No one set server/waiter!
In contrast to Western tradition, in Japan, you do not have one set server for your table. If it is a small restaurant, you will only have a waiter or two serving food. However, in a big restaurant, you will have a waiter taking you to the table and another one asking you what you would like to drink. When you are ready to order, just say "sumimasen" (meaning excuse me) and a waiter will come to take your order. In Japan, this is not considered rude, so do not hesitate to ask for what you need to enjoy your time at the restaurant!