.hack//Sign (trademarked as .hack//SIGN) is an 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 of the .hack franchise. Twenty six original episodes aired on TV and three additional bonus episodes (Intermezzo, Unison, and Gift) were released on DVD as original video animations (OVAs). The series features character design by Yoshiyuki Sadamoto, known for his work on Evangelion, and screenplay by Kazunori Itō, who penned the screenplay for the first Ghost in the Shell movie. The score was composed by Yuki Kajiura, marking her second collaboration with Kōichi Mashimo.
.hack//Sign is influenced by psychological and sociological subjects such as anxiety, escapism, and interpersonal relationships. The series focuses on a Wavemaster (magic user) named Tsukasa, a player character of a virtual-reality massively multiplayer online role-playing game (MMORPG) called The World. Tsukasa wakes up to find himself in a dungeon in The World, but he suffers from short-term memory loss as he wonders where he is and how he got there. The situation gets worse when he discovers he is unable to log out and is trapped in the game. From then on, along with other players Tsukasa embarks on a quest to figure out the truth behind his abnormal situation.
The show premiered in Japan on Tokyo between April 4, 2002 and September 25, 2002. It was broadcast across East Asia, Southeast Asia, South Asia, and Latin America by the anime television network, Animax; and across the United States, Nigeria, Canada, and United Kingdom by Cartoon Network, YTV, and AnimeCentral (English and Japanese) respectively. It is distributed across North America by Bandai Entertainment.
The storyline moves at a leisurely pace, and has multiple layers — 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. It relies on character development and has few action scenes; most of the time character interaction is presented in the form of dialogue. English language reception to .hack//Sign has been generally positive, but some of these sources have negatively criticised the series as a result of its slow pacing and character-driven storyline.