(CNN) — Almost every year since she was a child, Hokkaido resident Naomi has looked forward to her family's traditional Christmas meal: a KFC "party barrel" brimming with salad, cake and lots of fried chicken.

"In Japan , it is customary to eat chicken at Christmas," says the 30-something Japanese woman.

"Every year, I order the party barrel and enjoy it with my family. I like the delicious chicken and the cute picture plate that comes with it as a bonus."

Naomi, who asked only to be identified by her first name, and her family are far from the only Japanese residents who enjoy KFC for Christmas dinner.

Every year since the mid-1980s, life-size Colonel Sanders statues -- dressed as Santa during the holiday -- have welcomed droves of locals and tourists alike across the country.

According to figures released by the American fast-food chain, KFC Japan pulled in 6.9 billion yen (roughly US$63 million) from December 20 to 25 in 2018, with lines out the door starting on December 23.

KFC Japan's busiest day is usually December 24, on which they usually sell about five to 10 times more than typical days.

"As Christmas approaches, KFC commercials play on TV -- they look very delicious. We order early then go to the store at the designated time to pick up our bucket," says Naomi.

"Those who don't reserve a bucket see themselves in long queues for hours."

'KFC was everywhere'

To better understand how and why fried chicken became synonymous with Christmas in Japan, we have to rewind a few decades.

Following a period of austerity following World War II in the 1940s and '50s, Japan's economy started taking off.

"Japan's economic power was going through the roof ... and people had the cash to indulge in consumer culture for the first time," says Ted Bestor, a professor of Social Anthropology at Harvard University who has studied Japanese food and culture for the past 50 years.

"Since the US was a cultural powerhouse at the time, there was huge interest in Western fashion, foods, trips overseas -- Japan was really opening up."

In 2012, Japan Airlines teamed up with KFC to offer "AIR Kentucky Fried Chicken" -- a limited-time collaboration that took flight just in time for the holidays. KAZUHIRO NOGI/AFP via Getty Images

While living in the center of Tokyo in the early 1970s, Bestor recalls seeing many foreign franchises popping up, such as Baskin-Robbins, Mister Donut and The Original Pancake House.

During this period of rapid globalization, Japan's fast-food industry expanded 600% between 1970 and 1980, according to "Colonel Comes to Japan," a 1981 documentary directed by John Nathan.

KFC -- then known as Kentucky Fried Chicken -- was part of the pack, opening its first Japan outlet in Nagoya in 1970.

By 1981, the chain had opened 324 stores -- over 30 a year -- and made roughly US$200 million per year, according to the documentary.

"It seemed like, suddenly, Kentucky Fried Chicken was everywhere," recalls Bestor.

Kentucky for Christmas

Christmas was, and still is, a secular holiday in Japan -- a country where less than 1% of the population identifies as Christian -- and in the 1970s many people didn't have established family Christmas traditions.

That's where KFC came in. The company launched its "Kentucky for Christmas" marketing campaign in 1974 and the first iteration of the party buckets soon followed.

Some reports say that Takeshi Okawara, who managed the country's first KFC and later became CEO of KFC Japan, falsely marketed fried chicken as a traditional American Christmas food to drum up sales.

But according to KFC Japan, Okawara went to a Christmas party dressed as Santa. When the kids loved it, he saw a business opportunity.

Meanwhile, in 2017, the host of "The Rising Sun Show" -- a 30-minute TV show produced by the U.S. Army Garrison Japan Public Affairs -- interviewed a KFC meister, who said the concept caught on after a foreign customer asked KFC to deliver fried chicken in a Santa Claus costume on Christmas.

Other sources say Okawara simply overheard westerners seeking a replacement for turkey and thought up a worthy substitute.

Conflicting origin stories aside, KFC managed to capture the imagination of Japanese diners and create a national phenomenon.

Catchy Christmas marketing

A Japanese man, photographed in 2015, poses after buying KFC for his family on Christmas Eve in Tokyo. Taro Karibe/Getty Images

Of course, "Kentucky for Christmas" didn't catch on without a substantial advertising investment.

A typical KFC Christmas ad from the 1970s or '80s likely would have showcased a family enjoying a luscious feast of golden, fried chicken as the song "My Old Kentucky Home" played in the background.

"For anybody who grew up in America, you immediately knew that 'My Old Kentucky Home' is not a Christmas carol," says Bestor.

"But [these were] really beautifully done campaigns that linked fried chicken with Christmas as well as Christmas with the idea of consuming luxurious foods. Obviously, the idea took hold."

Such ads positioned KFC as an elegant, authentic way to celebrate in true American style, even if that wasn't quite true to reality.

"The festive commercials are what initially made me want to try to eat KFC for Christmas," Shuho Inazumi, a librarian who lives in Iwakuni on Honshu island, tells CNN Travel. "I'm from the countryside and there weren't too many KFCs around, so KFC was considered cool."

Familiar flavors

A screenshot fromf this year's KFC Japan Christmas TV commercial, in which a group of friends is surprised to discover they've all shown up to dinner with buckets of fried chicken. KFC Japan/Youtube

But to chalk up such lasting success solely to smart advertising wouldn't be totally fair -- it can also be attributed to KFC's compatibility with existing cultural norms.

For instance, Bestor says KFC is similar to a popular traditional Japanese dish called karaage, which comprises small pieces of panko-breaded, deep-fried meats like chicken or fish.

"In terms of flavor profiles, Kentucky Fried Chicken is not a stretch -- it's not a new taste or something that people have to get accustomed to," he says.

Likewise, the tradition of sharing a big "party barrel" of fried chicken, coleslaw and cake fits neatly into Japanese dining culture.

"Being able to share food is an important social practice in Japan. So a bucket of fried chicken both tastes familiar and fulfills this desire to eat together," he adds.

This year, KFC is once again luring diners with appetizing imagery of dishes like golden drumsticks, festive red cakes and glossy smoked chicken thighs. And while the company's Christmas packs and party barrels remain wildly popular, some Japanese people have formed new traditions over the years.

"When I used to buy KFC Christmas, there weren't a lot of holiday food options," says Inazumi.

"Now I can find recipes for roast beef, ham, and roasted chicken online, go to a potluck with friends, or visit a Christmas buffet at a hotel."

For Naomi, it's not a tradition she plans to give up anytime soon.