Manners at Restaurants
In Japan, bringing food or beverages bought at another restaurant is considered poor manners.
Even bringing plastic water bottles is not allowed. Tea or water is usually offered free in any restaurant so do make it a habit to keep your plastic bottles inside your bags. Always observe proper manners to experience good service from any establishment.
Also, when you enter the store, try to order one by one as much as possible. Sitting at a restaurant without ordering anything is not good since people who want to dine in cannot enter and will cause problems for the restaurant staff. Thus, there is a chance you will be given a warning by the restaurant staff.
Thus, let us observe these restaurant manners and enjoy our meal without discomforting other people.