They were used to show that we would USE THEM!
The Russians of course knew we had the bomb.
STalin knew more than Truman did while Truman was VP about the Atomic Bomb.
But Stalin had no idea that we had the will to use them.
The Nuking of Japan was definately a message to Stalin that we would and could.
STalin then went on to steal not only the technology for the nuclear bombs but also the delivery system...the B-29.
Are you saying the PRIMARY reason for the use of the Atomic bombs was to convince the Russians that we would use them - ?
"They were used to show that we would USE THEM!"
Ahem... Before The Bomb, having a weapon was enough reason to believe the one having it was going to use it; or better, there was no precedent of having a given weapon just for exhibition. The concept of "deterrent posession" was created after, and even because of Hiroshima and Nagasaki.