Okayama International Circuit (岡山国際サーキット), formerly known as TI Circuit Aida (TIサーキット英田) before 2005, is a 3.703 km (2.301 mi) 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".