Shirakiku is a Japanese soda drink in a bottle sealed at the top by a small marble. The marble held in place from the inside by the internal pressure. You open the bottle by pressing down on the marble, thereby releasing the pressure and allowing the marble to fall into a special crook at the neck of the bottle. The marble then clinks and rattles in the bottle as you drink. The taste is akin to 7up or Sprite. The English Shirakiku label is hysterically funny.