What do you think when you hear the word "drink"?
Then, what do you think when you hear the word "bar"?
You may think of beer, whisky, or your favorite cocktail.
In any case, it is related to alcoholic beverages.
If you pronouce the two words in a Japanese family restaurant, they do not mean alcohol at all.
It means the right to drink as much non-alocoholic drinks as you like.
Once you order a "drink bar", you can taste any soft drinks from the machines situated at a designated area. If you wish, you can try all kinds of them, and, if you please, you can drink 10 cups of hot chocolate.
Having seen the success of free coffee refill, some Japanese restaurant owners developped more genereous version of it.
That is "drink bar".