The reason you’re eating Japanese-inflected Italian food from the trio behind some of Washington’s most popular ramen stops boils down to a design feature they inherited from the Chinatown restaurant that preceded their new Tonari.

The oven made them do it — specifically the beautiful domed pizza cooker left behind by Graffiato. “We couldn’t think of taking it down,” says chef Katsuya Fukushima.

He and his business partners, Daisuke Utagawa and Yama Jewayni, own two other restaurants on the block, the adjacent Daikaya and Bantam King around the corner, plus Haikan and Hatoba in the Atlantic Plumbing Building and the Navy Yard neighborhood, respectively. Ahead of opening their fifth venue, the owners referred to the unnamed space as “next door” so often, Jewayni finally asked how it translated in Japanese. Tonari, he was told. The word stuck.

The concept has a name in Japan: wafu Italian. “The Japanese are good at borrowing from others and making it their own,” says Fukushima.

Good products help. The noodles for Tonari, made with flour from Hokkaido, come from the same company in Sapporo, Nishiyama Seimen, from which the owners buy their ramen joints. Expect some nice chewiness from the pasta. The dough for the pizza relies on flour milled in Japan and a base finished by Lyon Bakery in Maryland. The result yields a cross between focaccia and Detroit-style.

Consider a few small plates to start. Slivered snow peas, edamame and a drift of ricotta, a salad tied with yuzu vinaigrette, make a bright beginning. Tonnato and roasted avocado isn’t a marriage that occurred to me before. Trust me when I tell you the curtain of tuna-anchovy sauce over the buttery fruit is inspired, as are the grapefruit pieces nestled under the avocado, a surprise spark.

I’ve yet to encounter a pasta I wouldn’t want to twirl again. But if you’re looking for something you won’t find in an Italian restaurant, the springy tagliatelle tossed with baby sardines, olive oil and red pepper flakes rivals the long, thick bigoli made creamy and rich with a puree of sea urchin, white soy sauce and kombu (seaweed) stock. Tonari also makes a meaty Bolognese that gets its pleasant funk from natto, or fermented soybeans.

There’s no other pizza in town quite like Tonari’s. The seductive crust — pillowy in the center, crisp on the edges, faintly sweet (like Japanese bread) — is aided by a pan that’s brushed with the same kind of rice oil used to cook tempura.

“You can get clam, pepperoni, Hawaiian pizza anywhere,” a server says one night, pushing us instead toward a creamy topping of tangy Kewpie mayonnaise and canned corn, along with scallions and brick cheese. A companion compared the combination to dessert, and I agree, it’s too sweet for dinner. Savory is more my speed: sliced pepperoni with pickled jalapeños or a scattering of clam, edible seaweed and (lots of) garlic.

Utagawa says Tonari is “the least Japanese of our restaurants.” Yet the design renders it “the most Japanese looking.” Host to the showy tiled pizza oven, the ground floor is bright and bustling. My preference is a perch upstairs, where half the seating obliges diners to slip off their shoes, drop to the floor and tuck their legs into spacious holes beneath low tables. (Servers get a workout with all the bobbing up and down to fill water glasses and crouching to add and remove plates.) Standard tables populate the rest of the second floor, set off with a handsome moss garden and alive with the sound of jazz.

The space is certainly familiar to the owners, who looked at the building as a home for Daikaya before opting to open the ramen source next door.

An evening of pasta and pizza are best followed by something light for dessert. The kitchen obliges with a refreshing grapefruit granita covering vanilla ice cream, a combination that goes down like a creamsicle (easily). At the table, a server gives the confection a spritz of grapefruit perfume, a sensory enhancement Fukushima recalls from his time at the novel Minibar by José Andrés, and yet another reminder you’re eating somewhere deliciously different.

707 Sixth St. NW. 202-289-8900. tonaridc.com. Pizza and pasta, $12 to $17.

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