Why didn't Japan attack Russia during World War 2?

Answer 1

I was told by my high school history teacher (and he was very knowledgable) that a Russian spy (Rudolph Abel) actually posed as a German officer and basically told Japan that Germany "could handle" Russia and that they should attack south into Australia and other British Territories.  I cannot find anything on the internet to verify that.  But I would say thats a hard story to make up and it does explain why Japan never helped Germany in defeating Russia militarily.