Why was Japan attacking Pearl Harbor a surprise attack?

Answer 1

Because the U.S. told Japan to stop taking over China and Japan got mad. Also because Japan wanted to take over Hawaii. The attack was a surprise by the Japanese because they hoped to crush U.S. Naval forces in Pearl Harbor, including the carrier fleet. The carrier fleet was at sea, and the victory proved to only unite the U.S. and force America into war with Japan.

Answer 2

First answer:

Japan attacking Pearl Harbor was a surprise for a few reasons:

1. The Japanese delegation in Washington failed to deliver the war declaration prior to the attack, so there was no expectation that they would do so.

2. Japan was very busy with invading and controlling Asia at the time and the Nazis were busy with Europe. Even if some Americans expected the attack to come, it wouldn't have been expected to come so prematurely. The last thing the Axis powers needed was the Americans entering the war.

3. Japan attacking the States was also stupid from a strategic point of view. For one, it was like a kitten attacking a lion. No chance of victory, only certain outcome would be a STRONG counter attack. The US wasn't in the war and didn't plan on entering it. Without the US, the war would've gone differently and England would've fell next. (That's why a lot of conspiracy theorists believe England sent a group of fighters in Japanese planes to attack the US.

4. Most of the American fleet was out at sea at the time so it was also bad timing on the Japanese side. If they had successfully destroyed the entire pacific naval fleet, they would've delayed the American response by months and possibly had time to land Japanese troops on American soil.

My answer:

For security purposes, only specific Japanese military leaders in Japan and those that undertook the attack were aware of it. The Japanese went to great lengths to keep the operation secret. No person in a European country was told of this specific pending attack, including Hitler. Therefore, no one in Europe could provide a warning to the United States.

The US military had partially broken the primary Japanese diplomatic code before the attack. These are referred to by US intelligence as the "Magic intercept of the Purple Codes". However none of the messages sent by the diplomats included any reference to any attack at Pearl Harbor. The Japanese diplomats themselves were not privy to the information about this attack.

Contrary to popular belief, the urgent message from Tokyo being decoded in the Japanese Embassy in Washington, DC (at the time of the Pearl Harbor attack) was not a Japanese declaration of war. It was a message to the United States that negotiations between the two governments had reached an impasse.

Seven hours after the attack on Pearl Harbor started, the Japanese cabinet, with the Emperor present, voted to declare war on the United States & the "British Empire" (Great Britain, Australia, New Zealand, Canada, & South Africa).

Neither the British, Dutch or American military had been successful at breaking the Japanese Navy codes before the Pearl Harbor attack. In the popular movies: Tora, Tora, Tora & Pearl Harbor the coded messages that the US intelligence officers are reading, are the Diplomatic Messages only.

What the United States did know or suspect (by late 1941) was that the Japanese were planning to attack the British territories in Hong Kong, Malaysia & Borneo, and attack the Dutch East Indies in late November or early December 1941. There were no specific details available, just Japanese military preparations & "saber rattling".

The United States also considered that the Japanese may also attack the United States at the Philippines, Guam, Wake & Midway. Again, no specific information was available.

Some American military leaders, by late 1940, also thought that the Japanese could launch an attack against Hawaii, however that was considered less likely. US Army Chief of Staff General Marshall considered it a sufficient threat that he reinforced Hawaii with air & ground units in 1941, and assigned General Short with the specific task of using the Army units (air/ground) to defend the US Pacific Fleet at Pearl Harbor.

US military preparations for the likely war with Japan focused on the Philippines. Indeed, it was because of the US military presence in the Philippines that caused Japanese military leaders to decide that it would be necessary to attack the United States in addition to the British & Dutch. The Japanese were uncertain if the United States would remain neutral if the Japanese attacked the British & Dutch. So they decided, to their great disadvantage, to attack the United States.

Meanwhile late in 1941 in Moscow, Soviet Dictator Josef Stalin (now at war with Hitler) had learned from his spies in Japan, that Japan was planning to go to war with Britain & Netherlands, and not with him in Siberia. It is not clear if Stalin knew of Japan's plans to attack the United States. In any event, Stalin gave no warning to either of his future "allies", and actually welcomed the idea that Japan would leave him alone.

The coming war with Japan was becoming obvious to most American & British leaders (and some astute in the public) by late 1941; the only question was where & when. When the Japanese did attack, they attacked the British & Americans simultaneously everywhere they could reach, including at Hawaii.