# Why did Japan think attacking Pearl Harbor was a good idea? **URL:** \ **Category:** Great Debates\ **Created:** [May 29, 2018, 9:03pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089 "2018-05-29T21:03:36Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Malthus](https://avatars.discourse-cdn.com/v4/letter/m/85f322/32.png) [@Malthus](https://boards.straightdope.com/u/Malthus)\ **Post date:** [June 1, 2018, 2:35pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/61 "2018-06-01T14:35:55Z")
> [@pantom](#): > > My sharpest memory from reading The Rise and Fall of the Third Reich is that Dec 7 was either the same day or very close to the day that Albert Speer informed Hitler that Russia was unwinnable with the resources Germany had at hand. > It’s entirely possible to argue that Dec 7, 1941 was the day the Axis truly lost the war. Germany was realizing their mistake in invading Russia, Japan had a big China problem, and then Japan, much to Hitler’s surprise (and likely dismay) forced the US into it. Hitler compounded the problem by declaring war on the US! If he hadn’t done that, there may not have been one “world war”, but two, with the US focused entirely on Japan (instead of the Allies, including the US, deciding on a “Germany first” strategy). In his mind, he somehow managed to spin December 7 into a _good_ thing for his cause – that gaining Japan as a ally was worth gaining the US as an enemy. Churchill, needless to say, held the opposite view (he says something in his memoirs of going to sleep happy that his cause had been saved), and of course, he was right. ---
**Author:** ![aldiboronti](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@aldiboronti](https://boards.straightdope.com/u/aldiboronti)\ **Post date:** [June 1, 2018, 4:17pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/62 "2018-06-01T16:17:21Z")
> [@puddleglum](#): > > In pre war Japan the government was extremely dysfunctional. Both the Japanese Army and Navy were practically autonomous and had representatives in the Cabinet. Any prime minister who opposed anything favored by either branch was quickly assassinated. This meant there was no one to oversee the long term strategy. The Japanese Army was not informed of the Pearl Harbor plans until late August and the civilian cabinet was not informed until November. There was no one in the Japanese government who could have vetoed the Pearl Harbor plan if they had wanted to. Especially true given the fact that Emperor Hirohito was 100% behind the military. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [June 1, 2018, 4:38pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/63 "2018-06-01T16:38:54Z")
> [@TokyoBayer](#): > > There simply can’t be any reason to believe that the Japanese would expect the US to take until 1950 to achieve parity. That’s silly. There were enough Japanese who were familiar with the capability of the States. Is the United States capable of paying off the national debt? Yes, certainly. Do you think it’s likely that the national debt will be paid off by 2028? No, almost certainly not. We lack the political will to do something we know we should be doing. That’s the key point that the Japanese and Germans saw in 1941. The United States had a huge economy; but it wasn’t focused on military production. And that’s true even in 1941. The Roosevelt administration was constantly dealing with the problem of production delays in military contracts. 1941 was a boom year for car sales and manufacturers were pushing to build more cars rather than expanding their production of tanks and airplanes. Soldiers in the summer of 1941 were still drilling with broomsticks. Promised lend lease supplies to Britain and Russia couldn’t be delivered because the material hadn’t been produced. Then there was the political situation. There was still a strong sense of isolationism in America. Congress had barely passed the draft extension in October (it passed by one vote); if they hadn’t, the United States army would have begun breaking up units as the draftees finished their enlistment. The Axis powers were dictatorships. They looked at the democracies and told themselves, _“This is why we’ll win. Sure, the United States has a lot of potential power. But they’ll never get organized. There’s nobody that can give orders and get things done like there is here.”_ ---
**Author:** ![TheMightyFro](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/themightyfro/32/20081_2.png) [@TheMightyFro](https://boards.straightdope.com/u/TheMightyFro)\ **Post date:** [June 1, 2018, 5:41pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/64 "2018-06-01T17:41:07Z")
From what I understand, Japan has little if any natural oil resources on the home islands. The only way they saw victory was through taking out the Pacific US fleet, allowing for enough time to capture oil rich territory in Oceania. Pearl Harbor was to achieve this. It looked promising, since there were only a handful of airstrips capable of allowing the Allies to project air power, so if Pearl Harbor was a success, they could more or less buy a year of time before they would have to faced Allied power, in earnest. Obviously Pearl Harbor was a crushing blow, but not the mortal wound Japan needed. It bought time, but also a commitment to the destruction of the Japanese Empire. They could not have predicted the extent of American mobilization of industry. These and even more factors contributed to Pearl Harbor being less of a choice, and more of a requirement to even dream of a Japanese victory. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 1, 2018, 5:42pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/65 "2018-06-01T17:42:33Z")
> [@TokyoBayer](#): > > This is an excellent post. Supposedly Admiral Nimitz made a comment that this was one of the mistakes that the Japanese made. From an article in the [Washington Post](https://www.washingtonpost.com/archive/opinions/1991/12/01/blood-and-oil-why-japan-attacked-pearl/1238a2e3-6055-4d73-817d-baf67d3a9db8/?noredirect=on&utm_term=.1f518b7b44a9).This was been the subject of many debates, but as you pointed out, it could not have happened. Among other reasons, the Japanese did not carry AP rounds for their aircraft mounted 7.7 mm machine guns (at least at the time of Pearl Harbor). Their 20 mm cannons simply weren’t that accurate. Sure, not with their MGs, but bomb would do it, easily. Sure the oil might not ignite, but once it spills out, that might be even worse. ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [June 1, 2018, 5:46pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/66 "2018-06-01T17:46:34Z")
> [@TheMightyFro](#): > > From what I understand, Japan has little if any natural oil resources on the home islands. The only way they saw victory was through taking out the Pacific US fleet, allowing for enough time to capture oil rich territory in Oceania. Pearl Harbor was to achieve this. > > It looked promising, since there were only a handful of airstrips capable of allowing the Allies to project air power, so if Pearl Harbor was a success, they could more or less buy a year of time before they would have to faced Allied power, in earnest. > > Obviously Pearl Harbor was a crushing blow, but not the mortal wound Japan needed. It bought time, but also a commitment to the destruction of the Japanese Empire. They could not have predicted the extent of American mobilization of industry. > > These and even more factors contributed to Pearl Harbor being less of a choice, and more of a requirement to even dream of a Japanese victory. Would have been easier for Japan to bypass China and America altogether and just focus on Siberia and taking the oil resources there. Russians would have had a hard time reinforcing. ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [June 1, 2018, 7:37pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/67 "2018-06-01T19:37:38Z")
> [@Velocity](#): > > Would have been easier for Japan to bypass China and America altogether and just focus on Siberia and taking the oil resources there. Russians would have had a hard time reinforcing. Probably not. The [Khalkin Gol](https://en.wikipedia.org/wiki/Battles_of_Khalkhin_Gol) battles demonstrated that Japan really could not face the Soviet army and its mechanization. They were soundly defeated even with the Soviets using their mediocre BT tanks and T-26 tanks. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 1, 2018, 7:41pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/68 "2018-06-01T19:41:47Z")
> [@Mr.Miskatonic](#): > > Probably not. The [Khalkin Gol](https://en.wikipedia.org/wiki/Battles_of_Khalkhin_Gol) battles demonstrated that Japan really could not face the Soviet army and its mechanization. They were soundly defeated even with the Soviets using their mediocre BT tanks and T-26 tanks. Well, they were seriously outnumbered. And of course later, the USSR pulled the troops from that region. But Japan could have taken the Dutch East Indies, with it’s oil, quite easily. ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [June 1, 2018, 7:42pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/69 "2018-06-01T19:42:21Z")
> [@DrDeth](#): > > Sure, not with their MGs, but bomb would do it, easily. Sure the oil might not ignite, but once it spills out, that might be even worse. Read what I wrote in the post TokyoBayer was replying to. Even a direct AP bomb hit was unlikely to do much to the oil tanks. Any breakage would likely be in the top of the tanks and wouldn’t make much spillage. The system also had plenty of pumps and redundancies to deal with issues like aerial bomb attacks. Carrier bombers just couldn’t do the kind of damage to make much difference. ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [June 1, 2018, 7:49pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/70 "2018-06-01T19:49:08Z")
> [@DrDeth](#): > > Well, they were seriously outnumbered. And of course later, the USSR pulled the troops from that region. At the beginning of the battles they were not outnumbered, and their progress was, charitably, slow. Its not like the oil fields were right on the border, either. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 1, 2018, 7:50pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/71 "2018-06-01T19:50:44Z")
> [@Mr.Miskatonic](#): > > Read what I wrote in the post TokyoBayer was replying to. Even a direct AP bomb hit was unlikely to do much to the oil tanks. Any breakage would likely be in the top of the tanks and wouldn’t make much spillage. The system also had plenty of pumps and redundancies to deal with issues like aerial bomb attacks. > > Carrier bombers just couldn’t do the kind of damage to make much difference. A bomb at the base of a tank wouldn’t open it? ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 1, 2018, 7:54pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/72 "2018-06-01T19:54:34Z")
> [@Mr.Miskatonic](#): > > Read what I wrote in the post TokyoBayer was replying to. Even a direct AP bomb hit was unlikely to do much to the oil tanks. Any breakage would likely be in the top of the tanks and wouldn’t make much spillage. The system also had plenty of pumps and redundancies to deal with issues like aerial bomb attacks. > > Carrier bombers just couldn’t do the kind of damage to make much difference. Well, let’s just say that Admiral Nimitz disagrees. And they certainly could have sank the Neosho. I did read what you posted and you said “They can take just about everything shy of a direct hit from an armor piercing bomb,…” and then I proposed a direct hit from a bomb and now you say that wouldn’t work? Here’s another cite that says the Oil tanks wer vulnerable: > **[Sohbet Karbuz](http://karbuz.blogspot.com/2006/10/oil-logistics-lesson-from-wwii-2.html)** > > On U.S. Military Energy Consumption, Geopolitics, Energy Security, Twisted Truths and another: [https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/](https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/) ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [June 1, 2018, 8:03pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/73 "2018-06-01T20:03:18Z")
> [@carnivorousplant](#): > > A bomb at the base of a tank wouldn’t open it? A very unlikely hit indeed. Also, a bad angle for an AP bomb to penetrate the surface. Sorry, but unlikely even on the IJN’s best day. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 1, 2018, 8:08pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/74 "2018-06-01T20:08:36Z")
> [@Mr.Miskatonic](#): > > At the beginning of the battles they were not outnumbered, and their progress was, charitably, slow. Its not like the oil fields were right on the border, either. Agreed. It was a bad idea. However, the Soviets were also helped greatly by having Zhukov there, who had miraculously survived Stalins purges of the officer corps. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 1, 2018, 8:11pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/75 "2018-06-01T20:11:24Z")
> [@Mr.Miskatonic](#): > > A very unlikely hit indeed. Also, a bad angle for an AP bomb to penetrate the surface. > > Sorry, but unlikely even on the IJN’s best day. _I’m_ not sorry. 🙂 ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [June 1, 2018, 8:13pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/76 "2018-06-01T20:13:34Z")
> [@DrDeth](#): > > Well, let’s just say that Admiral Nimitz disagrees. We can also say that Nimitz is not a petroleum engineer. > [@](#): > > And they certainly could have sank the Neosho. > > I did read what you posted and you said “They can take just about everything shy of a direct hit from an armor piercing bomb,…” and then I proposed a direct hit from a bomb and now you say that wouldn’t work? I followed with “that would just crack the casing, not start any fires”. Cracking the casing wouldn’t do much, especially given that the most like hit would be on top. An AP bomb could crack the roof. Big deal. Nothing would spill and Fuel-Oil certainly would not ignite. You’d get more loss from the exposure afterwards than any splash the bomb might make. In a miracle shot they might, just might manage to hit the side with an AP bomb. (again, good luck with that). Now you have a poor angle for penetration after having made one hell of bombing run on a target vastly smaller than a BB. > [@](#): > > Here’s another cite that says the Oil tanks wer vulnerable: > [Sohbet Karbuz](http://karbuz.blogspot.com/2006/10/oil-logistics-lesson-from-wwii-2.html) This guy is not much of a source. He’s not familiar with the setup at PH. The fact that he triumphs with: > [@](#): > > One single bullet would be enough to blow off the area. Shows he really, really does not know what he is talking about. Sorry, this guy is more economist than Engineer. [QUOTE} and another: [https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/[/QUOTE]](https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/%5B/QUOTE%5D) [/QUOTE] This doesn’t really say anything about the oil. It is mentioned as one facility among many that were untouched by Japanese attacks. Japan couldn’t attack _everything_ you know. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 1, 2018, 8:19pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/77 "2018-06-01T20:19:17Z")
> [@DrDeth](#): > > Here’s another cite that says the Oil tanks wer vulnerable: > [Sohbet Karbuz](http://karbuz.blogspot.com/2006/10/oil-logistics-lesson-from-wwii-2.html) > > and another: > [https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/](https://visitpearlharbor.org/didnt-japan-finish-off-pearl-harbor/) Why a second attack with only two flying boats? Was the IJN already contained by the USN in March, 1941? ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [June 1, 2018, 8:24pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/78 "2018-06-01T20:24:57Z")
> [@Mr.Miskatonic](#): > > We can also say that Nimitz is not a petroleum engineer. > > I followed with “that would just crack the casing, not start any fires”. Cracking the casing wouldn’t do much, especially given that the most like hit would be on top. > > An AP bomb could crack the roof. Big deal. Nothing would spill and Fuel-Oil certainly would not ignite. You’d get more loss from the exposure afterwards than any splash the bomb might make. He doesnt have to be, he was the _Admiral_ who had hundreds of them at his disposal. I dont suppose you were around in 1941 and inspected those tanks? I think that the bomb would burst the tank. That’s 700 pounds of high explosive. It doesnt have to set the oil on fire. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [June 1, 2018, 9:33pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/79 "2018-06-01T21:33:35Z")
Being a liquid, petroleum is not really compressible. Suppose a bomb penetrated the top of a tank and exploded inside? Wouldn’t the shock wave through the medium cause the structural failure of the vessel? ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [June 1, 2018, 10:49pm UTC](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089/80 "2018-06-01T22:49:12Z")
> [@Velocity](#): > > Would have been easier for Japan to bypass China and America altogether and just focus on Siberia and taking the oil resources there. Russians would have had a hard time reinforcing. > [@Mr.Miskatonic](#): > > Probably not. The [Khalkin Gol](https://en.wikipedia.org/wiki/Battles_of_Khalkhin_Gol) battles demonstrated that Japan really could not face the Soviet army and its mechanization. They were soundly defeated even with the Soviets using their mediocre BT tanks and T-26 tanks. Keep in mind the Japanese army was already heavily committed to a war in China. Attacking Siberia would have been opening a second major land war with already limited military resources. But an attack on the East Indies would be primarily a naval war. And the Japanese navy was available for use in 1941. [Previous page](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089.md?page=3) [Next page](https://boards.straightdope.com/t/why-did-japan-think-attacking-pearl-harbor-was-a-good-idea/815089.md?page=5)