Seasoned Rice Vinegar is a ready-made version of what the Japanese call “Sushi-zu” (sushi vinegar: see separate entry.)
It is a vinegar made from sake, and flavoured for you with salt and sugar.
It is used for Japanese salads, and to flavour rice for sushi.
Some purists prefer to always mix this combination up themselves.
Per 1/2 cup (4 oz / 125ml) of white rice vinegar, add 1 tablespoon of sugar and 3/4 teaspoon of salt