Any attempt at takeover by China should be met with nukes. I see China moving toward a pre-WW2 Japan moves. If we ever got in a war with them they need to be decimated with nukes.
No. Now you're changing your original statement, which was:
I would nuke China with any aggression on their part.
Japan would be foolish to nuke China for any aggression. "Any"? Really? If Japan did that, China would counterstrike and level Japan with China's nukes.
Now you say any attempt at "takeover by China". That's a different statement. Even then, Japan has a stronger navy than China, and can use non-nuclear means to make China suffer if attempting a takeover of Japan. China and the Mongols have tried for almost two millennia to takeover Japan and failed. This back and forth fighting has gone on for many centuries, long before the war in the 1890s and WWII. Japan lost in these last two attempts to takeover China because of Western intervention. China lost in every attempt to takeover Japan in past history.
I think a modern war would be fought with conventional weapons, because both China and Japan would lose if they went nuclear. Japan is much stronger militarily than people think, despite having a "self-defense" military rather than an offensive one.