Why were the Japanese able to "sneak up" on Pearl Harbor?

Answer 1

Primitive radar, plus a lack of good monitoring and reporting of the radar we had, plus complacency on the part of the military.

Answer 2

First of all the US was pretty complacent about Japan and its abilities. Even though Japan had been at war in China since 1933 no one in Washington thought they would dare launch an attack against a US base. There were tensions with Japan but it wasn't thought that war was a big possibility, especially a sneak attack.

Pearl Harbor was not sending out scout planes, doing survelliance flights and other activities to have warning of a Japanese approach. Radar was still pretty primitive and radar capable of picking up a fleet of Japanese warships a couple of hundred miles off the coast did not exist. The Japanese fleet moved across the vast Pacific Ocean in radio silence, meaning there were no transmissions between ships or the homeland that would be picked up by any American listening posts.

While its true that the American's were reading the Japanese diplomatic codes, the code readers were behind on their work. Once again, complacency played its part. As for FDR knowing what was going to happen, or allowing it to happen well thats just so much hogwash. FDR loved the navy, he was a former assistant secretary of the Navy and its almost unthinkable that he would have sacrificed those men just to draw the US into a war. If FDR would have known about the impending attack then a scenario much more similar to the Battle of Midway would have occurred, where the Navy took a position of defense and ultimately inflicted severe damage on the Japanese fleet.

Answer 3

I recently read a superb book (At Dawn We Slept)on the attack on Pearl Harbour. What the success of the Japanese attack came down to was ,in a word, bureaucratic incompetence on behalf of the US civil and military planners and the singlemindedness of the Japanese and its planner, Minoru Genda, in their attempt to destroy the whole of the Pacific fleet. As is usually the way those responsible for the foul up in Hawaii didn't take the blame. We can all be thankful for the fact that the US carriers were not in Pearl at the time of the attack.

Answer 4

That's a splendid answer from lwjksu89 just above. Everything in it is spot on, whereas most of the earlier answers are fragments of the truth, or guesswork.

I think the key fact is that the Japanese fleet crossed the Pacific in strict radio silence. Up till then, the US had a pretty good idea of what they were doing, just from the volume and location of the ship-to-ship radio traffic, without even needing to decode it.

Answer 5

American military intelligence was woefully inadequate at this point. Plus, like many leaders in the rest of the world, American military leaders were unfamiliar with and underestimated air power.

Of course, there's the conspiracy theory that Franklin Roosevelt allowed Pearl Harbor attack to take place in order to rouse the American population. I'm not sure if I buy it, but it's a theory nevertheless.

Answer 6

All of the Japanese Purple Code decoders were strategically placed in Washington D.C., where they would not be available in the event of a surprise attack on Pearl Harbor.

Answer 7

Back in those days they didn't have satellite photos to track large scale naval movements. The Pacific is a huge ocean and it's easy to hide a naval fleet.

Answer 8

Sorry, but they did not sneak up on us. The USA, government know that the attack was comming. We had akready decoded their secreat codes using our spy technonlogy at the time. We just did not do anything about it.

Answer 9

And at the time, we were not at war with Japan, and they had just signed a non agression treaty with the U.S.

Answer 10

That is the way wars usually start.