Chaya is my favorite sushi restaurant in Pittsburgh.
While the sushi is obviously a big draw, the other appeal is the great selection of traditional Japanese food. It's the only place I've found that actually has natto (fermented soybeans) on the menu.
Other great selections: the delicious udon, the vegetable tempura, and the marinated octopus (tako).
Plus, all the waitresses wear kimonos and speak Japanese! It's the closest you'll come to a taste of Japan in Pittsburgh! ^_^