What happened when the Japanese attacked Pearl Harbor in 1941?

On the fateful morning of December 7, 1941, the skies over Pearl Harbor, Oahu, erupted in flames as Japanese fighter planes unleashed a devastating surprise attack on the United States Pacific Fleet.

In a matter of hours, over 2,400 American lives were lost, and a once-mighty fleet lay in ruins, forever altering the course of history and plunging the United States into World War II.

But what led Japan to make this audacious move?

What were the strategic errors and miscalculations on both sides?

And how did this cataclysmic event shape the future of the war? 

Imperial Japan had sought to create a Greater East Asia Co-Prosperity Sphere through military expansion in Southeast Asia.

This was seen as a necessary step to provide resources such as rubber and oil which were in short supply due to economic sanctions imposed on Japan by the United States.

However, the aggressive nature of Japanese expansion during the 1930s, especially its brutal actions during the Second Sino-Japanese War led to America imposing increasingly severe economic sanctions, culminating in an oil embargo in 1941.

This cut off the crucial resources that Japan needed to continue its war efforts, and so the decision was made by the Japanese high command to launch a surprise attack on Pearl Harbor which would cripple America's ability to interfere in the region and provide access to vital resources once more.

The attack on Pearl Harbor was the result of a long-standing plan by the Japanese military to neutralize the American Pacific Fleet.

The architect of this plan was Admiral Isoroku Yamamoto, who believed that a direct strike on the fleet would cripple their ability to interfere with Japan's plans for expansion.

Yamamoto also feared that if the US were to occupy Japan's conquered territories, the United States would be able to use them as bases for a blockade on Japanese shipping routes.

Yamamoto believed that this would result in starvation for his people and ultimately lead to their defeat by the Allies.

The attack itself was carried out by six aircraft carriers and 353 planes launched from four separate air groups.

The first wave of planes targeted the American airfields and military installations on Oahu, while the second wave attacked the Pacific Fleet anchored in Pearl Harbor. 

The first wave of planes was led by Commander Mitsuo Fuchida. The surprise attack caught the Americans completely off-guard when the first shots were fired at 7:55 am local time on Sunday, December 7th, 1941.

By 9:00 am all planes had returned safely to their carriers with only 29 being lost during the attack itself.

The American Pacific Fleet suffered significant damage. Specifically, the USS Arizona was sunk, killing over 1200 sailors and marines.

The battleships West Virginia, Oklahoma, California, and Tennessee were damaged or destroyed as well as many other smaller ships docked at Pearl Harbor.

In total, the Japanese attack resulted in over 2400 fatalities including civilians killed during strafing runs on Oahu by Japanese aircraft.

An additional 300 American aircraft located in the area were also damaged.

The attack on Pearl Harbor had a tremendous impact on both Japan and the United States.

Yamamoto's plan resulted in an immediate American declaration of war against Japan, which forced them to fight a two-front war with China as well.

The attack on Pearl Harbor was met with outrage by the American people and government.

On December 8th, President Franklin D. Roosevelt addressed a joint session of Congress to declare war on Japan.

In his speech, Roosevelt referred to the attack as "a date which will live in infamy" and vowed that the United States would seek "vengeance in full measure."

The attack on Pearl Harbor brought America into World War Two on the side of the Allies.

In response, just four days after Roosevelt's declaration, Hitler and Mussolini also declared war on America.

One of the most important factors in the attack was the realisation that the American aircraft carriers at Pearl Harbor were not present at the time of Yamamoto's raid.

Yamamoto made a serious error in failing to anticipate that the aircraft carriers would be absent from port on their way back from delivering fighters to Wake Island and Midway Atoll.

Yamamoto had hoped for an unopposed attack, but despite this intelligence failure, his plan did severely damage the fleet.

Despite suffering extensive damage, the Pacific Fleet was able to recover quickly. Yamamoto did not anticipate the United States' ability to rapidly repair and replace damaged ships using their industrial might, which ultimately led to his defeat at the Battle of Midway six months later.

Yamamoto's failure in this regard has been attributed largely due to a poor understanding of American culture as well as his own arrogance.

Also, the defeat was due to American code-breaking efforts, which allowed the U.S. to anticipate the attack.

Ultimately, Yamamoto's plan ultimately backfired and led directly to Japan's defeat.