Re: So how many years late
I reckon they'll get the demonstrator flying near enough to the planned 2030.
The idea that the first models will be in service by 2035 seems a bit... Optimistic? Unlikely? Delusional?
On the other hand F35 has been built now - as the first high production rate stealth aircraft. And a lot of the problems with that program are now software related. So if this can be less ambitious with the software - maybe it won't be as horribly delayed?
But the defence-industrial relationship with Japan is also quite new. So there could always be a massive falling-out there, to make things more fun.