Open for lunch Monday through Friday noon to 2:30 p.m., for dinner Sunday through Thursday 5:30 p.m. to 10:30 p.m., Friday and Saturday 5:30 p.m. to 11 p.m. AE. No reservations. Prices: At lunch, main dishes from $4 to $7, at dinner appetizers generally $1.50 to $3.50, main dishes including soup and salad $5 to $10.50. Full dinner with beer or wine, tax and tip about $15.

Talk about understatement! The waiter at Yosaku hands you, along with the menu, a page with handwritten rectangles slipped into its plastic pockets. "Jaw of Yellowtail," one rectangle might say. Another, "Flounder with Vinegar." And a third, "Tuna with Miso." Hardly tempting.

What you get, if you have been clever enough to order them, is, for one, a large wedge of yellowtail fish, the cheek, grilled so that the skin is crisp and salty, the meat inside -- ivory with a faintly pink tinge -- moist and steamy and delectable. That simple-sounding flounder with vinegar is raw fish sliced into paper-thin petals and arranged on a plate like a pink and white flower, so delicate that you can see the china's crosshatch design through it. Decorating this fish flower are raw vegetables carved into more flowers and a fresh flower. You pick up the fish petals with chopsticks and dip them into a sauce of vinegar, soy, scallion and horseradish, reluctant as you may be to disrupt the charming pattern. And the tuna with miso turns out to be perhaps less exquisite looking -- merely raw tuna cut into large dice and served in a bowl covered with a pale gold sauce. But that sauce is sweet and salty and truly intriguing, perhaps the most delicious thing I could imagine being done to raw fish. The dish is also available with squid instead of tuna, but the tuna is unbeatable.

In addition to the several daily special appetizers listed on the plastic sheet, the regular menu has more than a dozen appetizers plus a full array of sushi and sashimi available as appetizers or main courses. The appetizers are the heart and soul of Yosaku, a small, new Japanese restaurant that is an offspring of Bethesda's Nara but more interesting than its parent.

Some of the appetizers are astonishing bargains: several plump and juicy chicken wings fried to the lightest crispness for $1.50; an equivalent portion of flounder also fried in a very airy and crunchy batter for $2.50; a lovely little garden of sashimi in a propped-up abalone shell like a shadow box for $3.50. Some dishes are intriguingly new: tiny cubes of rice with a mosaic of avocado, fish cake and seaweed, called California Rolls; enormous soft-shell clams the size of large oysters, sliced and baked in their shells with sweetened soy sauce. And the sushi are precise and fresh tasting, a good representation of the art. More run-of-the-mill are the tempura, similarly available as appetizer or main course, and string beans in sesame sauce that were too sweet and cooked too long.

Yosaku's menu boasts that no MSG is used in its kitchen. It does, however, use too much sugar, perhaps in compensation. It's too bad, because the chicken teriyaki could be outstanding. The tiny cubes of chicken are lightly grilled, just barely crisped on the surface, and very tender, but their glistening brown teriyaki sauce swamps them with sweetness. The negimaki, too, suffers the same flaw, though the sliced rolls of paper-thin beef wrapped around scallions are otherwise excellent. Tonkatsu is a dish rarely done well, though at Yosaku it is better than in most local Japanese restaurants, mainly due to the light, crisp coating on these pork chops; the sauce has more tang and pizzazz than most, but again is quite sweet. The salmon teriyaki suffers from excess salt, which is typical of Japanese broiled fish, but in addition is ladled with another oversweet brown sauce. If it had been left bare it would have been a very satisfying portion of three diagonal slices of plump salmon grilled just enough to crisp the skin. Vegetable accompaniments, roll-cut cooked carrots and spinach, were disappointing, lacking savor.

Best of the main dishes I have tried, aside from the raw fish entrees, is yosenabe, an iron cauldron of seafood and vegetables in a light and warming broth. The seafoods -- fish, scallops, shrimp -- are good quality, the broth of full flavor and the dish an ideal winter endeavor. The menu also lists teriyakis of beef and shrimp, sukiyaki, nabeyaki and broiled eel. And dinners include miso soup to drink directly from lacquered bowls and a small dish of cold soy-marinated bean sprouts of no particular character.

Not all of Yosaku's special flavor is in the mouth. Small decorative touches increase the deliciousness of dinner. Dishes are garnished with fans of cucumber or carefully mounded scallions or grated radish. A flower or an autumn leaf is likely to complete the still life of each plate. The plates themselves are varied and pretty, and set on bare tables that look like patchwork of wood. The napkins are pink and folded into pyramids as the only table decorations. Japanese music, just soft enough, plays in the background. And carpeting further softens the noise. The dining room is simple and soothing, its focal point the sushi bar in the rear. And service is quietly efficient. The sake is warm, the beer is cold, the tea is kept refilled and dishes are brought and cleared swiftly.

Yosaku is a restaurant of modest size and price which goes beyond one's expectations. And though the sushi competition in Washington has grown intense, Yosaku quietly carries away a few prizes for fish presentations that are new to this city and priced with appetizing restraint.