Watch the leading elbow to determine the attack and its angle. The elbow represents (a) in the equation f=ma. The energy starts at the elbow so it is slower here and is easy to identify. Guard the center forces the opponent to take a circular path to reach you which is longer than a straight line.
Determine the angle of attack, straight or circular and either redirect the straight line of attack or interrupt the circular.
Cover the leading elbow, determine the pressure, redirect their energy and apply the most efficient technique.