It is known that Type 12 SSM-ER will be used from ground, sea and air vehicle
The chance that it will be integrated on F-2 is high but also there is patent from Kawasaki for adding this missiles for Kawasaki C-2 which would be dropped from inside
Tbh I would be very surprised if F-2 won’t get it and only C-2 will
So the development will last until FY2027. That mean they will have procure in FY2028 at earliest and receive it in FY2029.
If everything is according to the plan, F-2 is starting to retire at early 30s. The possibility of not integrated F-2 with type 12 SSM-ER is quite high.
With missile range of 1000km, you don’t really need a fighter jet to do the job.
There will be future F-35s that can use AIM-260 and Meteor. AAM-4 would be cool, but the latest variants of AIM-120 have superior performance to the AAM-4B. So Japan is probably doing cost-analysis here, since it would take a lot of resources to continue to upgrade AAM-4. AAM-5 on the F-35 would be amazing, though
The issue is more so that the AAM-4’s are a wider/thicker missile compared to the AIM-120’s, and that would be why they can’t fit in the bay from my understanding.
The program has ended with no production units planned.
The results of the program gave fruit to japan deciding to make their own successor in development