I’m aware that feudalism can be summed up as a single definition

You mean can't right?

The problem with this question is we need both a point of reference for Japan (which century) and Europe (which country and which century). But the general answer's probably the same no matter what: except the most superficial (ie de-facto hereditary groups of warrior-aristocrats given control of semi-autonomous polities in exchange for following the laws and resource/military mobilization orders of a higher level of power/government) nothing is the same.

Just saying Japan/Europe was "feudal" and stopping there decrease our understanding of the social-political-economic intricacies of the time, so is something academics don't really do.

If you're interested I briefly explained some similarities and differences between Japan and Europe here and half way down the page here