MikeHattsu
Member
They are valid on all JR trains and buses, not just the shinkansen. Don't worry too much about what trains are good or not, so long as you know that the Nozumi and the Mizuho shinkansen services are not valid. If you tried to enter a non-JR train line with your pass, the guards wouldn't let you through, so the chances of messing up are quite slim.
JR train stations usually got big JR signs and JR on the station name signs everywhere too, so it's hard to miss if you're in a JR station or not.