474,048 is the number of restaurants and cafeterias in Japan. It is the country in the world with the highest density of restaurants/cafeterias in the world with one restaurant for each 266 people. The second place is for United States with 566,020 and a density of one restaurant for each 547 people. Notice that in Japan there’s almost twice as much restaurants per person than in United States.
In Japan it is very common to eat outside a lot, as it is relatively cheap. For example, in Europe the price difference between cooking at home or eating out in a decent restaurant can be quite big. However, in Japan the difference is not so big, supermarket products are in general a little bit more expensive than in Europe but the food in restaurants is usually quite cheaper (even taking into account the current exchange rates). This causes that many people, mostly in big cities, don’t bother cooking (supermarket stuff is quite expensive) and almost always eat out. Because of this, restaurants are easily busy and more and more of them are opening; however I guess that their profit margin is lower than in other countries.
Another common characteristic of Japanese restaurants is their specialization. There are restaurants specialized in practically any kind of dish and in some of them only their specialty is served. For example, only takoyaki, or only gyoza. Clients love this because to their eyes sushi prepared in a restaurant that ONLY serves sushi has to be better than sushi in a restaurant that serves many different dishes.
To conclude, another characteristic of Japanese restaurants is that they are not designed to stay there for a long time. The most characteristic example are ramen restaurants; in some of them they start to give you the evil eye if you stay more than 20 minutes. They are usually very small restaurants for only 10-15 people, so their business is based on serving the highest number of people in the least time possible. Clients have to be fast so that the business is successful.