Before you begin eating, say “itadakimasu.”
As a rule, Japanese always say “itadakimasu” before they eat. It literally means “I partake.” There are many stories behind it, but it is considered to be a way of expressing gratitude to the chef, the people who grew/raised the ingredients that make up the meal, and the ingredients themselves since everything on one’s plate was once alive.
If the chopsticks are disposable chopsticks break the chopsticks by pulling them apart vertically.
Proper etiquette states that the chopsticks should be held horizontally, and pulled apart vertically over your knees. Do not pull your chopsticks apart horizontally.
If there isn’t a chopstick rest, make one with the paper your chopsticks came in.
Since it is rude to place your chopsticks over your bowls when you’re not using them, if there isn’t a chopstick rest, please make one using the paper sheath.
When you’re eating rice, hold your rice bowl in front of you in the opposite hand you use for chopsticks.
When you eat rice, make sure to lift your bowl in front of you. Not lifting your bowl is considered poor etiquette. The same rules apply to soup bowls.
Clean your plate.
Most places in Japan will not let you take food home for hygienic reasons, so please clean your plate.
When you finish eating, put your disposable chopsticks back in the paper and fold the end. After meals, please say “gochisousama deshita.”
“Gochisousama deshita” literally means “I feasted.” It derives from the word “chisou” which means “feast,” and is written with two characters that mean “to run,” it implies that the meal was created as the result of many people running around and working together. “Go” and “sama” are honorifics that take the phrase to politer level that implies thanks to the many people that came together to create this meal.
Many people say “itadakimasu” and “gochisousama deshita” with their hands put together as though in prayer, it’s not required and is often a regional behavior.
If at a restaurant saying “gochisousama deshita” to the staff when you exit is considered to be good manners as well.