Before there was Shokudo, before there was Momomo, Okonomiyaki Kai and Tsukuneya, there was Bistro A Un. Opened in 2003, this dark cocoon, hidden behind the ground-floor elevator at McCully Shopping Center, was the first of the newfangled, stylish izakaya, mixing traditional dishes with kooky hybrids that raise eyebrows but usually work. Fried cheese, anyone? How about a quasi eggplant parmesan (actually made with mozzarella and cheddar) with your natto-topped squid?

Yet the pioneering place remains under the radar. And that's how regulars like it. On a recent evening, four young guns, who divulged that they drop into Bistro A Un once a week to graze and gather around a bottle of shochu, said they prefer the spot to Shokudo, specifically because it's low-key. "And the food's good," said one.

And he's right. Chef Kazu (he doesn't seem to use his last name) was previously at high-end kaiseki restaurant Kyo-Ya. That explains the crisp presentation for even the most humble dishes.

Yes, the menu is about small plates to go with glass after glass of Kirin and fizzy chuhai Calpico cocktails, but that doesn't mean just edamame and yakitori.

Kazu makes a refreshingly unadulterated 'ahi tartare — a disc shaped from luxuriously ripe avocado bits topped by a disc shaped from bits of impeccably fresh 'ahi. No mayo, Sriracha sauce, tobiko (flying-fish roe) or other adornment. Naked, the two kinds of creamy are perfect. But if you need some flavor accent, Kazu decorates the plate with alternating dots of shoyu (thickened with cornstarch so that it seems like a reduction) and pesto.

He cleverly fashions "spring rolls" using yuba (tofu skin) as the wrapping, stuffing it with minutely sliced-and-diced carrots, bamboo shoots and shrimp.

You can order bacon-wrapped scallops (a sweet kiss between sweet and salty), lobster, and foie gras (two small pieces with a demiglace and daikon for $19.75, the highest price on the menu) — and Kazu does them justice.

But going lowbrow here is just as good. The tonkatsu just may be the best in town. Ultra-tender pork with a well-seasoned ultra-light skin of panko is served with omurice, that peculiar brand of Japanese fried rice made with ketchup (remember "Tampopo"?). This one comes as a dainty dome coated with a thin, shiny omelet.

Bistro A Un's deep-fried yaki-soba just happens to be the best cake noodle in town. The nest of crackling noodles is topped with high-quality bits of shrimp, scallop, squid and mushroom in a subtly earthy dashi-like sauce that puts to shame that mucousy, tasteless film served at all too many Chinese restaurants.

The okonomiyaki, a thick, rich cabbage-flecked flour pie topped with the requisite squiggles of mayo and sweet, brown sauce, rivals those of Okonomiyaki Kai, which specializes in the traditional street food.

According to manager T.J. Gannon, Bistro A Un owner Shinji Makigano used to own — and cook at — a string of modest Japanese restaurants in San Francisco. He devised most of the menu. And the tongue-twisting name — which, I thought was a play on French, as in menage a trois — is from a Buddhist term describing the state two people reach when they are around each other so long, they no longer need words to communicate, according to Gannon.

After the buzzing teen bubble-tea scene outside, entering the distressed metal doors (the windows are shrouded by what seem to be mod shower curtains), into the low-lit room with pale-green silk on the walls, recessed ceiling and pendant lamps overhead, and a banquette slung across one end, is like returning to the womb. Albeit one with a nine-stool bar and perky, pretty servers. You're sequestered from the outside world for as long as you want — Bistro A Un is open until 2 a.m.; the kitchen serves until 1 a.m. And in case you're wondering, it's pronounced ah-oon.

Reach Lesa Griffith at lgriffith@honoluluadvertiser.com.