them to negotiate a peace deal.

To achieve this, the Japanese organised a series of increasingly daring expeditions. This included ‘Fu-Go’ balloon bombs, hydrogen balloons carrying a bomb of varying sizes that were propelled eastward on the Gulf Stream to hit North America.

Thousands were launched in 1944-1945, many reached the American continent, but the impact was minimal – bar the deaths of six civilians in rural Oregon. Alongside these assaults was a growing suicide dimension to the Japanese war effort (discussed below).

Preparing for Okinawa

In 1945, the US aim was to seize a key island chain near the Japanese home islands known as the Ryukyu Islands, thereby denying key airfields to the Japanese, completing the blockade of Japan to the south-west, and setting up US forces for the final invasion of Japan – planned for mid-1945. Known as ‘Operation Iceberg’, it culminated on 1 April 1945 in the invasion of Okinawa by US forces.

The campaign was organised under the new joint Army-Navy force known as ‘Central Pacific Task Forces’, commanded by Admiral Raymond Spruance. Beneath him was a sprawling command structure that pulled together the strength of the 5th Fleet and Lieutenant General Simon Buckner’s 10th Army – 182,000 marines and soldiers plus an additional 120,000 men in logistics and technical roles.

Within the naval forces was a wide assemblage of capabilities, including the fast carrier forces of Task Force 58 (commanded by Vice-Admiral Mitscher), a British carrier force (known to the US as Task Force 57), expeditionary forces, and an array of aerial, reconnaissance, and monitoring assets.

A captured Japanese AA gun in Okinawa following the battle.

The 5th Fleet was a fearsome sight to behold: 40 carriers, 18 battleships, and nearly 200 destroyers.

From October 1944 to the invasion of Okinawa in April 1945, US forces put Japanese forces in this area of the Pacific under significant pressure through sustained aerial bombing and naval bombardment.

Mitscher launched an early strike on Okinawa on 10 October. His fast carrier force launched waves of planes from nine carriers, dropping 541 tonnes of bombs, and firing 652 rockets and 21 torpedoes. The capital Naha was left aflame, 111 enemy aircraft were destroyed, and – according to Japanese estimates – five million rounds of Japanese machine-gun ammunition were ruined.

The coral atoll of Uliti, around 1,300 miles south of Okinawa, served as advanced fleet base for Central Pacific Task Forces. Marine pilot Sam Hynes proclaimed when he saw the anchorage that he had ‘never seen so many ships – it was like seeing all the power in your corner.’

On the Japanese side, preparations sat within their overall strategy of negotiated peace. General Mitsuru Ushijima’s 32nd Army of 130,000 men was garrisoned on the island. The forces were generally well-supplied and were very well aware of the significance of their stand here – they were in the last line of defence stopping an American invasion of the Japanese home islands.

The shifting sands of the war had varying benefits for the Japanese. On the one hand, they lost the veteran 9th Division after it was redeployed to the Philippines in December 1944 following the US invasion of Formosa. Yet they benefited from disruption in supply shipments to Japanese territory further south, leaving them unusually well-stocked with automatic weapons and mortars.

ABOVE This wartime US military plan depicts a typical Japanese bunker system.
This wartime US military plan depicts a typical Japanese bunker system.

In the months running up to the battle, the Japanese laboured to set up advanced defences across Okinawa. Exploiting the advantageous mountainous geography of southern Okinawa, Ushijima focused on establishing three strong defensive lines around the capital Naha.

Well aware of the inevitable US assault on the island, and reckoning with regular US aerial bombardment, the Japanese filled this area with a labyrinthine network of enlarged natural caves, slit trenches, and tunnels.

This underground defence system could protect the vast majority of Japanese forces on Okinawa from US aerial assault. The goal was to use these defences to keep the US as much as possible in front of the Japanese lines. While the Japanese were sheltered from US bombing and shellfire, they would in theory have the American infantry under fire from their own artillery.

Crucially, as Max Hastings stressed in his Nemesis: the battle for Japan, 1944-45, ‘The hub of Japanese strategy … was an air assault upon the invasion fleet on a scale hitherto unseen in the Pacific theatre.’ Waves of aircraft, many the infamous kamikaze, were set to strike the US naval forces supporting the attack. The aim was to disable the fleet, leave ground forces stranded, and open the door for a Japanese counter-attack.

Easy landing

The first distinguishing feature of the Battle of Okinawa was the technical achievement of the US invasion. In the run-up to the battle, Admiral Blandy’s Task Force 52 led extensive mine-sweeping operations to clear the key approaches to Okinawa’s south-west beaches for the landings. In all, American mine-sweepers cleared about 3,000 square miles in 75 sweeps.

In addition, the US seized the nearby Kerama Islands (15 miles west of Okinawa), taking 350 suicide boats out of action and securing crucial anchorage and airfields in preparation for the invasion.

In the final days before the battle, underwater demolition teams cleared key landing beaches of mines and posts – supported by lines of US naval power covering them up to 2,000 yards inland.

The pressure ratcheted up every day: in the final seven days before fighting commenced on 1 April, US naval guns fired more than 13,000 large-calibre shells on Okinawa’s shore, destroying all known coast-defence guns.

Any historian writing about Okinawa makes clear the strangeness of the American landings on 1 April. At the time, it was the heaviest concentration of naval gunfire ever to support a landing of troops, with 10 battleships, 9 cruisers, 23 destroyers, and 177 gunboats all pounding the shore. All of this to land the marines and soldiers on empty beaches. The Japanese had withdrawn to their defensive lines in the south.

The first part of the battle was, undoubtedly, a success for the Americans. They achieved their initial objectives, rushing from the south-western beaches to split the island in two by 3 April. The 6th Marine Division then had little difficulty sweeping up the minimal Japanese forces in the north of Okinawa.

Trench warfare

Okinawa is roughly 70 miles long and 7 miles wide. The US had won roughly half the island. But the remainder of the battle required them to shake Japanese forces from their sprawling fortifications in the island’s south, where they were concentrated across a front nowhere more than around three miles wide (mitigating the US numerical superiority) and set amongst steep ridges that gave the Japanese every advantage.

Unusually for Japanese operations in the Pacific theatre, the 32nd Army were well-equipped with artillery, including 52 150mm howitzers, 12 150mm guns, and 96 81mm mortars. This put the US advance under sustained fire, reaching from US front lines right back to the rear. At one point, the XXIV Marine Corps estimated they were fired upon by 14,000 Japanese shells in 24 hours.

The battle formed into a war of attrition. With the Japanese in control of the high ground and ensconced in hardy turrets and pillboxes, the US were left with little option but to engage in costly frontal assaults. Okinawa descended into trench warfare, with men fighting with desperation for every yard of ground. Noted WWII historian James Holland summarised it as ‘a fight with rifles, machine guns, and mortars’.

US forces initially struggled with the ‘reverse-slope tactics’ of Japanese cave positions. This involved digging into a hillside opposite another slope, with that ‘reverse-slope’ becoming the one they concentrated fire upon. When the US attempted to advance en masse into these environments, the Japanese were able to mow them down.

US engineers use explosives to destroy a Japanese bunker on Okinawa.

In response, the US strategy shifted to the use of artillery fire to drive as many Japanese forces as possible underground into the protection of their caves. This created a window for US infantry to charge in small squads, attempt to penetrate a weak spot in the line, and then ‘clear out’ Japanese forces.

Blowtorch and corkscrew

Historian Thomas Huber contended in Japan’s Battle of Okinawa, April-June 1945 that a critical part of clinching success in these assaults was the American use of the tank. Facing the hardened fortifications of the Japanese lines, the US deployed M4 Sherman tanks to support their infantry. It was, argued Huber, ‘the instant symmetrical answer to the caves in this kind of warfare’.

The tanks supported breakthroughs by the infantry, exchanging fire with Japanese gun emplacements with their mix of machine-guns, heavy guns, and flamethrowers. Throughout these duels, the US infantry worked to protect the tank’s flanks and attempted to get beyond the Japanese angle of fire. Once past this ‘dead angle’, US forces were able to assault the caves and tunnels directly.

General Buckner described these manoeuvres as the ‘blowtorch and corkscrew’. The Sherman tank delivered the ‘blowtorch’ in the form of its flamethrower gun (filled with 300 gallons of napalm mixed with gasoline and a range of up to 200 yards) to set the Japanese positions aflame. This was often combined with a ‘corkscrew’ in the form of US demolition teams, either to kill any remaining Japanese troops or to simply seal up the cave.

In the warren of underground fortifications used by the Japanese, the ‘blowtorch and corkscrew’ did not always fully clear out an area. Sometimes the Japanese were able to redeploy down tunnels unknown to the Americans and successfully retreat.

Indeed, the longer the Japanese remained in this defensive posture, the greater their resilience in the face of US advances. Their greatest strategic mistake of the battle – the 3 May counter-attack – led to them revealing many of their hidden artillery positions to American planners. US forces, once they had rebuffed the assault, were able to proceed with much greater knowledge of Japanese positions and to coordinate their artillery and ground action accordingly.

Chaos in the skies

As the slog for supremacy on land continued, a cacophony of fighting was underway in the skies around Okinawa. The Japanese committed significant airpower, in an effort to cripple the American fleet and prevent victory on land.

This came in the form of traditional aerial attacks, kamikaze aircraft launching dive-bombing suicide attacks, and kaiten strikes – a modified naval torpedo with a small conning tower in which a pilot directed it to the target.

The pilots themselves were not all the fanatical acolytes of wartime propaganda. Some certainly were ready to die, however just as many were reluctant conscripts. The kamikaze can be considered an extreme expression of Japanese militarism – the Japanese form of fascism that had become dominant during the 1930s, above all amongst the Japanese officer corps.

right Flamethrowers were also used to clear bunkers.
Flamethrowers were also used to clear bunkers.

The occasions when kamikaze pilots took off on their last flights were sombre and emotive events. The instructions to kamikaze units went as follows: ‘Once you take off from here, you will not be coming back; you must leave your effects in an orderly state, so that you will not make trouble for others, or invite mockery.’

When they approached Okinawa, the kamikaze craft climbed and climbed to a high altitude of around 20,000 feet, and when they were above their target, dive-bombed the decks of the ships below – the Japanese aptly referred to them as ‘floating chrysanthemums’.

In their path was an intricate array of US aerial defences. They had to avoid Vought F4U Corsair interceptor aircraft launched from US carriers, a maze of wires held aloft by balloons floated around the fleet, and a hail of fire from the 40mm, 50mm, and 5-inch shells with proximity fuses.

Even for those that survived this onslaught, success was not guaranteed – many missed their targets and crashed straight into the ocean.

Most historians agree that the US successfully managed to counter the kamikaze with this mix of carrier-based aircraft and bombardment from the ships below. In addition, the Allies started air strikes against air bases from which the kamikazes were deploying and adopted new evasion tactics for their fleet.

Equally significant, the Japanese strategy had deficiencies that minimised kamikaze impact. In A World at Arms: a global history of World War II, historian Gerhard Weinberg pointed particularly to the Japanese propensity to focus on destroyers and destroyer escorts, which were on patrol ready to warn of approaching planes. The Japanese often bombarded these ships with an excessive number of attacks, continuing after they were disabled, and missed the opportunity to head for larger – and more important – units.

The kamikaze attacks did not manage to cripple the US 5th Fleet. They succeeded, however, in enacting a terrible toll on the US Navy at a time when naval commanders wanted to focus on supporting Army operations on Okinawa. These attacks inflicted the heaviest casualties of the war on the US Navy. Kamikazes sank 27 ships and damaged a further 164.

Four kamikaze pilots prepare for their final mission.
A kamikaze pilot fastens his bandana before setting out.

Out of the nearly 1,500 kamikaze aircraft deployed in the Battle of Okinawa, one in five hit a ship – a success rate ten times that of standard Japanese air assaults during the battle. Hastings summarised it perfectly: ‘For the sacrifice of a few hundred half-trained pilots, vastly more damage was inflicted upon the US Navy than the Japanese surface fleet had accomplished since Pearl Harbor.’

All this to say nothing for the huge sapping of morale for the US sailors who lived in constant fear of these terrifying waves of Japanese aircraft. One American carrier commander called this daily ritual ‘the most dangerous brand of routine to be found in the history of WWII.’

The price men paid

The men who fought on Okinawa faced a battle with very few parallels in the Second World War. Many veterans’ recollections, both American and Japanese, focused on the mud.

Pounding rain enveloped the island in May 1945, creating a hellish ooze that absorbed everything. Combined with endless shellfire wreaking devastation on the landscape, Okinawa quickly resembled a scene of desolation more akin to the First World War.

Survivors recalled a daily existence deprived of all human dignity, as soldiers camped amidst mud in sodden uniforms, and tried in vain to avoid the swarms of millions of flies that descended on the corpses. ‘The place was choked with the putrefaction of death, decay, and destruction,’ recalled Private First Class Eugene Sledge in his acclaimed memoir, With the Old Breed. ‘For several feet around every corpse, maggots crawled about in the muck… I believed we had been flung into Hell’s own cesspool.’

The steady humdrum of violence took a toll on many US soldiers on the frontline. Men broke down and refused to fight. Attacks were often random, with persistent risk of Japanese sniper fire and incursions at night. This left men so paranoid that on one occasion (according to Gunner Chris Dunner), an infantryman on duty at night reacted to a noise he heard by shooting five marines before he was himself shot.

‘You’re sleeping in a hole every night and anything you do could get you killed, including absolutely nothing,’ remembered US Marine Bill Pierce. ‘That’s what it felt like.’

The Japanese had their own problems with morale in their underground defensive systems. Men could easily become disconnected from reality in their world of caves and tunnels. Many struggled as well with the soaring humidity, stale air, and temperatures that could run in excess of 90ºF (32ºC). Operations Officer Yahara likened Shuri Castle, the ‘nightless palace’ where General Ushijima had his HQ, to ‘being dragged to the bottom of hell.’

The Japanese suffered appalling casualties. Regularly throughout the battle, exchanges with US forces might result in a Japanese death toll ten times that of their US counterparts. Captain Kouichi Ito recalled how his battalion suffered an extraordinary 300 casualties in their first two days of combat.

US marines in action on Wana Ridge.

From the US perspective, the casualty toll on Okinawa changed everything for the rest of the war. America had watched in horror at the price paid to take Okinawa. US planners were forced to rapidly readjust casualty calculations for Operation Downfall, the planned invasion of Japan’s home islands. Herbert Hoover estimated to President Truman that a final US defeat of Japan would cost half a million American and seven million Japanese lives.

Meanwhile, Japan refused to surrender – rejecting the Potsdam Declaration by the Allies on 26 July 1945. Legislation passed by the Diet on 12 June had already compelled all men aged 15-60 and women 17-40 to sign up for the People’s Volunteer Force.

The Bomb

America’s next move is well known. They dropped two atomic bombs, on Hiroshima and Nagasaki, between them killing nearly 100,000 people instantly. Japanese surrender followed on 15 August 1945.

The strategic calculus around these decisions, and their impact, continues to divide historians. Scholars such as Richard Newman and Richard Frank maintained that, for US commanders facing the colossal estimates of casualties in a ground invasion, dropping the bomb was a necessary evil to shock a Japanese leadership ready to fight to the last into surrendering.

However, in reality, Japan was not planning to fight into oblivion. Historian Sheldon Garon sees Japan as a country in collapse before the atomic bombs fell. The Japanese leadership had watched in horror the last stand of Nazi Germany and were overwhelmed by a social crisis as millions of Japanese civilians fled the cities in fear of bombardment. Further pressure was added when the USSR invaded Manchuria on 8 August.

ABOVE A few Japanese, like this man, were taken prisoner, especially towards the end of the battle. Most Japanese refused to surrender, and some of those who tried failed to have their surrender accepted. ABOVE RIGHT Among the prisoners were some of the Japanese child soldiers who had been pressed into service during the battle.
A few Japanese, like this man, were taken prisoner, especially towards the end of the battle. Most Japanese refused to surrender, and some of those who tried failed to have their surrender accepted.

The atomic bombs, in short, were a devastating final cataclysm for a nation already on a turbulent path towards surrender. A US ground invasion was never going to be necessary.

Among the prisoners were some of the Japanese child soldiers who had been pressed into service during the battle.

The victims of the double nuclear attack were all civilians. Their fate is a reminder that the great majority of the dead of the Second World War in the Far East were civilians (the majority of them Chinese).

The Battle of Okinawa, for example, was fought on an island with 500,000 civilian inhabitants, of whom one in five perished. Many civilians were drafted by the Japanese to fight, or to support the war effort in the form of labour or medical support staff.

Masako Nakazato was mobilised aged 18 to the Himeyuri Student Nurse corps, a support medical unit of girls aged 15-19 from the capital Naha. Fewer than half of the 222 girls mobilised returned home.

Nakazato’s experiences hint at the wider legacy of this battle. In an interview with the South China Morning Post, she recalled how Japanese forces ordered her to slit her throat or the advancing Americans would rape and kill her. She was only stopped by another Japanese soldier who told her that this was a lie: ‘I was saved at the last second and I am here today. Every day, I regret it that I am alive while they [her friends who committed suicide] aren’t.’

Her account is not alone. There were numerous incidents of Okinawan civilians killing themselves, rather than face the US forces they had been told for years represented the worst evil imaginable. In one cave near Yomitan village, 83 civilians killed themselves in a mass suicide.

Even so, the American record is far from spotless. There are recorded incidents of US soldiers shooting civilians assumed to be working for the Japanese, and reports of rape and other summary violence inflicted against the Okinawan people.

In the years since the Battle of Okinawa, the mists of historical memory have descended on this bloody chapter of the Second World War. For the Japanese, it is another part of a war filled with atrocities and abuses the country would prefer to forget. For Americans, it has tended to be overshadowed both by the war in Europe and by the climactic ending of the war in the Pacific in the two atomic explosions.

Okinawa deserves to be well-remembered as a struggle whose bestial ferocity was equal to that of any during the Second World War. •

Alexander Izza is a writer currently working in PR. He studied history at the University of Cambridge, completing an MPhil in American history and a dissertation on American soldiers’ identity in the Korean War.
All images: WIPL.