By day, the streets around Wilshire Boulevard in Koreatown are among the city’s busiest with thousands of office workers crowding the sidewalks, delivery vans fouling traffic, and noisy construction crews forever digging up pavement.

But in the evenings, the urban landscape takes on a different cast becoming a little-noticed world of restaurants, pool halls, karaoke parlors, cocktail lounges and discotheques amid the darkened highrises and steel-gated storefronts.

“This is like Hollywood for Koreans,” says Jenny Lee, a 27-year-old fabric buyer from Cerritos, nibbling on a spicy tuna hand roll at Nin Gen, a spare and stylish Korean-style sushi restaurant located in Chapman Market, an upscale shopping center on 6th Street.

With her multi-hued hair, dramatic eye makeup and dizzyingly high-heeled sandals, Lee would fit right in on the Sunset Strip or any of L.A.’s other trendy nightspots. But she prefers Koreatown.

“It’s like (Hollywood), but in a Korean way,” Lee said. “You don’t see a lot of Koreans hanging out on Melrose.”

The bulk of Koreatown’s new nightlife is centered just north of the Mid-Wilshire office district on Sixth Street, which some call the “Korean Melrose.” Even on weeknights, venues in the area tend to do a brisk businesses, with local office workers looking to unwind as well as twenty-something Korean trendies from across Southern California.

Koreatown is probably best known for its sprawl of smoky barbecue restaurants, noisy noodle houses and discount retailers along Olympic Boulevard.

But with a new generation of Korean American entrepreneurs steadily pushing Koreatown north from its traditional core at the intersection of Olympic and Vermont, a new Korean culture is beginning to emerge in Los Angeles.

Sixth Street “is like a mediator between the old generation and the next generation of Koreans,” says James Kim, a 41-year-old telecommunications executive who works on Wilshire Boulevard and frequents the area.

“This is a place for the younger generation,” says Kim, who emigrated to California two decades ago, and admits he often feels too old to be hanging out in the area. “But the atmosphere is like being in the middle of Seoul.”

That may be true, but it’s Seoul with a decidedly California twist, says Victor Han, owner of Classic Intercrew, a cafe in Chapman Market.

Eerily lit, with a Hollywood sign, posters of James Dean and Marilyn Monroe, and Fender Stratocasters artfully arranged on the wall, the cafe presents a curious collision of ’50s Americana kitsch and 21st century Asian chic.

“We’re picking up fashion and design trends from Korea, but we have to put it within the American culture of the Hard Rock Cafe or Planet Hollywood,” says Han, 31, who came to L.A. at the age of 16. “Our customers really seem to like it.”

The redevelopment of Chapman Market provides a good example of the changes sweeping through the area.

Built in 1929 in Spanish Colonial Revival style by the designers of the Mayan and Egyptian theaters in Hollywood, the large, ornate shopping center is known as one of L.A.’s first and grandest mini-malls. But by the early 1990s, the space was half empty, with only an Indian restaurant, a flower shop and a struggling grocery store as tenants.

Young Soo Hua, an insurance broker with an eye for real estate, noticed that the growing number of young Korean professionals moving onto Wilshire Boulevard had precious few retail or restaurant options in the neighborhood.

“There was no shopping on Wilshire Boulevard,” he recalls.

So in 1992, Hua purchased the property for $4.5 million, closed the market, subdivided the interior into 20 different spaces and began locating businesses to cater to a Korean clientele with money to spend.

Today, Chapman Market is fully occupied. Its courtyard is elegantly lit, with piped-in jazz music and a bubbling fountain. Most weeknights its parking lot is full; weekend crowds can number in the thousands, with people coming from as far as San Diego to patronize the center’s restaurants, cafes, retail shops, pool hall and noraebang studio.

John Lin, a 26-year-old car salesman from South Pasadena who emigrated from Korea just five years ago, says he dines or parties in the area several times a week.

With his slicked-back hair and fine Italian suit, Lin looks like an up-and-coming Westside executive. But he prefers Koreatown. “If I go to Westwood, my communication is not too good,” he says in fractured English.

Finishing his plate of sushi, Lin says he and his friends are planning to hit a music studio for some noraebang in which a group of people rent a small studio and sing to each other in relaxed environs, rather than singing before an audience in a karaoke bar.

About 30 noraebang studios have sprung up on or around Sixth Street, says Stephan Haah, a Mid-Wilshire real estate executive. The individual rooms rent for between $15 and $50 an hour and are especially popular as a place to sober up after the bars close.

Standing in a noraebang called Zeus Music Studio, Haah takes a deep breath, grabs a microphone and begins belting out an emotive power ballad by the popular Korean group called Green Belt.

“Koreans love to sing,” he says.

The successful conversion of long-troubled properties like Chapman Market may be remarkable, but it is by no means unique. Mid-Wilshire is dotted with establishments that were similarly derelict, only to be turned around by Korean entrepreneurs.

The former Hamburger Hamlet, for example, is now a Korean-owned sports bar called the Wolf and Fox that reportedly is favored by L.A. Dodger ace Chan Ho Park when he’s on the town. A cavernous space on the bottom floor of the Wilshire Collonade building is now Velfarre, the trendiest of Koreatown’s discotheques.

But perhaps the most dramatic example of Mid-Wilshire’s transformation is the Windsor, a bar and restaurant on 7th and Catalina streets.

Opened in 1932 on the ground floor of a brick apartment building, the restaurant’s dim lighting, dark wood furnishings, velvet wallpaper and miniature suits of armor typify the classic businessman’s watering hole of yesteryear.

When he purchased the Windsor four years ago, Joung Lee decided not to change a thing. In fact, besides the menu, the only thing that has changed at the Windsor is the clientele: Rather than the white Wilshire Boulevard corporate executives of yesterday, the Windsor is full of young Korean American office workers.

“Things are changing,” says Michelle Lee, a 32-year-old paralegal stuffed into a dark red vinyl booth with four of her friends.

Asked if she noted any irony in the Windsor’s transformation, Lee simply shrugs. “Why not,” she says. “It’s in the heart of Koreatown.”