I found these bottles of carbonated drink–a genuine product of Japan–at a local salvage store.
Here are the actual directions printed on the plastic wrap covering the top of the bottle:
“1. Serve Ramune drink chilled.
2. Remove the plastic film from the top.
3. Pop out the center from the cap, which will be used to open the bottle.
4. Place the opener at the top of the bottle and press down firmly.
5. Drink with the indented neck side facing down to trap the marble.
6. Enjoy the drink.”
In other words, instead of a simple crimped bottle cap, the bottle is sealed with a glass marble that must be dislodged with a piece from a two-part plastic cap. The marble then gets stuck in the neck of the bottle when it is tilted, allowing the drink to dribble out into a glass or your mouth. I’m not making this up.