>>13938293First of all Taiwan wouldn't be "colonised", since it is just a part of China and has been for centuries. The only ones colonising Taiwan are the American occupants.
Secondly, Japan like Taiwan already is a protectorate of America with no sovereignity, no armed forced with which it can defend itself and similarly to Germany a fake democracy with a phony constitution that only serves to keep the Japanese people under the boot of America.
It would be because of this foreign occupation that disallows Japan to be a sovereign country with its own army that Japan could be threatened to come under a new hegemon.
China already was the hegemon over Japan for most of Japan's history. It seems that China after multiple centuries of backwardness is now slowly rising to be on the top of the food chain as it was for most of ancient medieval and modern history. You can try to fight back against, but I think that chances are that China with the greater population labor force resources and proximity to other asian country will come out on top in the Asian theatre. It seems inevitable.