China is the only nation that has never been conquered?

See how you understand, Han, Mongolian and Manchu conquered us. This country is difficult to conquer. Because the country is culturally inherited. To say that the unconquered nation is probably the Yamato nation known as the Emperor's eternal line. Many powerful countries were conquered. If Greeks, Romans, Mongols and Germans don't want to be conquered, they need more luck. For example, Japan is pure luck.