Hint: the Japanese did not steal it from the Japanese natives.
I'm no Sinophile, but don't give the Japanese something they historically didn't have. Chinese have been resident on Taiwan since before it was called Taiwan. I'm not about to back the Reds here, but it's certainly more legitimately Chinese than Japanese.
It was not split from China in 1949.
History is on Taiwan's side on this issue and you can't go wrong citing it.