Improvements on Japan's F-15 fleet are being led by Mitsubishi, according to a 26 November 2007 story by Flight International. Tokyo plans on ordering new fighter aircraft, and has requested information about the Lockheed Martin F-22 Raptor and F-35 Joint Strike Fighter, Boeing F-15 and F/A-18E/F Super Hornet, Dassault Rafale, and the Eurofighter Typhoon.
Japan is most interested in the F-22, which incorporates stealth technology, but the U.S. is refusing to release information. This has resulted in a Japanese study of stealth technology. This might ultimately develop plans for the first indigenous fighter in almost 30 years. Some suggest the study might actually be designed to force the U.S. to release the desired F-22 information.
Pictures of the ATD-X were leaked to the press in August. It bears a strong resemblance to the F-22.