WITH its spare red-and-white sign, glowing macro-brew neons and mild sports barlike exterior, it's not immediately apparent what type of restaurant Oso wants people strolling by to think it is.

But that's because the people who actually go inside already know.

"Look, this is how much Koreans don't want white people to find their food," joked Steve Cho, gesturing to the unassuming strip mall, closer to a church-quiet residential Cheltenham block than bustling Cheltenham Avenue. "We're on some corner way off the street."

The sit-down, specializing in the cuisine of Jeollanam-do province, where Cho still has family, is an incredible restaurant. A huge spread of complimentary banchan, or meat, fish and vegetable side dishes, drops seconds after you order. Hot and sweet glazed monkfish with bean sprouts, funked-out fermented tofu soup and a deep-flavored pork intestine stew heated to raging boil and spooned out at the table are just three of innumerable family-style entrees on the Hangul menu.

Tote along your own soju, the heavily consumed distilled spirit, and the staff will hook you up with enough Coors Light tallboys to make "somek," a dangerously easy-to-drink soju/beer cocktail with a reputation for inspiring late nights.

But I would've never known about Oso had it not been for Cho, owner of Old City's Customs Coffee House, and his musician friend Christopher Lee, both of whom have taken it upon themselves to lead me, a nonspeaker, through their favorite North Philly restaurants over the years.

It made me wonder: Is there a larger mentality at play - an inherent protectiveness of cuisine and custom, and/or a built-in wariness of outsiders - that characterizes Korean cuisine in America, specifically Philadelphia?

Korean food accessibility

Korea has been a relevant topic in the local arts-and-culture discourse recently, thanks to the Philadelphia Museum of Art's "Treasures From Korea," a beautiful exhibit highlighting artifacts from the country's Joseon Dynasty, which runs through May 26. With Granite Hill, the museum's restaurant, presenting a modernized Korean menu, I started thinking about the huge differences between Korean food in this accessible context versus the unbridled cooking up in K-Town - soulful, authentic and engrossing, but nowhere near as accessible without a guide leading the way.

Why isn't there more in between?

"We're spreading it, but I think we're still holding some stuff back," said Cho, who previously ran a Korean restaurant called Meju next to his cafe. "We're still protective of it. There's lots of traditions that Americans don't yet understand."

But where does that leave non-natives eager to educate themselves?

"It's never that we're trying to exclude," said JaeHee Cho, the Korean-born sous chef of South Street's Serpico. (His boss, chef/owner Peter Serpico, is also of Korean descent.) "But for the most part, the community is amused and fascinated when people of other cultures become smitten with the food. It still surprises us a little bit."

The next big thing?

Speaking as one of those smitten people, I've long felt that the cuisine, built on a backbone of fermentation with a staggering variety of regional techniques and dishes, should earn more love in the mainstream, and I'm not alone.

"We believe that Korean cuisine is now on the cusp of exploding everywhere, like Japanese cuisine in the '80s and '90s," said Mee-Kyoung Kim, of the Korea Agro-Fisheries & Food Trade Corp., responsible for promoting exported Korean goods to buyers in cities like Philly. They've sponsored a Korean cuisine course at Drexel. "You can actually find kimchi in supermarkets in most metro areas."

One local who's been successful in planking the wide gap between tradition and innovation is Yong Chi, who opened Giwa, on Sansom Street, almost eight years ago. Originally from the city of Kunsan, the Web-designer-turned-self-taught-chef opened the quick-serve spot, specializing in dishes like dolsot bibimbap (a rice-based dish in a fiery-hot, sizzling stone bowl), plus fusion items like Korean-inspired tacos.

"If we want to make Korean food mainstream, it's going to take a long time," Chi said. "And for us to make it truly mainstream, we have to make adjustments."

For him, this translates into an English-speaking staff, more familiar menu items and ready-made products like his own "Yong's Kitchen" gochujang, a spicy-savory red chili sauce that can be used as a dip, marinade, stir-fry base or glaze. He hopes the sauce, carried in local Whole Foods stores, will appeal to America's many sriracha fanatics. (Saffron Road, an all-natural food company, is targeting this market, too, with its recently released line of frozen Korean dishes.)

Do Koreans eat there?

But Chi still seems to be in the minority, along with a handful of institutions like Seorabol and Kim's, as far as his desire to widen the relevance of Korean cooking, at least in Philly.

"A lot of these restaurants are frequented by Koreans and only Koreans, and they're not into marketing their food to non-Koreans," said Matt Rodbard, contributing editor of foodrepublic.com. With Deuki Hong, one of several New York-based chefs focused on expanding the scope of Korean cuisine, he's been exploring Korean communities throughout the states researching Koreatown USA, a cookbook that will be out in 2015.

Yet Rodbard emphasizes that he's never experienced trepidation from Korean restaurateurs when he strolls in for dinner as the only Caucasian for miles asking for gamjatang, a pork neck soup made with potato, perilla and black pepper. "They are thrilled that I want this highly traditional Korean dish . . . incredibly happy that someone knows about the cuisine that they're so proud of," he said.

Ultimately, that palpable sense of pride is what's going to propel Korean cuisine beyond its native borders and into a wider consciousness - it's just a matter of harnessing that momentum.

"Mainstream American culture starting to embrace Korean food is surprising to my father's generation," said the chef Cho. "We're very proud of the food, and we want to keep the integrity of it alive.

"I don't think it's on the priority list to try and introduce it to other cultures - even though I think it should be."