夏日大作戰
The film was announced at the 2008 Tokyo International Anime Fair. At the 2009 Otakon convention Madhouse president Masao Maruyama said that Hosoda insisted on including 80 family members as its main characters. Maruyama then quipped that he asked Hosoda to promise only two main characters and two years of production for his next film. "Summer Wars" was one film in Madhouse's larger theatrical film release strategy, to release one new film each season for the next year. The release of "Summer Wars" was followed by "Mai Mai Miracle" and "Yona Yona Penguin" in 2009 with "Redline" released during the first half of 2010.