South Korean artistic swimmers Byun Jae-jun and Kim Ji-hye have only been training and competing as a duo since April. But their friendship goes back much further -- to their elementary school days, in fact.

Byun and Kim, now 20 and 19, were in the same class in first grade. Though they weren't doing artistic swimming then, they developed quick friendship that has lasted over a decade. And after wrapping up their first world championships together here on Saturday, they credited their personal connection with helping them achieve quick success.

Byun and Kim finished 10th in both the mixed duet technical and mixed duet free events at the World Aquatics Championships. That they reached the finals in both events was a major coup for South Korean artistic swimming, with Byun still the only male artistic swimmer in the country.

Speaking to Yonhap News Agency at Marine Messe Fukuoka Hall A in the port city of Fukuoka, the two said the key to their partnership is to keep their personal ties and athletic pursuits separate.

"We're treating it as business," Byun said, when asked if there was any awkwardness between the two.

Finishing Byun's thought, Kim chimed in, "Away from the pool, we are still friends."

Byun added, "When one asks the other to smile (during a routine), you smile. And when one asks the other to frown, then you do just that."

Whatever disadvantages may exist with having a close friend as a partner, Byun said benefits far outweigh them.

"One downside to working with a friend is that we can get emotional with each other sometimes, because we're so comfortable in each other's company," Byun said. "If I am not close with someone, I wouldn't be so honest and blunt, and I would maybe hold things back a bit."

But the flip side of it is, in Kim's words, "We don't hold grudges or let our feelings simmer under the surface. We talk things over and move on right away."

Byun took his turn finishing Kim's thoughts, saying, "We may yell at each other from time to time, but we always make up pretty quickly."

World Aquatics, the governing body of water sports, opened the doors to male artistic swimmers at the worlds for the first time this year, as the male solo and mixed duet events made their debut.

Byun said he had been preparing for the solo events but ultimately decided to focus on the duet competition with his friend.

"If I had competed in the solo events here, I am confident I would have won a medal, and at least finish around fourth or fifth," Byun said. "It was frustrating to watch the men compete and not be able to be there with them. But I also know that it would have been tough to do both the solo and duet events, since this was my first world championship."

Byun's mother, Lee Ju-young, was a competitive artistic swimmer, too, and won a junior event in 1993. But his father is the more famous parent.

Byun Jin-sub was one of South Korea's most beloved crooners in the late 1980s, churning out hits and sweeping up end-of-year awards with ease. The junior Byun, who once performed a program set to one of his father's ballads, said he still doesn't fully grasp just how popular his father was back in his days.

The father didn't make the trip to Fukuoka. Only Lee did, and the son said his mother provides more of moral support rather than technical tips.

"Whenever I told her I was going through a hard time, she said, 'You have to overcome adversity to take the next step as an athlete,'" the young Byun said. "She takes a lot of interest in my programs, and she has always been very positive. I don't think she ever did any nitpicking." (Yonhap)