Answer:
The attack on Pearl Harbor was a surprise peacetime attack by the Imperial Japanese Navy Air Force on December 7, 1941, to the United States' Pacific fleet, which was anchored in Pearl Harbor, Hawaii.
With the attack, the Empire of Japan expanded the Pacific War that had been waged since 1937. With the attack, Japan wanted to shut down the U.S. Pacific fleet for six months to secure raw materials in Southeast Asia.
On December 8, 1941, the United States declared war on Japan. This made the attack on Pearl Harbor and its aftermath a decisive turning point in World War II, because the United States' declaration of war on Japan and the Axis powers' declaration of war against the United States led to the United States' entry into World War II.
Although the attack weakened the United States significantly militarily, the long-term consequences for Japan were fatal. Through the attack, which was perceived as "insidious" in the USA, the American government succeeded in mobilizing the largely pacifist or isolationist US population to enter the war, which led to the decision in favor of the Allies due to the enormous American industrial potential.
In short, this attack was a Japanese pyrrhic victory, because on the one hand, it unleashed a new battlefront with a very powerful enemy; on the other, he was unable to fulfill his objective of completely destroying the American fleet; and lastly, he activated a series of diplomatic connections that took away even more international support from the neutral nations in the conflict.
