It is increasingly looking like it will be impossible for Japan to have their own final assembly site for the F-35 JSF. (paid subscription required)

Japan has been manufacturing front line fighters locally since 191956, when it started taking deliveries of the Japanese assembled F-86 Sabers, and while aircraft in service have been foreign designs (F-4EJ, F-15J), or derivatives of foreign designs (The F-2 derivative of the F-16), this is a capability that the Japanese government and military see as important (otherwise they would not have flushed all that money down the toilet on the F-2 in the 1990s).

In addition to the F-35, the competitors for Japan’s next fighter requirement are the improved F-15FX and the F/A-18E/F from Boeing, or the Typhoon from Eurofighter:

Japan’s F-X fighter competition results will determine next year whether the national industry can sustain its tradition of domestic production of fast jets or instead be forced to accept a suspension and the risk of losing skills.

….

One Japanese official who has recently moved from the Defense Ministry to industry says that his former colleagues are inclined toward the Lockheed Martin F-35 Lightning to fill the F-X fighter requirement, but industry is lobbying for the Boeing F-15FX or F/A-18E/F Super Hornet or the Eurofighter Typhoon.

Simply put, the F-35 already has too many hard and fast contracts on work share for there to be any realistic opportunity for Japanese industry to participate.

What’s more, though this article does not discuss this, the aircraft is very tightly integrated, and so it becomes very difficult to involve local industry in upgrades.

There is the possibility that Japan could go it’s own way,with either something like their ADT-X stealth demonstrator, but the expense here would be enormous, particularly since the manufacturer would be prohibited from exporting the aircraft by the Japanese constitution.