Loop is the third in the series of Ring novels by Koji Suzuki. The story revolves around a simulated reality, exactly the same as our own, known as the Loop: created to simulate the emergence and evolution of life. In this alternate universe that the events of the previous novels, Ring and Spiral took place.
Birthday is an anthology by Japanese writer Koji Suzuki first published on February 5, 1999 in Japan. It is the fourth installment of Suzuki's Ring series.
Spiral is a 1995 Japanese novel, a part of author Koji Suzuki's Ring Cycle series. It is the second in the Ring Trilogy, and a film based on the book, Rasen was released in 1998. The English translation of the book was published by Vertical Press in the United States and by Harper Collins in Britain.