So the purpose of the marble is simply to seal the bottle. Codd-neck bottle was introduced to Japan in 1870s. Bottle originally enclosed lemonade and overtime lemonade turned into Ramune as we know of it today. In fact, origin of the word Ramune is lemonade. read more
Ramune is widely known for the distinctive design of its bottle, often called Codd-neck bottles after the inventor, Hiram Codd. They are made of glass and sealed with a marble; the codd head is held in place by the pressure of the carbonation in the drink. To open the bottle, a device to push the marble inward is provided. read more