The Korean Demilitarized Zone — a stretch of neutral territory between North and South Korea — is 155 miles long and two and a half miles wide. It’s littered with landmines and barbed wire, and is widely regarded as one of the world’s most fortified borders. To the surprise of many who travel to its periphery, the South Korean side also boasts 11 loudspeakers sites, stationed at undisclosed locations along its half of the otherwise barren strip.

Until recently, these speakers would broadcast anti-Pyongyang news and weather reports up to three times a day, along with an unusual propaganda tool: K-pop. But on the morning of April 24, for the first time in over three years, those speakers fell silent. In the lead-up to Friday’s historical meeting between the Supreme Leader of North Korea, Kim Jong-Un, and South Korean president Moon Jae-in, the decision signalled a notable de-escalation of tension between the two states.

Though it’s more widely known as Korea’s über catchy answer to western pop music, K-pop served a very different function at the border. Buoyant and irrepressibly upbeat, K-pop had the effect of irritating North Korean foot soldiers while impressing upon them what the South’s Defence Ministry has called the “happy life of South Koreans,” in a seeming attempt to lure defectors over to the other side. Since this strain of audio warfare between the two states began in the 1950s, the North has used its own speakers to blast scornful criticisms of Seoul and the “depraved capitalist” existence of its inhabitants, and the South has come to rely on an increasingly musical selection to drown them out. In 2015, after a skirmish at the border, Kim Jong-Un even ordered North Korean soldiers to prepare to attack South Korea's loudspeakers if they didn’t stop broadcasting propaganda.

“North Korean soldiers on the front line have no choice but to hear the K-pop music broadcast from South Korea’s loudspeakers,” says Dr Young Joon Lim, a professor from the University of Texas Rio Grande Valley who studies the propagandic impact of music broadcasted over the DMZ. “Both countries speak the same language, so the North Korean soldiers can’t help but understand the messages of the songs.”

South Korean soldiers at the Korean Demilitarized Zone

They also can’t really escape them. Research conducted by the BBC suggests that the loudspeakers can be heard up to 6 miles into North Korean territory, with many defectors testifying that their only knowledge of the South comes from these broadcasts. North Korean soldiers have certainly developed an appetite for K-pop’s sugary appeal, with the act of smuggling contraband K-pop music into the North via USB flash drives becoming increasingly commonplace in recent years. South Korean activists, for their part, have launched balloons and drones stocked with flash drives full of K-pop, among other materials, into the sky, hoping to educate the North on what outside life is like.

Recently, K-pop’s use as a propaganda tool came to a head, with the deployment of musical foot soldiers. On March 31, South Korea sent a delegation of 160 artists, including multiple K-pop stars, to perform a selection of concerts in North Korea, as part of an ongoing reciprocal cultural exchange between the states. The first concert, titled Spring Comes, took place on April 1 at the East Pyongyang Grand Theatre, and was attended by Kim Jong-un himself. The first North Korean leader to ever attend a South Korean K-pop concert, Kim was witnessed enjoying the performances. Reports from the North Korean state news agency KCNA claim the leader was “deeply moved” by what he saw. He reportedly even managed to “adjust his schedule” to meet members of the band Red Velvet, the sole all-female K-pop group at the event.

And who can blame him? Judging from its popularity overseas, K-pop has a pretty universal appeal, even among the soldiers forced to hear it on a daily basis. “It’s impossible to jump to conclusions, but it certainly seems effective,” said Dr Young. “A North Korean soldier fled who across the border into South Korea in December 2017 said he loved K-pop music.” This tale of K-pop infatuation was published in South Korean newspaper Dong-a Ilbo, which claimed that while recovering from gunshot wounds sustained during his escape, the soldier woke up in the hospital, and asked to hear a K-pop song.

A South Korean solider stands next to the speakers at the DMZ.

According to Professor Roald Maliangkay, director of the Korea Institute at The Australian National University, there’s a reason why K-pop has become South Korea’s musical export of choice. “K-pop group songs sound upbeat and powerful and the lyrics of the songs selected portray the image of a strongly unified South Korean front,” he told The Outline.

Though it’s possible the aforementioned soldier may have been enticed by the music, Professor Maliangkay holds a more pragmatic view. “It is more likely he simply became infatuated with the female K-pop idols,” he says. Clips for Red Velvet songs like “Ice Cream Cake” and “Russian Roulette” show the group’s members dressed in colorful costumes, performing elaborate dance moves in mesmeric unison. “K-pop is quite a powerful means of propaganda,” Maliangkay continues. “It depicts South Korea as a hyper-modern, wealthy nation solely populated by passionate and attractive people.”

An important part of this equation is K-pop’s parent-friendly branding. “[K-pop] has no political or religious messages, and no sex, drugs, or aggressive behavior. That’s what makes it a welcome alternative to much of whatever else is out there,” says Maliangkay.

To a citizen of the DPRK with no other knowledge of South Korea, the world presented by K-pop would appear to be one where societal vices like as sex and drugs don’t exist. This is, of course, a complete fabrication. “K-pop is important to a large part of Korean society, but it is not representative of Korean society as a whole,” says Maliangkay. “The lyrics do not express the socio-political concerns of the people. K-pop projects a mere image.”

In truth, that image stems partly from Korea’s strict censorship rules. Government bodies such as the Ministry of Gender Equality and Family have the power to censor any music they deem too “political.” Public broadcaster KBS even banned a song from K-pop superstar Psy’s latest album for containing lyrics that merely sounded like profanities.

Despite recent crackdowns on the so-called “slave contracts” employed by some management agencies, K-pop idols are still considered ambassadors for Korea, and often forced to convey perfection in every facet of their lives. Last year, T.O.P, a member of the boyband BigBang, wrote a public letter of apology after he tested positive for marijuana use while undergoing military service. Restrictive clauses in the contracts of many performers even prevent them from engaging in legal activities, like sex and dating. “The idols are ideally all virgins and single, so as to allow their fans to dream endlessly about a romantic, chance encounter,” says Professor Maliangkay.

South Korean musicians rehearse for a concert at East Pyongyang Grand Theatre in Pyongyang, North Korea, on April 1.

Unified in its faith of K-pop’s importance, South Korea made the genre an official priority back in 1998, when it formed the Ministry of Culture and Tourism. The agency contained an entire department dedicated solely to the genre, with the aim of bolstering the country’s pop music industry and facilitating the rise of early acts like Seo Taiji & Boys.

The Korean government has been known to support the K-pop industry financially, including the creation of a $1 billion fund to help support the industry back in 2005. It appears to have been a worthy investment. According to the Korea Creative Content Agency, K-pop concert tickets, streaming, and merchandise sales in 2016 amounted to a record $4.7 billion in global revenue. Keith Howard, professor of Music at SOAS, University of London, claims that South Korea has seen a return of roughly $5 for every $1 spent on K-pop. “Bubble-gum pop sells,” he said.

In addition to being profitable, it’s also a means of enhancing South Korea’s stature on the world stage. “K-pop is consciously crafted to appeal to a global audience,” says Professor Lie, “I don't think it's easy to shape an outsider’s perception, but it's fair to say that South Korean politicians and bureaucrats have latched onto K-pop to enhance South Korea's ‘soft power’ — to show how modern, sophisticated, and advanced the country is.”

While K-pop has been successful at getting Westerners to open their wallets, Professor Howard has hope that it might also be able to open their minds. “As propaganda — of the positive kind — yes, it's effective. Many universities have seen large increases in the number of students studying about Korea, or learning the Korean language, across the world.” As of October 2017,123,000 foreign students are said to be studying in South Korea – a 40 percent increase from 2007.

As for the North and South Korea relations? K-pop appears to have played at least a bit-part in bringing the nations closer. According to a report in NK News — an American subscription-based website that provides North Korea news updates — South Korea’s Minister of Culture, Do Jong-hwan, believes K-pop has had a “considerable cultural influence” on citizens of the DPRK. At the Spring Comes concert, Kim Jong-un himself reportedly told performers from the South that the two countries “should hold culture and art performances frequently.”

This Friday, only month after that historic event, Kim Jong-un will travel to the South Korea side of Panmunjon, a “truce village” along the KDZ, and attempt to negotiate a peace treaty with Moon Jae-in. A coincidence? Most likely. But as South Korea defense ministry spokesman Choi Hoi-hyun said in a statement yesterday, he hopes the speaker switch-off “will lead both Koreas to stop mutual criticism and propaganda against each other and also contribute in creating peace and a new beginning.” WIth North Korea’s nuclear arsenal still looming large as a potential bargaining chip for Kim Jong-Un, the fate of this “new beginning” remains to be seen. But given Kim Jong Un’s strange new taste for K-pop, this next chapter in the countries’ relationship may very well be soundtracked by the buoyant choruses of Red Velvet.