Teriyaki Sauce

1/2 cup mirin
1/4 cup sake
1/4 cup shoyu
2 tbs sugar

In a small saucepan, heat the mirin and sake over low to medium heat for 5 minutes. Add the shoyu and sugar, and stir until the sugar is dissolved. Cook the mixture over low heat for 25 minutes. Let the sauce cool and store in refrigerator for up to a week.