The ancient China was centralization, the emperor is very very powerful, while Japan was more feudalism, they have lords and feud, and their own admistration system. Yuan and Qing dynasty period of China was ruled by other races, while Japan was never invasioned. Kublai Khan(Emperor of Yuan) tried twice, but failed. And most time China was a big empire since Qin, while Japan was many kingdoms, ruled by clans.
