Ring is a 1998 Japanese supernatural psychological horror film directed by Hideo Nakata, based on the 1991 novel by Koji Suzuki. The film stars Nanako Matsushima, Miki Nakatani, and Hiroyuki Sanada, and follows a reporter who is racing to investigate the mystery behind a cursed video tape; whoever watches the tape dies seven days after doing so. The film is titled The Ring in English in Japan and released as Ringu in North America.

Sadako Yamamura , reimagined as Park Eun-seo (Korean: 박은서) and Samara Morgan for their respective adaptations, is the main antagonist of Koji Suzuki's Ring novel series and the film franchise of the same name. Sadako's fictional history alternates between continuities, but all depict her as the vengeful ghost of a psychic who was murdered and thrown into a well. As a ghost, she uses nensha, her most distinctive power and weapon, to create a cursed video tape. Whoever watches the tape will die exactly one week later unless the tape is copied and shown to another person, who must then repeat the same process.