Well, it seems there's not any in NH, from a few Google searches I've done on that. I love teriyaki but I usually just make it at home because I like mine with lots of ginger.
Are you familiar with
Urban Spoon? It's a great app and website to help you find restaurants by name, type of food, price range, etc.
It appears that the closest teriyaki restaurant to us is in
South Portland.
If you find something closer by, let me know - I'd be interested in trying it sometime...