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.<p><a href="http://i.imgur.com/nJaJtH7.png" rel="nofollow">http://i.imgur.com/nJaJtH7.png</a> (the site of the Steel Works is on the left)<p>Interesting, but I still don't know if it's true.<p>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<p>Google Maps link: <a href="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" rel="nofollow">https://www.google.com/maps/place/%E4%B8%AD%E5%A4%96%E7%82%8...</a>
A couple of photos of what a smokescreen covering a city looks like <a href="http://449th.org/ploesti.php" rel="nofollow">http://449th.org/ploesti.php</a><p>It's for a German city, but it is the same idea.
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) <a href="http://en.wikipedia.org/wiki/Trolley_problem" rel="nofollow">http://en.wikipedia.org/wiki/Trolley_problem</a>
It's interesting to read Wikipedia's entry on this matter (claiming it was caused by a huge firebombing raid):<p><a href="http://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_and_Nagasaki" rel="nofollow">http://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_an...</a><p>"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."
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.<p>Why did the bombers have to switch targets then?