Last weekend I had some friends over and family.
My brother-in-law who is into MMA ( watching not training) and a freind were debating MA and asked me what is the difference between the various styles and I gave a quick and politically correct summary.
But then the BIL asked what makes kung fu, kung fu?
I explained some of the technical uniqueness of kung fu, comapred the forms with karate and TKD but as I was doing so I realized that is NOT what makes kung fu, kung fu.
Many other systems have forms like kung fu, many other systems share the techniques, many others share the principles and many others share the "look and feel" of kung fu.
So I contemplated my navel ( as I do in situations like this) and realized that, for ME, what makes kung fu, kung fu is:
The Gungs.

And you?