Loosely translated, the word "amu" means "everything and nothing." Amu is a quiet sliver of a restaurant attached to the raucous Sushi Zanmai, easily missed by the masses but fervently supported by fans and Boulder's chefs, who spend hours in this authentic izakaya. Amu doesn't serve sushi, as the robed chefs behind the narrow bar will note when a guest walks through the door. Instead, it serves other classic Japanese dishes: glittering fried green mussels served in their shells with plenty of Japanese mayonnaise; a perfect piece of red tuna set on a soft, delicate paste made from mountain yam; mochi kakiage, a chewy Japanese rice cake that's battered and fried; and superb aged ashi tofu, delicate and silky with a crispy fried shell, served in a subtle ponzu broth with a pinch of minced green onions and a single pickled carrot cut into a tiny star resting atop the glorious, golden mass. The food may look so simple it seems like nothing, but that simplicity is everything to a fabulous Japanese meal.