K-pop may center around music, but it’s really an all-encompassing media package that comprises video, fashion, makeup, choreography, and concept (among dozens of other factors). The album, then, is a strange and insular unit of measurement to apply: How are you supposed to gauge the success of a work when all you’re looking at is a cross-section? Still -- since there’s no denying that K-pop is a significantly musical venture, there will always be value in tracing its sonic evolution, and the album is still the best way to do that. It’s a fortunate fact when you consider that the story of K-pop music in the 2010s reads more like a riddle than a novel. Obviously, it’s not far-fetched for a 2010 track to sound like it’s from a different universe than one released in 2019, but there’s a much more defined musical shift in the decade, originating somewhere around 2015, that spontaneously erupted into a bottomless schism separating two very different musical attitudes in K-pop. It’s the distance between the angsty chaos of BTS’ Dark & Wild (2014) and the heady sonic explorations of its followup, The Most Beautiful Moment in Life, Pt.1 (2015). It’s the gap separating 2NE1’s meteoric potential as realized in Crush (2014), from the group’s devastating disbandment just two years later.

READ MORE The 100 Greatest K-Pop Songs of the 2010s: Staff List Pin it on the glimpses of global success that acts like Psy and Girls Generation afforded, but when K-pop’s record labels set their sights on global appeal in the early decade, they reached out for it in their music. Producers turned up the hip-hop and R&B influences. Synth sounds blossomed from electro-pop to encompass UK garage, house, and synth-pop. Budgets expanded. Everywhere, Korean labels scrambled to find the perfect mix between Western influences and their own instincts. What resulted was a decade of K-pop music obsessed with experimentation and reinvention. The period’s best albums construct a brilliant mosaic of past and future, West and East, sophistication and camp, avant-garde and earworm. To commemorate the decade in K-pop, Billboard has compiled a selection of the era’s 25 greatest albums. 25. G-Dragon, Kwon Ji Yong (2017)

After making a career for oneself as the king of K-pop extravagance, G-Dragon’s Kwon Ji Yong arrived in 2017 to introduce the world to the man wearing the mask. A little bit evocative, a little bit brash, and all around introspective, the EP was a five-act show starring Kwon as G-Dragon, or perhaps G-Dragon as Kwon, for the first time blending his private and public personas. The comedic “Middle Fingers-Up” sets the tone before moving into the abrasive “??? (BULLS--T)” and its take down of his haters. The dire “Super Star” is both melancholic and punchy, as he sing-raps about the feeling of being alone at the top. “Untitled, 2014,” the album’s single, is a full-blown, piano-backed ballad over which Kwon sings mournfully about love. Things closed out on the haunting “Divina Commedia,” and its descent towards numbness serves up the final moments of emotional weightiness on this iconic release. -- TAMAR HERMAN 24. Twice, Fancy You (2019) Twice could have cruised forever on the timeless appeal of their early singles. Instead, in 2019, they dropped Fancy You -- a stylistic quantum leap from anything they’d done before, with heavier, darker undercurrents brought by producers like Charli XCX, MNEK, and K-pop superproducer Black Eyed Pilseung. “Strawberry,” co-written by group member Chaeyoung, reconciles Ariana Grande-level attitude with the simplicity of Selena Gomez’ “Bad Liar.” “Girls Like Us” elevates the ensemble’s knack for melody to phone-waving anthem levels. And then there’s the titular single “Fancy”: catchy, effervescent, with a hook as airtight as you could ever hope for. It might sound different, but it’s still undeniably, irresistibly Twice. -- JOSHUA CALIXTO

23. B.A.P, First Sensibility (2014) B.A.P will be remembered as an act with extreme international promise, and poor management curtailing their careers. Before things started to unravel, listeners were treated to their first studio album, flexing their multi-genre appeal that diverged from the hard hip-hop and EDM that characterized their breakthrough singles. Gospel-inspired lead single "1004 (Angel)" showed their pop promise, but the guys also delved into dance music (on "B.A.B.Y" and "Lovesick"), hard rock ("BangX2") and '90s hip-hop before it was trendy on "Spy." The LP is a bittersweet re of what could have been for one of K-pop's earliest potential breakouts. -- JEFF BENJAMIN READ MORE The 50 Best Albums of 2019: Staff Picks 22. BIGBANG, Alive EP (2012)

Alive is the moment when BIGBANG crossed the threshold from above-average hitmakers to full-fledged icons. The then-quintet reached the expert level of crafting a pop hook with bite, and this album was practically a vehicle for G-Dragon’s auteurship. The leader’s fingerprints are all over a tracklist that is interlaced with three of their most career-defining hits. “Fantastic Baby” hit instant-classic status with a deadpan delivery of the titular catchphrase. “Blue” got the Swizz Beatz cosign for good reason -- it’s their smoothest R&B concoction to date. Then there’s the Williamsburg-set MV for “Bad Boy,” which signaled that they already arrived on American soil. Alive went on to reach No. 150 on the Billboard 200 -- and it remains a beacon for BIGBANG’s status as game-changers. -- CAITLIN KELLEY 21. JJ Project, Verse 2 (2017) Before they were members of the internationally beloved boy band GOT7, members JB and Jinyoung were first introduced to the world in 2012 as JJ Project: a rebellious duo that tangled up electro-rap, dubstep, and rock on “Bounce.” Five years later, the guys returned with a 180 transformation, revamped as sentimental singer-songwriters for a stunning collection of heartfelt, harmony-heavy tunes. Album opener "Coming Home" creates a groovy mood to set the table for the emotional climax of the rock-inspired lead single, "Tomorrow, Today." Album cuts like "On&On" and "Icarus" worked through of-the-time moombahton and melancholic electronica, as the guys made it their own with their understated vocal chemistry. -- J.B.

20. BTS, Wings (2016) With Wings, the 2016 follow-up to BTS’ spectacular breakthrough The Most Beautiful Moment in Life, the group channeled their ambitions for global domination, proving that they could remain true to their hip-hop roots while exploring new soundscapes. With distinctive solos like rapper RM’s atmospheric “Reflection” and the chopped-up orchestral drama of Jimin’s “Lie,” the album stretches K-pop’s ensemble palette to its limits. Then there’s the baroque moombahton of “Blood, Sweat & Tears” and triumphant trap of “BTS Cypher 4" -- a manifesto of radical self-love that, in retrospect, feels like the opening salvo of a full-on takeover. -- J.C. 19. Epik High, Shoebox (2014)

For fans of their earlier stuff, Epik High took things towards in more of an old school route on Shoebox, their second album after joining YG Entertainment and the follow-up to the poppier 99. The LP is fronted by singles that include the pensive ambience of “Happen Ending” and the comedic slapback of “Born Hater,” the latter a response to a longtime smear campaign aimed at rapper Tablo that nearly ruined his career. Shoebox spends its length laying down the act’s thoughts on their experiences as artists, and they are joined by numerous collaborators as they vacillate the lines between philosophizing and provoking, upbeat and despondent. -- T.H. 18. 2NE1, Crush (2014) K-pop’s crossover trajectory in the States is often reduced to chart stats. It’s true that Crush hit No. 61 on the Billboard 200. But the LP’s real claim to fame in the U.S. is that it made 2NE1 a critical darling in a market where K-poptimism still hasn’t taken hold. The quartet’s sophomore album traverses a genre-blend of EDM, trap, and reggae -- and standouts include the sensory overload of “Come Back Home” and the deceptively cheerful pop of “Happy.” But “MTBD” is the show-stopping centerpiece where CL’s ferocious flow takes no prisoners amid twitching triple hi-hats and the bass going “boom boom boom.” The relatively restrained full-length proved 2NE1 knows when to pull back after firing on all cylinders. -- C.K.

READ MORE The 40 Greatest Dance Albums of the Decade: Staff List 17. Kahi, Please Come Back (2011) Kahi's place in the K-pop industry cannot be not forgotten as the ambitious singer-songwriter-dancer is responsible for putting together and leading one of the decade's most impressive girl groups: After School. But the visionary's solo work should not be overlooked either, as her debut EP saw her taking aspects of After School's charms and cranking up the intensity several notches. Lead single "Come Back You Bad Person" showed her ability to seamlessly shift from heartfelt crooning to thumping hip-hop. She owned the synth-pop/military march adventure of "Roller Coaster," early Rihanna-like R&B on "One Love," and even a piano ballad with "Present" with a compact record to spotlight her multiple talents. -- J.B. 16. EXO, Love Shot (2018)

There are few in the K-pop world with a catalog of such stalwart full-lengths as EXO, who have spent much of their seven-year career serving up one pristine album after another. Last year’s Love Shot -- a repackage of Don’t Mess Up My Tempo -- elevated the act’s sound to a more mature place with the excellent a capella explosion of “Tempo” and the smooth sensuality of “Love Shot.” This sleekly produced entity flits between groovy moments of vocal harmonizing in this smooth mixture of R&B and electro-pop. -- T.H. 15. EXID, Street (2016) EXID may not have blown up until a fancam of member Hani went viral, but maybe that’s what it took for the public to realize that this entire group oozes that same magnetic ferocity. Nowhere is that charisma better distilled than on the five-piece group’s 2016 album Street, where the deep house of “Cream” intertwines with the new jack swing affectations of “No Way” and cabaret disco of “Are You Hungry?” Much of the appeal here can be attributed to production from K-pop mainstay Shinsadong Tiger, but Street’s sheer variety could only be brought to life by the best, and EXID pull it off with magic to spare. -- J.C.

14. Day6, Sunrise (2017) Day6’s discography has a reputation for delving into the nuances of loss, loneliness, and nostalgia. But Sunrise traces the larger spectrum of romantic stages, from love at first sight to the messy task of breaking up with someone. It also happens to be a patchwork of their yearlong project, Every Day6, piecing together the first half of their “first thought, best thought” drops into a holistic work. The frontloaded run of Every Day6 cuts inhabits the sweet spot between pop-punk and arena rock, built on a foundation of power chords that make them sound huge even in a 1,500-seat theater. But the group's sound is expansive enough to zig-zag through reggae breaks and electronic flourishes, proving that they are a rock band with more than a few tricks up their sleeve. -- C.K. READ MORE The 50 Best Latin Albums of the Decade: Staff List 13. Orange Caramel, Lipstick (2012)

With the floofy wigs, nasal vocals, and extreme cosplay, Orange Caramel's musicianship risks being overlooked -- but their sole LP lets the trio's brilliant, experimental nature run its full course. "Bubble Bath" layers vocoder and baby coos with a dreamy synth-rock production that wouldn't be out of place on a Grimes record, while the girls mix romance and dessert on "Milkshake." Songs don't get catchier than "Lipstick," which samples the famous "Arabian riff" also utilized by Kesha on her hit "Take It Off," nor the kitschy cute "Aing?" and "Shanghai Romance" -- all representing how weird K-pop can be great K-pop. -- J.B. 12. AKMU, Play (2014) AKMU were more or less guaranteed a successful debut album after winning a Korean singing competition, but Play established the brother-sister duo as something far more than reality-show champs. A refreshing blend of modern folk music and snappy production backed AKMU's knack for gorgeous harmonies and smart lyricism. Singles "200%," a bouncy pop cut detailing a love story through rap-like deliveries, and "Melted," a chilling ballad about navigating in a cruel world, represent the sibling's full scope for "healing music" -- a term in Korea for soothing, comforting songs, which these two do almost too well given their young age. -- J.B.

11. SHINee, The Story of Light: Epilogue (2018) Despite being the first new album since the death of group vocalist Kim Jonghyun, SHINee’s The Story of Light isn’t an album strictly about loss. The wistfully optimistic “I Want You” could be a straightforward love song if not for lyrics like: “I hope you’ll come to me with a different ending than last time.” SHINee’s eclecticism is used throughout the album to stunning effect, from the intimate balladry of “Our Page” to the timeless 112 vocal sampling that grounds “Good Evening” in a gauzy, surreal numbness. The Story of Light re-envisions grief not as an all-consuming void, but as something almost musical: a multisensory phenomenon that molds us into new people. -- J.C. 10. Heize, She's Fine (2019)

Heize takes her uneasy listening to new depths on her debut album. This time, she doesn’t lean as heavily into the jazz influence of her repertoire’s past, but there are sporadic callbacks to her earlier discography. Her well-worn rain motif reappears on “Umbrella Calls For Rain,” where her jazz stylings are complemented by a hypnotic bassline. But the tracklist is a log of her knack for sonic exploration. The sassy title track dusts off a nosy gossipmonger with a thumping key change towards the end. Meanwhile, the SunWoo Jung-A-assisted “Hitch Hiding” is a sparse yet intricately textured track that proves that building emotional walls can result in good acoustics. She closes out the 11 tracks with a G-Funk-style portamento synth that livens up the bleary-eyed melancholy of “E.T’s Letter - empty ver.” On She’s Fine, Heize presides over lush soundscapes that position her as one of the most sonically adventurous artists in the game. -- C.K. 9. Jonghyun, She Is (2016) She Is spends its half hour of airtime breathing life into the way love makes one feel. Early moments of euphoria from album openers “She Is” and “White T-Shirt” slink into an overwhelming sense of sensuality that permeates throughout the rest of the album. Built around buoyant R&B, with electronic and funk elements filtering throughout, a sense of vibrancy permeates each listen of Jonghyun’s first LP, offering up a kaleidoscopic listening experience that is part sunshine, part desire, and all good. -- T.H.

8. Younha, Rescue (2017) For much of this decade, it has felt like things are only getting worse. But through the elegant sentimentality of Rescue, Younha gifted the world an album that offered some hope, a cathartic listening experience that reflected on hard times and hinted to the brightness beyond them. The singer-songwriter layered the album’s 11 songs with ambient alt-R&B and groovy electro-pop moments, with her soulful tone setting a stage that is all at once reflective and aspirational in the way it lays forth her emotional turmoil. -- T.H. READ MORE 15 Best Overlooked Hip-Hop & R&B Albums of the 2010s: Staff List 7. MAMAMOO, Melting (2016)

After rising on the charts for several years since their 2014 debut, Melting marked MAMAMOO's true arrival on the K-pop scene -- this statement album proved the girl group is a multifaceted tour-de-force. The soulful quartet did what they do best on lead single "You're the Best," a feel-good pop with touches of nostalgic brass and jazz, which landed them their first chart-topper in Korea. But the record dips into slinky hip-hop on "Taller Than You,” dreamy soul music on "Friday Night," and lets their vocals take center stage on acoustic jams like "Words Don't Come Easy" and "My Hometown." All these musical styles would be revisited later in MAMAMOO's career as the group became more confident in their place in the industry. But Melting is a snapshot of the greatness that was to come from the boundary-breaking girl group. -- J.B. 6. Brown Eyed Girls, Basic (2015) It’s almost comical that Brown Eyed Girls dubbed this album Basic, as it is anything but. Between the retro-pop vibes of the risqué “Warm Hole,” the disco styling of “Brave New World,” and the funky slink of “Wave,” the quartet spend this LP showing the world why they are among one of the best pop acts South Korea has to offer. The album is meant to get down to the nitty gritty and show the world who Brown Eyed Girls are at their most Basic. But it’s clear through its masterful production -- which bolsters the artful tones of the four women -- that BEG are performers who raise the bar to levels of excellence, carving a space for themselves where few others can hope to compete. -- T.H.

5. Red Velvet, Perfect Velvet (2017) A truly consistent pop album is hard to come by, but Red Velvet have made a few of them to date -- and Perfect Velvet may be their crowning jewel. The sinister tropical house of lead single “Peek-a-Boo” sets the stage for a literal horror show, with the song’s video featuring all five members tormenting an unsuspecting pizza guy in a Hollywood bungalow. The whole album is punctuated by this candy-coated violence -- a core theme of Red Velvet’s discography -- and blown to dizzying proportions, even on tracks that don’t betray it at first glance. “My Second Date” presents the outline of a midtempo R&B track, but is perforated by the paranoia of a second rendezvous -- from the toybox glockenspiel that traces out its melody, to the hyperactive dubstep of its chorus, to the manic guitar noodling that drops at around the halfway point. “I Just,” meanwhile, chugs along with locomotive urgency, a relentless meditation on turning the page in life. Red Velvet has always found euphoria amid the underlying menace of youth, and that anxiety shapes Perfect Velvet: a monumental work of discomfort and bliss. -- J.C.

4. Wonder Girls, Reboot (2015) So much has been said about how Wonder Girls pulled out all the stops when they threw back to the ‘80s in their 2015 album Reboot. They learned instruments so they could play the music live as a four-piece band. They nailed the essence of every ‘80s-specific sound they went for -- from dance-pop, to synth-rock, to old school hip-hop. They wrote most of the songs themselves. Less is said about how, in the process of putting together one of the most comprehensive concept albums ever conceived, Wonder Girls upended history itself. In 1987 -- the reference year for lead single “I Feel You” -- the type of music you find on Reboot didn’t exist. It’s not because the sounds hadn’t been invented: everything on this album has a precedent, and it’s clear that Wonder Girls and label JYP Entertainment took painstaking care in applying those influences in fresh, nuanced ways. It’s about circumstance. In 1987, K-pop and Wonder Girls had yet to take form, and Korean women weren’t dropping Salt-n-Pepa verses to New Jack Swing beats the way Hyelim and Yubin do on “Back.” Hi-NRG synth pop in the vein of Dead or Alive didn’t mingle with hip-hop the way it does in “One Black Night.”

This is music from an alternate universe, and yet, here it is, perfectly realized and resonant enough to make the charts. This LP is a testament to the power of pre-established musical genres as a transformative means of expressing oneself, independent from -- but still respectful of -- the people and cultures it stemmed from. Don’t call it a rehash: it’s a reboot. -- J.C. READ MORE Billboard's 100 Songs That Defined the Decade 3. BTS, The Most Beautiful Moment in Life: Young Forever (2016) Before their world takeover officially took off, BTS proved their true promise to the world with the one-two punch of The Most Beautiful Moment in Life, Pt. 1 and 2, where they infused their hip-hop styling with a gorgeous dose of pop magic. The guys finished off the remarkable era with a compilation LP titled Young Forever that acted as a victory lap, showing they had just a few more tricks up their sleeves as they wrapped up a near-perfect era.

Pts. 1 and 2 featured landmark songs in BTS' career, like breakout single "I Need U," the international anthem "Dope," a promise to breaking the status quo with "Silver Spoon (Baepsae)" and tracks that showed their brilliance with lyrical metaphors in "Whalien 52." New Young Forever songs "Fire" and "Save Me" cemented the band as multifaceted hitmakers, thanks to their respective displays of hard-hitting EDM/hip-hop and sentimental dance-pop. But more than the range of genres, Young Forever solidified and proved the importance of messaging in your music -- with those messages only growing stronger in BTS' further releases. The Most Beautiful Moment in Life, Pt. 2 was BTS' first album to enter the Billboard 200, while Young Forever lead single "Fire" was their first No. 1 on World Digital Song Sales. BTS truly cracked the formula for a larger, more meaningful support from listeners, and the end of this era indicated that only larger things were on the way. -- J.B. 2. IU, Modern Times (2013)

IU likes things “a little outdated” -- so much so that she rewound her third album back to the Jazz Age. Modern Times asserted the maturation of her artistry following a huge shift in her public perception. What better way for IU to dispose of the girl-next-door image of “Good Day” than to showcase her gift for brooding balladry on -- wait for it -- “Bad Day”? The artfulness of the LP lies in how she strings together bossa nova, swing, and folk while putting a modern spin on the sounds of the Roaring Twenties. After all, “Wait” is the kind of record-scratching beat that would sound at home on a jazz-rap hit. If K-pop is a multimedia phenomenon, Modern Times is an auditory journey that pays homage to the silver screen. Her mass referentialism serves larger narratives throughout the runtime, and the Chaplin-esque title track is a fan letter to the silent film icon, complete with allusions to movie moments like “The Nonsense Song.” But the apex of this Art-Deco handiwork is the Charleston-inducing single, “The Red Shoes” -- a big band extravaganza inspired by a fairy tale about a dancer with magic shoes that, uh, doesn’t end well. IU’s decidedly less gory adaptation jerks the tempo around to reflect that “Mr. Shoes” has a life of its own -- and the sped-up finale accompanies her submission to its will. Theatricality has always been part of her sonic recipe, and there’s a showtune feel to her earlier hits. But the densely layered instrumentation of “The Red Shoes” offers a satisfying echo to the dizzying storyline. As we head into a centennial decade fixated on questionable Gatsby parties, IU has already drawn a map of how to make this kind of throwback your own. -- C.K.

1. f(x), Pink Tape (2013) When f(x) released this grand pop opus, the market for full-length albums among idol groups was small. Most acts opted for a more streamlined single or EP release, and most LPs acted as a mish-mash of random tracks and previously released singles. Pink Tape proved the power of a full, sonically cohesive album, as a truly ambitious collection of experimental cuts. The lead single "Rum Pum Pum Pum" acts as the perfect centerpiece of this quirky pop feast. The samba percussion and funky guitar blend together with the "Little Drummer Boy” sample, while the bizarre lyrical metaphor of relating love to wisdom teeth is delivered with alien-like harmonies from the ladies. And that's just the first track. Proving K-pop's belief that one song needn't stick to a single sound or mood, and the unexpected is the only thing that can be routinely expected throughout the LP. "Airplane" blends euphoric EDM with a sing-talk chorus, "Signal" tempers borderline-saccharine melodies with a sleek disco sheen, while "Shadow" is the sound of a creepy doll come to life with a waltzy-pop swagger. It's all remarkably eccentric, but somehow works under the guise of f(x)'s bright Pink Tape concept.