This is a wonderfully fruity vinegar made from Japanese umeboshi, which, although they are usually called plums, are closer to apricots. The Japanese ascribe many health benefits to umeboshi, and a splash of this vinegar in a glass of water is often taken as a tonic. But, where umesu really shines is in the kitchen – in dressings, sauces, in any dish that calls for a white wine vinegar with a lot of fruit.