[LearnAmazingJapanese]

It looks like the main difference between ordinary and Green is the accommodation.

Green cars are "first class" - more legroom/ less seats, that sort of thing.

If I'm not mistaken, there's no difference in what trains you can ride, which to me would be more important, since the Nozomi class bullet train is faster (i.e. fewer stops) than the Hikari or Kodama class trains.

HTH.

PS. Reservations - I think you can reserve regardless of what type of rail pass you have, with the exception that you can't reserve a Green car seat w/out the Green rail pass, and you have to pay more if you want to ride the Nozomi class bullet train.