Japan Bullet Trains

Sure, you are welcome to return unused (and valid!) tickets if your plans have changed. But keep in mind that you won't be able to get a full price back, as there is a cancellation fee. It varies, so you should ask about it beforehand.

Feel free to eat on long-distance trains like Shinkansen and limited express, equipped with cupholders and trays at every seat. You can either buy some snacks and drinks (including alcohol) from a vendor trolley or bring something with you. It's better to avoid eating anything when you travel by short-distance train. It's not exactly forbidden but rather frowned upon in Japanese culture.

Yes, many Shinkansen trains are equipped with free Wi-Fi services, especially on major routes like the Tokaido Shinkansen. However, signal strength may vary, especially in tunnels and rural areas.

Yes, you can bring luggage on the Shinkansen. Each passenger is allowed to bring up to two pieces of luggage, but there are size and weight restrictions. Large suitcases may require a reservation for a designated luggage space, especially on the Tokaido, Sanyo, and Kyushu Shinkansen routes.