Ponzu Sauce II

Combine the mirin, vinegar, soy sauce, zest and bonito flakes in a saucepan and bring to a boil over medium heat. Remove from the heat and let cool.

Strain the sauce into a bowl; discard the solids. Stir in the yuzu juice.

Cover tightly and store in the refrigerator for up to a week. Taste before serving, adding more yuzu juice if desired.