In what ways was Pearl Harbor not a strategic blunder for Japan?

Answer 1

It was a great strategic blunder for Japan. It was not a wise decision. I recommend you read the book A World At Arms by Gerhard L. Weinberg.

The original Japanese intent was to hold the American military off for 6 months to a year. The Japanese navy leadership correctly understood that the United States was too strong to defeat in a long war. Instead the Japanese made the assumption that the US would not be willing to fight in Asia & the Pacific and would negotiate a peace that would allow the Japanese to keep its conquests.

Among the numerous mistakes of Japan was the idea (by the Japanese Army) that Japan had to attack the United States. Next was the idea, by Japanese Admiral Yamamoto, to initiate a surprise attack on the US Military at Pearl Harbor and other places in Hawaii. This surprise Sunday attack at Pearl Harbor had many unfortunate results for Japan, the most important are:

1) The attack was well documented by photographic means, proving to the American public that this was an intentionally planned surprise attack that did happen on US territory on a Sunday while the US was at-peace by the Japanese (versus a chance meeting at sea that got out of control).

2) It so angered the American public and the US leadership that the Japanese would have absolutely no chance for a peaceful settlement. Instead the American public would strongly support the utter & complete defeat of Japan, even if it meant bringing the horrors of war to the Japanese Home Islands and the Japanese people.

3) Because the attack was carried out in the shallow harbor of Pearl Harbor, it would allow several battleships that were sunk in the attack to be later refloated, raised, rebuilt, and put back into service during the war. It also allowed for the survival of most of the valuable US navy crews of the ships in the harbor.

4) Also because the attack on the US Navy occurred at the harbor, US anti-aircraft firepower (Navy & Army) was much more concentrated than it would have been at sea. Although US anti-aircraft defenses were un-manned at the start, they were able to shoot down nine Japanese aircraft in the first wave, and then 20 Japanese aircraft in the second wave of the attack. The US Navy also sank several Japanese midget-submarines in-and-around the harbor. These are actually fairly heavy losses for Japan's best navy aircrews in a surprise attack. The Japanese Navy up until this time only produced 100 pilots per year, so it would take them almost four months to replace these losses (with much less experienced pilots).

5) The temporary loss of battleships in the Pacific forced the US Navy leadership to adopt & successfully fight the early months of the war with only its aircraft carrier & cruiser task forces. This would create a new way for the US Navy to fight & win in the Pacific. This concept was improved as the war went on, and as many more US Aircraft Carriers were built & put into service, the US Navy would gain naval supremacy in aircraft carrier combat operations.

6) The US Navy was given a first-hand (& very personal) lesson on the absolute importance of having good anti-aircraft defenses on-board all its ships. Very quickly US ships replaced their .50 cal machine-guns with the more powerful & potent 20mm & 40mm anti-aircraft cannons in very large numbers. Also these weapons would be manned by additional & dedicated crews that were trained especially for this duty. The earlier practice of manning these guns with anybody available (cooks, clerks, etc.) during an air-raid was discarded in favor of highly trained specialists. By the end of the war, US warships had AA guns installed on just about every available free space on the deck, superstructure & even on top of major gun turrets. Ship crews grew in numbers by adding the AA crews. Additionally the US Navy adopted & practiced very effective AA tactics for ships using "mutual-support" between ships. US ships, during enemy air-attacks, were close enough to one-another to be able to provide AA fire to protect other nearby ships. This required that these ships maneuver together in-formation to avoid collisions, hence the importance of lot of practice & training. Side-note: The Japanese never learned this particular method of AA defense.

7) The Japanese leadership & public were given the false impression that their victory was at-hand, and that they were invincible. This "victory disease", as the Japanese would later call it, led them to make several strategic & tactical mistakes in combat with the Americans & Australians.

Answer 2

It seems almost impossible to not see the Imperial Japanese blunder in its decision to bomb Pearl Harbor and bring the US into World War Two. One blunder surrounded Japan's idea that Hitler would happily declare war on the US., making the US fight a two front war. This was not a happy decision to make. Only a crazed dictator like Hitler would have honored any agreement to bring the US into the war. Clearly Japan made an enemy of a country that would never be invaded. And yes, Japan saw itself a half world away, but it again underestimated how short a distance that would become in a very short time.Secondly, Japan failed to recognize the large US population and its capacity to manufacture war supplies along with domestic products.