i came across one that looks very close to the one i used when i worked at a very good local restaurant years ago. here it is; naturally, you can double the recipe as needed.: 1/2 cup soy sauce 1/4 cup white wine 2 cloves garlic, crushed 2 Tbsp. sugar small piece fresh ginger or 1 Tbsp. ground ginger simmer and dissolve the ingredients, then let cool and use or store. this makes a great marinade or sauce. we also thickened it with a little bit of cornstarch. usually 2 or 3 teaspoons of cornstarch stirred into an equal amount of wine or water will be enough, then stirred into the sauce as it simmers. it should thicken to the same consistency as really good maple syrup. japanese sake and dark brown sugar than white would probably be more "authentic," but either will of course work. i probably don't need to tell you that fresh ginger is much better than ground.