
Steel worker reveals blocking view of U.S. aircraft on day of atomic bombing - devchuk
http://mainichi.jp/english/english/features/news/20140726p2a00m0na014000c.html
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FatalLogic
I wanted to know if this was plausible, so I located the Yawata Steel Works
(the source of the smoke screen) and the Kokura Arsenal (the aiming point for
the bomb) on a map. They were about 4.4km apart.

[http://i.imgur.com/nJaJtH7.png](http://i.imgur.com/nJaJtH7.png) (the site of
the Steel Works is on the left)

Interesting, but I still don't know if it's true.

edit: Wikipedia's page on Smokescreens says "One 50 gallon drum of fog oil can
obscure 60 miles (97 km) of land in 15 minutes", so I suppose it was easily
possible for them to have hidden the target if the wind direction was right

Google Maps link:
[https://www.google.com/maps/place/%E4%B8%AD%E5%A4%96%E7%82%8...](https://www.google.com/maps/place/%E4%B8%AD%E5%A4%96%E7%82%89%E5%B7%A5%E6%A5%AD%EF%BC%88%E6%A0%AA%EF%BC%89+%E5%B0%8F%E5%80%89%E5%B7%A5%E5%A0%B4/@33.8999819,130.8525735,13z/data=!4m7!1m4!3m3!1s0x0:0x0!2zMzPCsDU0JzEwLjAiTiAxMzDCsDQ5JzQ4LjAiRQ!3b1!3m1!1s0x0:0x6a522cb4a3d20415?hl=en)

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colanderman
97 _square_ kilometers? 97 kilometer _radius_? tsk tsk Wikipedia…

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cdwhite
So I read this as "within 15 minutes, land up to 60 miles downwind of the
generator is obscured."

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endianswap
Wouldn't that require 240mph winds, though?

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cdwhite
... yeah. Oops. Guess that reading's out.

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spingsprong
A couple of photos of what a smokescreen covering a city looks like
[http://449th.org/ploesti.php](http://449th.org/ploesti.php)

It's for a German city, but it is the same idea.

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tbdr
correction: for a Romanian city -
[http://en.wikipedia.org/wiki/Ploie%C8%99ti](http://en.wikipedia.org/wiki/Ploie%C8%99ti)

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mkmk
Does the Trolley problem apply here? (i.e. diverting the enemy from your town,
if you know it is likely they will just attack the next town over)
[http://en.wikipedia.org/wiki/Trolley_problem](http://en.wikipedia.org/wiki/Trolley_problem)

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FatalLogic
Maybe we can see it as a type of market in which participants simply tried to
keep bombers away from their own city, without considering the effects on
other cities? Over time, competition within this macabre market would produce
increasingly efficient and effective means of repelling bombers. If the cities
had cooperated, rather than competing, maybe they would have not evolved such
efficient countermeasures?

A competitive strategy could produce a net benefit for all the cities, because
diverted bombers might be less likely to carry out an effective attack on
their secondary target.

In fact, that's what happened in this case (assuming the smokescreen had an
effect). By the time the bomber diverted from Kokura to Nagasaki, it was so
short of fuel that it could only attempt one bombing run. Visibility was poor,
and the bomb detonated off target above a valley, with the result that parts
of the city were shielded. The death toll of 40-80,000 was 'only' about half
that of Hiroshima, despite the bomb being more powerful

edit: The outcome could have been even better, because the orders for the
mission stated that they had to clearly see the target. If not, they were to
return with the bomb. Really, it sounds like they ignored these orders,
perhaps because they didn't have enough fuel to carry the bomb back.

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programmer_dude
How much coal tar would you need to burn to block an airplane's view?

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ekianjo
Not sure, but it seems a little bit unlikely that the smoke could be enough to
obstruct the vision of a plane cruising at 30000+ feet.

~~~
FatalLogic
They only had to obscure the target zone, which was a very small area (a
single factory complex, the Kokura Arsenal), and by chance it happened to be
obscured during the 30 minutes or so that the plane was overhead.

This wasn't a normal bombing run. It had elements of an experiment - they
wanted to understand how the bomb worked, so they wanted to control the drop
precisely and be able to observe the effects.

The aiming points were very precise (a bridge in the case of Hiroshima), and
they were chosen well in advance, and the mission orders were quite rigid. If
the crew couldn't see the target clearly after several attempts, they didn't
have the authority to randomly drop the bomb somewhere else - they had to go
on to the next city.

Ironically, after all that, I think they eventually missed the aiming point in
Nagasaki by 2 km or so, because it was also obscured. By then, the plane was
low on fuel though, so I guess they were forced to do the best they could.
I've read that they weren't supposed to do that, according to the mission
rules. The plane came very close to running out of fuel, which I guess might
have made them drop the bomb to reduce weight.

edit: This is Field Order 13 - for the attack on Hiroshima. It includes Kokura
and Nagasaki as secondary targets, so you can see how precise they were about
the aiming points. I'm pretty sure the target details would be exactly the
same for the Nagasaki attack (Field Order 17, which I can't find online).

[https://www.flickr.com/photos/kafaikan/6693719785/sizes/l](https://www.flickr.com/photos/kafaikan/6693719785/sizes/l)

edit2: Bomber crew member's diary which explains what happened over Kokura -
[http://www.mphpa.org/classic/COLLECTIONS/CG-
ASPI/01/Pages/CG...](http://www.mphpa.org/classic/COLLECTIONS/CG-
ASPI/01/Pages/CGP-ASPI-024.htm)

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dangayle
That diary is a fantastic read. The language, the drama, the bird's eye view
of one of the most pivotal moments in world history. Beats fiction any day.

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ckozlowski
I'm reading this page here: [http://www.mphpa.org/classic/COLLECTIONS/CG-
ASPI/01/Pages/CG...](http://www.mphpa.org/classic/COLLECTIONS/CG-
ASPI/01/Pages/CGP-ASPI-030.htm)

Just thought I'd share some of my puzzlement here; but it sounded as if they'd
dropped a third atomic bomb. I though this unlikely, unless the diary is
revealing a secret kept (the drop sounds as if it'd failed), but then I came
across this:
[http://en.wikipedia.org/wiki/Pumpkin_bomb](http://en.wikipedia.org/wiki/Pumpkin_bomb)

So, in addition to the nuclear models, they dropped identical conventional
bombs of that type as well. Never knew that.

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adventured
It's interesting to read Wikipedia's entry on this matter (claiming it was
caused by a huge firebombing raid):

[http://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_an...](http://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_and_Nagasaki)

"The delay at the rendezvous had resulted in clouds and drifting smoke from
fires started by a major firebombing raid by 224 B-29s on nearby Yahata the
previous day covering 70% of the area over Kokura, obscuring the aiming
point."

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christudor
Yep, one of the reasons Hiroshima and Nagasaki were selected as targets was
because they were one of the few major Japanese cities that /hadn't/ been
firebombed in the preceding weeks. People forget that the deadliest 24 hours
in the Second World War was not either of the atomic bombings (which killed c.
120,000 people), but the firebombing of Tokyo, which burned down 12 square
miles of a city which had average population density of 100,000 people per
square mile.

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pilsetnieks
Also, Kyoto was one of the original targets but because of its cultural
significance it was replaced with Nagasaki.

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gwern
Thank goodness, though. The bombings were a bad idea, but at least they didn't
bomb Kyoto!

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outworlder
Ok, so the target area was blocked. So what? This was not a precision ammo, it
was an a-bomb! Even those early designs could just be detonated in the general
area and still destroy the target and everything else.

Why did the bombers have to switch targets then?

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christudor
This is not quite true; the Nagasaki bomb missed its target by almost two
miles because of cloud cover, and as a result only half the number of people
were killed compared to Hiroshima. Even with an atomic bomb you had to be
/relatively/ precise. (Source:
[https://www.youtube.com/watch?v=kYphE841lfY](https://www.youtube.com/watch?v=kYphE841lfY))

