Formerly a single nation that was annexed by Japan in 1910, the Korean Peninsula was divided into occupation zones since the end of World War II on 2 September 1945.

Under President Moon Jae-in, beginning with North Korea's participation in the 2018 Winter Olympics, the relationship saw a major diplomatic breakthrough and become significantly warmer.

The US government therefore requested Soviet forces halt their advance at the 38th parallel north, leaving the south of the peninsula, including the capital, Seoul, to be occupied by the US.

US forces left the South the following year, though the US Korean Military Advisory Group remained to train the Republic of Korea Army.

[41] However, at the same time, amid a global thawing of the Cold War, the newly elected South Korean President Roh Tae-woo launched a diplomatic initiative known as Nordpolitik.

South Korean President Lee Myung-bak convened an emergency meeting of security officials and ordered the military to focus on rescuing the sailors.

The crisis was marked by extreme escalation of rhetoric by the new North Korean administration under Kim Jong Un and actions suggesting imminent nuclear attacks against South Korea, Japan, and the United States.

On 31 March, following an exchange of artillery fire into the waters of the NLL, a North Korean drone was found crashed on Baengnyeongdo.

[98] In his New Year address for 2018, North Korean leader Kim Jong Un proposed sending a delegation to the upcoming Winter Olympics in South Korea.

[100] At the Winter Olympics, North and South Korea marched together in the opening ceremony and fielded a united women's ice hockey team.

[105] On 1 April, South Korean K-pop stars performed a concert in Pyongyang entitled "Spring is Coming", which was attended by Kim Jong Un and his wife.

[113] As part of the Panmunjom Declaration which was signed by leaders of both countries, both sides also called for the end of longstanding military activities in the region of the Korean border and a reunification of Korea.

[119] The second meeting, involving the Red Cross and military, was held at North Korea's Mount Kumgang resort on 22 June where it was agreed that family reunions would resume.

[125] The co-operation extended to the film industry, with South Korea giving their approval to screen North Korean movies at the country's local festival while inviting several moviemakers from the latter.

[129] In September, at a summit with Moon in Pyongyang, Kim agreed to dismantle North Korea's nuclear weapons facilities if the United States took reciprocal action.

On 16 August 2019, North Korea's ruling party made a statement criticizing the South for participating in the drills and for buying US military hardware, calling it a "grave provocation" and saying there would be no more negotiation.

This came after Pyongyang had repeatedly warned Seoul regarding matters such as the failure of the South to stop North Korean expatriate activists from sending anti-regime propaganda leaflets across the border.

The Korean Central News Agency described it as "the first step of the determination to completely shut down all contact means with South Korea and get rid of unnecessary things".

[150] A week prior to these actions, Kim Yo Jong had called North Korean defectors "human scum" and "mongrel dogs".

[151] On 13 June, Kim Yo Jong warned that "before long, a tragic scene of the useless North-South joint liaison office completely collapsed would be seen."

The request followed the North's statement that it was ready to send 12 million leaflets, which could potentially become the largest psychological campaign against South Korea.

"Love's Emergency Landing") was a 2019–2020 South Korean television series directed by Lee Jeong-hyeo and featuring Hyun Bin, Son Ye-jin, Kim Jung-hyun, and Seo Ji-hye.

[166] On January 15, 2024, Kim Jong Un announced that peaceful reunification was no longer possible and proposed identifying South Korea as a hostile state in the North Korean constitution.

It was also announced that North Korea would dissolve the Committee for the Peaceful Reunification of the Fatherland, the National Economic Cooperation Bureau and the Mount Kumgang International Tourism Administration.

[170] On 9 June 2024, South Korea announced to resume loudspeaker broadcasts of anti-North Korean propaganda after Pyongyang sent over 300 rubbish-filled balloons across the border.

This response followed weeks of activists in the South launching balloons carrying K-pop, dollar bills, and anti-Kim Jong-un propaganda, which had infuriated Pyongyang.

The loudspeaker broadcasts resumed after South Korea suspended a 2018 tension-easing agreement, allowing for propaganda campaigns and potential military exercises near the border.

These drones, possibly acquired from Russia and strongly resembling the ZALA Lancet, are capable of striking targets on land and sea, raising security concerns for South Korea.

Although South Korea's defense minister refuted these claims, the Joint Chiefs of Staff stated they couldn't fully verify the incidents.

[178] On 11 December 2024, North Korea released its first statements on the martial law declaration through an article published in the state newspaper Rodong Sinmun, describing it as an "insane act" that was "akin to the coup d'état of the decades-ago military dictatorship era".