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Fans frequently refer to “generations” of idol acts when talking about K-pop. The first generation is typically considered to be comprised of the acts of the late ‘90s and early ‘00s. The second began in the mid 2000s and, depending on who you ask, ended with the artists and groups that debuted between 2009 and 2012, when YouTube helped K-pop’s international ascent and Psy’s “Gangnam Style” broke the East-West radio barrier. As it becomes more crowded, the K-pop arena continues to become increasingly competitive and eras more loosely defined. But with 2017 being one of the most transitional years the industry has seen in some time, it's clear that we've hit the end of one era and the start of a new, very different wave of K-pop.

The year saw immense changes with stalwart acts like Girls’ Generation, Sistar, INFINITE, T-Ara, Teen Top, and Wonder Girls facing member departures or complete disbandments, and others like Super Junior and BIGBANG confronting personal turmoil, leaving the playing field open for newer acts. The year was filled with upward movement in the K-pop industry as younger and emerging acts like BTS, EXO, Winner, Seventeen, Nu’Est W, Heize and Wanna One proved their ability to make an impact in the scene. Older girl groups in particular saw a near demise, with Red Velvet and TWICE moving in to fill the void with highly successful releases, like Perfect Velvet and twicetagram, respectively. Even the music itself saw a shift in 2017, with many idols achieving solo success while Korean R&B and hip hop gained widespread attention in the domestic market and beyond.

The generational divide within K-pop was most visible at the Mnet Asian Music Awards on December 1. At MAMA 2017, it became apparent that — aside from a handful of the most successful acts who weren’t even in attendance — an entire generation of groups have all but entirely gone by the wayside and aged out of the K-pop scene: not a single group who performed had begun their career in the years between Super Junior's 2005 debut and EXO's 2012 debut. Coincidentally, that seven year gap spans the average life-span of most K-pop acts, as contracts are typically up for renewal at the end of that period.

Perhaps more than the internal dynamics of the K-pop industry, it’s K-pop's recent resurgence in America's music scene that has revealed just how much Korea’s music scene has shifted in 2017. Due to the fan-propelled ascent of BTS, no longer is Psy the be all and end all of what Korean music means to many around the globe. Between the group's successes on the Billboard charts and appearances at major American award shows, the Korean septet has introduced a fresh iteration of what K-pop is. And it is that shift, from “Gangnam Style” to “DNA” and “Mic Drop (Remix),” that declares 2017 as one of K-pop’s most important years this decade.

The K-pop we started out with in 2017 and the K-pop we’ve ended up with as 2018 looms are two different beasts, and the future of Korean music and how it intersects with the rest of the world is going to be defined by it for years to come. For now, though, check out these must-hear K-pop (and K-pop adjacent!) releases from this week: