[littlestymaar]

You're just missing an entire half of the story here: which is the USSR attacking on the 9th of August!

Of course if you omit the second most important factor then things start becoming obvious, but in reality the answer to this question is far from obvious (in neither direction, needless to say, the tankies who claim with certainty that the bombing was not needed are equally wrong)

[cocodill]

well, by August 12, the Red Army had broken through in almost all positions.

[littlestymaar]

In Manchuria, but the question of mainland Japan was still open.

But overlooking the Soviet invasion is clearly missing half the picture here.

[cocodill]

I believe it was the Soviet Union's entry into the war and quick breakthrough that forced the Japanese to quickly surrender on favorable terms.

[littlestymaar]

But that belief is unfortunately not more verifiable than the one that assumes it's the atomic bomb that did it.

We cannot categorically rule out any of the three hypothesis:

- the Manchuria invasion was sufficient

- the nuclear bombing was sufficient

- they were both necessary for the immediate surrender of Japan