The concept for the film originated when Kunio Katō was studying at
Tama Art University in
Tokyo. It initially took the form of a painting featuring box-shaped houses arranged in stacks. During this time, Kunio was introduced to the world of animation when he watched
Mark Baker's 1989 debut short film,
The Hill Farm. This experience significantly influenced Kunio's creative direction. He collaborated with his colleague and screenwriter, Kenya Hirata, to bring the project to life. However, despite receiving acclaim afterward, Kunio remained unsatisfied with the project as a whole. ==Accolades==