Linebarrels of Iron is a Japanese manga series created by Eiichi Shimizu and Tomohiro Shimoguchi. The series was first serialized in Akita Shoten's monthly shōnen manga magazine, Champion Red, in 2005. It has since been compiled into eleven tankōbon, as of November 20, 2008. The story centers around Kouichi Hayase, a fourteen-year-old boy living a mediocre life, until an accident turns him into the pilot of a gigantic robot called "Linebarrel" and leads him to encounter a mysterious girl.
An anime adaptation of the manga series was announced in the February issue of Animage magazine. The anime is directed by Masamitsu Hidaka and animated by Gonzo. Though the world premiere of the first episode took place at Southern California's 2008 Anime Expo, the series premiered in Japan on the television network TBS on October 3, 2008. The anime broadcast a total of twenty-four episodes, the last of which aired on March 20, 2009. To commemorate the series' anime adaptation, Shimizu and Shimoguchi decided to create a one shot manga, recreating the entire first episode of the anime, in which the plot differs in many aspects compared to the beginning of the manga..