On December 7, 1941, the Japanese attacked pearl harbor on the U.S. naval and air base, announcing the outbreak of the Pacific War. Just a few hours later, more than 400,000 members of the Japanese Southern Army, commanded by Terauchi Shouichi, began to attack Southeast Asia in several ways.
Many people do not understand that Japan's invasion of Southeast Asia is to obtain strategic resources in Southeast Asia, so why should it provoke the United States?
Japan is an island country with extremely scarce resources, and they also know that they cannot sustain a war on their own for long, so they will use war to feed themselves in China. Southeast Asia is rich in resources, and the Netherlands is a treasure trove of oil, far from being comparable to Japan.
Of course, the geographical location of Southeast Asia is also very important, after the occupation can cut off the communication line for Chinese aid, to the west can enter the Indian Ocean, to the south can directly threaten Australia, so Japan has long targeted its own target in Southeast Asia.
These areas are colonies of Western countries such as Britain, France and the United States. In addition to Thailand, Vietnam is French Indochina, the Philippines was taken from Spain by the United States, and Indonesia belonged to the small European country of the Netherlands. So if you invade Southeast Asia, the biggest obstacle is not the locals, but these colonists.
Countries such as Britain, France, and the Netherlands naturally do not have to worry, these countries are in Europe, they are mixed up by Germany, and even the Netherlands and France have been destroyed. The only thing that keeps Japan in the heart is the United States.
At first, the United States also engaged in appeasement in the Pacific, believing that it should "europe before Asia", so part of the American Pacific fleet went to the Atlantic to help solve the British crisis, which greatly weakened the defense of Southeast Asia. This also gave Japan the opportunity to attack Southeast Asia.
In the face of Japan's pressing aggressive posture, the United States and Britain finally began to move, and the United States imposed a "moral embargo", "export license", "economic embargo" and other measures on Japan, and after Japan entered Indochina, it implemented a scrap steel export license system for Japan. The United States and Britain also froze Japan's capital in the United States and Britain, and imposed an oil embargo on Japan.
This is something that Japan absolutely cannot accept, and it has also choked the lifeblood of the Japanese.
So everything made Japan have to fight against the United States, but Japan probably did not have the confidence to defeat the United States, as long as it could eliminate the Pacific Fleet, it could alleviate the pressure on Southeast Asia, so that the United States had no time to take care of it.
After all, the American Atlantic Fleet was in the Atlantic, helping Britain deal with Germany. If you want to support, it is also a matter of the Year of the Monkey and the Moon of the Horse.
Moreover, Japan had planned to adopt a surprise attack, coupled with the arrogance of the Japanese Navy, which made the Japanese base camp think that it could achieve the best results.