RESTAURANT REVIEW : Nothing Special, but Curiously Popular : In threadbare surroundings, Tokyo Sukiyaki in Oxnard serves up fare that disappoints.

No matter how they are configured, Japanese restaurants typically rely upon two things: freshness in seafood and spare, sometimes ascetic, dining space. The Japanese dining experience is designed, indeed, to impart an elegant simplicity, a subtle cuisine unencumbered by goopy sauces, overwrought handling, hoopla in dining room decor. The result, when everything works, is a light but fortifying fare, artfully presented and not without some incendiary surprises.

Tokyo Sukiyaki is sandwiched between a bar and a bodega in a small strip mall on Gonzales Road in Oxnard. Its dining space is designed to give the secluded ryokan impression: slender, wood-accented, intimate spaces with booths kept separate from the kitchen by wood-slat walls, all beneath wood and paper lantern lights. And its menu is heavily seafood.

But both of those familiar values are undermined.

The room feels and looks tired, even threadbare, though things are clean. And the food, in visits taken over many months, has varied widely--some of it good, some of it just OK, some of it barred from success by misconception, some of it perilously stale.

The place seems no shorter on customers for these problems, a fact that mystifies. But popularity does not an assessment make, and, sadly, this one is without happy comment on an otherwise preferred and cunning island cuisine.

Among appetizers, the gyoza ($3.25) was most reliable--nicely seared and plump with fresh ground pork filling. But the dipping sauce only once had the right slightly sweet, slightly tart, vinegar edge; on another visit it suffered from a massive overdose of chili oil, requiring dilution with soy sauce.

Shrimp and vegetable tempura ($3.95 and $3.50, respectively) were adequate, if a bit plain. Happily, the shrimp, which were cooked just until done, were fresh. The same cannot be said about the octopus sushi ($2.95 apiece). In one recent visit it was over the hill, its once-pearly white meat going gray, its once sea-sweet scent bearing a sour edge, its once-spongy texture going tough. It went uneaten. Tuna sushi, however, was fresh and just as it should be--clear in flavor, bright in color, and virtually free of scent. Spareribs ($4.50) were under-flavored and over-cooked.

The small dinner salad ($1.50 or included with entree orders) is straight iceberg, lightly tossed in rice vinegar and oil with sesame seeds--again, adequate at best. Dinners are accompanied, however, by a simple miso broth, suffused with flower-shaped carrot slice and fine noodles, and the result is altogether light and refreshing.

The most successful entrees were the most Americanized: salmon teriyaki ($13.95) and chicken teriyaki ($10.50). In each case, large premium filets were properly cooked and dressed with a densely flavorful sauce.

Still, tuna teriyaki ($10.95) was featured as a special one night, and the beautifully cut tuna steak was clearly straddling that nervous place no sauce can hide: the zone between fresh and stale, between rosy red and brownish purple, between light flavor and meat-like heaviness. It went largely uneaten.

Spicy tuna teriyaki ($8.95), another special, was dry and overcooked and a massive presence of chopped fresh jalapenos overwhelmed fish and sauce.

Yosenabe ($13.95), or soup stew, was quite satisfying. Its ample helping of tiny sweet clams was tender from infusion at the last minute, and its generous fish fillet, fresh vegetables and thick noodles were worthy complements to the light seafood broth.

Perhaps most disappointing of all was a near success called Salmon Batayaki (on special for $12 and on the menu as Butter-Yaki Salmon for $14.95). Akin to French salmon in parchment paper with fresh spring vegetables, this version encases in waxed paper a generous salmon fillet atop sliced onions, one lemon slice (with bitter peel), fresh parsley (with peppery stems), and butter.

Alas, the fish was slightly overbaked, less than that-day fresh, and lacking in light vegetable essences, fragrance, or balanced flavor. Adequate enough for the truly hungry and certainly not a complete flop, this dish still begs the ugly question: Why bother?

Dessert? I passed every time.

It just seemed too much bother.

Details

* WHAT: Tokyo Sukiyaki.

* WHERE: 1333 W. Gonzales Road, Oxnard, 485-7337.

* WHEN: Lunch from 11:30 a.m. to 2 p.m. Tuesday through Friday, dinner from 5 to 9 p.m. Tuesday through Sunday.

* FYI: Major credit cards. Dinner for two, food only: $22-$40.