The brother and sister in the film are played by real life brother and sister Aoi Miyazaki and Masaru Miyazaki.
Shot in color and desaturated.
Shinji Aoyama's intention was to tell his story in as meticulous detail as possible. Hence the four hour running time.
The main inspiration for the film was the sarin gas attack on the Tokyo underground in 1995.
Two of Shinji Aoyama's main influences on the film were John Ford's La Prisonnière du désert (1956) and the Sonic Youth album, "Daydream Nation".