I happened to be in Andover around lunchtime on Sunday and having eaten a Flour Bakery + Cafe sticky bun for breakfast, we decided that sushi would make a good lunch. I ordered the luncheon sushi & sashimi special and my DC ordered 2 hot appetizers for his lunch: a baked dish of shrimp and mushrooms in a Japanese mayo sauce, and the Hamachi Kama, which is called Yellowtail chin on the menu. We shared a glass of plum wine at the end of the meal.
While everything was really good, the yellowtail was the star. The fish was incredibly buttery both in flavor and in the way it melted in your mouth. The fish collar was broiled (or baked?) and was served on a pool of pleasantly salty and sweet sauce - probably a soy + ginger combination. Neither of us had ever had Hamachi Kama before so we don't have much basis for comparison, but it is great at Yama.