These rule and taboo have in all places on the earth and in all professions. These rules had been formed long time ago. They are the crystallization of a culture and a nation with elements of local culture combined with cultural elements from outside of country due to the exchange between cultures. Thanks to the rule that people know to behaves reasonably in every region and every culture. Here are some notes in a meal of Vietnamese which you should know to have appropriate behavior when you travel to Vietnam.

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Do not put a pair of chopsticks into the rice bowl straight up.
You should not push a pair of chopsticks in a bowl of rice with the vertical. This is a taboo thing. Because it is only for the rice bowl offering the dead. The cause is in Vietnam culture has the custom of worshiping the dead. when the dead are buried under ground completely, the dead’s family will make a big plate include: fruits, incense, sweet soup … and a bowl of rice with a pair of chopsticks is put vertically to send to the soul of the dead for using on the way to the heaven or the hell. So, when you have a meal with Vietnamese and you push a pair of chopsticks into your rice bowl vertically, people around will feel uncomfortable, because this is an action for the dead only. So you should never do that.
Put rice into the bowl
In the meal of Vietnamese, dishes of the food are generally shown on the table for everyone, what you like to eat you take and put into your bowl. Food will not be divided in sections for each diners as eating style of Europeans. Rice is the main food of Vietnamese. How to ladle rice into the bowl is also very important. Normally, a person will ladle rice into the bowl for everybody. First, open the rice cooker and use a dipper to stir rice until loosing rice seed. Then put the rice into the bowl. There are two things to note:
Do not take a big dipper making the bowl full of the rice, it means you ladle rice only 1 time. People only do this when they ladle rice to worship the dead.
You should not ladle rice into the bowl too full. Some people think that is impolite. You should put the rice into the bowl about 2/3 of the bowl is perfect.
Flipping over a whole fish when people have finished one side
Normally, when you have finished one side of a fish, you will turn it over to eat the rest part, but this is taboo for seafarers and fishermen, they are not allow to do that. Because they think that action symbolizes for the ship will be turned over (upside down), this is horrible accident for fisherman. So if you dine with the fisherman in Vietnam, you should not flip over side of the fish when you eat fish. The best way is you take fish bones out and eat the other half of the fish.
Making a toast with the older
This rule is very popular in the north of Vietnam. In a party: wedding party, birthday party, New Year party…, people often invite each other with a cup of wine or a glass of beer to share the joy. If you are a younger, once you make a toast with the older, your glass has to be put lower than older people’s glass a little bit. Do not put glass equal or higher, this is disrespectful.
Beating chopsticks to your bowl side
You should not beat your chopsticks into the bowl side. Vietnam people believe that when you beat the chopstick into the bowl side as you are calling the hungry ghosts around to dine with you. This belief comes from an ancient agriculture and has become the custom of some areas in Vietnam.
Do not use your cell phone while eating
You know this rule but you still do that, don’t you? Today, the life of people seems to be very busy, they often work with their cell mobile even during meals. Let’s quit that habit in Vietnam. Because dining is the time for relaxing of Vietnamese, so they do not want other people to bother with any job or something. So you should not do other things while dining with Vietnamese people.
Rule seven: Do not mess-up food
Maybe, because you have grown accustomed to have a meal with your family so when you eat with the others, you still keep the habit of pushing some food to the side of plate to find your favorite food. But it is impolite. While eating, you have to take food from the top to the bottom and from the outside to the inside of the plate. Do not mess-up food in order to take under food.
Gesturing with the waiter
Vietnam people do not have the habit of making the gesture with the waiter. When they want to order for food or ask anything, they would speak directly to the waiter. Therefore, while dining, you can ask directly what you want without making the gesture.
Napkin
Napkin is used to protect clothing from stain and wipe your mouth while eating. There are 2 kinds of napkin: cotton and paper tissue. In a banquet with a lot of dishes you should not use paper tissue. Paper tissue should be used only when drinking coffee or during breakfast.
Do not wrap the napkin around the neck; also do not put the napkin under plates. You should put the napkin on your lap, if you have to stand up while dining, so temporarily folded napkin and put down the seat. After finishing your food, fold your napkin and put it on the table, next to your plate.