Four years ago, my wife and I spent two weeks in Russia and Belarus, it was an unforgettable journey. Compared to the crammed and densely-populated Kanto region where we live, everything there appeared huge and spacious: food, trains, roads, museums, we were quite impressed.
Communicating wasn't always easy, as few people spoke English, but everyone we met was quite helpful. One thing we learned fast was to have coins down to your last kopek ready in supermarkets, as the ladies at the cashier were visibly displeased when they had to return change. Acquiring tourist visa was pretty time-consuming; we had to secure flight tickets and hotel reservations prior to our application. One can only hope that these procedures have been loosened.
Most Japanese tourists travel in groups and will never encounter any of these issues. My (Japanese) parents-in-law visited Moscow and St. Petersburg without ever leaving their JTB-provided bubble.
I'd really like to see the Russian Far East one day, Vladivostok is just a 2-hour flight from Haneda.