>While there are currently no known plans in Japan to produce nuclear weapons, it has been argued Japan has the technology, raw materials, and the capital to produce nuclear weapons within one year if necessary, and many analysts consider it a de facto nuclear state for this reason.[32][33] For this reason Japan is often said to be a "screwdriver's turn"[34][35] away from possessing nuclear weapons, or to possess a "bomb in the basement

https://en.wikipedia.org/wiki/Japanese_nuclear_weapons_progr...

This is fact known for a very long time....

The reason Japan won't have nuke is more so it's politically impossible. Even if USA and LDP wanted to, more than 80%+ of Japan (last survey I read) is strongly against it, and there's no way a reimpretation of the peace constitution can in anyway justify nuke, so a referendum is required

Japan also have advanced space programs so the method of delivery, is also not something that is something they can develop quickly. (and more recently, also chips etc required)

To be completely fair, we've also seen what happens to countries with nukes as well. It seems like almost every major military power on the planet has been hollowed out by institutional rot and grifters and I would fully believe the same of China's military if they got into a stupid conflict like the US. Traditional military power doesn't matter in a world where a country can buy a hundred thousand drones for dirt cheap and make any sort of invasion suicidal.