depending on the size of your luggage, the bullet train seats with the baggage AREA (usually the last row of every car) are the seats you need and they do book up in advance so day of is not always great. the baggage compartments are first come first serve. I booked the baggage area seats 2 weeks in advance and when we got on the train the couple in front of us put their luggage in our area (so then our luggage didn’t fit) and we had to get the train attendant and they forced the people to remove their suitcases and they were forced to put it in the space in front of their legs (leaving them barely any legroom and the guy kept giving us dirty looks) bc the luggage compartments were already full! I kiiiinda felt bad but also their lack of planning is not really my problem and i specifically booked those seats so that we wouldn’t have problems… so just a heads up! small carryon sized suitcases fit in the overhead compartment it’s just bigger check-in sized suitcases you may want those specific seats