Sumimasen means excuse me or sorry. If you need to ask a question, walk past people in crowded places, or about to order then sumimasen is the word to use. At restaurants, you can use the word sumimasen to summon the waiter/waitress as well. In Japan, waiters and waitresses won’t come to your table unless you call them. It is polite for the waiter/waitress to come to your table only if you are called as they don’t want to bother you during your meal.
A simple way to say thank you. Arigato means thank you and the gozaimasu at the end is to make it the word polite. Often times, you might hear the word otsukaresamadesu almost as a replacement. Literally translated it basically means you are so tired, thank you. It’s a common greeting usually at the end of work, class, phone call or when you are eating with your colleagues at the end of a hard days work.
After finishing a meal in Japan, it is polite to say gochisousama (Goh-chee-sou-sama). This is an expression after the meal to express gratitude to the meal (and to someone who may be treating you). The translation can roughly be seen as “Thank you for the meal”. Now don’t get gochisousama mixed with arigatou! While both may have thank you in them, arigatou should be used when thanking someone, while gochisousama is strictly used after a meal.
Before eating a meal in Japan, it is always common to put your hands together (or not) and say Itadakimasu (EE-ta-da-kee-masu). It is an expression of gratitude, but its literal meaning means to receive or to accept. A more common term that is a bit similar to itadakimasu is “bon apetit”. Make sure to say it before eating!
Often times, most restaurants in Japan will give you an oshibori as soon as you sit down. An oshibori is a hot or cold small towel (nowadays restaurants might just use one-time wipes) used to clean your hands before you eat. It is a common hospitality practice in Japan. So, if you receive a small towel at a restaurant and don’t know what to do with it, simply clean your hands with them, and then neatly fold them next to you to use throughout your meal if your hands get dirty again!