In a small saucepan, combine the rice vinegar, Vegetarian Dashi, and sugar over medium heat.
Heat the mixture, stirring constantly, until the sugar has completely dissolved.
Bring the sauce to a near boil, then immediately remove the saucepan from the heat.
Allow the sauce to cool completely to room temperature before using.
Transfer the cooled sauce to an airtight container. Store in the refrigerator for up to two weeks.
Don't let the mixture come to a rolling boil, as this can alter the delicate flavor of the vinegar.