.hack//Sign (stylized as .hack//SIGN) is a Japanese anime television series directed by Kōichi Mashimo, and produced by studio Bee Train and Bandai Visual, that makes up one of the four original storylines for the .hack franchise.

[5][6] The series focuses on a Wavemaster (magic user) named Tsukasa, a player character in a virtual reality massively multiplayer online role-playing game called The World.

The storyline moves at a leisurely pace,[7] and has multiple layers[8]—the viewer is often fed false information and red herrings, potentially leading to confusion until the true nature of events is unveiled towards the end of the series.

[12] Two years later free access to the networks recovers, bringing with it the release of The World: the first online game since Pluto's Kiss, developed for Altimit OS.

[11] The World is portrayed as a fantasy setting wherein player characters can be different classes, adventure by themselves to go searching through dungeons or join with others and form parties, fight monsters and level up, collect new items and participate in special events.

He secretly designed the game as a virtual womb in order to create the ultimate artificial intelligence (AI), by receiving emotional and psychological data from the players.

His motivation is revealed to be the death of Emma Wielant, a German poet with whom he was in love; the AI, who was named Aura, would serve as the "daughter" they never had.

[15] Harald left the gathering of the required data for Aura's development at the care of the core system of The World itself, an omnipresent AI called Morganna Mode Gone.

Tsukasa isolates himself, but eventually he begins to get closer to other players, and builds strong relationships with some of them; the most important is the one born between him and Subaru, a kind and thoughtful female Heavy Axeman.

[10][16] In the meantime, the series follows the quest for the Key of the Twilight (黄昏の鍵, Tasogare no Kagi), a legendary item rumored to have the ability to bypass the system in The World.

Near the end of the series, Tsukasa's real-life identity takes a more central place in the storyline, particularly in relation to his growing bond with Subaru.

Morganna conceived the plan to link Aura to a character who could corrupt her with negative emotional data, placing her in a state where she would never awaken.

[citation needed] The project development began in early 2000 as a joint effort between Bandai and CyberConnect2, with the original idea of producing an online game.

[25][26] Taking advantage of the PlayStation 2's capability to read DVD-Video, the authors also decided making an OVA series (.hack//Liminality) comprised by four episodes, one to go with each game.

[25] The virtual environment depicted in .hack//Sign draws on medieval imagery:[27] settings range from a Venice-like city to a Gothic stone church, passing by settlements such as villages and castles; the series' scenery shows examples of Celtic art.

[5] Scenes of the real world show people living an apprehensive, even painful reality:[27] characters' background includes subjects such as dysfunctional families and physical impediments.

[citation needed] Tsukasa himself is psychologically affected by years of physical abuse and neglect,[6] a state that gets worse throughout his experience in the game, where his reality disappears and he begins to doubt his own existence.

[5] When anxiety is excessive (like in the case depicted by Tsukasa's story) and can not be relieved by practical problem-solving methods, "the human ego uses maneuvers such as a defense mechanism to deny, falsify or even distort reality.

[10] Initially Tsukasa shows no respect for any values or other people, but as he engages in relationships, he begins to gradually change, learning to care about others and acquiring the strength to face the reality of his life.

[51] Following the multimedia concept of the franchise,[52] Bandai also acquired the license for the .hack games,[48] the first one being released the same month the anime series began broadcast.

[55][56] Following the closure of Bandai Entertainment, Funimation (later Crunchyroll, LLC) announced at SDCC 2013, that they acquired four .hack titles including SIGN.

The book, called Encyclopedia .hack (ISBN 4-8291-7530-3), is a compilation of theories and information about storyline, setting, and characters of the franchise, taken from the series itself.

[60] Negative criticism focuses on the slow-paced story and the almost total absence of action sequences, elements which are also considered as what makes the series "most unique".

[7][9] Bamboo Dong of Anime News Network called the series "interesting to watch," saying the story gets more "detailed and complex" by the show's fourth episode, praised the music selection, the voice casting, and the artwork.

[62] He further said that the show puts you in the middle of relationships between the character and although these are not originally described, views come to understand the logic behind their actions, and added that the "underlying art" of the series holds up.

He also said that the series has consistent backgrounds, a diverse music score, and calls the anime, ultimately, a story of "anxiety and identity and virtual selves."

[3] Tasha Robinson from SCI FI Weekly says that "The World's hugely varied settings provide ever-changing backgrounds,"[9] which are considered by Rob Lineberger of DVD Verdict as "detailed and innovative".

[2][3][64] Reviewers appreciated the English voice acting: Lauren Synger from DVD Vision Japan feels that "everyone was very appropriate to their characters", noting that Brianne Sidal did an excellent work capturing Saiga's Tsukasa.

[8] Bamboo Dong of Anime News Network thinks for her part that Mimiru sounded bland and poorly executed, but overall, the actors did a good job "delivering their lines and giving life to their characters.

"[33] Ridwan Khan of Animefringe welcomes the "excellent" .hack//Sign score composed by Yuki Kajiura,[32] which is hailed by Mark McPherson from Anime Boredom as "the best orchestrated track ever made for a television series".