When I first ate at Tocqueville, Marco Moreira’s understated French-American restaurant, I wrote that the chef/owner’s early sushi training showed in the elegant, ingredient-centered cooking. Seven years later, Mr. Moreira and his co-owner and wife, Jo-Ann Makovitzky, have removed Tocqueville to a larger haven down the block, and turned the familiar old room into a den of Japanese subtlety, just as the first days foreshadowed.

The shallow 35-seat space, painted gray, has become sparer and finer, and gained a bright sushi bar, which is manned by Masato Shimizu, who was formerly in charge of the East Village’s dainty Jewel Bako. The bulk of 15 East’s offerings are his, platters of raw rarities from the sea.

A 10-piece selection of sushi or sashimi runs $55, which it earns through sheer glamour. Spread out dramatically along a plate that takes the full width of the table, the fish glows with freshness. I didn’t take notes, but I can vividly remember each piece a week later: lush toro tuna; silky amberjack; a redder, leaner tuna slice marinated in soy, with complex, keen flavor; creamy, tangy salmon; salmony arctic char; an intense composition of chopped horse mackerel wrapped in a shiso leaf; sweet, milky-colored shrimp; slippery sliced scallop, which may have been the group’s best, and mild cooked sea eel. Okay, I only remember nine of the 10. But that’s my lapse, not the chef’s: Every piece had a luminous quality that added up to a dramatic whole.

Accented with real wasabi root grated fresh at the table, the platter satisfies a number of senses, but not the appetite: $55 later, I was still craving dinner. That insubstantiality is even more apparent in a “tuna flight,” $75 worth of rosy tastings from six different cuts of tuna that make a beautiful spread and a fine education, but not a meal.

The cooked fare has more substance, if sometimes less flair.

A meal at 15 East works best when it incorporates elements from the restaurant’s various strengths. The raw fish preparations are exciting but ethereal, while the blandly sturdy cooked main courses can make up the other side of the coin, like a casserole of mildly seasoned rice ($32), tossed with pieces of snow crab and savory snapper. Designed to be shared, it makes a filling cap to a meal that starts with a bit more thrill. Another casserole, of udon noodles in limpid broth ($22), does not bear the menu’s entreaty “for two,” though it’s at least as hefty as the rice dish, which does. Unfortunately, cooking in a sealed casserole turns the doughy noodles into a bloated, pulpy tangle, and leaves the tempura prawn with which they’re ensconced in the pot a bit spongy as well.

A block of cold, rich tofu layered with smokily seasoned eel ($12) forms a delicately sophisticated starter, as does a small helping of black heirloom edamame ($6). But the kitchen really shines when austerity takes a rest, as it does in a kakiage appetizer ($14), a pair of oily, fantastically flavorful cakes of tempura-fried shredded vegetables that the menu aptly translates as “latkes.” The loose-structured, crispy pancakes are sweet with scallions and meaty miniature pieces of shrimp; a little sheaf of sea salt provides the simplest possible accent.

Salmon three ways ($26) has a higher concept, as well as flavor and vigor to spare; it tastes like a dish from a different restaurant, perhaps Tocqueville. On an expansive plate strewn with salty salmon roe, a tour of wild salmon comprises three stops: first, the raw material, two marvelously buttery slices of bright-colored salmon sashimi; then a firm, grilled skin-on filet redolent with the taste of smoke; and a tender poached piece, striated with creamy wild-salmon fat.

For dessert, a pretty helping of sesame custard, formed into three little cubes and smeared artistically with black sesame paste, has considerably more vibrancy than typical Japanese sweets, and the wonderful accompanying elderberry syrup and sorbet make a sweetly thrilling contrast to the subtleties that have come before. The dessert card lists three sweet sakes too; a fine sampling from the 50-strong sake list. I found it hard to get guidance through the list from the servers: one’s hands-off stance suggested that any choice I made would be good; another server was significantly more voluble and opinionated, but with an accent that was difficult to penetrate.

The slight difficulty of navigation is the restaurant’s biggest hurdle. It’s easy to spend a couple of hundred dollars and leave peckish; or fill oneself for under $50. Making that path easier would make what’s already a very fine experience friendlier.

15 East (15 E. 15th St., between Fifth Avenue and Union Square West, 212-647-0015).