Japan have best quietest subs in world and can easily make carriers but chose not to.  Russia can’t even build carriers and wanted to buy 2 French ones.  China refurbished garbage carrier from Soviet/Ukraine.
After china spy stole USA/companies secret, USA had to upgrade Aegis with Japanese version.  Japan also have awesome missiles.  Kawasaki P1 can be used for sub patrol and as a bomber. Extremely well maintained F15/F3 is good enough against china/russia with great radar and missiles.  Japan also have very highly trained pilots.  Japan is developing F3 which probably will be better than F22,  Japan also have drone that shape almost ready to be awesome cruise missile.
I always thought Japan had nuke ready to be assembled in few hours.  But with recent chinese aggression, it might be ready in few second now days lol.  Probably automated and press a button and it move things couple inches and nuke is built.