The Rakuten Japan Open Tennis Championships is a tennistournament held in Ariake Tennis Forest Park with its center court Ariake Coliseum, located in Kōtō, Tokyo, Japan. The championship includes both men's and women's, as well as singles and doubles competitions. On the women's side the tournament has been held since 1972 and has had famous champions such as Kimiko Date (4 victories between 1992 to 1996), Ai Sugiyama, Monica Seles and Maria Sharapova (twice).
Prior to the advent of the ATP Tour, the Japan Open was known as the Tokyo Outdoor Grand Prix and was part of the Grand Prix tennis tour between 1972 and 1989.