The net effect of Little Boy and Fat Man

Little Boy killed about 70,000 people in Hiroshima in 6 August, 1945.

Fat Man killed another 40,000 in Nagasaki on 9 August, 1945.

Tojo and Emperor Hirohito had 3 full days to save the people in Nagasaki. They decided to wait and take chance.

A total of 110,000 were killed as a result of these two bombs. Including the injured who are dead subsequently, the number could increase by another 20-35%.

Of the killed, perhaps only 10% or so are military pesonnels, plus another 15-30% engaged in military industry, as shown in the maps here.

Total death of the atomic bombs in WWII in then about 110,000 to 140,000 (according to the wiki source above).

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Total death in the Asian Theatre of WWII, according to wiki data, is about 29M (including civilians and military personnels).

Total number of days of WWII (from 8/Dec/1941 to 15/Aug/1945) is 1464 days, For China, the war started on 7/Jul/1937 and the total length is 2961 days.

The death/day, according to calculation here, is 12,889 people per day. i.e. had the war been prolonged for one more day, about 13,000 more people from all countries would have died.

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Therefore, if Little Boy and Fat Man had together ended the war by 140,000/12889 = 11 days earlier, they had reduced the total number of people died in the war.

If they ended the war half a year earlier, it would have saved (183-11=172) x 12889= 2.2 million people

If the war was ended one year earlier as a result, the number of people saved would have been (365-11=354) x 12889 = 4.6 million lives

The Japanese lives that were killed per day is 1790. So from Japan's perspective the sacrifice of the people of Hiroshima and Nagasaki would be "worthwhile" if the war was ended 140,000/1,790 = 78 days earlier. (i.e. less than 3 months)

Of course it is unfair to the people who lived in these two cities, especially those who were not even engaged in the military industry, who were the ladies, the elderlies, and the children. The tragedy is that it had to take all their lives to convince Tojo and Emperor Hirohito (Showa) that the war was over for them.

But in a war the victims are quite random. If it were not for them, it would be the residents in Tokyo...

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The Tokyo firebomb killed 80,000 to 100,000 Japanese people.

If Little Boy and Fat Man had avoided 2 such firebombs which might have been launched subsequently, they had reduced the net casualties of Japanese civilians.

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Total death in the Battle of Okinawa is about 77,500 (12.5k US soldiers, and 66k Japanese militia and soldiers).

If 2 of such battles were avoided as a result of Little Boy and Fat Man, they would have saved 155000-140000=15000 lives.

The population of Okinawa is about 1% of the total population of Japan. If conventional war had to go to Tokyo from the south, at least 60-75% of Japan would be battleground like Okinawa.
i.e. total death would have been 60-75 x 77,500 = 4.6-5.8M people.

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Fumio Kyuma might have been kissing up his US ally, or what he said was not exactly the right reason. The fact that the two bombs were necessary was something that could really "not be helped", as Fyuma stated. But to characterise the strategic importance of the two bombs as the beginning of the Cold War is gravely wrong, and is a great dis-respect to those who died in the two cities.

• The Soviet entered the war on August 8, 1945. After Little Boy was dropped, and shortly before Fat Man arrived. Therefore, it its totally against any logic that US dropped the 2 bombs to prevent the Soviets from entering. The more realistic scenario is, that, Tojo and his clan is more afraid of the Soviets than the American, and decided to surrender.

Remember this when you visit Hiroshima or Nagasaki next time. Remember the sacrifice of the innocent Japanese who died in August 1945. Remember how many lives they have saved for their own country, and for the world.

Remember Manhattan Project. Remember Oppenheimer. Remember Einstein.