Also known as: ラムネ, 波子汽水
A carbonated soft Drink sold in Japan, typically in Codd-neck bottles, which use a glass marble as a stopper to keep the drink carbonated. The original formula is lemon-lime; nowadays there are many other flavors as well. At least one manufacturer labels it "Ramuné" for the North American market, indicating how it's meant to be pronounced.
For the game and anime, use the tag Lamune.