Itzakayas have lately taken the city by storm. These Japanese pubs have added creative dishes to the national canon, and thus expanded our idea of what Japanese food can be. Ariyoshi"s menu is a multiplex document that could take a half-hour to study, but includes every Japanese dish you"ve ever heard of, with some American and English ones thrown in. The sushi and sashimi are way above average, and the sushi assortment deluxe is a generous and pristine aquatic parade. Among the more creative dishes, we loved the mushroom steamed in parchment with shreds of garlic, the rock-shrimp tempura, the tiny Berkshire pork sausages, and the kushi-age assortment -- little deep-fried skewers of surprising ingredients. The sake list is an able primer for the uninitiated.