Box art of the visual novel
|Genre||Psychological, Sci-fi, Supernatural, Thriller, Romance|
Naotaka Hayashi (scenario writer)
|Platform||PC, Xbox 360, PSP, PlayStation 3, iPhone, iPod Touch, iPad, Android|
|Released||April 25, 2008 (PC)
February 26, 2009 (Xbox 360)
June 24, 2010 (PSP)
November 18, 2010 (iOS)
January 24, 2012 (Android)
March 1, 2012 (PSN)
November 22, 2012 (PS3)
|Written by||Nitroplus and 5pb.|
|Published by||ASCII Media Works|
|Original run||May 21, 2008 – May 21, 2009|
|Chaos;Head -Blue Complex-|
|Written by||Nitroplus and 5pb.|
|Illustrated by||Nagako Sakaki|
|Published by||Media Factory|
|Magazine||Monthly Comic Alive|
|Original run||August 26, 2008 – ongoing|
|Written by||Nitroplus and 5pb.|
|Illustrated by||Takehito Mizuki|
|Original run||September 26, 2008 – ongoing|
|Anime television series|
|Directed by||Ishiyama Takaaki|
|Written by||Inoue Toshiki|
|Licensed by|| Funimation Entertainment
|Network||Kids Station, Tokyo MX, TV Tokyo, TV Saitama, TV Chiba, TV Kanagawa|
|English network||Funimation Channel|
|Original run||October 9, 2008 – December 25, 2008|
Chaos;Head (カオスヘッド Kaosu Heddo?), stylized as ChäoS;HEAd, is a Japanese visual novel developed by 5pb. and Nitroplus that was released on April 25, 2008 for the PC. A port of the game, named Chaos;Head Noah (カオスヘッドノア Kaosu Heddo Noa?), for the Xbox 360 console was released on February 26, 2009 followed by releases on the PlayStation Portable, iOS, Android & PlayStation 3. The game is the first in 5pb.'s Science Adventure series, and is described by the development team as a "Delusional Science NVL" (妄想科学NVL Mōsō Kagaku NVL?). The game's premise revolves around a high school student named Takumi Nishijō who unknowingly walks into the scene of a gruesome murder on his way home. More mysterious events start happening afterwards as more gruesome murders occur in the area. Takumi struggles to cope with reality and the delusions he experiences as he tries to avoid getting caught by the perpetrator behind the chain of murders. Although no release outside of Japan is planned, an unofficial English fan translation has been released.
The game's story has been adapted into a manga that started serialization on May 21, 2008 in ASCII Media Works' shōnen manga magazine Dengeki Daioh. A second manga adaptation that focuses on Sena Aoi and Kozue Orihara began serialization in Media Factory's seinen manga magazine Monthly Comic Alive on August 28, 2008. It has been decided for this adaptation to be a side story to the original visual novel. A third adaptation begun serializing in Jive's shōnen manga magazine Comic Rush magazine on September 26, 2008. The anime adaptation of Chaos;Head by Madhouse aired in Japan between October 9, 2008 and December 25, 2008.
The gameplay of Chaos;Head, like other visual novels, requires little player interaction as the game is primarily made up of text dialogues. The player only needs to read and click through the text to advance through the game. The text that is displayed on the screen depicts conversations between different characters or their thoughts.
Chaos;Head presents choices to the player through a unique "delusional trigger" (妄想トリガー mōsō torigā?) system. This system presents the player with three choices relating to Takumi's psychological state. Two cardiac cycles will be displayed on the screen. A green, stable one will be on the top left hand corner and a red, unstable one will be on the top right hand corner. The third choice is not visible to the player as it requires no player interaction. The player may choose to click on the green or red cardiac cycle, or to simply proceed through the game without selecting either of them. The player is not required to make a choice immediately as the two cardiac cycles will remain on the screen until a predetermined number of lines has been passed since they appeared.
Selecting the cardiac cycles will often decide what kind of delusions Takumi will experience. The stable choice often shows a happy or humorous scene whereas the unstable choice will show very negative scenes possibly with gore and violence added. Yes and no questions also show up at times although they are much less frequent than the delusional triggers.
Setting and themes
Chaos;Head primarily takes place in Shibuya, Tokyo. Many of Shibuya's physical locales like its busy pedestrian scramble and the Loft building appear in the game although their names have been altered slightly. Some notable Internet websites like Wikipedia, 2channel, YouTube, Google, and Yahoo! also show up in the game with modified names to avoid trademark issues, and as jokes, as We-Key Pedophiria, @-channel, MewTube, Deluoode, and Taboo!.
As the title implies, psychological themes relating to one's psyche and mind plays a large role in Chaos;Head. Delusions and the method of projecting one's own delusions onto the physical world, or onto someone else's visual system, is a key driver behind the story. Other scientific themes such as the concepts of matter, antimatter, and the Dirac sea are also brought up.
Chaos;Head's story is set in 2009 in Shibuya and is centered around Takumi Nishijō, a high school student at the private Suimei Academy, and the strange and brutal murders that have recently occurred in the Shibuya area, known as the "New Generation" (ニュージェネレーション?) Madness. The story begins on September 28 with Takumi talking to an online friend called Grim (グリム Gurimu?). Grim is trying to bring Takumi up to speed about the recent New Generation events since Takumi is not interested in local or international news. A person named Shogun (将軍?) joins the chat room midway through Grim and Takumi's conversation. After Grim leaves the chat room, Shōgun begins to talk. He speaks in a very cryptic and confusing manner, leaving Takumi nervous. He then sends Takumi a barrage of image links, one of which appears to be of a brutal murder of a man being pinned by stakes to a wall.
The next day, Takumi comes across a real life murder scene. Witnessing a mysterious pink-haired girl pinning a man up by stakes in an alleyway, he immediately realizes he is witnessing the very murder detailed in the pictures he received the day before. Convinced Shogun is targeting him and the girl he saw committing the murder is somehow connected to him, Takumi tries to avoid getting involved with other New Generation events. However, as Takumi begins attempting to distance himself from the crime he witnessed, he soon catches interest of the police.
With the police suspecting him, and himself convinced that he is being targeted by Shogun, Takumi finds himself caught in a spiral of delusions and paranoia, as he desperately tries to keep himself safe and figure out why he is apparently being targeted. He eventually comes into contact with several other people related to the events, including the girl he saw committing the murder herself. Unsure of what is real or who he can trust, Takumi finds himself thrust into a much larger scheme than he ever thought possible, as the mysterious company NOZOMI carefully plots something from behind the scenes.
- Takumi Nishijō (西條 拓巳 Nishijō Takumi?)
- Takumi is the main character of the series. He is withdrawn and is not interested in 3D things. He suffers from intense delusions as a result of his apparent schizophrenia and the extremely secluded lifestyle he lives as a hikkikomori. He only attends school in order to fulfill the minimum for graduation requirements. He avoids conversations with others whenever possible. He prefers to engage in watching anime, playing eroge, and massively multiplayer online role-playing games. He is a second-year student at Suimei Academy (翠明学園 Suimei Gakuen?). He is hinted to appear in Steins;Gate's sequel, Steins;Gate: Henikuukan no Octet, as the main character, Rintarō Okabe, receives a D-Mail telling him to reclaim an IBN 5100 from a person under the alias of "Neidhardt", Takumi's name in his favorite MMORPG. The D-Mail also states that "Neidhardt" lives in Shibuya and has "inherent, supernatural abilities", a reference to his power as a gigalomaniac. The username "Neidhardt" also briefly appears on Kaito Yashio's PokeCom tablet in Episode 9 of Robotics;Notes.
- Rimi Sakihata (咲畑 梨深 Sakihata Rimi?)
- Rimi is a mysterious pink-haired girl that Takumi encounters at the crime scene on his way home. Rimi was wearing Suimei Academy's uniform at the time and appeared to recognize Takumi. She later claims to have known Takumi for a long time, something that only Takumi seems to be unable to remember, yet she claims to have no idea what he is talking about in regards to the murder.
- Nanami Nishijō (西條 七海 Nishijō Nanami?)
- Nanami is Takumi's younger sister and is a first-year Suimei Academy student. She often puts up a strong front and seems to argue with her brother whenever they meet but she is actually really concerned about him.
- Ayase Kishimoto (岸本 あやせ Kishimoto Ayase?)
- Ayase is a second-year Suimei Academy student by day and vocalist by night. She sings for a popular rock band named "Phantasm" (ファンタズム Fantazumu?). Her stage name is "FES". The lyrics in her songs appears to describe the events of the recent murders, leading the police to see her as a potential suspect. She is also the most spiritual and eccentric of the main characters. She (besides Takumi) is another connection to Steins;Gate: Yui Sakakibara (singer of Steins;Gate ending) credited as FES. Her likeness can be seen on various posters throughout Steins;Gate.
- Yua Kusunoki (楠 優愛 Kusunoki Yua?)
- Yua is a third-year student at Suimei Academy who seems to be stalking Takumi but later seemingly befriends him. She seems to be quite into anime and manga. However, this is all later shown to be an act where she is investigating him as she suspects Takumi of being the criminal behind the recent murders.
- Sena Aoi (蒼井 セナ Aoi Sena?)
- Sena is a third-year student at Suimei Academy. Takumi first encounters her in a hallway at school but quickly excuses himself after facing her ominous glare. She is often seen standing around Shibuya holding a very long sword and eating a light blue ice pop. A short cross-over story involves her meeting Rintarō Okabe in the streets of Shibuya, one year before the events of Steins;Gate.
- Kozue Orihara (折原 梢 Orihara Kozue?)
Voiced by: Ayumi Tsuji (Japanese), Kara Edwards (English)
- Kozue is a second-year student that transfers into Suimei Academy early on in the story. She is not shown to be speaking but appears to have telepathic abilities. She calls herself Kozupii.
- Grim (グリム Gurimu?)
- Grim is Takumi's online friend, who talks to him almost everyday through their mutual favorite online game, Ensue. He often encourages Takumi to have more courage while dealing with the "third dimension", and supports Takumi throughout his many ordeals. He is very interested in the New Generation incidents and frequently updates Takumi with gory details regarding the murders. As his interests in anime, manga, and games are very similar to Takumi's, the two get along very well, although later his frequent use of the "Whose eyes are those eyes?" phrase seriously bothers Takumi.
- Shogun (将軍 Shōgun?)
- Shogun is a mysterious person that Takumi meets during a chatting session. He sends gore pictures relating to the New Generation incident to Takumi, the equation "fun^10xint^40=Ir2", and the phrase "Those eyes, whose are they?", which Takumi often used. This event gives Takumi paranoia throughout the story, thinking that Shogun is spying on him and trying to kill him. As the story goes on Shogun is shown as a wheelchair bound man only noticed by Takumi (initially). In spite of Takumi's denial, other characters are suspicious of Shogun and think that Takumi is Shogun (via split personality). It is later revealed that Shogun is not a figment of Takumi's imagination, instead that Takumi is a figment of Shogun's delusion. Shogun, the real Takumi, is stricken with Progeria and created the real existence of the healthy Takumi via a "realboot" using his powers as a Giglomaniac. In the English dub, he is called the General.
- Seira Orgel (星来 オルジェル Seira Orujeru?)
- Seira is the main heroine from Takumi's favorite anime "Blood Tunes the Animation", and also Takumi's favorite character. Occasionally, she shows up in Takumi's delusions, trying to deviate him from reality and push him to be a shut-in. Her delusional appearance is in fact Takumi's own weaknesses given voice. She briefly appears as an image on Rintarō Okabe's phone in the visual novel of Steins;Gate. A poster of her can be seen in the background of Maguyan's room in episode 14 of Robotics;Notes.
- Daisuke Misumi (三住 大輔 Misumi Daisuke?)
Voiced by: Daisuke Ono (Japanese), Joel McDonald (English)
- Daisuke is the only friend Takumi has in his class. A handsome man, he is well liked by almost all girls in his school.
- Yasuji Ban (判 安二 Ban Yasuji?)
- Ban is a detective of the Tokyo Metropolitan Police Department Criminal Investigation Division. He initially suspects Takumi of being the criminal behind the New Generation murders, but he soon finds himself investigating other leads, including the company NOZOMI and a well-known religious cult. He is shot dead by his partner Suwa after it is revealed Suwa is with the NOZOMI Group.
- Mamoru Suwa (諏訪 護 Suwa Mamoru?)
Voiced by: Makoto Yasumura (Japanese), Scott Freeman (English)
- Mamoru is a detective of the Tokyo Metropolitan Police Department Criminal Investigation Division. He is Ban's junior, and Ban considers him to be both an underling and a friend. His hobby is watching movies, especially Spark Wars, a parody to Star Wars. He is a member of the "Church of Divine Light" and the NOZOMI Group. In the alternate ending of the visual novel, it is revealed that he, along with his childhood friend and lover Hazuki Shino, worked together as the true New-Gen Criminals. He used a mask of Darth Spider to hide his identity and used pseudo Giglomaniac abilities to commit the crimes along side Hazuki Shino actions. He fights Takumi with his new-found Giglomaniac abilities, which take the form of stakes of blue energy, but Takumi, who is more experienced with his Gigalomaniacal abilities, reverses the technique on Suwa and pierces him multiple times with his own stakes, killing him.
- Hazuki Shino (葉月 志乃 Shino Hazuki?)
Voiced by: Noriko Aoki (Japanese), Monica Rial (English)
- Hazuki is a nurse at Tokyo AH General Hospital. She was the assistant of Takumi's old doctor during his stay in the psychiatric division. She is later revealed to be the person behind the persona Grim that Takumi frequently contacted over the internet, as well as being one half of the true New-Gen criminals, along with her childhood friend and lover Mamoru Suwa. She is a member of the cult detective Ban is investigating, known as the "Church of Divine Light", which has ties to the NOZOMI Group. She kills herself in the visual novel by slitting her own throat with a scalpel, and in the anime by driving a stake used in the third crime into her throat.
- Genichi Norose (野呂瀬 玄一 Norose Gen'ichi?)
- Norose is the president of the NOZOMI Technology Group. His role is kept a mystery throughout most of the story, until he is revealed to be the main antagonist, and the creator of the Noah II device, capable of manipulating brain waves and causing delusions to become reality. He has been gathering people with special psychic powers as young children, and torturing them for the sake of completing his twisted desires. He is killed when Takumi impales him to Noah II with his Di-Sword, which had manifested a serpent of anti-matter, causing the device to explode and kill him.
Chaos;Head is a collaborative production between 5pb. and Nitroplus with additional assistance from Red Flagship. The original concept art and scenario came from two 5pb. staff members, Yukihiro Matsuo and Naotaka Hayashi respectively. The character designer was Mutsumi Sasaki and Choco handled the product's design. 5zizz studio contributed the music to the game and Nitroplus handled the development and production of the game. Chaos;Head was temporarily named as Gigalomaniacs (ギガロマニアックス Gigaromaniakkusu?) when it was first announced. The decision to port the game to the Xbox 360 was decided around June 2008. Ayumi Tsuji, the voice for Kozue Orihara, noted that Orihara's new route that was introduced in Chaos;Head Noah was likely the cause behind the game receiving an 18+ Z rating from CERO. The PlayStation 3 version was rated 17+ D from CERO but is exactly the same as its Xbox 360 counterpart with nothing cut out.
Chaos;Head had two demo releases prior to its final product release. The first version of the demo was released on March 21, 2008 which included the first chapter of the game. The second version of the demo was released on April 11, 2008. This second version included the first chapter of the game like the first version as well as a separate "Chapter 1 Reflection Meeting" (第1章反省会 Dai Isshō Hanseikai?) which included all of the main characters trying to determine who the main heroine of the game was. The full game was released on April 25, 2008. Pre-orders of the game came with two bonuses. The first was a patch that added a "Lingerie Conversion System" that swapped the lead female characters' models with models that only wore undergarments and the second was a telephone card. A consumer console port, named Chaos;Head Noah, was published by 5pb. The game was released on the Xbox 360 on February 26, 2009. The port contains new routes for the heroines of the game as well as new CG graphics. The CGs are rendered at a resolution of 1280x720, improving on the PC version's scaling of 800x600. Interestingly, Chaos;Head Noah has also been released in America as an iPod Touch/iPhone app, and in HD for the iPad. An Android version was released as well. However, the game still only supports Japanese. A downloadable version of the PlayStation Portable game was released on the Japanese PlayStation Store March 1, 2012 and is compatible to play on PlayStation Vita. A PlayStation 3 version was released November 22, 2012 alongside Chaos;Head Love Chu Chu!. Unlike its Xbox 360 counterpart, The PS3 version supports 1080p HD with all CGs rendered at a resolution of 1920x1080.
Internet radio show
An Internet radio show named Chaos;Head Radio Delusional Radio Channel (Chaos;Head ラジオ 妄想電波局 Chaos;Head Rajio Mōsō Denpakyoku?) began airing on March 28, 2008 to help promote the visual novel. The show was hosted by Hiroyuki Yoshino and Eri Kitamura who voiced Takumi Nishijō and Rimi Sakihata respectively. Other voice actors from the game like Hitomi Nabatame and Chiaki Takahashi also appeared on the show on select episodes. The show was streamed online every Friday and lasted for ten episodes with the last episode airing on May 30, 2008. A soundtrack named Chaos;Head Radio CD Delusional Radio Channel (Chaos;Head ラジオ 妄想電波局 Chaos;Head Rajio Mōsō Denpakyoku?) containing two CDs was released on August 29, 2008. The first CD contained all ten episodes of the Internet radio show and an eleventh show titled "Chaos;Head Radio Evaluation Meeting" (Chaos;Head ラジオ 妄想反省会 Chaos;Head Rajio Hanseikai?). All eleven tracks are in MP3 format. The second CD is in regular audio format containing "Blood Tune The Radio" (ブラッドチューン The Radio Buraddochūn The Radio?) and "Takumi Nishijō's Everyday Life" (西條拓巳の日常 Nishijō Takumi no Nichijō?).
A manga series based on the visual novel, illustrated by Sumihey, has started its serialization in ASCII Media Works' shōnen manga magazine Dengeki Daioh on May 21, 2008. A second manga adaptation, named Chaos;Head -Blue Complex-, revolving around Sena Aoi and Kozue Orihara began serialization in Media Factory's seinen manga magazine Monthly Comic Alive on August 26, 2008. The illustrations are provided by Nagako Sakaki. A third adaptation entitled Chaos;Head H (かおすへっどH Kaosu Heddo H?) began serializing on September 23, 2008 in Jive's Comic Rush magazine.
An anime adaptation of the visual novel was produced by Madhouse Studios and first aired in 2008. The anime adaptation features exactly the same cast of voice actors from the PC game. The anime is licensed by Funimation Entertainment and was released in North America in a DVD/Blu-ray Disc combo boxset on November 29, 2011.
Both Chaos;Head's opening theme, "Find the Blue", and ending theme, "Desire Blue Sky", are performed by Kanako Itō. The CD single was released on May 7, 2008. The single was able to stay on the Oricon charts for three weeks with a peak position of 54th place. A single for the game's insert song, "Zaika ni Keiyaku no Chi o" (罪過に契約の血を?), and third ending theme, Gurajiōru (グラジオール?), performed by Yui Sakakibara was released on June 25, 2008. Sakakibara's single peaked at 63rd place on Oricon and stayed there for two weeks. The soundtrack for the game was released on July 4, 2008 in a two CD set with seventeen tracks each. The soundtrack's second CD included the second ending theme, "Cry" (クライ?), sung by Kanako Itō.
The anime opening theme song, titled "F.D.D.", was sung by Kanako Itō and the ending theme, titled "Super Special", was sung by Seira Kagami. The CD single for "F.D.D." (with additional song "Fly to the sky", both in original and off vocal versions) was released on October 29, 2008. The CD single for "First Sight" (with original and exclusive edits), which included the ending theme "Super Special" as its B-side, was released on November 21, 2008. Also, the CD single "Phantasm. FES cv. Yui Sakakibara" was released and contained "Haritsuke no Misa" and "Haruka Naru Idiyona" songs (both in original and off vocal versions), which can be heard in Episode 3 on Phantasm club performance (end of "Haruka Naru Idiyona", first couplet of "Haritsuke no Misa" and begin of "Haruka Naru Idiyona").
Reception and legacy
|This section requires expansion with: reviews from the further reading section. (December 2011)|
During the month of March 2008, one month before Chaos;Head's release on April 25, 2008, Chaos;Head ranked fourth in national PC game pre-orders in Japan. Chaos;Head came out in third place in sales ranking in April and twenty-nine for May 2008. Chaos;Head became the 16th bestselling visual novel on Getchu.com during the first half of 2008 and 35th overall for the year of 2008. Chaos;Head Noah placed 11th during its first week of release selling 17,952 copies.
Phantom Breaker is an Xbox 360 game that features Rimi as a guest character. It was released in Japan on June 2, 2011.
- "Chaos;Head Noah official website" (in Japanese). 5pb. Games. 2010-01-25. Retrieved 2010-01-25.
- "Official Chaos;Head anime website" (in Japanese). 2008-09-10. Retrieved 2008-09-11.
- "Nitroplus's Chaos;Head product description" (in Japanese). Nitroplus. Retrieved 2008-05-24.
- "5pb. Games' product listing for 2008" (in Japanese). 5pb. Retrieved 2008-06-01.
- "Dengeki Moeoh Blog" (in Japanese). ASCII Media Works. 2008-04-19. Archived from the original on May 2, 2008. Retrieved 2008-05-12.
- "Comic Alive "Chaos;Head" second comic serialization begins!" (in Japanese). Nitroplus. 2008-08-26. Retrieved 2008-08-31.
- "Chaos;Head Game Gets Third Manga in Comic Rush Mag". Anime News Network. 2008-09-04. Retrieved 2008-09-07.
- "Comic Alive December Issue on sale today!!" (in Japanese). Monthly Comic Alive. 2008-07-26. Retrieved 2008-07-26.
- "TVA "Chaos;Head" staff announcement." (in Japanese). Moon Phase. 2008-07-28. Retrieved 2008-07-29.
- Shinji Tamura (2008-05-22). "4Gamer.net's 33rd "Character Game" series article on Chaos;Head" (in Japanese). 4Gamer.net. Retrieved 2008-06-01.
- "Chaos;Head and Shibuya Street: In Front of Shibuya Station, Part I" (in Japanese). 2008-05-06. Retrieved 2008-06-03.
- "Chaos;Head and Shibuya Street: Center Street Part 3" (in Japanese). 2008-05-12. Retrieved 2008-06-03.
- "5pb's We-Key Pedophiria website" (in Japanese). 5pb. Retrieved 2008-09-26.
- "Deluoode Google Search Engine" (in Japanese). Deluoode. Retrieved 2008-09-26.
- "That is Chaos;Gate’s choice… ~That is, the Gigalomaniacs’ version of Steins;Gate’s choice~". Tempus Edax Rerum. Retrieved 10 June 2013.
- "Animate's Chaos;Head promotional release website" (in Japanese). Archived from the original on May 1, 2008. Retrieved 2008-05-15.
- "Choco's blog entry about the Windows software Chaos;Head" (in Japanese). 2008-04-28. Retrieved 2008-06-01.
- ""Chaos;Head" Original Soundtrack" (in Japanese). Zizz Studio. Retrieved 2008-08-14.
- "Comiket 72 - New PC game from Nitroplus x 5gk. in the coming spring" (in Japanese). animate.tv. Retrieved 2008-07-23.
- "Game Creator's Interview - Production interview with Chaos;Head Noah Creators with Tatsuya Matsuhara and Hayashi Naotaka from 5pb. (Part 2)" (in Japanesedate=2009-02-10). animate.tv. Retrieved 2009-02-11.
- "The reason behind the Z rating revealed!? Chaos;Head Noah's release commemoration event begins" (in Japanese). Famitsu. 2009-03-01. Retrieved 2009-03-01.
- "Nitroplus's official Chaos;Head website's "News" section" (in Japanese). Nitroplus. 2008-03-21. Retrieved 2008-05-29.
- "Nitroplus User Support page for Chaos;Head" (in Japanese). Nitroplus. Retrieved 2008-05-24.
- "Surpara Shop's product description for Chaos;Head" (in Japanese). Surpara. Retrieved 2008-05-24.
- "Famitsu Game & Entertainment" (in Japanese). Famitsu. 2012-07-18. Retrieved 2012-08-20.
- "Nitrplus's official Chaos;Head website's "Radio" section" (in Japanese). Nitroplus. 2008-05-30. Retrieved 2008-05-31.
- "Nitrplus's music product lineup for Chaos;Head" (in Japanese). Nitroplus. Retrieved 2008-07-26.
- "Comic Alive November Issue Back Number". Media Factory. Retrieved 2008-11-09.
- "Funimation Adds Rosario+Vampire Anime And More". Anime News Network. 2010-05-15.
- "Psycho-suspense "novel game" Chaos;Head theme song! Kanako Itō's new single "Find the blue", on sale May 5!" (in Japanese). Axive. 2008-04-18. Retrieved 2008-04-21.[dead link]
- "5pb. Records' product description for "Find the blue"" (in Japanese). 5pb. Records. Retrieved 2008-05-29.
- "Oricon Style's CD information for "Find the blue"" (in Japanese). Oricon. Retrieved 2008-05-31.
- "5pb. Records' product description for "Zaika ni Kieiyaku no Chi wo" (罪過に契約の血を)" (in Japanese). 5pb. Records. Retrieved 2008-05-29.
- "Oricon Style's CD information for "Zaika ni Keiyaku no Chi o" (罪過に契約の血を)" (in Japanese). Oricon. Retrieved 2008-07-28.
- "5pb. Records' product description for "Chaos;Head Original Soundtrack"" (in Japanese). 5pb. Records. Retrieved 2008-06-09.
- "PCpress's Pre-order Ranking Log for March 2008" (in Japanese). PCpress. Retrieved 2008-05-31.
- "PCpress's Software Sales Ranking for April 2008" (in Japanese). PCpress. Retrieved 2008-05-31.
- "April 2008 sales ranking" (in Japanese). Getchu.com. Retrieved 2008-07-17.
- "May 2008 sales ranking" (in Japanese). Getchu.com. Retrieved 2008-07-17.
- "Getchu.com PC visual novel sales rankings for the first half of 2008" (in Japanese). Getchu.com. Retrieved 2008-07-30.
- "Getchu.com PC visual novel sales rankings for 2008" (in Japanese). Getchu.com. Retrieved 2009-03-01.
- ""Game Software Sales Ranking" Data Gathering Time: February 23, 2009 ~ March 1, 2009" (in Japanese). Famitsu. March 13, 2009. Retrieved November 8, 2009.
- McNeil, Sheena (28 November 2011). "Chaos;HEAd - the Complete Series". Sequential Tart.
- Yegulalp, Serdar. "Chaos;HEAd: The Complete Series". About.com. The New York Times Company.
- Yegulalp, Serdar (30 November 2011). "Anime Review: 'Chaos;HEAd'". About.com. The New York Times Company.
- Meek, Bradley. "Chaos;HEAd". T.H.E.M. Anime Reviews.
- Jomes, Davey C. (29 November 2011). "Chaos; Head Complete Series". Active Anime.
- Official Chaos;Head website (Japanese)
- Official Chaos;Head Noah website (Japanese)
- Chaos;Head Noah PlayStation 3 version page (Japanese)
- Anime official website (Japanese)
- Chaos;Head at Funimation
- Chaos;Head (anime) at Anime News Network's Encyclopedia