What happened when the Japanese attacked Pearl Harbor in 1941?

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 a proposal was made by the Japanese high command about a potential surprise attack on Pearl Harbor.

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

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

As a result, Yamamoto believed that a sudden and decisive strike on the American navy resources stationed in Hawaii could be a key element in a quick victory that would force the United States to withdraw from the Pacific region.

However, Yamamoto feared that if the attack wasn't an overwhelming victory, it could lead to a prolonged war with the United States, where the industrial capacity of the U.S. would eventually overwhelm Japan.

Then, the final trigger came after months of failed diplomatic negotiations with the United States, when the famous 'Hull Note' was delivered to Japanese negotiators Ambassador Kichisaburo Nomura and Special Envoy Saburo Kurusu on November 26, 1941.

In it, U.S. Secretary of State Cordell Hull demanded that Japan withdraw from China and Indochina, which was seen by Japan as an unacceptable ultimatum.

On November 26, 1941, the First Air Fleet, commanded by Vice Admiral Chuichi Nagumo, set sail from the remote anchorage of Hitokappu Bay in the Kuril Islands, far to the north of Japan’s main islands.

The fleet consisted of six aircraft carriers, two battleships, three cruisers, nine destroyers, and several support vessels.

To avoid detection, they chose a northern route that kept them away from major shipping lanes and areas where they might encounter American or Allied ships.

For much of the journey, the Japanese fleet maintained strict radio silence, refraining from any communication that could betray their location.

Instead, during their voyage, they relied on a disciplined communication system that utilized pre-arranged light signals and flags for essential communication between ships.

As they moved closer to Hawaii, the fleet also benefited from heavy clouds and rough seas in the northern Pacific, which provided natural cover.

It made any potential aerial reconnaissance by American planes more difficult.

Moreover, the U.S. military had not anticipated an attack from this direction, which further contributed to the success of the silent Japanese approach.

In addition, the Americans had deployed limited long-range patrols and relied on untested detection methods, such as radar stations that were not yet fully trusted by military personnel. 

Finally, the Japanese fleet had launched several submarines and midget submarines to take up position near Pearl Harbor to provide intelligence and disrupt any American countermeasures.

The attack on Pearl Harbor began at 6:10 AM of December 7, 1941, when 353 planes began launching from the six aircraft carriers sitting north of Oahu.

These planes included fighters, dive bombers, and torpedo bombers, which formed up for two separate attack waves.

In fact, a radar operator at Pearl Harbor detected the incoming Japanese planes, but the sighting was mistakenly dismissed as a flight of American B-17 bombers arriving from the mainland.

The first wave of 183 planes caught the Americans completely off-guard at 7:55 AM.

They were led by Commander Mitsuo Fuchida, and immediately targeted key military installations.

The torpedo bombers targeted the battleships moored at Ford Island, while dive bombers attacked airfields to neutralize American aircraft sitting on the tarmac.

Within minutes, chaos erupted as ships and planes caught fire, explosions rocked the harbor, and smoke filled the air.

At 8:10am, the USS Arizona suffered a direct hit from a Japanese bomber, causing its forward ammunition magazine to explode and sinking it quickly.

At the same time, Japanese Zero fighters strafed parked aircraft with their machineguns.

American forces scrambled to mount a defense, but their efforts were hampered by widespread confusion about what was happening.

Then, the second wave of 171 Japanese aircraft arrived at 8:54am and continued the assault, focusing on any remaining ships and facilities that had not been destroyed in the initial strike.

The battleship USS Oklahoma capsized after multiple torpedo hits, sadly trapping hundreds of sailors inside.

In contrast, ships like the USS Nevada attempted to make a break for the open sea but faced relentless enemy fire and were eventually sunk by their own sailors to avoid the wreck blocking the harbor's narrow entrance.

Despite being caught off guard, U.S. forces eventually managed to mount an anti-aircraft response that downed several Japanese planes during the second wave of the attack.

Also, some American pilots did reach their planes to try and defend their base, but many were shot down before they could even leave the ground.

A few managed to get airborne and engage the enemy in dogfights above the island.

By 10:00 AM, the attack was over. In the space of just two hours, the American Pacific Fleet had suffered significant damage.

8 battleships, 3 cruisers, and 4 destroyers were all destroyed. The worse casualties occurred in the sinking of the USS Arizona, which had killed 1,177 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.

Also, approximately 188 American aircraft were destroyed, and 159 were damaged.

In comparison, the Japanese had only lost 29 planes, five midget submarines, and fewer than 100 men.

However, there were some very powerful acts of heroism on the day. For Example, an African American cook on the USS West Virginia, named Doris Miller, displayed remarkable bravery by manning an anti-aircraft gun and fired at Japanese planes.

He would be awarded the Navy Cross for this.

The devastating defeat immediately caused a round of finger-pointing to try and assign blame.

Admiral Husband E. Kimmel and Lieutenant General Walter C. Short, the commanders of the Pacific Fleet and Army forces in Hawaii, respectively, were relieved of their commands and criticized for not being adequately prepared for the attack.

However, many observers knew that the Japanese attack, which had occurred before any official declaration of war had been made, was almost impossible to have predicted.

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.

While the Japanese had achieved a tactical victory, they failed to destroy vital targets, such as the American aircraft carriers, which were not in port at the time.

Yamamoto did not anticipate that the aircraft carriers would be absent from port, as they were on missions delivering fighters to Wake Island and Midway Atoll.

Also, the Japanese attacked had entirely missed the vital fuel storage facilities at Pearl Harbor.

These facilities were not targeted at all, which many consider to be a significant oversight.

In fact, the survival of the fuel depots would eventually allow the U.S. Navy to maintain logistical support in the Pacific, which would contribute to subsequent American military operations.

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 Midway defeat was due to American code-breaking efforts, which allowed the US to anticipate the attack.

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