This recipe and others can be found in the article "In Hawaii, Barbecue Means a Luau" by Mike Stines, Ph.B.
1/2 cup tamari soy sauce
1/2 cup sake or dry sherry
1/4 cup sesame oil
1/4 cup rice vinegar
1/3 cup brown sugar, packed
3 cloves garlic, minced (about 2 tablespoons)
1 (3-inch) piece fresh ginger, grated
1 teaspoon wasabi powder
1/2 cup sliced green onion
In a mixing bowl, combine the soy sauce, sake, sesame oil and rice vinegar. Stir in the sugar and whisk until the sugar dissolves. Add the garlic, ginger, wasabi powder and green onion; stir to combine.