Summer Wars (2009)

August 1, 2009 (JP) • Animation, Science Fiction • 114m

Overview

Teenage math whiz Kenji Koiso agrees to take a summer job at the Nagano hometown of his crush, Natsuki. When he arrives, he finds that her family have reunited to celebrate the 90th birthday of their matriarch. His job: pretend to be Natsuki's fiancé. Meanwhile, his attempt to solve a mathematical equation causes a parallel world's collision with Earth.

Director

Mamoru Hosoda

Writer

Satoko Okudera

Top Billed

Ryunosuke Kamiki

Keywords

card game artificial intelligence (a.i.) computer hacker virtual reality family holiday adult animation cybercrime anime

Where to watch

Free / Included

HBO Max Amazon Channel

Rent

Buy

Top Billed Cast

Ryunosuke Kamiki

Kenji Koiso (voice)

Hitomi Miyauchi

Natsuki Shinohara (voice)

Mitsuki Tanimura

Kazuma Ikezawa (voice)

Sumiko Fuji

Sakae Jinnouchi (voice)

Ayumu Saito

Wabisuke Jinnouchi (voice)

Takahiro Yokokawa

Takashi Sakuma (voice)

Kiyomi Tanigawa

Yukiko Shinohara (voice)

Mutsumi Sasaki

Kazuo Shinohara (voice)

Mieko Nobusawa

Mariko Jinnouchi (voice)

Takuya Kirimoto

Riichi Jinnouchi (voice)

Sakiko Tamagawa

Rika Jinnouchi (voice)

Ichiro Nagai

Mansuke Jinnouchi (voice)

Takashi Kobayashi

Tasuke Jinnouchi (voice)

Yutaka Shimizu

Shota Jinnouchi (voice)

Kaori Yamagata

Naomi Miwa (voice)

Tagame Tamura

Kiyomi Ikezawa (voice)

Tadashi Nakamura

Mansaku Jinnouchi (voice)

Yoji Tanaka

Yorihiko Jinnouchi (voice)

Hashiya Nakamura

Kunihiko Jinnouchi (voice)

Mitsutaka Itakura

Katsuhiko Jinnouchi (voice)

Eiko Kanazawa

Noriko Jinnouchi (voice)

Chigusa Takaku

Nana Jinnouchi (voice)

Riisa Naka

Yumi Jinnouchi (voice)

Naoto Adachi

Ryohei Jinnouchi (voice)

Rikito Ota

Yuhei Jinnouchi (voice)

Yuki Imai

Shingo Jinnouchi (voice)

Sumire Morohoshi

Mao Jinnouchi (voice)

Hinano Minagawa

Kana Jinnouchi (voice)

Crew

Nozomu Takahashi

Producer

Takuya Ito

Producer

Mamoru Hosoda

Director

Yuichiro Saito

Producer

Akihiko Matsumoto

Original Music Composer

Shigeru Nishiyama

Editor

Satoko Okudera

Screenplay

Yasuyuki Konno

Sound Effects

Kazutaka Ozaki

Animation Director

Ayumi Arahata

Special Effects

Mami Yamaguchi

Key Animation

Aya Takano

Key Animation

Yuki Hayashi

Key Animation

Nobumasa Shinkawa

Key Animation

Tadashi Sakazaki

Key Animation

Takashi Mukoda

Key Animation

Keisuke Masunaga

Key Animation

Anri Jojo

Art Designer

Nobutake Ito

Key Animation

Shigeru Fujita

Animation Director

Kumiko Taniguchi

Special Effects

Hiroshi Kawaguchi

Key Animation

Soichiro Matsuda

Key Animation

Hiroyuki Aoyama

Key Animation

Tatsuro Yamashita

Theme Song Performance

Takashi Okazaki

Character Designer

Tatsuzo Nishida

Animation Director

Kaori Kobayashi

Special Effects

Takashi Hashimoto

Key Animation

Kunihiko Hamada

Animation Director

Kumiko Kawana

Key Animation

Michio Fukuda

Key Animation

Junko Ina

Background Designer

Chiemi Irisa

Special Effects

Kouichi Arai

Key Animation

Tadashi Abiru

Key Animation

Keiko Itogawa

Special Effects

Ayako Hata

Key Animation

Michiyo Suzuki

Key Animation

Yuzo Yamada

Key Animation

Katsuyoshi Nakatsuru

Key Animation

Tatsuzo Nishida

Key Animation

Yumi Ishii

Background Designer

Chikako Kamata

Color Designer

Chie Uratani

Key Animation

Yasunori Miyazawa

Key Animation

Miwa Sasaki

Key Animation

Takaaki Hirayama

Key Animation

Shougo Furuya

Key Animation

Yoshio Obara

Sound Recordist

Takayuki Hamada

Key Animation

Mitsuko Baba

Key Animation

Naruyo Kiriyama

Background Designer

Tomohisa Shimoyama

Key Animation

Yoshiyuki Sadamoto

Character Designer

Mina Okazaki

Character Designer

Hiroyuki Aoyama

Animation Director

Hideki Takahashi

Key Animation

Hiroko Minowa

Key Animation

Jun Sekiguchi

Key Animation

Yukihiro Masumoto

Director of Photography

Kazutaka Ozaki

Key Animation

Ryotaro Makihara

Key Animation

Yoshihiro Kitano

Key Animation

Yasuhiro Nakura

Key Animation

Masaru Hamada

Character Designer

Kenji Hachizaki

Key Animation

Akitoshi Yokoyama

Key Animation

Atsuko Tanaka

Key Animation

Tadashi Matsuzaki

Key Animation

Ayumi Kawai

Background Designer

Ken Ootsuka

Key Animation

Masako Sato

Key Animation

Shiho Sato

Background Designer

Akane Iwakuma

Background Designer

Izumi Muta

Background Designer

Kohei Tanada

Compositing Artist

Kozue Okada

Music Producer

Masayuki Onoue

Music Editor

Takashi Muratani

Key Animation

Kuniko Iwatani

Background Designer

Yuji Ikeda

Background Designer

Naomi Takahashi

Compositing Artist

Hiromasa Ogura

Background Designer

Yoichi Nishikawa

Background Designer

Kazuyuki Hashimoto

Background Designer

Yoshikazu Fukutome

Background Designer

Kenji Fujita

Compositing Artist

Toshiharu Mizutani

Background Designer

Hitoshi Nagasaki

Background Designer

Ayami Aritake

Background Designer

Kei Machida

Compositing Artist

Yoshiyuki Ito

Key Animation

Takafumi Hori

Key Animation

Sawako Miyamoto

Key Animation

Mika Nishimura

Background Designer

Naoto Abe

Background Designer

Hideaki Yoshio

Key Animation

Katsushi Aoki

Background Designer

Shinichi Uehara

Background Designer

Seiko Yoshioka

Background Designer

Yasuhiro Asagi

Compositing Artist

Satoko Nakamura

Background Designer

Hitomi Sudo

Assistant Editor

Yuki Kawashita

Compositing Artist

Kanako Yamada

Compositing Artist

Shigeaki Miyata

Compositing Artist

Shigeki Nemoto

Compositing Artist

Yukiya Imamura

Compositing Artist

Kang Myoung-joo

Compositing Artist

Kentaro Yayama

Compositing Artist

Keiko Ishizuka

Compositing Artist

Atsuro Saito

Compositing Artist

Natsuko Sato

Compositing Artist

Mamiko Katakura

Music Editor

Tomohiko Ito

Assistant Director

Naoki Tate

Key Animation

Seiji Okuda

Executive Producer

Takashi Watanabe

Producer

Yoji Takeshige

Art Direction

Hiroyuki Inage

Thanks

Yuji Furuya

Foley

Naoki Akahira

Foley

Kazuo Oga

Background Designer

Koji Shinomiya

Thanks

Masayasu Arimatsu

Other

Mamoru Hosoda

Original Story

Reviews

CinemaSerf

⭐ 7/10

August 6, 2025

It’s really quite apposite to watch this film at a time when governments across the world are merrily acquiescing to the demands of global tech to facilitate the rampant advance of AI. This story quite cleverly illustrates just how easily a collection of “Will Hunting” types can be used to crack even the most complex (2,000 digit) numeric code and allow nefarious access to a global network which manages just about everything we do - from using our phones to firing a nuclear missile. It’s bright spark - but maybe just a touch inept - “Kenji” who has accepted a task that is definitely not what he was expecting from “Natsuki” and so finds himself at her grandmother’s ninetieth birthday luncheon posing as her beau. A bit of a nervous wreck, he is later presented with an online puzzle by “OZ”, the network in question and he manages to message back a solution. Next thing we all know, it’s been hacked by an increasingly violent AI that is bent on a quest for knowledge and power, and that will stop at nothing. When poor old “Kenji” is identified and gets the blame, only an unique sort of intervention from granny and a solid series of team efforts from her family and from his friends might enable them to thwart this menacing creation. The animation starts off with images that reminded me of one of those childhood kaleidoscopes that brought vibrant crystalline shapes together, before heading full pelt into a frequently quite pithily comedic look at family traditions, teenage hormones and menacing nasties threatening the entire fabric of the internet. You’ll possibly never see a more potent cinematic demonstration of just how dependent and inter-dependant we are on this network of cables and zeroes and ones for much, if not most, of modern life. Not just our social lives, but our actual lives too are controlled and once control of that falls into malevolent hands, well humanity risks being well and truly stuffed. The last half hour focuses a little more on dealing with that problem, and the quickly paced action animation is underpinned by a plausible degree of science too. In many ways, it’s almost a horror movie - especially if you think on it: first love or online demons?

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21 Status

Released

Original Language

Budget

—

Revenue

$18,434,328

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Summer Wars (2009)

Where to watch

Top Billed Cast

Crew