The seating and facilities in “Ordinary” or “Tourist” class carriages of JR trains, particularly the Bullet trains, are pretty roomy and comfortable. “Green” or first-class carriages offer more room (e.g., 2 + 2 seats across a carriage, compared to 2 + 3 seats in Ordinary class) and more peace and quiet. But bear in mind that seat reservation is compulsory in the Green class – non-reserved carriages do not exist in the Green class.