Seven Seas 1776 Jefferson St., Rockville 770-5020 Hours: 11 a.m. to 1 a.m. Monday through Saturday; noon to 1 a.m. Sunday. Prices: Most dinner entrees $7 to $9. Credit Cards: MasterCard, Visa.

Mixed-menu oriental restaurants seem to be a new trend. Several Korean-Japanese places have opened in this area recently, and now Rockville has Seven Seas, a Chinese-Japanese restaurant on the site of the former Szechuan and Hunan.

The menu offers an immense variety among the Chinese dishes, with an emphasis on seafood, and a limited number of Japanese selections, mainly sushi, sashimi, tempura and teriyaki.

Prices are reasonable, and the bright, cheery, remodeled dining room is quite handsome. The food has been very erratic -- there are some exemplary dishes here, worth a trip in themselves, but there also are some duds. Predicting what's going to be in which category can be difficult.

The servers are friendly, eager and solicitous, but there's more than the usual confusion and the pace is sometimes less than speedy. That's a problem that should iron itself out with time.

To begin with, an unusual and thoroughly delightful appetizer, Japanese in origin, is the crispy Seven Seas roll, in which a thin sheet of seaweed is wrapped around a mixture of minced seafood and scrambled egg and quickly fried. The result is a lovely combination of gentle flavors.

Even more impressive is the sometimes-available smoked tuna appetizer, perfectly fresh, juicy, light on the smokiness, a subtle jewel. Lettuce-wrapped shrimp is out of the ordinary, too, a mixture of diced shrimp and vegetables curled in a lettuce leaf. But the flavor is so delicate it can be dull.

Another excellent and unusual item is the seafood dumplings, with a fluffy minced seafood-vegetable filling. Be sure to order them steamed, because the fried variety had tough wrappers. The traditional pork-filled dumplings are very good, too.

The sauces here are excellent: deftly flavored, well-balanced, unthickened. One of the best is the black bean sauce, laced with diced ginger and garlic. It comes with several dishes, among them a mountain of exquisite, briny-fresh baby clams. These clams alone justify a visit to Seven Seas.

The yu shiang sauce, hot, garlicky and slightly sweet, is another gem. We had it with huge, very fresh, sweet-tasting shrimp. That success led us to order a seafood combination dish called "seafood crown" on our next visit. It was a disaster, a disappointing mush of not very fresh fish, shrimp and scallops, which was missing the crab and clams listed on the menu. There's no predicting.

Back to a winner with the steamed whole sea bass, a delicate masterpiece, perfectly fresh, beautifully presented with a topping of slivered vegetables, in a mild, subtle sauce with anise and bits of ginger. (If the waiter forgets to debone the fish, ask.) The fried squid is excellent, too, fresh and tender, generously portioned, with a light, golden, aromatic batter zipped with pepper and ginger.

On the Japanese menu, the tempura was unusually poor, with a soft, strangely gluey batter. The tuna teriyaki featured a lovely slab of fresh tuna, served sizzling on a metal platter, but its delicate flavor was overwhelmed by a very smoky-flavored teriyaki sauce.