Country is a starting map
China and Japan both have varied tea production. Pan-fired Longjing and steamed sencha offer a useful pair to explore. They cannot stand for all tea in either country. Cultivar, harvest and processing choices matter.
Compare a pair
Try small amounts with suitable instructions. Notice aroma, body and finish. Instead of asking which country makes better tea, look for a style that fits your taste. Chinese tea spans several processing categories; Japanese green-tea styles offer their own range.
A roast is not a measurement
Roasted oolong and hojicha can both offer toasted aromas. That does not make their caffeine levels equal or known. Do not use country or roast as a shortcut for a caffeine-free recommendation.
Ready for a starting point that fits your taste?
Find my tea