Four years ago, PSY was making K-pop history as “Gangnam Style” spent a fourth week at its No. 2 peak on the Billboard Hot 100. On Oct. 16, Korean boy band BTS (also known as Bangtan Boys) hit a new landmark for the scene with no songs in English, no U.S. ­promotion -- and no horsey dancing.

The septet’s second full-length, Wings, debuts at No. 26 on the Oct. 29 Billboard 200, with 16,000 units earned in the week ending Oct. 13, according to Nielsen Music, marking the ­strongest-ever week for a K-pop album. Previously, 2NE1’s Crush held the top chart rank for a K-pop act (No. 61 with 2014’s Crush), and EXO logged the best sales frame (6,000 in first-week sales for 2015’s Exodus).

2NE1 and EXO come from ­established Korean labels: 2NE1 is a labelmate of PSY on YG Entertainment, and EXO is on SM Entertainment, Korea’s ­largest label. BTS is on the smaller BigHit Entertainment -- so what has let the upstart group and label succeed where so many others fell short?

Primarily, a keen focus on America and a different take on the typically surface-level material in K-pop. In 2015, BTS embarked on two U.S. tours, ­selling out both despite having released just one full-length album. SubKulture Entertainment acted as promoter for BTS’ first trek, and CEO Derek Lee tells Billboard, “All four shows sold out in less than one day, with some of the venues ­selling out in less than an hour. I don’t think any of us anticipated such a stampede.”

BTS also headlined both stops of this summer’s KCON ­festival, which attracted more than 110,000 fans during its three days at Los Angeles’ Staples Center and two days at the Prudential Center in Newark, N.J.

But most of all, the messaging seems to connect with American fans. “The group blends ­individual artistry, which is what the U.S. ­audience expects in their music, and the K-pop system, which focuses more on the group sound and teamwork,” says Grace Jeong, editor-in-chief of Soompi, an 18-year-old K-pop news and media site. “BTS has something to say, and has a great ­marketing strategy that doesn’t alienate non-Korean-speaking fans.”

Indeed, the Major Lazer-esque lead single “Blood Sweat & Tears” details a life-derailing ­relationship over a dance ­breakdown. Elsewhere on the album, the group sings about mental health, takes digs at the Korean-pop “idol” scene and delivers a female-empowerment anthem -- unusual subject matter in culturally conservative South Korea, where most acts stick to safe topics like partying and breakups.

Still, to truly break into the ­mainstream, BTS may need to look to its galloping rival. “BTS still needs that one viral song that ­everyone knows, even without knowing their name,” adds Jeong. “Like ‘Gangnam Style.’”

This article originally appeared in the Oct. 29 issue of Billboard.