[however1]

"China has no claim on Taiwan whatsoever".

Japan to Asia at the end of 19 century and the first
half of 20 century was nothing difference from Nazi
Germany. If you think the Treaty of Shimonoseki to
be valid, I can name a number of treaties which claim
the entire Asia to be Japan's territory.

People in Taiwan speak Taiwanese/Chinese and has an
origin from China. The problem of Taiwan is only between
Taiwan and mainland China. It has nothing to do with
Japan. It is humiliating to hear that Taiwan is part
of Japan.

[inquest]

The problem of Taiwan is only between Taiwan and mainland China.

You're making it sound as though it's an internal Chinese matter. That effectively concedes Beijing's side of the argument.

[tallhappy]

To reiterate: China has no legal or legitimate claim over Taiwan by any stretch of the imagination.

Look at the ludicrous argument in this article: citing press releases after meetings of Allied leaders during WWII.