Don, thank you for citing the secret of all jiu-jitsu. Really the idea is that once you control an extension of the body )i.e. head, arm, leg) you can apply pressure at certain angles to control the rest of the body.
Originally Posted by The Don
remember where the head goes the body will follow.
In BJJ and JJJ there's alot of using the arms. JJJ (like Don said) expands into manipulating the head where BJJ really only goes as far as the chokes.
This insight is really the basic idea for being a really good grappler and submitter.