Nowhere are manners more important than in crowded situations such as bullet trains (shinkansen). Here are a few pointers that will help you to impress your fellow bullet train passengers with your social graces.
1. Skipping the lineShinkansen have both reserved and non-reserved cars. For both types of cars, people form a line. It's more complex than you might imagine to even find your line. If you can find it (don't be shy to ask) — stand in it. Japanese society is orderly — lines are taken seriously.
If there's just one person waiting stand behind them.
Always allow all passengers to get off before getting on.
2. Stealing a seatIf you have a reserved seat be sure to find the correct seat. If you don't — look for a seat in a non-reserved car. Your ticket will be checked. Being in the wrong car will prove embarrassing (you'll have to move or pay up).
3. Talking on the phoneIn Japan, it's considered rude to talk on the phone in public areas such as trains. You should also keep your phone on vibrate (manner mode). If you must talk on the phone go to the area between cars. Don't be this guy.
(poster is from a subway train, not a shinkansen)
Once you get accustomed to this point of etiquette you may grow to like it. It makes life more pleasant for everyone. Japanese people also don't talk on the phone in stores, cafes etc...
4. Leaving garbage on the trainWhen your shinkansen reaches its final destination a big crew of cleaners will clean the massive train within seconds. Help them out by taking your garbage with you.
In Japan, leaving garbage behind or littering of any form looks barbaric. People will look at you like you just spit on the floor.
5. Reckless recliningIt's a custom in Japan to check behind you before reclining a seat. Give the person a heads up that you plan to recline.
If the person behind you is eating, jammed with luggage or working on something — consider not reclining your seat.
6. Blocking the aislesLuggage can be stored overhead, in luggage storage areas and in front of you in your seat. Never block the aisles with your bags.
7. Getting off in a panicWhen you're close to your station listen for your station to be called. Shinkansen are incredibly punctual (within 6 seconds of schedule). Stops at rural stations are fairly short. It's just enough time for passengers to comfortably get off and on. The last thing you want to be doing is rushing for the door when people are already boarding.
Things You Can Do (Not Considered Rude)
✓ Food is OkThere's a long standing custom of bringing food and beverages on the shinkansen. Enjoy!
✓ Parties are OkUnlike airplanes, there's a custom of having parties on shinkansen. Let's say you go on a weekend ski trip with 6 friends. A party on the return shinkansen is essentially expected. Shinkansen seats rotate to 6 seat and 4 seat configurations.
Be aware of your environment. If you're on a morning train full of business people preparing for their day — it's not a good time to be loud. There's safety in numbers. If you're just two people it's not cool to be loud. If you're 10 people — it's more acceptable. After all, you can't expect Japan to be a quiet place.