Olympics 2018: Arirang, the folk song that unites South Korea and North Korea Arirang, a folk song that speaks to both Koreas, was performed at the Olympics.

PYEONGCHANG, South Korea -- South Korea President Moon introduced the slogan for the 2018 Olympics as "Peace in Motion." And nothing captured that theme more than athletes from rival countries -- South Korea and North Korea -- marching together to a song that speaks to all Korean people.

Excited Korean athletes marched under a unified flag, to a folk song called Arirang, to open the 23rd Winter Olympics. South Korean bobsledder Won Yun-jong and North Korean ice hockey player Hwang Chung-geum led the way, waving the Korean peninsula flag together. An electric version of Arirang filled the background, a melody shared by all Korean race.

It was the first time since the Changchun Winter Asian games in 2017 that rival Koreas marched together under a shared flag. The historic moment sent out a message of peace to the world.

And then, an 80-year-old singer filled the stadium with his voice, striking the chord of every spectator. Kim Nam-ki, the oldest man alive to have sung the original version of Jeongseon Arirang.

Kim was also the oldest performer to take part in the opening ceremony. He told Gangwon province’s daily press Gangwon Ilbo that he hoped to have delivered the message for peace and harmony embodied in Arirang.

So what is Arirang, and why was it selected for these Olympics?

Arirang is a song that best represents the Olympic spirit of "peace" and "concord." It also speaks to the culture and spirit of Korean people.

Arirang was inscribed on the UNESCO’s list of Intangible Cultural Heritage of Humanity in 2012.

The folk song was shared among Korean people for more than 600 years. According to UNESCO, there are more than 3,000 variations of the song.

Emotions ranging from love to sorrow is reflected in its tune. The Jeongseon Arirang rendition that was performed in these Olympics is the only version that is designated as Korea’s cultural asset. It's named after the town from which it originated -- Jeongseon in Gangwon province.

The town of Jeongseon is remote from the secular society. Scholars during the Chosun dynasty who took refuge in Jeongseon to avoid the calamity of literary were inspired by their own situations to write lyrics for the Jeongseon Arirang, according to an Encyclopedia of Korean Music.

Putting aside all historical assumptions, Arirang is a song that is widely known to all Koreans, regardless of age. It is even included in 3rd-grade elementary school curricula.

At the moment, Korea is the only nation still divided by war. It has been divided into two countries since the Korean War ended in 1953.

The Korean peninsula portrayed as one under the shared unification flag during the joint march -- with Arirang echoing within the stadium -- was enough to express the pain of separation in a once single nation. And there will be another chance to listen to Arirang if Korea’s unified women’s hockey team rings the victory bell in the upcoming game on Saturday and Sunday.