On December 7, 1941, the Japanese Navy launched a surprise attack on Pearl Harbor in Hawaii, causing heavy losses to the U.S. Navy and Air Force, and also led to the official entry of the United States into World War II. This event is considered Japan's greatest victory in the Pacific War and the greatest humiliation of the United States in World War II.
But, you know what? Japan actually made a very stupid mistake in this attack, and that was the failure of declassification.
Japan had been listening to and deciphering U.S. diplomatic cables for a long time before planning its attack on Pearl Harbor. Japan's intelligence services used a device called a "purple cipher machine" that could convert the Japanese language into a series of numbers before sending them out by radio. Japan believes that such a code is absolutely secure and cannot be cracked by the United States. However, they couldn't have been more wrong.
As early as 1939, American codebreakers had cracked the principle of the "purple cipher machine" and built a machine that could decipher Japanese telegraphs, codenamed "Magic". The United States learned of Japan's plan to attack Pearl Harbor through "magic", but due to incomplete intelligence and miscalculation, effective defensive measures were not taken in time, which led to the fiasco of Pearl Harbor.
However, Japan's declassification failures did not stop there.
Before attacking Pearl Harbor, Japan also sent a 14-page diplomatic cable to the United States, announcing the rupture of relations between Japan and the United States, which amounted to a declaration of war. This telegram was supposed to reach the United States within half an hour before the attack began*** to show Japan's justice and sincerity. However, the delay in the telegram was caused by the slow decryption of the staff of the Japanese embassy in the United States.
By the time the telegram reached the United States, the attack on Pearl Harbor had already begun more than an hour, and Roosevelt had already learned of it. When Roosevelt saw the telegram, he said angrily: "This is a shameless sneak attack statement!" Then he immediately delivered the famous "Infamous Day" speech to Congress, calling for a declaration of war on Japan.
Japan's failure to declassify not only made the United States feel anger and hatred, but also caused Japan to lose the sympathy and support of the international community. This mistake of Japan may have been an important reason for its eventual defeat in the Pacific War.
In addition to the failure to declassify, Japan made a number of other mistakes in Pearl Harbor, such as:
Japan did not attack Pearl Harbor's fuel storage facilities, dockyards, and repair facilities, which allowed the United States to quickly restore Pearl Harbor's combat capability.
Japan did not conduct a search and attack on American aircraft carriers near Pearl Harbor, which allowed the United States to retain its main power in the Pacific Ocean.
Japan did not carry out a third wave of attacks, which allowed the United States to keep a number of important military facilities and **, such as radar stations and torpedoes.
Japan did not anticipate a strong reaction from the United States, which led to a full mobilization of the United States after Pearl Harbor, joining the anti-fascist coalition and launching fierce retaliation against Japan.
These mistakes led to Japan's strategic mistakes in the Pearl Harbor attack and laid the groundwork for its defeat in the Pacific War.
References: [Pearl Harbor - Wikipedia, Encyclopedia of Freedom], American History.