A study done for Secretary of War Henry Stimson’s staff by William Shockley estimated that conquering Japan would cost 1.7–4 million American casualties, including 400,000–800,000 fatalities, and five to ten million Japanese fatalities. The key assumption was large-scale participation by civilians in the defense of Japan.
dolphinboy: A few tidbits gleaned from the History Channel (sorry, no cites):
Big Boy (Nagasaki) was the bomb tested at Trinity. That bomb called for the implosion of a sphere of Plutonium. The outer sphere of explosives had to be detonated perfectly or fission would not occur.
Little Boy (Hiroshima) involved “shooting” one mass of Uranium into another. The resulting chain reaction was taken for granted – no test necessary.
Japan had plans to drop a “dirty” bomb over the West Coast from a submarine launched plane. The instrument of surrender was signed 2 weeks before the attack was scheduled to take place.
[opinion] A demonstration would have been interpreted as a sign of weakness by one that has no compassion for the enemy. A delay of even two weeks could have proved fatal. [/opinion]
Peace
Only through Liberty
rwjefferson
I think that people’s comments have done a pretty good job of explaining this already, but I feel compelled to comment on two facts:
-
The question in dolphinboy’s OP appears to derive from confusing vague memories of two facts: that the Trinity test was conducted prior to the bombing of Hiroshima, and that the idea of a demonstration on non-inhabited area was raised, but decided against (in favor of moving directly to bombing Japanese cities) in first deciding how to handle the reality of the availability of the atomic bomb.
-
There are all kinds of reports of the casualty assessments of the invasion of Japan on the internet; the variation in numbers is due to exactly who is arguing what, with Japanese military and/or civilian casualties and different assessments of Allied (mostly American) casualties being totalled to come up with a wide range of figures.
It seems clear that, whatever your views on the morality of the bombing of Hiroshima and Nagasaki, and the degree to which they hastened the surrender of Japan, it caused significantly fewer casualties than even the most optimistic estimate of total casualties from a full-scale invasion of Japan. (Whether Japan would have surrendered without invasion and without A-bombing is a quite different question, and one that I believe has an answer of “They would not, at least not soon.”)
Another argument that was made against a demonstration: if the Japanese had known that a single plane could drop a city-destroying bomb, they would have made much more serious attempts to shoot down all approaching bombers. In preparation for the nuclear attack, the AAF had been routinely sending single B-29s on high-altitude reconaissance missions to get the Japanese used to their presence as non-threats.
This is a point of contention. I haven’t got a cite at hand, but my recollection is that there is evidence that there was such confusion and lack of communication in and around Hiroshima after the bombing that the Japanese leadership had no clear idea of what had happened before Nagasaki was hit.
Add to this Groves’ famous prediction – months before – that it would take two bombs to make Japan surrender, that he actually had two bombs ready, and that he had spent $4 billion up to that point (back when a billion dollars was worth something), and knew that he would have to account for that enormous expenditure when the war was over, and I, for one, am willing to believe that the bombing of Nagasaki might have been averted.
Given the OP’s interest in the subject, we might recommend a reading list. I’ll start:
The Making of the Atomic Bomb, Richard Rhodes.
The Manhattan Project, Stephane Groueff (out of print)
Now It Can Be Told, Gen. Leslie Groves (much post-war propaganda, but interesting nevertheless.)
I know you said no cites, but this is the first time I’ve heard of this claim.
It was a recent show. I just did a quick search, but could come up with nothing.
rwj
Where is that cite from?
Nevermind, I’ve found a reference to Shockley’s study in one of my books on the bombing. It does estimate millions of casualties, but came out on July 21st, after the idea of a demonstration bomb was raised and dismissed, and “there is no current evidence that Truman or Stimson saw Shockley’s paper” (quoted from Downfall by Richard B. Frank), so I don’t think it affected the decision making process.
I’ve heard the same thing, but I don’t believe it to be true. There’s evidence that the Japanese were aware of Truman’s address in which he announced the use of the atomic bomb, that communiques between Hiroshima and Tokyo stated that the city had been destroyed by a single bomb, and by August 7th members of the upper levels of the Japanese government believed an atomic bomb had been used.
I think both Nagasaki and Soviet entry were necessary for Japanese surrender, but I think that issue is straying a bit into GD territory.
Just so folks are aware of some terminology …
In MilSpeak the term “casualties” does not refer to people killed. It refers to people injured.
Without taking an opinion on the validitiy of any numbers (not out of squeamishness or political sensitivity, simply ignorance of the details), simultaneous estimates of 800,000 killed and 4,000,000 casualties are NOT inconsistent.
Typical figures for WWII-era combat are about 5-to-10 to one on KIA vs wounded. To the degree one assumes the Japanese civilians would have fought to the death, the KIA figure might asymptotically approach 100% of the casualty figure on their side.
I was under the impression that “casualties” comprised both injured and killed. No?
Dead casualties are assumed to have died from injuries. So defining casualties as the total number injured is also correct. Disease is also often included in casualty reports, including a breakdown of number afflicted and number killed.
In 1945 the only causilties that mattered to our side were American causilties. After four years of war 100K or 1M japan causilties didn’t really matter to the American people. 
They just wanted it finished and to have there boys back home. Easy polictical solution. F**K the Enemy, they don’t vote.
A viewpoint held by every nation in a war, ever, in history.
Oddly enough, after expending Billions of dollars knocking them flat, we then spent money to build them back up.
True, but that wasn’t the case at first. It wasn’t until really after China went communist and we needed a new East Asian ally that we began helping the Japanese to rebuild.
One of the odd contradictions of the early occupation of Japan was the idea of building up a democratic nation without building up the kind of economic base necessary for a middle class.
My post at the end of this old thread was answering someone asking about what was possibly the same documentary.
I’ll add that it’s clearer to me now that the story almost entirely derives from Robert Wilcox’s Japan’s Secret War (Marlowe, 1995). I haven’t had a chance to see the book, but I have read versions of his argument as repeated by other authors and have not been impressed. As is typical for the crappier end of writing on wartime nuclear research, he seems to assume that various large industrial complexes (in this case, in northern Korea) must have been nuclear weapons related and uncritically accept any rumour or tale so long as it accords with his thesis.
The demonstration (“A bomb test.”) was quite limited as to observers, although the flash was seen from a long way from Almagordo NM.
Educate yourself!
Satisfy your curiosity to the fullest.
Go to your local library and ask the reference desk for help in finding books published in the late forties about the atomic bomb project. Actually termed The Manhattan Project for histories of the bomb, its development, testing, and actual use to bring the war in the western Pacific to an early life saving end. Had it been necessary to invade the islands of Japan the loss of life for soldiers and civilians alike would have eclipesed those dying from the bomb by far. There are waiting lists, interlibrary loans and other options to persue. Persistence will pay off.
You will learn a lot more by reading the histories than from a few responses on SDMB which is more of a starting point. The SDMB will provide sources to seek out for the full story.
Strictly speaking, isn’t a casualty any soldier who is removed from combat by enemy action? So a POW, for instance, would be a casualty even if he was taken uninjured, and a person who sustains a minor injury (such that he’s able to keep fighting unimpaired) is not a casualty.