Vinegar, known as o-su in Japanese, has long been an important ingredient in Japanese cuisine. It is the condiment that gives the rice in sushi its sharp flavor, for example. What is more, vinegar is considered to be good for the health, particularly for improving circulation and countering fatigue. Now more and more Japanese are seeking the benefits of vinegar not only by eating food containing it but by drinking vinegar-based beverages. Further fueled by reports that rice vinegar is effective in promoting weight loss, a wide range of vinegar-based drinks have hit the market recently.