Why Did Japanese Attack Pearl Harbor

The attack on Pearl Harbor refers to the surprise military attack carried by the air wing of the Imperial Japanese Navy on the US naval base in Pearl Harbor, Hawaii on 7th December 1941. The attack is often credited for bringing the US into the 2nd World War for the Allies. The attack, although seeming suicidal and a tactical blunder at present, was a brilliantly planned and meticulously detailed attack by the Imperial Japan on the US soil which took the whole country by complete surprise as the two nations had still not declared war on each other. Japan intended to send a message to the American through the attack and dissuade them from interfering in their planned invasions in the oversea European colonies of South-East Asia.

pearl harbor
Pearl Harbor – Wikipedia.org

The attack started around 7:48 a.m. local time. The air wing of IJN attacked the Pearl Harbor naval base using 353 Imperial Japanese aircraft, which included bombers and fighters in two waves, which were launched via six IJN aircraft carriers. U.S. Navy incurred heavy losses with all of their eight battleships destroyed; four of them being sunk. All of them except USS Arizona were recovered through with six of them seeing a return to service and going on to fight in the war.

The IJN also destroyed three U.S. Navy cruisers along with three destroyers, an anti-aircraft training ship, and one minelayer. U.S Air Force lost 188 aircrafts while 2,403 Americans lost their lives including 68 civilians and 1,178 suffered injuries of all kinds. IJN for some reasons avoided attacking important base installations like the dry dock, power station, maintenance, shipyard, torpedo, and fuel storage facilities, besides submarine piers and the headquarters building. The attack also saw some light casualties to the Japanese side too with IJN losing 29 aircrafts along with five midget submarines and 64 servicemen. Kazuo Sakamaki, a Japanese sailor was captured by the Americans.

The attacks on Pearl Harbor have been a subject of great studies, debates, researchers and lessons in history. But why was the attack carried out in the first place? When USA and Japan were not at war, what prompted the Japanese to such action? In short, why did the Japanese attacked Pearl Harbor?

There was always a high possibility of war between the USA and Japan and both nations were aware of the fact since the 1920s. Both of them had readied contingency plans in case of a war with the other two. But there was no tension initially between the two nations until the Japanese invasion of Manchuria in 1931. The next decade witnessed the continued Japanese expansion in China bringing the two countries at war in 1937. The Japanese carried out great campaigns for isolating China and were able to attain adequate resource independence to gain victory over the Chinese mainland. The Southern Operation of the Japan was intended to support these efforts.

More than 200,000 Chinese lost their lives starting from December 1937 because of Japanese activities including the attack on USS Panay, the Nanking Massacre, and the Allison incident. This estimate is highly debated though with other sources estimating the number to be between 40,000 to 300,000. All these Japanese advances helped to mold the Western public opinion against Japan. The US, UK, and France started providing support and loans to China for war supply contracts fearing a Japanese advancement.

1940 witnessed the Japanese invasion of French Indochina for the purpose of controlling the supplies to China. The United States retaliated by ceasing the US supplies of airplanes, machine tools, parts and aviation gasoline to Japan. The Japanese perceived these actions as unfriendly on US part. Still, the USA refrained from stopping the oil exports to Japan at the time because of the prevailing opinion in Washington that such an action would be considered extreme by the Japanese who may consider it as a provocation, as Japan was completely reliant on the US for its oil needs.

In 1941, the US President Franklin D. Roosevelt decided to move the Pacific Fleet from San Diego to Hawaii and ordered a military accumulation around the Philippines with the intent of dispiriting the Japanese assaults in South East. The Japanese high command saw a ravaging preemptive strike on the USA as the only option to avoid US Navy’s interference as they were almost convinced that any attack on the British Southeast Asian colonial territories would see the US entering the war, although they were mistaken. The invasion of Philippines was also crucial for the Japanese.

The War Plan Orange developed by the USA proposed the defense of Philippines by an elite force of 40,000 members. The plan was vigorously opposed by Douglas MacArthur who argued that a force ten times the size is needed, but the plan was never implemented though. US planners started perceiving abandonment as the best option in case of a war in the Philippines and the orders for the same were given to Admiral Thomas Hart in late 1941.

The USA finally halted oil exports to Japan by July 1941, after the Japanese invasion of the French Indochina following the Fall of France. This prompted the Japanese to take further actions in implementing their plans to capture the oil-rich territory of Dutch East Indies. President Roosevelt, in August 1941 gave a warning to Japan of U.S. actions against them if Japan decided to attack their “neighboring countries”. The Japanese were now confronting the option of either withdrawing from China and facing humiliation or capturing and obtaining new sources of raw materials from the European colonies of Southeast Asia, traditional resource-rich territories.

USA and Japan continued negotiations with each other throughout 1941 with the intent of improving relations, though largely unsuccessful. Japan even offered withdrawal of its troops from the mainland China and Indochina during the negotiations after brokering peace with the Nationalist government and adoption of an autonomous elucidation of the Tripartite Pact with stopping the discrimination in trade if all the other nations reciprocated their opinions. But the USA rejected all these proposals. The Japanese PM, Konoye, then wished to meet with President Roosevelt himself personally, but Roosevelt asserted that any meeting would be possible only after coming to an agreement.

The US ambassador to Japan repeatedly advised President Roosevelt to meet the Japanese PM claiming it to be the only method for preserving the Konoye government along with peace in the Pacific region. But his advice was completely ignored with Roosevelt who continued to insist on his previous stand. The government of Konoye fell in the next month when the Japanese military refused to withdraw all of its troops from the Chinese territory at all.

The Japanese offered their final proposal on November 20, offering the withdrawal of their forces from Southern Indochina and stopping their plans of advancing in Southeast Asia if the UK, Netherlands and the USA stop their aids to China and lift all sanctions against Japan. The Americans retaliated with a counter-proposal on 26th November 1941(the Hull note) asking Japan to withdraw from China completely without any conditions and sign non-aggression pacts with the Pacific powers. But the Japanese attack fleet had left for Pearl Harbor a day before the Hull note reached the Japanese.

There were many objectives behind the attacks from the Japanese. Foremost of them was their intention of destroying the critical American fleets and thwarting any attempts by the US Pacific Fleet from interfering with the Japanese plans for conquering Malay and Dutch East Indies and controlling the important parts of East Asia without much interference. Another major objective behind the attacks was to buy some time for strengthening their position as well as increasing the Japanese naval strength before the shipbuilding authorization due to the 1940 Vinson-Walsh Act of USA rub out any chances of Japanese victory.

Thirdly, the Japanese intended to provide a major blow to the mobilization abilities of the USA in the Pacific Ocean. American battleships were targeted prominently by the Japanese airplanes during the attacks as they were the esteemed ships of navies around the world at that time. Their final objective or rather a notion was that the attacks would discourage America from any interventions in the war by blowing down their morale and the country would bow down to the Japanese demands and come to the negotiation table with them.
But carrying a strike on the Pacific Fleet at in the Pearl Harbor anchor also consisted with two major hindrances.

First, the ships were in the very shallow water, so salvaging and then repairing them for reuse would have been easier, and secondly, there was a high chance for most of the crews to survive the strikes as they would be on shore leave mostly or could be rescued easily. Another major downside of this attack was its timing, as the Japanese intelligence knew that all three aircraft carriers of the US Pacific Fleet namely Saratoga, Enterprise and Lexington were away from the harbor. Despite such overwhelming odds, the IJN top command decided to proceed with the attacks due to Admiral Mahan’s insistence and the “Decisive battle” doctrine.

The Japanese were so confident of their capabilities in achieving victories in short and blitzkrieg attacking wars that they chose to ignore crucial harbor targets in the Pearl Harbor such as the naval yard, submarine base, and oil tank farms. They were of the view that there would be no need for such utilities for the American as they would bow down to Japan after the attacks. This proved to be a grave miscalculation on the Japanese part.

Possibility of a third wave

Several junior sailors and officers advised the commander Nagumo for carrying out a third wave of strikes for demolishing the fuel, maintenance, dry dock facilities and torpedo storage as much as possible. Officer Genda, who had unsuccessfully pitched a plan for invading Hawaii after the initial air attacks argued that there was a need for at least three attacks to destroy much of the base in case the invasion is not happening. Even all the captains of the other five aircraft carriers of the task force were completely ready and behind the idea of carrying out another round of attacks. And many military historians agree that another round of attacks would have seriously damaged the base and the US ability to intervene in the Pacific rather than destroying the battleships only. Almost all of them including former Admiral of the US Navy agrees that the destruction of the Pearl Harbor base after the third wave of attacks would have postponed any US operations in the Pacific by at least two years.

However, Admiral of the Japanese task force Nagumo refrained from a third wave of attacks due to following reasons –

• The performance of the American anti-aircraft installations had improved significantly during the second strike with two-thirds of the whole Japanese losses occurring in the second strike only. Nagumo was of the view that a third strike would risk almost three-quarters of the Combined Fleet’s strength in a bid to clear the remaining targets while the losses suffered by the IJN aircrafts would be higher this time.

• The location of the American aircraft carriers was still unknown to both the IJN and the task force during the attacks. The admiral was also worried that the task force now stood within the American bomber’s range. Nagumo was also uncertain about the number of US airplanes surviving the attacks to carry out counterattacks to the Japanese task force.

• A third wave also needed considerable time to prepare and turnaround meaning the planes returning after the attacks may have to land at night. And only the Royal Navy was capable of night landings at that time.

• The fuel conditions of the task force also were prompting him to move out of the Pacific waters due to fewer logistics support available at their disposal.

Nagumo was also under the belief that the second strike had done enough to satisfy all the major objectives of his attacks which were the deactivation of the American Pacific Fleet. He, thus, did not want to risk further damages to the force unnecessarily. But the sparing of major vital base facilities meant the U.S. still possessed the ability to carry out counter operations in the Pacific which turned out to be a major reason for American victory later.

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