Why there are two China's?

Answer 1

It might seem that there are two Chinas, but there is only one. The country of China is divided up into provinces that each govern themselves, but also are under the direction of the one government.

Answer 2

Because, between 1927 and 1949, China (then the Republic of China on the mainland) was engaged in civil war, alongside the Second World War. The Nationalists vs. The Communists. The Communists won and established the People's Republic of China (PRC) on the mainland. The Nationalists were forced to move the Republic of China (ROC) to Taiwan. The PRC is now commonly known as "China" and the ROC as "Taiwan". Both sides still officially claim to be the sole legitimate government of all of China, but the ROC was kicked out of the UN and many other international organisations in the 1970s and replaced by the PRC.