Technically this is probably not a postcard.  It is 4″ x 7-1/2″ and looks as though it may have been #10 in a set.  The reverse has many lines of printed (Russian only) text extending into what would be the address area, and there is also a written message from the sender, who put it into an envelope.  However it could easily have been mailed as a postcard if someone had wanted to do that.  Grade: 4