Foreign relations of South Korea
On January 18, 1952 The first president of South Korea Syngman Rhee declared that the vicinity of Dokdo was a territory of South Korea (Syngman Rhee line). Subsequently, some 3,000 Japanese fishermen who conducted fishery operations in this vicinity were captured. This incident, called the Dai Ichi Daihoumaru Ship case strained relations between South Korea and Japan.
Sunshine Policy
In May 2017 Moon Jae-in was elected President of South Korea with a promise to return to the Sunshine Policy. 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. The Seoul–Pyongyang hotline was reopened after almost two years. At the Winter Olympics, North and South Korea marched together in the opening ceremony and fielded a united women's ice hockey team. As well as the athletes, North Korea sent an unprecedented high-level delegation, headed by Kim Yo-jong, sister of Kim Jong-un, and President Kim Yong-nam, and including performers like the Samjiyon Orchestra. The delegation passed on an invitation to President Moon to visit North Korea. 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. 
On 27 April, a summit took place between Moon and Kim in the South Korean side of the Joint Security Area. The summit ended with both countries pledging to work towards complete denuclearization of the Korean Peninsula. They also vowed to declare an official end to the Korean War within a year. 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. Also, the leaders agreed to work together to connect and modernise their railways.