From the perspective of Taiwan Province Province, it is the Republic of China.
From a historical point of view, just like the Three Kingdoms, it can be called Wei, Jin, Southern and Northern Dynasties, or the Three Kingdoms, Jin and Southern and Northern Dynasties. It can be said to be the land and sea era, or the direct continental era. After all, the area occupied by the mainland in China is much larger than that occupied by Taiwan Province Province in China, and it is internationally recognized that the mainland accounts for the vast majority.