Methinks Jun Fan is the dude's name...that and it was just another 'style' of Gong Fu.
That's what the dude taught before developing JKD, the fight he had using Jun Fan Gong Fu took too long, so he had some heavy, like REALLY HEAVY thinking going on.
It must've really been THAT heavy, to not create, but descover that kind of fighting, Bruce was a genius. I think he even got a PhD, which would explain alot.
Oh, hold up a sec, I though it tool like 8 years to get a Philosohpy Doctorate.