Rome vs Japan

[Tarbicus]

It doesn't matter. The Romans had the tactical, logistical, technological, motivational, organisational, engneering and martial skils that saw them at the top of the food chain for the better part of a thousand years in western europe. They got their arses kicked now and again, but they always learned from those mistakes and were quite willing to turn their enemies' own methods against them, and do it better. They wouldn't give up.

When it came to fighting other nations they were the best during the most part of their time. Had Perry sailed up the Tiber with gunships I'm damned sure the Romans would have had their own metal fleet at Ravenna within five years, by hook or by crook, and there would have been legions of riflemen ready to deploy from hot air balloons invented by Greeks