Defence analysts monitoring the three-way dogfight for the multi-billion contract say Tokyo has been impressed with the stealth technology of the Lockheed Martin F-35, which will enable it to carry out clandestine monitoring of Chinese, North Korean and Russian military assets in the region.
It also remains indebted to Washington for the assistance the US military provided in the aftermath of the March 11 earthquake.
“Even before March 11 there were many factors in favour of the F-35, but since then that national security relationship between the two governments has become much closer,” one analyst with knowledge of the bidding told The Daily Telegraph.
The third aircraft in the running for the contract is the Boeing F/A18 Super Hornet and representatives of Eurofighter and Boeing have scheduled a joint press conference in Tokyo on Wednesday to debate the merits of their aircraft.
The consortium behind the Eurofighter Typhoon is continuing to promote the aircraft, however, and remains confident in its product.
“We are in daily contact with the Japanese Ministry of Defence regarding their F-X evaluation,” said Andy Latham, vice president of Typhoon exports.
“We maintain that our cost-effective proposal offers Eurofighter Typhoon, the world’s most advanced multi-role combat aircraft, as Japan’s best option to meet the requirement for its F-X programme and the most capable deterrent to regional threats,” he said.
A decision is expected in December and opting for Typhoon would be particularly welcomed by BAE Systems, one of the three European companies building the plane, which in September announced nearly 3,000 potential job losses across Britain.
However BAE is also building part of the F-35 for Lockheed.
RAF Typhoons flew around 3,000 operational hours over Libya, reporting a 99pc success rate against fixed targets and 98pc against mobile targets. That combat experience is seen as vital to the bid.
Eurofighter has declined to reveal the price tag on the aircraft, but each jet is believed to cost around £65m.
The Typhoon is in service with the air forces of the four countries that collaborated on the project and has been sold to Austria and Saudi Arabia
The governments of India, Greece, Qatar, Oman, South Korea, Denmark, Switzerland, Turkey, Romania, Malaysia and Bulgaria are all also reportedly considering acquiring the aircraft.