What Was the Significance of the Battles of Iwo Jima and Okinawa?

Harry Atkins

3 mins

21 Jun 2018

The Battles of Iwo Jima and Okinawa in 1945 undoubtedly saw some of World War Two’s fiercest fighting. Both engagements occurred towards the end of the Pacific War, as the United States sought to capture strategically important territories ahead of a planned invasion of Japan. Both battles resulted in huge numbers of casualties.

As we now know, America’s planned invasion of Japan never happened. Instead, two atomic bomb attacks on the Japanese cities of Hiroshima and Nagasaki, together with the Soviet Invasion of Manchuria, finally broke Japan’s stubborn resolve.

With the benefit of hindsight, we might therefore question the necessity the US’s engagements in Iwo Jima and Okinawa, especially given the huge losses that both battles incurred.

Why did the US invade Iwo Jima?

Having captured the Mariana Islands in the North Pacific Ocean from Japan in 1944, the US recognised that the small volcanic island of Iwo Jima could have great strategic importance.

It was situated half-way between the Mariana Islands – where America now had airfields – and the Japanese homeland, and thus presented the next logical step on the route towards an assault on Japan.

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Iwo Jima was also home to an operational Japanese airbase, from which Japan launched fighters to intercept American B-29 Superfortress bombers en route to Tokyo.

Capturing Iwo Jima would not only clear a path for bombing assaults on the Japanese homeland, it would also provide the US with an emergency landing and refuelling field and a base from which to provide fighter escorts for the B-29 bombers.

Why did the US invade Okinawa?

The invasion of Okinawa, which lies just 340 miles south-west of the Japanese mainland, was another step on America’s island-hopping campaign through the Pacific. Its capture would provide a base for a planned Allied invasion of Kyushu – the most southwesterly of Japan’s four main islands – and ensure that the entire Japanese homeland was now within bombing range.

Two US Marines engage Japanese forces on Okinawa.

Okinawa was effectively viewed as the final push before an invasion of the mainland and thus a vital step towards ending the war. But by the same token, the island was Japan’s last stand in the Pacific and thus vitally important to their efforts to hold back an Allied invasion.

Japanese resistance

At both Iwo Jima and Okinawa, US forces were met with fierce Japanese resistance. In both engagements Japanese commanders favoured a drawn-out deep defence that delayed Allied progress while inflicting as many casualties as possible.

The Japanese made full use of the islands’ difficult terrain to ensure that the Americans were forced to fight for every inch of land. Pillboxes, bunkers, tunnels and concealed artillery emplacements were employed to deadly effect and Japanese troops fought with fanatical commitment.

American aircraft carrier USS Bunker Hill burns after being hit by two kamikaze planes during the Battle of Okinawa.

By the end of the Iwo Jima engagement – which was fought from 19 February to 26 March – US casualties stood at 26,000, including 6,800 dead. The Battle for Okinawa, which took place between 1 April and 22 June, resulted in an even higher number of US casualties – 82,000, of whom more than 12,500 were killed or missing.

Were the battles necessary?

Ultimately, the significance of these bloody battles is hard to gauge. At the time of their planning both invasions looked like strategically important steps towards an invasion of Japan, which at that time was still widely regarded as the best hope of ending World War Two.

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The necessity of both battles is often questioned in light of Japan’s decision to surrender following the atomic attacks on Hiroshima and Nagasaki

But it might also be suggested that the ferocity of the Japanese resistance at Iwo Jima and Okinawa was a factor in the decision to deploy atomic bombs rather than pursue an invasion of the Japanese homeland, which would almost certainly have led to many more Allied casualties.