Battle of Okinawa (1945): The Last Great Battle of the Pacific

The Battle of Okinawa, fought from 1 April to 22 June 1945, was the largest amphibious assault of the Pacific War and one of the last major land battles of the Second World War. American forces invaded the island of Okinawa, about 550 km south-west of Japan’s main islands, to use it as a base for the final invasion of Japan.

The nearly three-month campaign was one of the deadliest of the war. Mass kamikaze attacks struck the Allied fleet offshore, Japanese and American soldiers fought for weeks over a line of ridges in the south, and the island’s civilian population suffered catastrophic losses.

Background

Okinawa is the largest of the Ryukyu Islands, once an independent kingdom that Japan annexed in 1879 after centuries of influence dating back to the Satsuma invasion of 1609. By 1945 it had a population of roughly 450,000–490,000, most of them farmers and fishermen.

After capturing the Philippines and Iwo Jima, American planners needed a base close to Japan for the planned invasion of Kyushu. Okinawa had room for airfields and large anchorages. The operation was code-named Iceberg.

Japan’s leaders knew the island could not be held. The Imperial General Headquarters treated Okinawa as a delaying battle, intended to inflict losses heavy enough to make the Allies consider a negotiated peace and to buy time for the defence of the home islands.

The war had already reached Okinawa before the invasion. In August 1944 the evacuation ship Tsushima Maru, carrying civilians including hundreds of schoolchildren to Kyushu, was sunk by an American submarine with the loss of well over 1,000 lives. On 10 October 1944 American carrier aircraft raided the island and destroyed most of the capital, Naha.

The forces

The US Tenth Army, under Lieutenant General Simon Bolivar Buckner Jr., combined Army and Marine Corps divisions, with around 180,000 combat troops in the initial assault. They were supported by an enormous fleet of more than 1,000 ships under Admiral Raymond Spruance, including the British Pacific Fleet.

The Japanese 32nd Army under Lieutenant General Mitsuru Ushijima numbered roughly 100,000 men, including Okinawan conscripts and militia. His staff, influenced by the operations officer Colonel Hiromichi Yahara, decided not to defend the beaches. Instead they concentrated their forces in the hilly south, around the ancient castle town of Shuri, in a deep belt of caves, tunnels and fortified ridges.

The landing and the advance

Preliminary landings took the nearby Kerama Islands from 26 March, securing an anchorage. On 1 April 1945, Easter Sunday, the main force landed on the Hagushi beaches on Okinawa’s west coast. To the Americans’ astonishment they met almost no resistance, and some 60,000 troops were ashore by nightfall.

The assault was led by four divisions: the 1st and 6th Marine Divisions in the north of the landing area and the Army’s 7th and 96th Infantry Divisions in the south. The landing split the island in two, and American troops reached the east coast within days.

Marines quickly cleared the north of the island, while Army divisions turned south. Within a week they ran into the outer defences of the Shuri Line. Battles for positions such as Kakazu Ridge, Sugar Loaf Hill and Conical Hill lasted weeks, in heavy rain that turned the ground to mud.

A Japanese counteroffensive on 4–5 May, urged by the chief of staff Lieutenant General Isamu Chō against Yahara’s advice, failed with heavy losses. Late in May the 32nd Army withdrew from Shuri to a last line in the far south. Shuri Castle fell on 29 May, its historic buildings destroyed.

The nearby island of Ie Shima, with its airfield, was taken by the 77th Infantry Division between 16 and 21 April. During the fighting there, on 18 April, the American war correspondent Ernie Pyle, one of the best-known journalists of the war, was killed by Japanese machine-gun fire.

Kamikazes and the Yamato

Offshore, Japan launched the largest campaign of suicide air attacks of the war. Waves of aircraft, known as kikusui (“floating chrysanthemums”), struck picket destroyers and carriers. These kamikaze attacks, together with conventional air raids and suicide boats, sank more than 30 ships and damaged more than 350.

On 6 April the battleship Yamato, the largest ever built, sailed with a small escort on a one-way mission to beach itself on Okinawa and fight as a fortress. American carrier aircraft sank it the next day, 7 April 1945, south-west of Kyushu, killing most of its crew of more than 3,000.

The air campaign was directed largely by Vice Admiral Matome Ugaki’s Fifth Air Fleet from bases on Kyushu. Between April and June there were ten major kikusui operations, alongside many smaller raids, and Japan also used the Ohka, a rocket-powered glider bomb steered by a pilot. On 11 May two suicide aircraft struck the carrier USS Bunker Hill, killing nearly 400 of its crew. The armoured flight decks of the British carriers proved more resistant to such hits than the wooden decks of American ships.

For the sailors on the radar picket destroyers stationed around the island, the strain was immense. The US Navy lost nearly 5,000 men killed at Okinawa, more than in any other campaign of the war.

The final weeks

In the south, the fighting became a struggle for caves and ridges. Civilians who had fled there were trapped among the retreating soldiers. On 18 June General Buckner was killed by Japanese artillery while visiting a forward observation post, making him one of the highest-ranking American officers killed by enemy fire in the war.

The physical and mental toll on the attackers was severe. Weeks of rain, mud, constant shelling and close-quarters fighting produced tens of thousands of non-battle casualties, including a very large number of cases of what was then called combat fatigue.

Organised Japanese resistance ended around 22 June. Ushijima and Chō took their own lives near their headquarters at Mabuni; the date is usually given as 22 or 23 June. The United States declared the campaign over on 2 July. Yahara was captured disguised as a civilian and later wrote an account of the battle.

The civilian tragedy

Okinawa’s civilians suffered more than in any other battle of the Pacific War fought on populated Japanese soil. Many were killed by artillery and bombing; others died of starvation and disease in caves. Some were driven out of shelters by Japanese soldiers or killed on suspicion of spying, as Okinawan dialects were regarded with distrust.

Japanese propaganda had told civilians that American troops would torture and kill them. In several places, notably on the Kerama Islands, hundreds of people died in so-called group suicides, sometimes under pressure from soldiers who handed out grenades. The role of the military in these deaths remains a sensitive issue in Japan and has been the subject of court cases and textbook disputes.

Among the best-remembered victims are the Himeyuri students, schoolgirls mobilised as nurses, most of whom died in the final weeks. Their story is commemorated at the Himeyuri Peace Museum in southern Okinawa.

By the numbers

The large number of Japanese prisoners, by Pacific War standards, included many Okinawan conscripts who surrendered in the final days.

Consequences and legacy

Okinawa was quickly turned into a vast base for the planned invasion of Japan, Operation Downfall. The losses on Okinawa and Iwo Jima convinced American planners that an invasion of the home islands would be extremely costly, and this formed part of the background to the atomic bombing of Hiroshima in August. The first stage of the invasion, Operation Olympic against southern Kyushu, was scheduled for November 1945, and planners’ casualty estimates for it varied widely and remain the subject of historical argument.

The battle also left a deep mark on the relationship between Okinawa and mainland Japan. Many Okinawans came to feel that their island had been sacrificed to protect the home islands, and memories of the conduct of Japanese troops towards civilians remain a sensitive issue.

After the war Okinawa remained under American administration until 15 May 1972, long after the rest of Japan regained its sovereignty. Large US military bases remain on the island, a continuing source of political debate.

Okinawa commemorates the battle every year on 23 June, Okinawa Memorial Day. At Mabuni, the Cornerstone of Peace, unveiled in 1995, lists the names of more than 240,000 people who died in the battle and related events, regardless of nationality, including Okinawans, Japanese soldiers, Americans, Britons, Koreans and Taiwanese.

Timeline

• 1945, 26 March: US troops land on the Kerama Islands.
• 1945, 1 April: The main landing takes place on the Hagushi beaches.
• 1945, 7 April: The battleship Yamato is sunk by US carrier aircraft.
• 1945, 4–5 May: A Japanese counteroffensive fails.
• 1945, 29 May: US forces capture Shuri Castle.
• 1945, 18 June: General Buckner is killed by artillery fire.
• 1945, 22 June: Organised Japanese resistance ends.
• 1945, 2 July: The United States declares the campaign over.

Why it matters

Okinawa was the last and largest of the Pacific island battles and a preview of what an invasion of Japan might cost. Its enormous civilian toll, the scale of the kamikaze campaign and the long American presence that followed have made it one of the most significant and painful chapters of the war, both in Japan and in the United States.