Kinmen Island
How close is this to China?
Like most countries in that region of the world, Taiwan is actually a chain of 168 islands.
The biggest island – and the one most people think of when they think of “Taiwan” – is called Formosa, and it comprises 99% of the total land area of the chain. The largest city, Taipei, is located here, as is almost all the population.
Formosa is about 100 miles off the coast of mainland China, across the Taiwan Strait.
However, Kinmen Island is much, much closer – it literally sits in the opening of Xiamen Bay outside the city of Xiamen. It’s just six miles off the coast of China.
When discussing the defense of Taiwan, it’s disputed whether or not an invasion of Kinmen would be considered an invasion of Taiwan itself. Some politicians have said they would not move to defend Kinmen. In particular, during the 1960 presidential debates, Kennedy stated that the islands were indefensible and should be abandoned. Nixon disagreed, saying he would protect them as part of Taiwan proper.
Why I Looked It Up
In the novel Reamde, several characters flee from Xiamen across the bay to Kinmen. I was shocked that Taiwan was so close to China, until I realized that Kinmen is an outlying island, and Formosa is considerably further away.
Postscript
Added on
There’s a short mention of Kinmen in Chip War:
China’s Fujian Province is right across the straits from Taiwan. In the harbor of Fujian’s historic port city of Xiamen sits the Taiwanese-controlled island of Kinmen, which Mao Zedong’s armies repeatedly shelled during the tensest moments of the Cold War