Why did the Japanese attack US Pearl harbour?? what trigged it??

The USA was in their way. They had drawn on a map the region they needed to conquer to become self-sufficent. That circle just happened to incluce (among many other things) the Phillipines which was held by the USA. You saw a Naval arms race -- Japan vs the USA -- throughout the 30's. The USA knew Japan wanted the Phillipines and other US holdings in the Pacific. We knew they would likely resort to military attack.

The USA planned its strategy based on the belief that the Phillipines would be attacked first. The bulk of the USA's Navy was relocated from San Francisco and Los Angeles to Pearl Harbor in Hawaii -- where it would be better positioned to counter-attack in the event of a Japanese attack on the Phillipines. The Phillipines were equipped with numerous anti-naval artillery pieces throughout its ports.

The Japanese out-thought the USA and attacked the naval forces at Pearl Harbor, wiped out the majority of the USA's Pacific Fleet, and THEN invaded the Phillipines. Essentially, they wiped out our counterstrike first, then went for the goal. It was pure luck that the Carriers were out of port that day.

aah..then the US dropped A-bomb......

Originally Posted by mR.Hassan

aah..then the US dropped A-bomb......

No there was about 4 years of war thru out the pacific before that.

Originally Posted by mR.Hassan

aah..then the US dropped A-bomb......

Jeebus! Someone needs a few war books!

The attack on Pear harbor was never meant to be a suprise. The Japanese ambassador was waiting with a declaration of war in hand but was not seen, buy the US, until after the attack had take place. This is important to remember because the attack was supposed to cripple frighten and force the united states to bargin with Japan. The objective was to strike fast and hard forcing the united states to the bargining table early so that Japan would not have to face the united States in a drawn out confect over who had control of the pacific.

Unfortunately for Japan the suprise of the attack angered the United States bringing the United States into the war.

The Japanese admiral in charge of the attack on learning that the attack came as a suprise said "we have awoken a sleeping giant and fill him with a terrible resolve."

Originally Posted by swordrapier

The attack on Pear harbor was never meant to be a suprise.

Not quite true, but I will explain.

Originally Posted by swordrapier

The Japanese ambassador was waiting with a declaration of war in hand but was not seen, by the US, until after the attack had take place. This is important to remember because the attack was supposed to cripple frighten and force the united states to bargin with Japan. The objective was to strike fast and hard forcing the united states to the bargining table early so that Japan would not have to face the united States in a drawn out confect over who had control of the pacific.

Okay, so to clarify: The Japanese team of Ambassadors had been sent to the USA with the mission of working to foster better relations between the USA and Japan. They left Japan without any idea of Japan's true purpose for sending them. It was either the day before, or the morning of the attack by Japan on Pearl Harbor that the Japanese government had them contacted and instructed to hand the USA a Declaration of War at a specific time and date.

The attack on Pearl Harbor was intended to occur only a couple hours after the Declaration of War had been delivered -- not affording nearly enough time for the USA to have contacted the military to notify them, but still doing it "by the book". It was always intended to be a surprise attack. For a variety of reasons, there was substantial delay on getting the Declaration of War delivered, partly because the Ambassadors didn't know how to type in English well enough to have the Declaration ready until 3 hours late.

Originally Posted by swordrapier

Unfortunately for Japan the suprise of the attack angered the United States bringing the United States into the war.

The Japanese admiral in charge of the attack on learning that the attack came as a suprise said "we have awoken a sleeping giant and fill him with a terrible resolve."

That was Yamamoto. Admiral Yamamoto was never all that excited about the prospect of attacking the USA. Other military leaders, most of the very warhawkish, pushed the war agenda forward against the better advice of Yamamoto. One of the few relatively accurate war movies ever made -- "Tora, Tora, Tora!!!" tells it very well.

The mistaken assumption (that Yamamoto never personally bought into) was the idea that the shock would end up with the USA running with its tail between its legs.

Okay so you described it better than I did.

The Idea that I was trying to convey is this: to the Japanese culture the idea of killing someone while they are sleeping is dishonorable. However, it is perfectly acceptable to kick them awake then kill them before they have a chance to defend themselves. This is what they intended to do at pearl harbour.

It was supposed to be a suprise attack but, not a sneak attack. They wanted to kick the United States awake just before they kill him.

I agree that Japan assumed that the shock would send the United States running. It didn't work.

Amazing paralell with the 9/11 attacks, don't you think? Osama and terrorists in general think they are going get the USA to do or not do what they wish by attacks of that sort. That also didn't work out so well for them. Two nations that were safe ground for terrorists on one level or another with -- Afganistan and Iraq -- are somewhat limited as terrorist bases of opperations now.

Japan's oil supplies were being hurt by the US Navy and the Royal Navy. When Pearl Harbor was attacked, so was Singapore at pretty much the same time.
By knocking both navies out of the picture, Japan could get its oil from Indonesia without much issues.
The Army was pressing the Navy to do this because it needed fuel to run its army against the Chinese.