Right a concise history of Ring (Ringu)
Movies
Ring (Ringu) - 1998
The movie based on the book The Ring by Suzuki Koji
The Spiral (Rasen) - 1998
The second book by Suzuki Koji, which is a follow up to the book Ring. Made by the same company as Ring at the same time as Ring, but by a totally different crew. Not very good by all accounts and is the "forgotten sequel"
Ring 2 (Ringu 2) - 1999
The sequel to the movie Ring.
Ring 0 (Ringu 0) - 2000
The prequel to the movie Ring.
Ring Virus - 1999
Another telling of the Original The Ring book, this time co-funded by Japanese and Korean film makers (the first film ever to be funded in this way) Tho, its considered to be a remake of the first film, with elements of the book put back into it.
The Ring - 2002
The US remake of "Ring"
The Ring 2 - 2004
The sequel to the US remake "The Ring". Not a remake of "Ring 2"
Books
Ring - 1991
Rasen - 1995
Loop - 1998
The Birthday - 1999
TV
Ring : The Complete Edition - 1995
made before the movies, more honest to the original book.
Ring : The Final Chapter - 1999
12 episode series, mixing book and movie storylines
and
Rasen : The Series - 1999
13 episode series, based on the book but wildly changing parts.
So all in all
Seven movies
four books
three TV shows