Meh even they are copying everything, Chinese can invade Japan in less than a week, Tokyo unfortunately will not resist too much.
The Japanese after the wwII are against war and I don't think their army alone will get a chance.
No need to talk about the nuke.
China will be able to invade Japan in less than a week? The Japanese Navy is ten times stronger than the PLA Navy. And in modern warfare, population is insignificant. If it was so, then the Serbs (at that time less than 10% of the Kosovan population) wouldn't have been able to beat the shit out of the Muslims (more than 90% of the population) in Kosovo. Hmm... that is, before the NATO bombing of the Serbian orphanages and kindergartens.