I have heard this claim a few times from some random people, and recently came across it in pravda.ru as well:
There is such a statistics: 25 per cent of young Japanese people believe that the bombings were carried out by the USSR, and not the USA.
Attempts to revise the history of World War II are not new at all, although the current scale of the revision of history is more than just impressive - it is shocking. Many Japanese people, under the influence of their propaganda machine, already believe that it was the USSR that dropped atomic bombs on Hiroshima and Nagasaki.
The USA and its controlled countries distort historical facts so much that in Japan, many people think that it was Russia, not America, that dropped the atomic bomb on them.
So, does a substantial number of people in Japan believe that USSR bombed Hiroshima and Nagasaki?