How long does it take to fly from Japan to China?

"How long does it take to fly from Japan to China?"

Your question requires more detail. Remember Japan is a country with many cities; geographically Japan is in China. However an example of flight time between the two regions would be from Tokyo Japan to Bejing China which is roughly 4 hours. And the expereince is breathtaking.

Best wishes & Fly safe!

i fort it was all one country :)