[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.