Exterior of Kanji-Kana, a Japanese restaurant on the third floor of a downtown D.C. building. (Deb Lindsey /For The Washington Post)

The sign in the window stopped me in my tracks. It held out the promise of donburi, ramen and bento boxes — the power trio of casual Japanese dining — if only I would drag my bones to the third floor of this apparently elevator-less building on Vermont Avenue NW. I sort of resented the implied bargain: I’d have to exercise for my lunch.

But the rewards were apparent the moment I finished my stair workout: The entrance to Kanji-Kana looks like a doll house inflated to adult proportions. Flower boxes lie at your feet. A picture window, its pink drapes pulled back, offers a peeping-Tom view of the interior. Once you’ve made eye contact with someone inside, you are practically required to walk into this “home,” lest they deem you a stalker lurking outside the window.

Once inside, you feel more like you’ve entered the brain of a Japanese illustrator than the living room of a house. The two-toned walls — mostly tea green but with a strip of pastel pink around the ceiling — resemble the background panels of an anime series. A television next to the beverage cooler provides a continuous loop of kodomomuke cartoons, which are aimed at kids but seem to hypnotize anyone older than 4. You half expect Hello Kitty to take your order.

Kanji-Kana (named for the character groups that comprise the modern Japanese writing system) comes from the same team behind Tonton Chicken, the beloved lunch spot on the ground floor. The two establishments share more than a building. They share an operating philosophy that’s at once dated and timeless: Target the largest possible pool of office workers with food that’s tasty, affordable and none too foreign. Think of Kanji-Kana as the old downtown deli rejiggered for the ramen generation.

Chef Fon Kongsukh and co-owner Matt Ditta and in the dining room at Kanji-Kana. (Deb Lindsey /For The Washington Post)

The very breadth of Kanji-Kana’s Japanese menu suggests a deli’s comforting inclusiveness, not an artisan’s alienating obsessiveness over a single dish. No one here will give you the stink eye if you don’t know the difference between a cloudy paitan and a clear chintan broth. This is a safe place for the beginner, free from the judgments of the urban dineratti and their insufferable knowingness.

The chef at Kanji-Kana is something of a newbie herself: Fon Kongsukh is not Japanese. The Thai chef and partner is not even one of those Japanophiles who has immersed herself in the country’s ramen culture for years before opening her own slurpatorium. Kongsukh has a background in institutional food service, working at the kind of corporate cafeterias where diners do not genuflect before the person in chef’s whites. You either develop your chops fast at these places, or you exit the premises in tears. Graduates of these demanding kitchens know how to cook, period.

For Kanji-Kana, Kongsukh is collaborating with co-owner Sumiko Abe, who guides the chef on the finer points of Japanese cooking. The pair have put together a smart, efficient menu, stuffed with good, easygoing fare from one end to another. They take pains to focus on the Japanese flavors that have wormed their way into the American mainstream — even if those flavors are sometimes at war with one another.

Tonkotsu ramen with chashu. (Deb Lindsey /For The Washington Post)

Take, for instance, my order of miso ramen with chicken teriyaki (one of five proteins available for pairing with a soup base). The miso broth is an opaque vegetarian elixir that, in my case, was supplemented with the floral spice of pickled ginger, an added topping. I could have slurped that broth all afternoon, using the fresh springy noodles as my delivery system. I could have, that is, as long as I avoided the chicken teriyaki: The dry breast meat had none of lacquered sheen and grill flavor you expect. It was an alien presence, a distraction, an organ grinder at Cirque du Soleil.

I had a similar experience with the tonkotsu ramen, a rich, cloudy, paitan broth built with chicken and pork. I added luxuriant, soy-flavored slices of chashu, cut from a roll of slow-roasted pork belly. It was all divine — save for the addition of a hard-boiled egg, sliced in half to reveal its overcooked, green-tinted yolks. These bloated ovals drifted in my soup like floaters on the East River. With nary a drop of yolk to enrich the broth, I was left with a standard hard-boiled egg, unseasoned, which contributed a kind of egg-salad essence to the broth.

One thing you’ll notice about Kanji-Kana is that the kitchen relies on the same proteins across multiple categories. So if you like the chashu in your ramen, you’ll probably enjoy it in your bento box or atop your donburi rice bowl, too, both of which come with pickled veggies to cut the richness. Personally, I’d leave the pork belly in the ramen, where it belongs. I prefer my donburi with barbecued unagi, all sweet and salty, or with shrimp tempura teriyaki, these crunchy lengths of deep-fried crustacean marked with parallel lines of the Japanese sauce, a double-barrel blast of the fifth taste. The latter donburi is so irresistible they should call it: Come to Umami.

Unagi donburi. (Deb Lindsey /For The Washington Post)

The lone misstep with the bento boxes is the cured salmon, paired with tobiko roe and a bracing honey-wasabi sauce, two carnival barkers who shout over the sweet, soft-spoken slices of fish. Fortunately, even if you order the salmon, the bento box doubles as a giving tree: It comes with several items found on the appetizers list, including a delicate miso soup, a lovely deep-fried vegetarian spring roll and these ghostly, Japanese-style shumai, which I could pound down like shrimp poppers at a sports bar.

No one should walk away hungry from Kanji-Kana, which knows that Americans may embrace Japanese minimalism in design, but when it comes to food, we still prefer pure volume. Now that I think of it, you may want to schedule a post-lunch stairs workout, too.

If you go

1018 Vermont Ave. NW, third floor.

Hours: Monday-Friday 11:30 a.m. to 9 p.m.; Saturday and Sunday noon to 9 p.m.

Nearest Metro: McPherson Square, with a short walk to the restaurant.

Prices: Soups, salads and appetizers, $5-$8. Bento boxes, donburi and ramen, $9-$14 (not including extra toppings).