Why Were Casualties So High in the Battle of Okinawa?

Cassie Pope

3 mins

21 Jun 2018

The Battle of Okinawa began on 1 April, 1945 with the largest amphibious assault of the Pacific War. The United States, having “hopped” their way across the Pacific Ocean, planned to use the island as a base for an assault on the Japanese mainland.

The Okinawa campaign lasted 82 days, ending on 22 June, and witnessed some of the highest casualty rates of the war, across both combatants and civilians.

A key position

Okinawa is the largest of the Ryukyu Islands, located just 350 miles south of the Japanese mainland. The United States, believing an invasion of Japan would be necessary to end the Pacific War, needed to secure the island’s airfields to provide air support.

So critical was the capture of the island, that the United States mustered the largest amphibious assault force of the Pacific campaign, with 60,000 soldiers landing on the first day.

Marines attack a cave system on Okinawa using dynamite

Japanese fortifications

The Japanese defence of Okinawa was under the command of Lieutenant General Mitsuru Ushijima. Ushijima based his forces in the hilly southern region of the island, in a heavily fortified system of caves, tunnels, bunkers and trenches.

He planned to allow the Americans to come ashore almost unopposed, and then to wear them down against his entrenched forces. Knowing an invasion of Japan was America’s next move, Ushijima wanted to delay the attack on his homeland for as long as possible to give them time to prepare.

Kamikaze

By 1945, Japanese airpower was incapable of mounting any serious challenge one-on-one against their American counterparts. The US fleet witnessed the first organised kamikaze attacks at the Battle of Leyte Gulf. At Okinawa, they came en masse.

Almost 1500 pilots hurled their aircraft at the warships of the US 5th and British Pacific Fleets, sinking or damaging about 30 vessels. The USS Bunker Hill was hit by two kamikaze planes whilst refuelling aircraft on deck, resulting in 390 deaths.

The carrier USS Bunker Hill in the midst of a kamikaze attack off Okinawa. The wooden decks of the American carriers, favoured due to increased capacity, left them more vulnerable to such attacks than the British carriers.

No surrender

The Americans had already witnessed the willingness of Japanese soldiers to fight to the death in battles such as Iwo Jima and Saipan.

In Saipan, thousands of soldiers carried out a suicidal charge in the face of American machine guns on the orders of their commander. Such charges were not the policy of Ushijima on Okinawa.

The Japanese would hold each line of defence until the last possible moment, expending great manpower in the process, but when it became untenable they would retreat to the next line and begin the process again. Nevertheless, when facing capture, Japanese soldiers often still favoured suicide. As the battle entered its final stages, Ushijima himself committed seppuku – ritual suicide.

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Civilian casualties

As many as 100,000 civilians, or one quarter of the pre-war population of Okinawa, died during the campaign.

Some were caught in the cross-fire, killed by American artillery or air attacks, which utilised napalm. Others died of starvation as the Japanese occupying forces stockpiled the island’s food supplies.

Locals were also pressed into service by the Japanese; used as human shields or suicide attackers. Even students, some as young as 14, were mobilised. Of 1500 students drafted into the Iron and Blood Imperial Corps (Tekketsu Kinnotai) 800 were killed during the fighting. But most notable of all were the suicides.

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Japanese propaganda painted American soldiers as inhuman and warned that captive civilians would be subjected to rape and torture. The result, whether voluntary or enforced by the Japanese, was mass suicides among the civilian population.

By the time the Battle of Okinawa came to an end on 22 June, American forces had suffered more than 45,000 casualties, including 12,500 killed. Japanese deaths may have been higher than 100,000. Add to this the civilian death toll and the terrible cost of Okinawa becomes clear.

This high toll persuaded President Truman to look elsewhere for a means to win the war, rather than send an invasion force to Japan. Ultimately, this was a factor in the approval of the use of atomic bombs against Hiroshima and Nagasaki in August 1945.