[ipnon]

Perhaps it would have been simply best to note that island nations are generally insulated from invasion in ways that continental nations are not. Great Britain had the long term national security to forge an empire while the continental nations of Europe were engaged in endless back-and-forth wars (often at the instigation of Great Britain). Japan had centuries of peaceful self-imposed isolation while the continental nations of China and Indochina were engaged in endless wars, which was utilized to build up an empire while safely protected by the Sea of Japan. Being an island nation is an immense geostrategic advantage that is apparently not completely obvious to all observers of history.

[yongjik]

It's pretty off-topic, but ...

> Japan had centuries of peaceful self-imposed isolation while the continental nations of China and Indochina were engaged in endless wars, which was utilized to build up an empire while safely protected by the Sea of Japan.

While Japan had a stable border, it also had many periods of feudal lords fighting each other. Also, the reason Japan became an Empire was that it received and internalized Western knowledges much earlier than many other countries (starting with Rangaku "Dutch learnings" in the 17th century), and later was forced to open its ports by Western powers, which resulted in disagreement over the nation's course, a series of bloody civil wars, and the Meiji Restoration, which made the emperor an iron-fisted ruler of a modern nation.

It's not exactly a story of an island enjoying isolated peace and suddenly emerging as a superpower. Korea was a country that enjoyed almost total isolation during the same period (16-19th centuries) and look where it got them.

[dirtyid]

UK could be resupplied across the Atlantic by world's preeminenant industrial producer while German power projection of era couldn't comprehensively cripple GBR. German Blitz+blockade didn't achieve strategic goals of destroying GBR industries while also being distracted by land war. TW has even less food/resource security and entirely within range of PRC weapon platforms, who has more industrial capacity than US during peak of WW2 production. Also consider UK managed to hold onto Falklands. It's really about industrial capacity to wage attritional war - TW has an initial defensive bonus but massive resupply penalty. If PRC gains air superiority and deter outside intervention, taking over island is only matter of time. Merchant fleet assets alone is enough to ferry 100,000s anywhere on TW if PRC wants to human wave / million man swim in days. Dunkirk moved 350k bodies on 800 ships in a week. PRC has 50-80k fishing boats that can make the journey. It's hard to overstate PRC industrial advantage relative to TW.