Reddit reviews Mr. Selden's Map of China

Trade, exploration, suffering from poverty etc.

In early Ming, there were several diplomatic missions led by Zheng He traveling to South Asia. Rumor was that he was ordered by Yongle Emperor to search the missing Jianwen Emperor (who was the nephew of Yongle and voided by his uncle.) I don't think that Ming was when the Chinese people started to travel by sea, but it seemed Ming was when my history texts began having lengthy descriptions about sea travel and trade. You would also find several English books highlighting the Ming dynasty. After that, the administration and later the Qing dynasty had an unfriendly marine policy in the sense that you were not allowed to travel by sea. But things were tough back then for the ordinary person. In Fujian and Canton, people were suffering from poverty and would rather work with pirates (then becoming one) or take risk going south or elsewhere to search for new land and new possibilities.

One thing I should add is that the way people navigated back then was to travel closely to the Chinese coast, and in the early period, it was technically very hard for them to get to Taiwan because of the ocean current. As an amateur I think that's why Zheng He went through South China Sea instead of going to Taiwan. It actually required some luck even for the Dutch people to get to Taiwan from Southeastern China if I remember right. Because it was technically challenging to get to Taiwan from China, there used to be only scattered Chinese residents before Dutch VOC arranged a deal with China so that the company could introduce Han labors to Taiwan (and these people could own lands and paid taxes to the company.)
Then, there came Koxinga, who defeated the Dutch people and brought his own people to Taiwan.

On a side note, there had been a certain amount of Arabians living in China before Ming already for trade, and they were gradually Han-ized while remaining keen to sea travel. Quanzhou was among the major trade ports for these people.

edit: If anyone is interested in the Chinese voyage, take a look at this book: Mr. Selden’s Map of China: The Spice Trade, a Lost Chart and the South China Sea