Typically nukes don't start flying out of nowhere. There's a chain of escalations that leads up to their first strike use.

Typically we do not know shit about it. If / when it starts we will.

and of course the attacker would not know that and would give time to japan or south korea for them to acquire nuke tech?

Really?

What? Are you saying that a potential attacker would preemptively nuke Japan before tensions escalate if Japan started developing nukes? Because if so, what ridiculous world do you live in? That'd be like Russia flat out nuking Ukraine last year instead of bothering with an invasion.

What does make you believe all attackers would behave like putin? Do you realize how lucky has been Ukraine in this abomination of war?

I am not sure I am the delusional guy here.