Open Monday through Thursday, 11 a.m. to 11 p.m., Friday and Saturday until midnight, Sunday until 10 p.m. BA, AE

Food: Highly skilled preparation of sophisticated Chinese food

Style: Elaborately Chinese, with touches of Arabian Nights

Price: Moderate

CHINATOWN WAITED LONG enough for a Szechuan restaurant, but it was worth the wait. This is no ordinary Szechuan restaurant. The menu lists more than thirty appetizers and soups, nearly 150 entrees. The menu's breadth is equally impressive. Seafood offerings march on from the regulars to such items as sea cucumbers, abalone, cuttlefish, conch and snails. In few other Chinese restaurants will you find marinated smoked fish or cabbage core in garlic sauce.

Of course, being Szechuanese, the restaurant specializes in spicy dishes, which can be ordered mild, warm or hot; if you don't specify, they come quite hot. And if you don't watch out, you could put your palate out of commission by going from hot and sour soup through bon bon chicken to lamb sauteed in garlic sauce (called, in Chinese, "fish fragrant lamb" because the use of vinegar is meant to evoke the flavor of fish). All of these dishes are worth ordering, as long as you contrast them with mild alternative; the soup is dark brown and teasingly balanced between the hot and the sour, and bon bon chicken in its toffee-colored sauce of sesame paste with scallions, hot peppers and ginger is an exciting contrast of bland chicken shreds with the hot bite of seasonings.

Appetizers are particularly worth investigating at Szechuan, for there is a wide assortment of cold meats marinated or sauced with spices like star anise and Szechguan peppercorns, moistened with soy sauce and wine. Besides the bon bon chicken, Szechuan serves marinated beef, pork, even crunchy shreds of jellyfish. Hot appetizers, more familiar, are less enticing. The puu puu tray of fried shrimp, spareribs, egg rolls, shrimp chips and cho cho almost struck out, saved only by the skewered meat and the chicken steamed in foil, which was unexpectedly included. Even the meat-filled dumplings, which can be ordered steamed, boiled or fried, wouldn't finish in the finals of a local dumpling competition.

So, from the cold appetizers head right into the main dishes and the impossible choices you will have to make. Lamb with garlic is worth considering, the thinly sliced meat in good company with water chestnuts, scallions and the little ruffled fungus known as tree ears, seesawing between the heat of the peppers and the tang of the vinegar. Beef with scallops, heavily gingered, is a good choice if you like a little warmth rather than a roaring fire; the beef is left slightly rare and contrasts well with tender scallops and crisp pea pods. Szechuan is a good place to try a whole fish, either steamed with balck beans, shredded ginger and scallions or with bits of meat and garlic in a brown bean sauce, the house special. Duck is prepared five different ways, among them a lean, moist camphor-and-tea-smoked duck with a delicate fragrance.

They do a good job - a very good job - with the food at Szechuan, especially if you order their specialties. The waiters are communicative, helpful, efficient, and it is wise to ask their advice. When we strayed on our own, we encountered our greatest disappointment, a dry, drab version of lemon chicken.

While Szechuan seems to be well patronized by Chinese at lunch and dinner - which one takes as a good sign, of course - it practically serves as Chinatown's community center Saturday and Sunday afternoons, when the dim sum or dumpling menu takes over. Besides about fifteen steamed, baked and fried pastries, the menu offers over half a dozen noodle dishes and several of the cold dishes which appear on the regular menu. The big seller, at least among Chinese, is a long, unsweetened doughnut called a crisp twist roll which is traditionally dunked in chalky-looking bean milk. It is a subtle dish which one can easily learn to love. Along with these unusual pastries, Szechuan does well by fried meat buns in a thick dough and studded with sesame seeds; juicy steamed shrimp and pork dumplings: flaky scallion-flavored puffs; and crisp spring rolls, their delicious elastic dough stuffed with shrimp and vegetables. With the dumplings are served four dipping sauces. Dim sum range from about 50 cents each to $3.50 for a platter of ten; you could easily overeat for $5 a person.

The days of bargain-priced Chinese food seem to be waning, but Szechuan's prices are still moderate, considerably below some of the Mandarin and Szechuan restaurants outside of Chinatown. Most main dishes are $4 to $6. Soups run 75 cents to $2.50 a person. While many of the appetizers cost $2 to $4, they are meant to be shared. And luncheon specials are under $3. One could easily eat for under $10, but you might be tempted to boost the bill with one of the Plynesian drmks, which are good here, but cost about $2.50. There is also a short wine list, including half a dozen Oriental wines. But most of the Chinese I have seen dining at Szechuan have been drinking tea at lunch, beer - usually Chinese beer - at dinner.

The ambition in the menu and service at Szechuan is reflected in the decor, an opulent mix of swirling three-dimensional abstract paintings, rich draperies, designs painted on the ceilings and woven in the carpets.

In its first few months, Szechuan had its fits and starts, with the service bogging down and the food sometimes missing a beat. But it now seems settled into the kind of reliable restaurant where you can expect the tea to appear immediately, the food to be served generously on hot plates, and the cooking to meet high expectations. It is the kind of restaurant where the waiter takes the trouble to say, "Enjoy your dinner." We certainly did.