[inetsee]

I think you have it backwards; China considers Taiwan to be part of China. https://www.cfr.org/backgrounder/china-taiwan-relations

[lumost]

The current govt of Taiwan held the China seat on the UN Security Council until 1979. The history on this issue is complex.

[ipnon]

The Cross-Strait issue is explicitly mentioned in the preamble of the PRC'S constitution.

>Taiwan is part of the sacred territory of the People's Republic of China. It is the lofty duty of the entire Chinese people, including our compatriots in Taiwan, to accomplish the great task of reunifying the motherland.

http://en.people.cn/constitution/constitution.html

[publicola1990]

Taiwan also claims the entire mainland as their territory, and KMT especially continuing to claim Taiwan as the "true" China.