How and why are China, Japan, and Korea considered "East Asian Civilizations?"

by Rwtfnow

I am in desperate need of help for my final. I am so overrun with studies that I am freaking out. How do China, Japan, and Korea compare? Did they influence eachother during modernization?

MushroomMountain123

Are you asking why they are considered to fall under the same "civilization", or a run down of the civilization itself?