You probably hear it all the time that the United States and Ancient Rome are alike, people have written books on it, and blah blah. I want to point out how many similarities are there between the Roman Empire and Japan (running from the Shogunate to the World War Two Japan)?
One thing that I have been looking at recently is the status of the 'Gods of the Sacred Spaces' or the Local Gods. For the Romans it is the Lares and for Shintoism it is the Kami. These gods are much more personal to the people rather then the big names usually associated with the Pantheons. Given that they looked after the family, the household, towns, forests, etc. Both erected special shrines to 'house' the gods and had similar styles of tribute.
I also want to point out the Emperor's divine status in both. As both for Rome and Japan the divinity of the ruling figurehead has grown and changed over time. In Japan it reached its peak with the late established State Shintoism.
What other aspects many be similar?