WebBusan. / 35.18000°N 129.07500°E / 35.18000; 129.07500. Busan ( Korean : 부산, pronounced [pusan] ), officially Busan Metropolitan City, is South Korea 's second most populous city after Seoul, with a population of over 3.4 million inhabitants as of 2017. [4] Formerly romanized as Pusan (and Fuzan under Japanese rule), it is the ...