Post-World War II relations between Japan and the Korean peninsula started after the unconditional surrender of Japan in 1945 and the end of the Japanese colonization of the Korean peninsula. After lengthy normalization talks, which were initiated in 1952, Japan and the Republic of Korea (ROK) normalized diplomatic relations in 1965.
Unlike the Rhee Syngman Administration from 1948 to 1960, which was pro-U.S. and anti-Japan, President Park Chunghee, who gave high priority to Korean industrialization and economic growth, promoted economic relations with Japan.1 The ROK imported parts, intermediary goods and capital goods from Japan and other western countries, which were assembled in the ROK and exported to the United States and other overseas markets. This resulted in remarkable economic growth. The ROK used the Japanese industrial and export policy models with great success; Korean products have been catching up with Japanese goods in overseas markets, even overtaking them in sectors such as electronics, steel, shipping, and semiconductors.2
On the political side, Japanese Prime Minister Yasuhiro Nakasone visited the ROK in 1983, the first incumbent prime minister of Japan to do so; the following year, President Chun Doo-hwan became the first head of state of the ROK to visit Japan. Japan and the ROK have developed broader and closer ties with each other despite territorial disputes over Takeshima,3 historical disputes between the two countries, and other outstanding issues. Security and defense cooperation began in the mid-1990s.4 Cultural exchanges were accelerated after President Kim Dae-jung’s visit to Japan in 1998. Trade volume between the two countries reached about $53 billion in 2003, with 3.7 million people traveling between the two countries; only 10,000 people traveled between Japan and the ROK in 1965.5
On the other hand, while Japan has had 12 rounds of normalization talks since 1991, it has not established diplomatic relations with North Korea. Trade volume between Japan and North Korea was about $270 million in 2003.
[Regarding the lack of detailed progress in North Korea's disarmament] I’m shocked at how superficial things have been...I think the North Koreans smell dysfunction and they see dysfunction in [President Trump]’s tweets and his compliments and his willingness to meet again.