Sweet & Sour Sauce

1/4 cup white sugar
1/3 cup white vinegar
2/3 cup water

1/4 cup soy sauce
1 tablespoon ketchup
2 tablespoons cornstarch

Place the sugar, vinegar, water, soy sauce, ketchup and cornstarch in a medium saucepan, and bring to a boil. Stir continuously until the mixture has thickened.