Pearl Harbor: Japanese Military Motives.

Japanese Motives Leading to the Attack on Pearl Harbor 

The Japanese attack on Pearl Harbor caused the involvement of the United States into World War II. This event was a surprise attack by Japanese fighter planes attacking the United States Naval ships ultimately leading to a total of 2,403 deaths, both civilian and military.1 Many ships were damaged but at the end important supplies and many bases were left untouched leading to a relatively quick bounce back by the American military. The attack on Pearl Harbor was seemingly a completely surprise attack by the Japanese the issue was the lack of understanding why.   

Japan sought China as the fix to all their problems. Japan was becoming very overpopulated and the great depression happening all around the world caused them to seek out to take over China and move their people in to fix the countries issues. With this being the plan Japan needed to increase everything in terms of resources so now outside trade was crucial in getting them what they needed for the big war at hand.2 Whilst Japan saw this as the way out of the depression the rest of the world saw the devastation of Chinese culture and destruction on lands. The world did not seek to help Japan but prevent them from doing the only thing they felt they needed to do. The United States was one of the countries against Japan while not exactly engaging in battle with them but more of subtlety helping China albeit very limited help. Slowly decreasing trade and supplies to Japan whilst also stationing a few troops into China to help aid them. Although these were very limited helps it would increase tension with Japan being that this was the time they needed supplies the most.3 This would serve as the first steps for Japan towards war with the U.S. 

The United States were not wanting to get involved with the war but only placing restrictions on limits of supplies traded to stop Japan from attacking China and expanding so much. Not wanting to get into the war due to the depression being in the not so distant past the U.S. wanted to stay neutral but with China being a major trader and important to the economy they could not let Japan take them over. The Nanjing massacre and the devastating war Japan was in with China put the world on notice. There was now an obligation to help China without just focusing on trade and money. Japan was very reliant on trade with the U.S. getting war supplies such as steel, iron, and with Japan needing especially oil in order to continue their conquest against China and to be part of the World War already taking place. 4The U.S. also had troops stationed in China in order to help them fight off Japan and further stop the Japanese takeover of China. With no resources being allocated to the Japanese from the United States, Japan would be forced to completely stop their conquest and takeover of China and completely retreat. With Japan now giving up on their takeover of China they now had major animosity towards the U.S. for causing this. Seeing the U.S. as the enemy now the planning of an attack was imminent.  

The embargo was the tipping point in causing the Japanese leader Hideki Tojo to plan an attack on Pearl Harbor. The embargo was the United States completely stopping all trade with Japan in order to stop them from accomplishing their conquest of China. The embargo although was not a military attack it crippled the Japanese military as if it was. The supplies were needed and relied upon by Japan so much that their own home nation would not survive let alone their war with China. Japan estimated they had less than two years of bunker oil left and by the rate the war was going also with the threat of an even bigger world war Japan had no choice but to retaliate.5  

Leaders figured that attacking Pearl Harbor would devastate the U.S. and force them to lift all their embargoes and sanctions on Japanese trade and allow them to complete their task. Also, The United States then increased the supplies given to China further going against the Japanese and causing more and more tension altogether ultimately serving as the tipping point for Japan to go ahead and attack the United States.6 The attack was meant to be a deterrent rather than a declaration of war. Japan did not intend to go to war with the United States with the attack, but to send them a warning to re open trade and go back to giving supplies to them. With Pearl Harbor being a major oil and fueling station for ships and planes Japan saw this as a major asset to the United States and attacking it would cripple their military. This was a dishonor no Japanese leader would accept causing the planning of the attack of Pearl Harbor. 

The Japanese military was under immense pressure with problems seemingly all pilling up on them. Their country was in disarray and overpopulation was starting to cause huge issues. The only logical way to fix things was thought to be the Takeover of China. In order to complete this Japan needed the rest of the world to indirectly help by trading more supplies especially the United States with their oil. After embargoes were placed Japan was left with no choice but to retaliate. The attack on Pearl Harbor was seemingly a completely surprise attack by the Japanese the issue was the lack of understanding why. 

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Oral History  

With the trade embargo by the United States on Japan coming into effect the Japanese military is forced to stop its takeover of China and must retract their forces. This combining with the fact that Britain has also stopped their supplies to Japan is starting to cripple them as a nation not just in the war. Japanese leader had honor and could not tell his people of failure. Japan had no choice but to fully go into world war II alone.  Japan used its power to take over other nations such as India and had other military victories But, with the Ally’s being so powerful Japan was no match. Even so Japan would not surrender as it would be a dishonor.  

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Christopher Riches, A Dictionary of Contemporary World History (Oxford: Oxford University Press, 2016). 

Feis, Herbert. The Road to Pearl Harbor: The Coming of the War between the United States and Japan. Princeton, NJ: Princeton University Press, 2015. 

"Bankrupting the Enemy: The U.S. Financial Siege of Japan before Pearl Harbor." The SHAFR Guide Online. 

Hideki, Tojo. “My Blood Boiled at the News” Japan at War an Oral History. Transcript of an oral History by Haruko Cook and Theodore Cook, The New York London Press, pg.72-73 


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