At the beginning of the twenty-first century, Japan, seeking to replace its aging fleet of fighter aircraft, began making overtures to the United States on the topic of purchasing several Lockheed Martin F-22 Raptor fighters. However the U.S. Congress had banned the exporting of the aircraft in order to safeguard secrets of the aircraft's technology such as its extensive use of stealth; this rejection necessitated Japan to develop its own modern fighter, to be equipped with stealth features and other advanced systems.