Harrison Kim knows it may be a while before the seersucker-blue palates of Chestnut Hill make it past the safety of a cooked California roll to embrace the raw and racy.

"Right now, it's still, 'California roll, California roll, California roll...' " sighs Kim, who runs Osaka, which stands atop the stone-cobbled hill on Germantown Avenue.

But when that daring moment arrives, it will be an epiphany: Eyes pursed in nervous concentration suddenly relaxing, then widening in excitement as the forbidden sweetness of pristine, naked seafood - mmmmm! - swells inside the mouth. More, more!

That's the look I witnessed across the table one recent night as two of my guests sat in this handsome new spot and shed their inhibitions. They swished their chopsticks in the yuzu juice-splashed scallop shell and clamored for the last slippery live scallop.

They moved swiftly for the creamy orange blooms of sea urchin, the pale pink ribbons of fatty toro tuna, and the blushing opaque sheets of pleasantly chewy, lemony madai, a.k.a. Japanese red snapper.

This isn't to say that Osaka is the region's best sushi emporium. The fish is always very fresh and of high quality, but it's often cut too amply for my taste. Great sushi doesn't need girth; it reveals the complex wonders of texture, temperature and taste in a single thrilling bite.

The assorted maki rolls can be awkward, too, with sweetly glazed strips of eel occasionally springing out like a defiant cowlick instead of clinging to the curve of the rice-and-seaweed roll.

But these are fine points. What's important is that Osaka exists at all, a cause for celebration among my Chestnut Hill friends who are always longing for another fine restaurant.

And Osaka is just that.

The appealing dining rooms, in a split-level former Xando coffee bar, are stylish but not showy, with muted wasabi green walls and light oak trim. The young staff is personable and enthusiastic.

There is an excellent affordable wine list with smart international whites, including a stony Austrian gruner veltliner and a tart Quincy from the Loire, as well as an excellent selection of sake. (Try the floral Kaori, at $42 a much better value than the $62 Shoin.)

Aside from learning on the job at his parents' other Osaka restaurant, in Wayne (and at their previous chain, Hoagie City), Kim, 28, spent an eye-opening year working for his idol, Masaharu Morimoto. And he has a good sense of what a mass-market restaurant should be.

So there is plenty to choose from here besides sushi. In fact, the cooked food from executive chef Michael Fee, a Morimoto alum, often outshines the menu's raw side. The kitchen isn't afraid to wander from the more traditional Asian flavors to contemporary ideas, and they usually work.

One appetizer layers downy nuggets of cooked striped bass and fluke with caramelized onions between crisp sheets of phyllo over a creamy butter sauce sparked with freshly grated wasabi.

A grilled appetizer of Texas-raised Kobe rib-eye is an indulgence at $14 for two ounces, but it melts the instant it touches the tongue. Add truffled foie gras for an additional $6, and wrap each slice of beef around a chunk of the foie gras for an extra burst of richness.

The same foie gras makes a perfect foil for the superbly tender grilled Angus sirloin entree.

The tuna carpaccio was less successful. The slices of seared fish got lost in peppery brambles of snipped pea shoots, and the phyllo base turned soggy in too much vinaigrette.

A seared tuna tataki starter was also a little bland. And the kitchen's teriyaki sauce was sticky-sweet.

No such problems, though, with the usuzukuri, a translucent white fan of thinly sliced raw fluke beside a citrusy soy ponzu sauce.

I also loved the mushroom salad, three heaps of sauteed criminis and shiitakes glazed in a balsamic-soy reduction and nestled in leaves of butter lettuce ready to be rolled into tubes. The crisp, spice-dusted fried calamari brought another deft fusion touch, a minty dip of shiso leaf-avocado pesto that both cooled and provided an herbal twist.

Noodles play a small but notable role at Osaka. The thick, chewy ropes of udon were satisfying, but the medley of seafood in the spicy broth was overcooked.

Simplicity was the essence of the cha soba's success. A striking green mound of springy, tea-infused buckwheat noodles was paired with a cup of sweet soy broth for dipping. It may be the most refreshing dish I've eaten all summer.

I can't say the same for the fragrant roasted lobster toban, which arrived in a ceramic casserole and was literally drowned in a pool of sake butter, or the butter-sauced lobster ravioli, which were delicate but didn't taste enough like lobster, or the miso-glazed black cod, which was like every other version of that dish I've tasted: sweet to the point of treacly.

Still, a few slips are part of any relatively new restaurant's evolution (as is trying to find some interesting desserts, which Osaka so far hasn't).

And this newcomer already does so many things right that it's easy to see which way it's headed. Especially when you behold a bento box piled high with perfect tempura-fried shrimp and crispy plugs of eggplant, or a thick slice of grilled Chilean sea bass so permeated with garlicky sake-soy marinade that its tang lingers long after the fish is gone.

Or how about the crabcake, as big as a CD and posed on a deep-purple pedestal of Thai sticky rice ringed with gingered tomato compote?

It's a taste of adventure - at once familiar and generous, yet exotic - and even the most conservative crowd shouldn't hesitate plunging into it.

Contact Craig LaBan at 215-854-2682 or claban@phillynews.com.