Kōtō
The Japan Open (currently sponsored by Rakuten) is a men's tennis tournament held in Ariake Tennis Forest Park with its center court Ariake Coliseum, located in Koto, Tokyo, Japan. In 2018, the venue switched to the Musashino Forest Sports Plaza as the Ariake Coliseum is being renovated for the tennis events at the 2020 Summer Olympics. Held since 1973, the championship includes men's singles and doubles competitions.