The animation was done in North and South Korea by AKOM (in South Korea) and The Chosun April 26th Children Film Studio (also known as Studio SEK in North Korea), and the score was also recorded in the North by the Pyongyang Film and Broadcasting Orchestra. In a move unusual for the Korean film industry, the character voices were recorded in both the South and the North due to differences in dialect. For the definitive international release version, the South Korean dub is the one used. More information can be found HERE.