KAZ SUSHI BISTRO -- 1915 I ST. NW. 202-530-5500. Open: for lunch Monday through Friday 11:30 a.m. to 2:30 p.m.; for dinner Monday through Saturday 6 to 10 p.m. Closed Sunday. AE, MC, V. Reservations suggested. No smoking. Prices: sushi $3 to $6 per pair; appetizers $3.25 to $6.50; "small dishes" $4.75 to $12; lunch entrees $9.50 to $15.50; dinner entrees $11.25 to $21. Full dinner with wine or beer, tax and tip $35 to $50 per person.

It's time to put entrees in the past tense. At Kaz Sushi Bistro, there are hardly any, and those few are listed in a backwater section of the menu. While this New Age temple of raw fish is a major restaurant, it's a place for sampling, grazing and nibbling. As if to further de-emphasize the entrees, most of the main courses appear also as "small dishes," or are collections of small dishes themselves.

The menu is changeable, as it should be in a restaurant celebrating raw fish, that most perishable of foodstuffs. But it is just what chef Kazuhiro "Kaz" Okochi's fans, from the years he spent at Sushi-Ko, would hope it to be. There's raw fish as sushi -- both the classics and newly created versions such as seared bonito with garlic chips (don't miss it) and salmon with mango sauce (two bites of summer on a plate). Then there are the small dishes, a step up in size, price and elaboration. Here's where you'll find once again the sea trout napoleon that was such a hit when Okochi created it at Sushi-Ko. It's chopped raw fish tossed with cilantro, soy-ginger dressing and peanuts for crunch, layered between crisp rounds of fried won ton skins. That's the kind of inventiveness that makes good on this restaurant's promise of "free-style Japanese cuisine."

The restaurant also offers a couple of soups and salads, a few side dishes, a long list of bento boxes at lunch and a short one at dinner, and some desserts that may change your mind about Japanese sweets -- they're delicious. Beneath all the drama of carpaccio of eggplant or tuna sushi with black olive pesto, even the basics are worth noting. At most Japanese restaurants, the fixed-price sushi assortment fills out the plate with low-rent items such as omelet or tofu skin. Not here. The basic $14.50 plate ($12.50 at lunch) is good, and the fancier one at $17.50 ($15.50 at lunch) includes such choice seafood as eel, sweet shrimp, salmon roe and sea urchin.

The sushi bar at Kaz can be an education. What's the difference between top-quality sushi and the kind that's sold cheaply at neighborhood sushi bars? First, here you'll find the commitment and connections that bring the chef the best of the catch. Second, Okochi buys the fish whole and cuts it himself. Third, it's a given that the rice will be properly cooked, seasoned precisely, served at just the right temperature and shaped skillfully. Notice the clean, fresh taste of the fish. See how evenly -- and generously -- it's sliced. Okochi goes so far as to make his own soy sauce, and for a slight extra charge you can order pungent fresh wasabi rather than the usual reconstituted powder.

His sushi also goes beyond seafood, to foie gras, which is marinated in plum wine and melts on the tongue like butter and honey. Foie gras is also teamed with tuna for a remarkable contrast. The only other meats on the menu are chicken teriyaki and short ribs, the small boneless chunks of ribs cooked slowly with soy sauce and sweet sake until they're as soft as pudding.

Nor is all the fish raw. Thumb-size octopuses are grilled with sweet soy and accompanied by a shredded daikon salad. Giant mussels are broiled and embedded in a spicy, tangy and faintly sweet mayonnaise-textured sauce that makes you want to lick the shells clean. Sweet shrimp are wrapped and fried in an armor of potato shreds. The soft-shell crab is a perfect crab in a faint crackle of batter, to be dipped in a lemony ponzu sauce. At $12 it's an extravagant few bites, but it's hard to resist.

The first disappointment I found among the fish was Chilean sea bass, its miso and sake marinade pedestrian and its emerald sauce brighter in color than flavor. The eel here is crunchy and lush in a sushi roll, but flabby as a whole barbecued chunk in a bento box. Nor does the chef evoke the most from salmon skin; as a salad topping and a sushi roll filling, it is soft and bland rather than crisp and saline. A flounder carpaccio doesn't deliver much discernible taste either, but its splash of tart-hot umeboshi sauce and granita of the citrusy fruit called yuzu are sparkles of lush flavor. The grilled yellowtail jaw seems too sweet from its soy glaze, though its meat is velvet.

Okochi doesn't show an instinct for vegetables, either. Grilled portobellos could use a glisten of oil to keep them from turning dry and bitter. And a side dish of spinach with tofu tastes like old-style health food: stolid. If you're seeking vegetables here, stick to asparagus or take advantage of Okochi's expert tempura technique.

I thought I'd seen enough tiramisu for one lifetime, but the pale green-tea version at Kaz reminded me how sumptuous this creamy fresh-cheese and moistened cake combination can be. The sake granita, icy and sweetly alcoholic, is a dessert made for a Washington summer. It's sheer refreshment.

What I also appreciate particularly in summer is that this very serious restaurant has a lighthearted dining room. Laminated tables, grass-cloth walls, a small rocky waterfall at the entrance and a clock with plastic sushi numerals soften what might have been traditional Japanese formality. The cozy dining room is bounded by a wall of bamboo-framed windows in front and the sushi bar in back. The waiters are a breezy, friendly bunch. They keep the multitude of small dishes parading swiftly and the sake and beer flowing efficiently. They also know what Okochi is doing, how and why.

Not that his Asian homage to fish needs much translation.

Turning Tables

Pricing is an art, they say. It is also a science. Take a serving of yellowtail sushi. The price reflects the cost of the fish -- which varies, depending on the quality as well as how impeccably it's trimmed or generously it's cut. The price also factors in variations in a restaurant's rent, salaries and even the quality of the tableware. Logic tells us that prices downtown should be higher than in the suburbs, since urban rents are generally more expensive. And you'd expect Makoto, Kaz and Sushi-Ko to be pricier than storefront restaurants with less elegant tableware or furnishings.

Not always. I called 19 Japanese restaurants to ask their prices for a two-piece serving of yellowtail sushi. Those in the District tended to be the highest ($4.50 to $5.50), with Makoto, Tono Sushi and Ginza at the lower end, Sushi-Ko and Sushi Taro at the higher. Kaz fell in the middle, cheaper than Yosaku but equal to Hisago and Kawasaki. But Tachibana in McLean matched the highest at $5.50. Arlington's Sushi-Zen and Bethesda's Tako Grill ran $4.50. If you're looking for a full-service Japanese restaurant that sells yellowtail sushi for $4 or under, you've got to seek it in Maryland or Virginia. The cheapest I found, at $3, was Sushi Sushi in Bethesda, though Atami, in Clarendon, at $3.25, and Matuba, in Bethesda and Arlington, at $3.50, weren't far above it. -- P.C.R.

CAPTION: Where have all the entrees gone? Kaz specializes in little dishes, from sake granita to sea trout napoleon.