Chart highlights from the K-Pop Hot 100 and beyond featuring TVXQ!, Brown Eyed Soul, Super Junior, SISTAR, Busker Busker

The lead single from the repackage version of IU's impressive "Modern Times" album, the bouncy "Friday," debuts at No. 1 on the K-Pop Hot 100 -- earning the 20-year-old her fourth chart topper. The feat ties her for the most No. 1s on the chart with girl group SISTAR and indie pop-rock act Busker Busker.

Written and composed by IU, "Friday" is mid-tempo, acoustic swing-pop number that features the singer's own guitar playing. The track features Jang Yi-Jeong, a member of rookie boy band HISTORY, who compliments IU's light vocal delivery.

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The throwback sound falls in line with the rest of the throwback-inspired "Modern Times" LP that features elements of bossa nova, folk, Latin grooves and jazz on the lead single, and IU's third No. 1, "The Red Shoes."

Furthermore, IU sending "Friday" to No. 1 means the solo singer ties the record for acts with most No. 1s on Billboard's K-Pop chart.

Since its September 2011 introduction, IU earned earned her first chart topper on Dec. 17, 2011 with "You and I," meaning it took the soloist two years and one month to snag four No. 1s. Comparatively, it took Busker Busker just under two years from October 2011's "Tokyo Girl" to last October's "Love, At First." Meanwhile, it only took SISTAR one year and 10 months to hit the goal from September 2011's "So Cool" to last July's "Give It to Me." The race is on for who can pull ahead with a fifth.

IU at No. 1 sends last week's chart topper, Jellyfish Entertainment's "Winter Confession," to the No. 2 slot.

Brown Eyed Soul, made its successful comeback with "Always Be There" in late October. On Dec. 19, the quartet released its highly-anticipated EP, "Thank Your Soul," landing three out of four songs on the K-Pop Hot 100 this week. The lead single "You" debuts at No. 3, while "You Are Beautiful" sits at No. 24 and their "Philly Love Song" at No. 48.

"You" is an R&B ballad that showcases the group's perfect synergy, based on 10 years of performing together. Lead singer Naul's powerful vocals, mixed with his bandmates' sensuous harmony, makes for a classic tearjerker. The music video (watch below), featuring actor Kim Young Kwang with Kyung Soo Jin, takes viewers on a couple's trip down memory lane after they bump into each other by accident. On a brighter note, "You Are So Beautiful," expresses a man's excitement about his new found love with a '70s mood, while "Philly Love Song," is a rhythmic, feel-good, Philly soul-inspired number with hi-hat fills and disco beats, that talks about a man who doesn't know how to approach his new love interest.

No Holiday No. 1? Notably, it looks like K-Pop Hot 100 will not see a song take over this holiday season. Since the chart's mid-2011 inception, every year saw one single break records by taking over the charts in the midst of winter. When 2011 transitioned to 2012, IU's "Good Day" spent five weeks at No. 1 -- a K-Pop chart record at the time -- starting Dec. 17, 2011 and ending on Jan. 21, 2012. Fast forward to the 2012-2013 holiday season and Lee Seung Gi's "Return" hit No. 1 on Dec. 8, 2012 and refused to let go of the top until Jan. 19, 2013 -- an unmatched six-week reign on top.

This December has seen a new No. 1 each week (from rapper San E, SISTAR vocalist Hyorin, male soloist Seo In Kuk, Jellyfish Entertainment's aforementioned chart topper and IU). With a slew of much-anticipated comebacks set for January -- including Ailee, Girl's Day, U-KISS and K-pop vets TVXQ! and Rain...all in the same week! -- expect great chart competition in the quickly-moving K-pop industry, unless one can truly rise above the others.

K-Pop on Other Billboard Charts:

--Japan Hot 100: TVXQ!'s "Very Merry Xmas" rises to No. 15, from No. 27, in its fourth week on the chart. U-KISS' "Fall in Love" debuts at No. 37.

--YouTube: PSY's "Gentleman" falls to No. 25, from No. 22, in its 34th non-consecutive week on the chart.

--World Digital Songs (Highlights - Full Chart Available to Billboard Subscribers): PSY's "Gangnam Style" is the highest-selling K-pop song in America at No. 2 this week. "Still You," a collaboration between Super Junior members Donghae and Eunhyuk (watch below), debuts at No. 5.