The Cursed Videotape is a video created by Sadako Yamamura as a means of transmitting her curse to the rest of the world. In the original novels and Rasen, the tape is used to spread Sadako's virus strand whilst the other films turned the curse into a supernatural one. The viewers have seven days to copy the tape and show it to someone else, otherwise Sadako will kill them.
The Videotape seems to be a tape without label. When an analysis is done on it, there is no sign of who recorded it. The tape plays just fine in a VCR. It can be copied to other videotapes. This will cause more cursed tapes to be made. No matter if someone watches a copy or the original, the effects of the curse will be the exact same.
The video shows a panorama of odd and disturbing images relating to Sadako's past, but also possibly relating to the viewer. The video is not completely in black-and-white, but most images are, or feature black and white as the predominant colours. The first scene is a shot of Heihachiro Ikuma looking down at Sadako from the top of the well she was thrown into. Shizuko Yamamura then appears, combing her hair in a mirror and Sadako walking in on her; Shizuko's mirror briefly disappears and one showing Sadako appears, then Shizuko reappears looking towards Sadako. Then, a newspaper article about Shizuko predicting the eruption of Mount Mihara appears, but the kanji float about and only the word 'eruption' is stable. People are then depicted crawling on the floor and apparently dying -- aftermath of Mount Mihara's eruption.
It appears to be a shot of Ryuji Takayama standing in the sea, but there is a towel covering his face and he is pointing at something. This image is odd because Ryuji takes this form after his death, which occurs after Reiko watches the tape, although the image is already on the tape. Next there is a close-up of Sadako's eye, with the kanji for sada (part of her name, meaning chaste) reflected in it. Last, there is a shot of the well which Sadako was thrown into. This part of the video seems to extend itself at times; when Reiko first watches the video nothing happens to the well, but when she watches it again, Sadako's arm comes out of it. When Yoichi Asakawa, her son, is seen watching it, Sadako's other arm emerges from the well as she begins to pull herself up.
Lastly, when Sadako comes to kill Ryuji (and presumably her other victims), the scene plays on the nearest TV (whether the video is in it or not) and Sadako completely emerges from the well, slowly walks towards the screen and proceeds to crawl out of the TV.
Throughout the video a number of unearthly sounds play. It is unknown what makes these sounds, but they are very unnerving.
In the novels, the curse is actually a smallpox virus mutated by Sadako. It creates a tumour in the victim's throat and after seven days, they will die of a heart attack, the face of horror being a side effect. The virus also contains a strand of Sadako's DNA, which can be fertilised and lead to her resurrection as seen in the second novel Spiral, along with other deceased characters.
In the films, after the viewer finishes watching the tape, the phone will ring if they are in Cabin B4 at Izu Pacific Land, directly above where Sadako's well is hidden. If they are anywhere else, there will be no phone call, but they will still have been cursed. If anyone takes their photo, it will appear distorted, another sign that they are cursed. They have seven days to reverse the curse by copying the tape and showing it to someone else, or Sadako will appear and kill them. The victims are left with facial expression of terror and may appear in odd places. Tomoko's corpse was found in her bedroom closet, even though she died in the living room downstairs. Those who witness or have a connection to the deaths may develop psychic powers as seen with Masami Kurahashi.
If they die of the curse, their spirit may appear as an onryo like Sadako and try to kill other people to turn their other spirits int Onryos and cause the Onryo Apocalypse by making them watch the tape (Tomoko) or appear as a more benevolent spirit (Ryuji), or they may not appear as a ghost at all. In Ring 2, Kanae Sawaguchi completely returns as a vengeful spirit and haunts Okazaki.
The curse appears in other forms. In Spiral and Rasen, Kazuyuki Asakawa's journal of the curse (or Reiko Asakawa's in Rasen) becomes a carrier and is published as a best selling novel. An early version of the curse is unknowingly created by Sadako before her death as an audio recording.
Unlike victims of Samara Morgan's tape, the victims of Sadako's do not show any signs of being cursed other than having a distorted photo. This is in contrast to Samara's tape, which causes its victims to undergo several unnerving physical phenomenae linked to Samara.
The casualty list of Sadako's curse differs in the novels and films. This list also extends to characters affected by Sadako's powers before and after the tape's creation.These people witnessed this tape
- Hisho Acting Troupe Members - The acting troupe suffer from the audio version of Sadako's curse, and several deaths occur including that of the troupe leader Yusaku Shigemori.
- Nagao Jotaro - The doctor who raped Sadako and chucked her down the well. He had a strand of smallpox that made up the curse/virus.
- Tomoko, Iwata, Yoko Tsuji, Tadehiko Nomu - The niece of Kazuyuki Asakawa and three others who watched the tape. They died a week later from heart attacks.
- Ryuji Takayama - A close friend to Kazuyuki, Ryuji helps him solve the curse's origins. However, Ryuji realises what the curse really is but dies before he can warn Kazuyuki. He is resurrected by Sadako in Spiral.
- Kazuyuki Asakawa and his family - After Ryuji die, Kazuyuki, and his cursed wife and daughter and caught in a car crash, his family dying. Kazuyuki dies several weeks later in hospital.
- Mai Takano - Ryuji's girlfriend, who becomes the incubator for the resurrected Sadako. She is eventually killed when Sadako is reborn.
- Mitsuo Ando - The other half of the incubator used to resurrect Sadako. Unlike Mai, he is spared and Sadako revives his dead son for him.
- The Loop world - Kazuyuki's journal is published as a best selling novel, and millions of people become carriers of the curse. In Loop, the curse is revealed to have spread to every living organism in the original timeline of the Loop prior to Kaoru Futami's intervention.
- Miyaji and other journalists - A journalist who heckles Shizuko Yamamura at her public demonstration, but is murdered by Sadako via a heart attack. This causes Sadako to split into two girls. In Ring 0: Birthday, it is revealed the other journalists were all killed by Sadako's curse.
- Shizuko Yamamura - Sadako's mother. After the demonstration, Shizuko was mentally affected by Sadako's actions. She went insane and eventually killed herself. In the novels, she died from depression.
- Aiko - An actress in the acting troupe. She sees hallucinations of the evil Sadako and is eventually killed by her.
- Sadako's Doctor - Sadako's therapist who helps her to control her powers. Unfortunately, she accidentally kills him via a heart attack.
- Hiroshi Toyama, Etsuko Tachihara, Akiko Miyaji and the Hisho Acting Troupe - All of the members are murdered by the combined forms of Sadako. Toyama is killed offscreen by Sadako accidentally. Akiko, the wife of Miyaji, commits suicide with Etsuko.
- Tomoko, Iwata, Yoko, Tadehiko - Watched the tape at Izu Pacific Land Resort, and then all died a week later. Tomoko was known to be directly killed by Sadako, whilst the others were found dead on vehicles.
- Ryuji Takayama - Reiko Asakawa's ex-husband. He was killed by Sadako's ghost when she crawled out of his television and scared him to death.
- Yoshino - A journalist who appears in Rasen. He was killed after handling Reiko's journal.
- Koichi Asakawa - Reiko's father. He willingly watched the tape to save Yoichi but did not make a copy and died to end the curse, although this failed.
- Masami Kurahashi - Tomoko's best friend who witnessed her death. She went mad and was institutionalised. In Ring 2, she gains psychic powers but dies after Ishi Kawajiri tries to remove them.
- Kanae Sawaguchi - A schoolgirl who watched the tape whilst getting a copy for journalist Okazaki. She died but like Sadako, rose again as a vengeful spirit seeking Okazaki after he promised to watch the tape to save her and he did not.
- Reiko Asakawa - The ex-wife of Ryuji and film equivalent of Kazuyuki. She and her son Yoichi flee the police after Yoichi attacks them with psychic powers, but Reiko is hit by a truck and dies.
- Takashi Yamamura - Sadako's uncle. He commits suicide in a swimming pool, sacrificing himself to Sadako to spare the others.
- Doctor Ishi Kawajiri - A doctor who studies psychic powers. He is driven mad by Sadako's powers and commits suicide by diving into a swimming pool whilst carrying electrial equipment. His nurse assistant is also killed.
- Sadako - Sadako herself is a victim of her own powers, leading to her death in both continuities.