Japan has formally launched its F-X fighter competition by sending a request for proposals to three potential bidders.
Boeing and Lockheed Martin have confirmed a US government representative has received Japan's RFP on behalf of the F/A-18E/F Super Hornet and F-35 Lightning II, respectively.
A UK representative is also understood to have picked up the RFP for a possible bid by the Eurofighter Typhoon.
Each bidder should receive a copy of the solicitation soon.
Japan has released the RFP just a few weeks after the country was hit by an earthquake, tsunami and nuclear crisis, leaving an estimated 26,000 people dead and public safety still at risk.
Damage caused by the disasters may have included an entire squadron of 18 Mitsubishi F-2B trainers, at least some of which were engulfed by seawater when the tsunami struck Matsushima air base.
Meanwhile, Japan has already started decommissioning its fleet of ageing McDonnell Douglas F-4 Phantom IIs, which it plans to replace with the F-X fighter.
Tokyo had originally expressed interest in importing the Lockheed Martin F-22A Raptor, but the US Congress decided not to waive or rescind the export ban on the fifth-generation air superiority fighter.
Instead, Japan has launched the F-X competition while funding internal development of the ATD-X stealth demonstrator.