I don't know where you read that but it makes no sense. The Russians could not have taken Japan if they wanted to, they had to go through the US navy to do that. The Soviet Navy at the time was not much to speak of and it also happened to be on the other side of the earth.
A big chunk of the Japanese army surrendered to the Russians (as they were stuck in China), and also, if I remember correctly, the Japanese tried to use the Russians as mediators in their negotiations with the Americans, but there was no chance of the Soviet Union taking over Japan. First, they could not get there even if they wanted, and secondly Stalin was not about to openly defy the US at that point.
Although Russia definitely did want Japan's conquered territory in China and the rest of mainland Asia - the main lasting effect of the Atomic Bombs on the geo-political outcomes of the war was giving the Americans the ability to force the surrender before Russia began its invasion of Manchuria.
This is why the Japanese attempts to negotiate a measured surrender through the Soviets were ultimately futile - it was actually in Stalin's interests to not pass on the Japanese proposals to the US, as an early peace deal would kill his opportunity to land grab in Asia.
Yes, as i said they were trying to get the Russians to mediate a peace deal for them. This is why togo said that they were seeking peace through the good offices of Russia.
It was long suspected--no less by the Soviets--that another motive for the atomic bombings was to warn off Stalin. (Of course, there were enough idealistic traitors in the Manhattan Project that Stalin knew all about it and got his very own atomic bombs a few years later, so the joke was on us.)
A big chunk of the Japanese army surrendered to the Russians (as they were stuck in China), and also, if I remember correctly, the Japanese tried to use the Russians as mediators in their negotiations with the Americans, but there was no chance of the Soviet Union taking over Japan. First, they could not get there even if they wanted, and secondly Stalin was not about to openly defy the US at that point.