Okayama International Circuit (岡山国際サーキット), named TI Circuit Aida (TIサーキット英田) until December 31, 2004, is a 2.301-mile (3.7 km) private motorsport race track in Mimasaka, Okayama Prefecture, Japan. TI was the abbreviation of "Tanaka International" after the name of the golf club owner, Hajime Tanaka, though the name of the circuit was officially "TI Circuit Aida".
As well as hosting racing events, the circuit has rental facilities including bikes and go-carts available.
The course was opened in 1990 as a private race track for the wealthy. Soon, it hosted its first race, staged by veteran British drivers.
In 1994 and 1995, the TI Circuit hosted the Formula OnePacific Grand Prix; both events were won by Michael Schumacher in his early title-winning years. This race made Japan one of only seven countries to ever host more than one Formula One event in the same year. It was discontinued primarily due to its location in a remote area of Japan.
In March 2003, "Tanaka International Company", parent company of "TI Circuit Company", applied for Civil Rehabilitation Law. After the application, Unimat Holding Co., Ltd.  announced that it would support TI Circuit Company. The owner of the circuit was renamed Okayama International Circuit Co., Ltd. on May 1, 2004, and the name of the circuit was renamed "Okayama International Circuit" on January 1, 2005.