418 S. Washington St. Falls Church 532-7729 Hours: 10 a.m. to 10 p.m. Sunday through Thursday; 10 a.m. to 3 a.m. Friday and Saturday. Prices: Soups and appetizers $2.25 to $6.75; main course soups and entrees $4.25 to $16.50, mostly $5.45 to $7.45. Cards: None accepted. No nonsmoking section.

This two-month-old, Vietnamese/Chinese restaurant already turns out satisfying versions of both cuisines. I suspect that if the familiar menu doesn't generate excitement, it's partly because in Northern Virginia many of us have been spoiled by the many good Vietnamese restaurants in the Falls Church/Arlington area.

Another reason may be that the split menu imposes some limits on the possibilities for unusual, interesting dishes. Nonetheless, Dong Khanh holds its own in a crowded field. (Also, if you're on the lookout for a late-night meal, it's worth noting that this family-run enterprise stays open until 3 a.m. on Friday and Saturday nights.)

The high-ceilinged interior of this former computer store is spacious and modestly, but pleasantly, decorated. The upbeat red and white color scheme is accented by numerous black lacquer wall hangings and one oversized, gold fan featuring a tiger.

For starters, the spring rolls are delicious, if a bit oily, with a light filling of shrimp and crab meat. But my favorite opener was a soup, the gingery congee ($4.25), which can serve two or three people. The thin, flavorful base of pureed rice and chicken broth comes studded with tasty shrimp, delicate fish balls and slices of tender chicken, pork and beef. The variety of meat and fish additions can be tailored to suit individual preferences.

Also good is the won ton soup with six of the meaty dumplings in a faintly peppery chicken broth garnished with leaves of bright green Boston lettuce.

A South Vietnamese staple, sweet and sour shrimp soup, had all the right flavors, but was sweeter than I prefer.

Seafood is generally a good choice here. The caramel fish, baked in a clay pot, had a rich, soy-based sauce that was pungent but without the extreme saltiness I've encountered in other Vietnamese restaurants. A steamed whole sea bass ($11) with black bean sauce was first-rate -- perfectly done with shaved pork for added flavor.

Another enjoyable way to savor the salty, sweet and earthy black bean sauce is on steamed crab "Dong Khanh-style." For $7.45 you get five small crabs, split and cracked, and so thoroughly permeated with the addictive sauce that it barely mattered that the crabs were not the most flavorful.

Also good are the Vietnamese barbecue dishes such as the lemon chicken -- flattened pieces of marinated white meat grilled and then lightly sprinkled with tiny bits of finely ground peanuts, fried round onion and chopped green onion. A similar preparation with tender pork strips and sweet, whole shrimp comes with thin rice noodles and crunchy fresh bean sprouts adding a pleasant contrast in textures.

The roast half duck ($8.50), glazed with an anise flavored brown sauce, was a hit at my table and made deliciously messy finger food.

For an attractive Cantonese-style dish, try the "fairy combination," a well-executed mix of seafood, meat, and vegetables in a lightly thickened gravy, encircled by a pale yellow halo of fried vermicelli. Another good stand-by is the Hunan chicken, tender and appropriately fiery in a rich, sweet sauce.

The one dark cloud over the restaurant's offerings was the orange beef -- tough, stringy meat in a slippery, gummy coating that a terrific sauce could not rescue.

The desserts are limited to a sweet bean custard, a toffee banana, and a decent batter-fried honey banana rolled in sesame seeds.

A language barrier sometimes intrudes between diners and staff, but with a little patience it is not insurmountable. Although service was friendly and prompt, Dong Khanh has yet to be discovered -- on three recent visits the dining room was nearly empty -- so it remains to be seen how service will hold up with a full house.