Park had been a big fan of Japanese animation director Hayao Miyazaki's work since he watched "Future Boy Conan" as a child. One of Miyazaki's most important collaborators was composer Joe Hisaishi. Park liked Hisaishi's music so much that he wrote the script thinking about his music, visualizing the scenes in his mind while listening to his past work. During pre-production, producer Lee Eun-ha asked Park who the best music director for the project would be; Park immediately answered, "Joe Hisaishi." Lee then wrote a very heartfelt letter to Hisaishi, explaining their situation and translating the script into Japanese for Hisaishi's consideration. Hisaishi accepted the proposal, later stating that he was moved by the enthusiasm and sincerity in the letter, choosing "Welcome to Dongmakgol" as his first ever Korean film.