Japan does not have the capablity to launch another round of
offense after Midway. Their top-notch pilots died in the battle,
the one of the Japanese top brass was killed by an accident. It is
not an overstatement to say that the Japanese were at their wit's
end.
The Japanese at that time wanted to bid their time as they
speculate that the Americans dare not pay the heavy casualties, due
to the pressure in US, so they just beefed up their defence at
various point in the country and wait. It's a very passive
strategy. They think, eventually the Allies will be tired of the
war and just acknowledge the Japanese possession of the conquered
territories.
This was what the Japanese are thinking at that moment but the US
were thinking of another thing.
The US just acquired a new toy and tested it out in a no man's
land. They wanted to confirm the effect of the new toy, to counter
the communist Russians. Who was the best test subject at that
moment? A face-off with Russia was a very stupid move. There is no
need to use the bomb on Germans as they had already surrender. The
best cai tao was the Japanese.