North Korea
Japan tried to suppress Korean traditions and culture and ran the economy primarily for its own benefit. Korean resistance groups known as Dongnipgun (Liberation Army) operated along the Sino-Korean border, fighting guerrilla warfare against Japanese forces. Some of them took part in allied action in China and parts of South East Asia. One of the guerrilla leaders was the communist Kim Il-sung, who later became the first leader of North Korea.
Kim Jong-un
Despite tense relations, North Korea agreed to participate in the 2018 Winter Olympics in Pyeongchang. Following the Olympics, Kim Jong-un and President Moon Jae-in conducted the April 2018 inter-Korean summit. It was the first time since the end of the Korean War in 1953 that a North Korean leader entered the South's territory. On 12 June 2018, Kim Jong-un and US President Donald Trump met for the 2018 North Korea–United States summit in Singapore, the first-ever talks held between a North Korean leader and a sitting US President, to discuss the North Korean nuclear program.