Yamaguchi uses a camera no bigger than a Tamagotchi. He told the Guardian "You can get close to the cast - like, five centimetres away - and take a really good picture". The camera was strapped to the back of a smartphone, which was used as a handheld monitor so Yamaguchi could watch the footage back as he followed the actors.
As seen in the behind-the-scenes footage that plays alongside its credits, the film was partially shot with a mobile phone.