SISTAR19 is made up of Bora (left) who raps and Hyorin who sings. The duo has held the No. 1 spot on the K-Pop Hot 100 four weeks with their new single "Gone Not Around Any Longer."

Last year, "Gangnam Style" defined K-pop. Not only was the PSY smash the No. 1 song on 2012's year-end K-Pop Hot 100 chart, but it brought K-pop culture to a global audience. But in 2013, despite PSY's success, most Korean artists didn't succumb to copying to hit the top of the charts; opting for alternate routes to land themselves among 2013's top K-Pop Hot 100 entries.

YEAR-END K-POP HOT 100 CHART

The year kicked off on an innovative note when Girls' Generation dropped "I Got a Boy" on New Years Day. Jam packed with clunky electro-pop, minimal drum'n'bass and drastic tempo changes, "I Got a Boy" was 2013's first new No. 1 -- ending Lee Seung Gi's record-breaking, six-week reign.

The standard was set high, but acts rose to the chart challenge.

While the genre mashing in "I Got a Boy" was smoothed over with peppy, oh-so-catchy hooks, other acts found success going darker: Sistar19's melancholic "Gone Not Around Any Longer" held the year's longest run for K-Pop No. 1 with four weeks at the top - and now it takes its place as the K-Pop Hot 100's top song of 2013.

BAE CHI GI and Ailee's moody collaboration, "Shower of Tears" was a winter smash and has come in at No. 4 on the year-end K-Pop Hot 100 tally. Monster rookie Lee Hi compared herself to a thorny "Rose" on her third chart topper; all of which utilized darker lyricism and chilling arrangements to hook listeners.

But that doesn't mean K-pop didn't have loads of fun either. Girl groups like 4Minute, f(x) and SISTAR turned up the tempo to snag K-Pop Hot 100 No. 1s during the year. And both 4Minute ("What's Your Name?") and SISTAR ("Give It To Me") have landed on the 2013 year-end K-Pop Hot 100 chart, at No. 6 and No. 8 respectively.

THE BEST OF 2013: THE YEAR IN MUSIC MAIN PAGE

The K-Pop Hot 100 also saw much-missed veterans return with feel-good tracks: Cho Yong Pil's "Bounce" now owns No. 2 on the 2013 year-end K-Pop Hot 100. Lee Seung Chul brought bouncy synths for "My Love" and has landed at No. 3 on the 2013 K-Pop list.

Despite the colorful variety, the year's most unexpected success story comes from one who capitalized on PSY's hitmaking formula: Crayon Pop with their viral hit, "Bar Bar Bar," which earned the No. 9 slot on the 2013 year-end K-Pop Hot 100.

The rookie girl group hadn't even charted on the K-Pop Hot 100 with prior singles, but "Bar Bar Bar," with its quirky video, fun dance and catchy hook, sent the track on a slow, six-week rise to the top during the year. While the adorably-quirky "straight-five engine dance" didn't catch international eyes a la PSY's horsey dance, it did captivate the K-pop scene to shoot the girls to domestic stardom.

Last year, it was easy to pinpoint a track defining the 2012 in K-pop. One can't do that as easily in 2013. K-pop listeners showed lasting love for soundtrack ballads and uptempo bangers, supporting veterans and newcomers, embracing viral hits and honoring top vocal performances and proving that an artist showing a different side of themselves -- whether as a soloist, in a sub-unit or via an innovative collaboration -- can lead to big chart success.