別冊少年マガジン
is a Japanese manga series written and illustrated by Yoshitoki Ōima. The series was originally published as a one-shot in Kodansha's "Bessatsu Shōnen Magazine" and was later serialized in "Weekly Shōnen Magazine" from August 2013 to November 2014. Its chapters were collected in seven "tankōbon" volumes. The manga was digitally released in English by Crunchyroll Manga and was licensed by Kodansha USA in North America. An anime theatrical film adaptation produced by Kyoto Animation was released in September 2016.