To my understanding, feudalism in Europe and Japan shared many key similarities, but developed during times of relatively little contact between the two regions. Were there similar conditions that caused the development of feudalism in those regions but not others? Was one inspired by the other?
The similarities are very superficial, born out of a system of increasingly weak central government unable to completely reign in the increasingly strong and independent local government. We see similar processes throughout history all over the world.
Once we get down to the details, the institutions and cultures were very different. Heck, they were very different within different times and places within Europe/Japan, without even needing to compare to each other.
If you're interested I briefly explained some similarity and differences between Japan and Europe here and half way down the page here