Japan has selected the Lockheed Martin F-35A joint strike fighter (JSF) for its F-X contract, which purchases 42 aircraft to replace an ageing fleet of McDonnell Douglas F-4Js.
The contract award announced on 20 December makes Japan the second country outside the nine F-35 development partners after Israel to select the jet. The initial contract will be for four jets in Japan Fiscal Year 2012, which begins 1 April, 2012.
The announcement also dealt a fresh blow to the Boeing F/A-18E/F Super Hornet and Eurofighter Typhoon.
However, the Typhoon remains in competition with the Dassault Rafale in India, while the F/A-18E/F continues to look for new sales in the Middle East and Brazil.
Japan's decision also provides a timely boost for an F-35 programme that faces budget cutbacks and even higher scrutiny over new technical challenges by the US government
Despite an at least five-year delay and major cost overruns, the Japan deal shows the F-35 remains viable for the export market.
The F-35A combines the features of a stealthy airframe, an integrated suite of advanced sensors and supersonic speed.
It was designed to function as a premier ground attack aircraft, but Lockheed and the US government claims stealth and advanced sensors make it six times more effective in air combat than the fighters it replaces.
Lockheed says the F-35A can be delivered for an average unit cost of about $75 million, although that number assumes the US and eight partner countries order more than 3,100 jets during the next 25 years.
In service with the Japan air self-defence forces, the F-35A will join the Mitsubishi F-2 multi-role fighter and the Mitsubishi F-15J interceptor.