Why didn’t Japan attack the West Coast of the United States during World War II?
二战期间日本为何没有进攻美国西海岸？

Steven Haddock
Studied at York University (Canada)
Upvoted by Steven Smith, former Aviation Electronics Technician at United States Armed Forces (1997-2006) and Wendy Weaver, B.A. History & Mathematics, Willamette University (1973)

史蒂文·哈多克
曾就读于加拿大约克大学
获史蒂文·史密斯（1997-2006年任美国武装部队航空电子技术员）和温迪·韦弗（1973年获威廉米特大学历史与数学学士学位）

To paraphrase Douglas Adams:
“The Pacific Ocean is big. Really big. I mean, you wouldn’t believe how mind bogglingly big it is. I mean, you may think it’s a long walk to the pharmacy, but that’s nothing compared to the Pacific Ocean.
Because many map projections cut the Pacific in half, it gives a misleading impression.
Doesn’t look so big does it.
But if you look at a globe…
Yep, the Pacific covers about 90% of half the planet.
And a quick Google search notes the distance - 8,269 km Tokyo to San Francisco.
By comparison, Honolulu is only 6,206 km from Tokyo. When the Japanese planned Pearl Harbor, they had the advantage of complete surprise, a big ocean to sail in with nothing in it, and they were still at the very outer edge of their operational range. Any further and they wouldn’t have enough fuel to get back.
To get to the U.S. west coast, well, that would be a one-way trip against a power that was now looking out for them and was constantly patrolling the area with airplanes. It’s why Pearl Harbor wouldn’t work more than once - a fleet would have been spotted.
The U.S. response to Pearl Harbor, the Doolittle Raid, was a one way trip that nearly didn’t work because the Hornet, the carrier carrying the bombers, was found out before she was in proper range. The pilots’ original plan was to fly to bases in China, but most of them ran out of fuel before they got to them.

套用道格拉斯·亚当斯的话来说：
“太平洋很大，真的很大。我是说，你根本想象不到它大得有多离谱。我是说，你可能觉得走到药店要走很远，但和太平洋比起来，那根本不算什么。
由于很多地图投影会把太平洋一分为二，这就给人造成了一种误导性的印象。
看起来没那么大，是吧？
但如果你看看地球仪……
没错，太平洋大约占据了地球一半面积的90%。
随便在谷歌上一搜就能查到距离——从东京到旧金山有8269公里。
相比之下，檀香山距离东京只有6206公里。日本人策划珍珠港事件时，虽有出其不意的优势，有一片可供航行且空旷无物的广阔海洋，但他们仍已处于自身作战半径的最边缘。再往远走，他们就没有足够的燃料返航了。
要抵达美国西海岸，那基本上就是一趟单程旅行，而且面对的是一个此刻正严密戒备、并不断用飞机在该区域巡逻的强国。这就是为什么珍珠港事件的模式只能成功一次——再派舰队过去就会被发现。
美国对珍珠港事件的回应是杜立特空袭，这次空袭本就是一趟单程行动，且险些失败，因为搭载轰炸机的“大黄蜂”号航母在进入合适作战范围之前就被发现了。飞行员最初的计划是飞往中国的基地，但大多数人在抵达目的地之前就耗尽了燃料。


Kee Nethery
Upvoted by John Campbell, M.A Literature & History and Robert Jones, former Retired at United States Armed Forces (1981-1990)

基·内瑟里
获约翰·坎贝尔（文学与历史硕士）和罗伯特·琼斯（1981-1990年在美国武装部队服役，现已退休）

I grew up in Texas.
My high school history teacher said that his father had a machine shop in Houston when Pearl Harbor was attacked. He said in a very short number of days his father got a priority order for naval gun mounts to be shipped to Denver.
As a history person it always puzzled him so after graduating from college he spent time researching it.
As he told it, the West Coast was defended by a few batteries in San Francisco and a few elsewhere, basically nothing. The whole west coast had almost no defenses to repel an invasion.
The idea behind the gun mounts was to fortify the continental divide and if there was a successful invasion, defend at the Rocky Mountains.
He said there were many reasons the Japanese did not invade (supply lines, etc) and that one reason was that they didn’t know where our defenses were located because they were so well camouflaged. Without knowing where and how to eliminate our west coast defenses, an attack would be risky.
He never mentioned whether the guns were deployed or not, only that his dad did ship naval gun mounts to Denver.

我在得克萨斯州长大。
我的高中历史老师说，珍珠港事件发生时，他的父亲在休斯顿有一家机械厂。他说，短短几天内，他父亲就接到了一份优先订单，要求生产海军炮架并运往丹佛。
作为一个学历史的人，这件事一直让他很困惑，所以大学毕业后，他花了些时间研究这个问题。
据他所说，当时美国西海岸的防御仅靠旧金山的几座炮台和其他地方的少数防御设施，基本上可以说是毫无防备。整个西海岸几乎没有能抵御入侵的防御力量。
运送炮架的目的是为了加固大陆分水岭，如果入侵真的成功，就以落基山脉为防线进行抵抗。
他说，日本没有发动入侵的原因有很多（比如补给线问题等），其中一个原因是，由于美国的防御工事伪装得非常好，日本人不知道这些防御设施的具体位置。在不清楚美国西海岸防御部署以及如何摧毁这些防御的情况下，发动进攻会面临巨大风险。
他从未提及这些火炮最终是否部署到位，只提到他的父亲确实把海军炮架运往了丹佛。


Daniel C Swanson
5 years in the navy
Upvoted by Ravi Vaish, MA English Literature & History (1990) and Boyce Robbins, MA History & Physics, Chemistry, Maths, and Computer Science (1970)

丹尼尔·C·斯旺森
拥有5年海军服役经历
获拉维·瓦伊什（1990年获英语文学与历史硕士学位）和博伊斯·罗宾斯（1970年获历史、物理、化学、数学与计算机科学硕士学位）

Their were a number of reasons that did not happen, but one of them was because of Admiral Yamamoto. As many of you may know he was one of the architects of Pearl Harbor. He knew america very well, having lived here for a number of years, going to school, and later working in the Japanese Consulate. He was dead set against going to war with the United States, but it was the Japanese Army that was running the show, and they were confident in the ability of the army to win. Having lived in this country, he understood the overwhelming ability of the United States to out produce any other nation. Now back to Pearl Harbor. If the attack was a success, the army wanted to mount a invasion of the west coast, but Yamamoto said that Japan did not have a large enough army to win an invasion, and even if they did, the navy did not have enough troop ships to take them to the west coast. The army generals said he was crazy, that the united states did not have any military installations that could stop them. Yamamoto said that the United States was not like Japan, where the normal citizen was not allowed by law to have weapons. That in the United States, most homes did have guns and any invasion force would end up fighting against millions of armed citizens. He said any invasion force would most likely end up being wiped out. He convinced them that taking other areas for supplies was much easier, You have to remember, Japan hand no oil wells and depending on oil from other countries. Us stopping the flow of oil from the United States to Japan was one of the reason Pearl Harbor ended up being attacked, it was our defensive position for defending some of the nations in that area, and Japan needed them for their oil and rubber.

日本没有进攻美国西海岸，原因有很多，其中一个与山本五十六海军上将有关。想必很多人都知道，他是珍珠港事件的策划者之一。他对美国非常了解，曾在美国生活多年，在这里上学，后来还在日本驻美领事馆工作过。他坚决反对与美国开战，但当时日本陆军掌握着实权，而且他们对自己军队的作战能力充满信心。由于曾在美国生活，山本五十六深知美国拥有远超其他国家的生产能力。我们再回到珍珠港事件。陆军认为，如果这次袭击成功，就应该趁机对美国西海岸发动入侵，但山本五十六表示，日本没有足够规模的军队来确保入侵成功，即便有足够的军队，海军也没有足够的运兵船将这些军队运送到西海岸。陆军将领们认为他是疯了，还声称美国没有任何能阻挡他们的军事设施。山本五十六则反驳说，美国和日本不同——在日本，法律禁止普通公民持有武器，而在美国，大多数家庭都有枪支，任何入侵部队最终都要面对数百万武装平民的抵抗。他表示，任何入侵部队都很可能会被彻底消灭。他还说服他们，夺取其他地区来获取补给要容易得多。要知道，日本本身没有油井，完全依赖从其他国家进口石油。美国切断对日本的石油供应，是珍珠港事件爆发的原因之一——美国当时的立场是保护该地区的一些国家，而日本却需要从这些国家获取石油和橡胶。

Scott Dismukes
Former Vietnam Vet. at U S Navy (1971–1975)

斯科特·迪斯米克斯
前越南战争老兵，1971-1975年在美国海军服役

One of the major reasons the Japanese Empire was rolled back the way it had been, was because their supply lines were almost entirely on ships, and we had a large number of good submarines. Eventually we even got good torpedoes. We pretty much crippled their merchant fleet, and sank a good number of troop transports and the thousands of troops that were on them. Their biggest military ships turned out to hardly be a factor because of our sea power supported by aircraft.
Their supply lines even out to Pearl were going to be very vulnerable - stretch them 3,000 more miles to the West Coast, and they become untenable. It took my supply ship sailing from Subic Bay to San Francisco, at around 14 knots, near-on 3 weeks at sea.
The Japanese would have needed longer because their merchant ships didn’t travel at 14 knots, but closer to 6 or 8. So perhaps 5–6 weeks at sea to get supplies to troops who will likely have moved in the meantime… Offload, then 5–6 weeks back. Close on 11–13 weeks to make a round trip? You could make perhaps 4 round trips, per ship, in a year, not counting downtime for maintenance. When you look at what we needed to support Operation Overlord, the literally thousands of ships needed to equip our forces in Europe, the Japanese just didn’t have that many available ships, and that’s not counting their losses to submarines.
They certainly didn’t have the troops to occupy the entire West Coast - so what do you do about those many, many ports and cities you didn’t occupy?
Then once ashore, where do they go? You have troops fighting you across several deserts just to get to the Rockies. Just getting through the passes in the Sierra Nevada range out to those deserts would be like Thermopylae.
From any given city they were in, there is a very limited number of passes available to get their equipment moving East. We have a culture of hunting and self sufficiency in the Cascades and all over the ranch country on the West Coast. “Every blade of grass will have a man with a rifle behind it”…. Your attrition rate for fighting troops will be horrendous, not to mention their land-based supply lines. Picture the targets for aircraft attacking a supply train crossing the Mojave or the Great Salt Lake. Shooting fish in a barrel, no place to hide. It would have been a catastrophically colossal blunder - far worse than attacking Pearl turned out to be.

日本帝国之所以会节节败退，其中一个主要原因是他们的补给线几乎完全依赖船只，而当时美国拥有大量性能优良的潜艇，后来甚至还配备了先进的鱼雷。我们几乎摧毁了日本的商船队，击沉了多艘运兵船，船上成千上万的士兵也随之葬身大海。由于美国拥有空中支援的海上力量，日本那些最大型的军舰最终也几乎起不到任何作用。
日本到珍珠港的补给线就已十分脆弱，如果再将补给线延长3000多英里到美国西海岸，这条线路就完全无法维持了。我曾服役的补给船从苏比克湾航行到旧金山，以约14节的速度行驶，在海上就要花近3周时间。
而日本需要的时间会更长，因为他们的商船速度达不到14节，只能接近6到8节。所以，要把补给运送到可能已经转移了位置的部队手中，可能需要在海上航行5到6周……卸货之后，再花5到6周返回，一次往返差不多要11到13周？这样算下来，不算维护停工时间，一艘船一年可能只能往返4次。再看看我们为支援“霸王行动”（诺曼底登陆）所需要的物资——单是为欧洲战场上的部队配备装备就需要数千艘船，而日本根本没有这么多可用的船只，这还没算上他们被潜艇击沉的船只数量。
日本显然没有足够的兵力占领整个美国西海岸——那么，对于那些众多未被占领的港口和城市，他们该如何应对？
即便成功登陆，他们又能往哪里推进？要抵达落基山脉，他们需要穿越好几片沙漠，而每一片沙漠都会有美军进行抵抗。单是穿过内华达山脉的山口进入那些沙漠，就会像当年的温泉关战役一样艰难（注：温泉关战役中，斯巴达军队依托狭窄关口阻击波斯大军）。
无论他们占据哪座城市，能够让装备向东推进的山口数量都非常有限。在美国西海岸的喀斯喀特山脉以及所有牧场地区，人们有着狩猎和自给自足的文化传统，正如那句俗语所说：“每一片草叶后面都会有一个持枪的人”……如此一来，日军作战部队的伤亡率会高得惊人，更不用说他们的陆路补给线了。想象一下，一列补给火车穿越莫哈韦沙漠或大盐湖时，会成为美军飞机多么明显的攻击目标——这简直就像在桶里射鱼，无处可藏。如果日本真的进攻美国西海岸，那将是一个灾难性的巨大错误，比珍珠港事件的后果还要严重得多。


Answered by Hugh Caley
回答者：休·卡利

They couldn’t. They didn’t have any bases close enough to the United States from which to stage such an attack. There were no nuclear ships in those days; you had to have enough fuel to get to your target and return. The United States only attacked Japan directly after they had taken back all the islands between Hawaii and Japan. Look at Google Earth and check out the distances between Japan, Hawaii, and the United States. Japan would have had to take Hawaii in order to be able to attack the mainland United States, whereas The United States eventually took Guam and even Okinawa from Japan before they really started blasting Japan.
The Japanese Battleship Yamato
And secondly, even if they’d had bases for such an attack, they didn’t have the resources to fight on American soil. Remember, the attack on Pearl Harbor was meant to destroy the American Navy, to the point where the Americans wouldn’t have the will or the seapower to continue the fight. That the carriers weren’t in Pearl Harbor at the time of the attack made it that much more difficult for Japan. The war was about resources, at least from the Japanese point of view, and they knew they couldn’t beat the United States if the war went on for a long time.

日本根本做不到进攻美国西海岸，因为他们没有距离美国足够近的基地来发起这样的攻击。那时候还没有核动力舰船，舰船必须携带足够的燃料才能抵达目标地并返航。美国也是在夺回夏威夷和日本之间的所有岛屿后，才开始直接攻击日本本土的。你可以打开谷歌地球看看日本、夏威夷和美国本土之间的距离——日本要想攻击美国本土，就必须先占领夏威夷；而美国则是在夺取了关岛甚至冲绳岛之后，才真正开始对日本本土发动大规模打击。
其次，即便日本有发起这类攻击的基地，他们也没有足够的资源在美国领土上作战。要知道，珍珠港事件的目的是摧毁美国海军，让美国失去继续作战的意志和海上力量。但袭击发生时，美国的航空母舰并不在珍珠港，这使得日本的计划难度大增。这场战争的核心是资源争夺，至少从日本的角度来看是这样，而且他们清楚，如果战争拖得太久，自己根本无法战胜美国。、

Answered by Jim Grupé
回答者：吉姆·格鲁佩

They tried.
But they needed to establish bases close enough to support any sort of invasion. If you recall, they planned to work their way around using the Aleutian Islands. They got as far as occupying the outermost one.
Without bases from which to stockpile fuel and ammunition needed to advance, the Japanese could not mount any offensive on mainland USA.
They *did* try some unconventional weapons - large hydrogen filled paper balloons with incendiary bombs were floated over the USA using the prevailing winds. But these were pretty ineffective. They used barometric pressure switches to release sandbags that kept the balloon in the jet stream over the Pacific as the balloon lost lift. Knowing the general speed of the jet stream, they calculated how many sandbags would be dropped before the balloon reached the West Coast. Then the balloon would release a bomb instead, and self-destruct. Over 9000 were launched. 900 were expected to reach the USA. About 300 actually did. Five people were killed in Oregon after finding a malfunctioning balloon and accidentally setting off the bomb. Two floated back to Japan and dropped the bomb there.
The last balloon found was discovered in 1960. If you’re hiking in some remote area, don’t poke any canisters with Japanese writing on them.

日本其实尝试过进攻美国西海岸。
但要发起任何形式的入侵，他们都需要建立足够近的基地来提供支援。如果你还有印象的话，日本曾计划通过阿留申群岛逐步推进，最远曾占领过该群岛最外围的一个岛屿。
没有基地来储存推进所需的燃料和弹药，日本就无法对美国本土发动任何攻势。
不过，日本确实尝试过使用一些非常规武器——他们制作了装满氢气的大型纸质气球，上面携带燃烧弹，利用盛行风将气球飘向美国。但这些武器的效果非常糟糕。他们在气球上安装了气压开关，当气球失去升力时，开关会释放沙袋，使气球能保持在太平洋上空的急流中。日本人根据急流的大致速度，计算出气球在抵达西海岸前需要投放多少个沙袋，之后气球就会投下炸弹并自行销毁。他们总共发射了9000多个这样的气球，原本预计有900个能抵达美国，实际却只有约300个成功到达。在俄勒冈州，有5人因发现了一个故障气球并意外触发炸弹而死亡。还有两个气球飘回了日本，并在日本本土投下了炸弹。
最后一个此类气球是在1960年被发现的。如果你在偏远地区徒步，遇到带有日文标识的金属罐，千万不要去触碰。

Answered by HK Hagol
回答者：HK·哈格尔

They did.
They shelled an oil refinery near Santa Barbara and a small fort near the mouth of the Columbia River, and certainly once - maybe twice - an aircraft dropped two incendiary bombs on forests in Oregon. These attacks were all launched from submarines.
Slipping a single submarine into American coastal waters, then undertaking a quick covert hit-and-run strike was all Japan could do. Look, the West Coast is 2000 miles from Hawaii, and even the Pearl Harbor attack - which was no invasion force - was stretching the limits of Japan’s logistical abilities to the max.
Japan could do no more.

日本其实发动过针对美国西海岸的攻击。
他们炮击了圣巴巴拉附近的一座炼油厂和哥伦比亚河河口附近的一座小型堡垒，而且肯定有一次（也可能是两次），一架飞机向俄勒冈州的森林投下了两枚燃烧弹。这些攻击都是从潜艇上发起的。
日本所能做的，也只是悄悄派遣一艘潜艇进入美国沿海水域，然后快速发动一次隐蔽的突袭，得手后立即撤离。要知道，美国西海岸距离夏威夷有2000英里，即便只是发起珍珠港事件（并非入侵部队），都已经把日本的后勤能力推向了极限。
日本根本没有能力发动更大规模的攻击。

Anthony Cady
Proud American at The United States of America (1976–present)

安东尼·卡迪
自豪的美国人，1976年至今居住于美国

These hypotheticals all (with both Germany and Japan) ignore one giant fact of the war. Both Japan and Germany were waging wars of conquest. Why do you wage a war of conquest? Resources! The Germans and Japanese were both missing one big resource in particular. Oil. You could hypothetically say the Japanese could have taken oil if they invaded California but why? Southeast Asia was closer, and the Japanese pretended their whole thing was “liberating” oppressed Asians, who had been colonized. Even though they were colonizing them.
The Japanese attacked Pearl Harbor because they needed to disable the American Pacific Fleet, so they could not respond quickly to attacks in The Philipines which contained American troops, and the British in Malayasia to get oil. The United States embargoed the Japanese, and negotiations fell apart.
这些关于德国和日本的假设，都忽略了战争中的一个重要事实：德日两国发动的都是征服战争。为什么要发动征服战争？答案是资源！德国和日本都特别缺乏一种重要资源——石油。理论上你可能会说，日本如果入侵加利福尼亚也能获取石油，但他们为什么不这么做呢？因为东南亚距离更近，而且日本还打着“解放”被殖民压迫的亚洲人民的幌子（尽管他们自己也在对这些地区进行殖民统治）。
日本袭击珍珠港，是因为他们需要摧毁美国太平洋舰队，使其无法快速回应日本对菲律宾（当时驻有美军）和英国控制下的马来亚（日本想从中获取石油）的进攻。当时美国对日本实施了禁运，双方的谈判也破裂了。

Japan is an island nation with little resources and no oil. They needed it and attacking the Americans at Pearl Harbor would slow the US response down (not as much as they hoped). Attacking the US mainland would not be possible until they were in control of all of southeast Asia’s oil resources. They attacked in Alaska but that was a small distraction and they could do it because the distance was much shorter.
日本是一个资源匮乏且没有石油的岛国，他们迫切需要石油，而袭击珍珠港可以延缓美国的反应速度（尽管延缓的程度没有他们预期的那么高）。在控制东南亚所有石油资源之前，日本根本不可能进攻美国本土。他们确实对阿拉斯加发动过攻击，但那只是一次小规模的牵制行动，之所以能这么做，是因为阿拉斯加距离日本近得多。

The Japanese invaded New Guinea. In that invasion they had planned to take an airfield that would give them the ability to attack and invade the North of Australia. Anzac volunteers with almost no training were hurried there, put up a stout defense and with regular forces and later American forces pushed them back, but the Japanese Army had already canceled plans to invade Australia because their supply lines were already stretched way to thin and it would take too many soldiers.
That was a cancelation of plans to invade Australia…which was well closer than mainland USA. The Germans also wanted Japan to invade Madagascar, which the Japanese Army said no to as well. After Midway, the Japanese Navy was in no shape to be invading much of anything, and by the time the Philipines were lost, the small navy the Japanese still had was pretty much out of fuel anyway.
日本曾入侵新几内亚，计划夺取那里的一座机场，以便有能力攻击并入侵澳大利亚北部。几乎没有接受过训练的澳新军团志愿者被紧急派往该地，进行了顽强的防御，随后在正规军和美军的支援下击退了日军。但在此之前，日本陆军就已经取消了入侵澳大利亚的计划，因为他们的补给线已经拉得过长，而且需要投入的兵力也太多。

Going to the California coast was not a real option. There are stories some submarines made it. The Japanese did discover the jet stream which they used to send balloons armed with bombs over to the US mainland, but until they had taken over a whole hell of a lot more gas stations they couldn’t send ship after ship across the Pacific. Especially when they didn’t even fully accomplish the mission at Pearl Harbor.
要知道，澳大利亚比美国本土近得多，日本连入侵澳大利亚的计划都取消了。德国还曾希望日本入侵马达加斯加，同样遭到了日本陆军的拒绝。中途岛战役后，日本海军的实力已不足以发动任何大规模入侵；等到菲律宾失守时，日本仅存的少量海军也几乎耗尽了燃料。
因此，进攻加利福尼亚海岸根本不是一个可行的选择。虽然有传闻说一些日本潜艇抵达过那里，而且日本确实发现了急流，并利用急流将携带炸弹的气球送往美国本土，但在控制更多石油资源之前，他们根本无法派遣一艘又一艘的船只横渡太平洋，更何况他们连珍珠港的任务都没有完全完成。