Masu Izakaya is named for the square boxes, or masu, that Japanese drinkers perch their glasses of sake in. Once used to measure out rice, the boxes catch the liquid that spills over the glasses’ sides from overgenerous pours. At the end of the night, drinkers swallow the lukewarm accumulated slosh.

For the price of a creamy shrimp tempura roll ($10), restaurant regulars can buy a personalized masu, dozens of which already sit on shelves behind the bar. Marked up with names and slogans, they’re a low-key take on the personal wine locker.

Styling itself as one of Chicago’s first Japanese gastropubs, Masu Izakaya is the newest offering from chef Steven Song, formerly of the Gold Coast’s now-defunct Tsunami.

Dominated by a marble-topped bar and windows that open onto the street, the restaurant’s wood-paneled front room has a bistro feel, as though patrons might be expected to gulp their sake at the bar, standing.

Though there’s a serenely lit room in back, the sunny storefront is more conducive to enjoyment of the restaurant’s laid-back fare. Small-plate foods ranging from traditional sushi-house dishes to less-familiar Japanese bar snacks are ordered in rounds, as drinks will be once the place receives its liquor license (for now, it’s BYOB, without a corkage fee).

The food is pointedly simple: concise menu descriptions tend to describe exactly what you’re going to get. Two grilled whole squid ($7) are sliced into flavorful, gently chewy rings. A tempura dish including gently battered bell peppers, onion and lotus root ($5) served with a tangy orange sauce is tasty and worth the bang for your buck. A mild dish of grilled salmon ($7) and gummy rice served in a characterless green-tea broth is less successful, despite an earthy sprinkle of toasted nori.

One of several piggy offerings is the delicious braised mugi fuji pork belly ($8), sweet and briskety in a scallion-steeped broth. Come prepared to steer away from too-familiar sushi. Maki rolls, including the heavy, panko-choked shrimp tempura ($10) and a rice-heavy spicy tuna ($7) are passable, but far less interesting than either Masu Izakaya’s other offerings or the maki rolls at other, more focused sushi restaurants.

It remains to be seen whether Masu Izakaya turns out to be more about style than substance, but its relaxed room and continuous stream of hot and speedy Japanese dishes make it an excellent place to gird your stomach for a night of after-work drinks, sake or otherwise.