East Asia is the eastern subregion of the Asian continent, which can be defined in either geographical[1] or ethno-cultural[2] terms. Geographically and geopolitically, it includes China (including Hong Kong and Macau), Mongolia, Korea (North and South), Japan and Taiwan; it covers about 12,000,000 km2 (4,600,000 sq mi), or about 28% of the Asian continent.
https://en.wikipedia.org/wiki/East_Asia