Min Kang wrote:
To summarize my long-winded scenario, by reactive, I mean waiting for the attack, andn then doing the technique. By proactive, I mean perceiving the uke's tripping of the threat perimeter as initiation of your attack and ending the engagement on your terms.
This scenario makes sense to me. It assumes a committed attack to an end, and affords time to do a technique. Aikido was all about movement, distance and timing to me from the beginning but I couldn't see how they fit together in a martial sense ...
Just to clarify what I have written earlier and to support what was said by others, I think Aikido is an extremely proactive Budo in its true martial expression. One never waits for an attack, one is controlling the angles, distance and type of attack by subtle use of vision focus (metsuke) and ones own body language to setup the attacker to strike or grab where the Aikidoka wants him to. One only reacts in kata practice where the attack and ma ai is already known. In randori where anything goes one has to control all aspects of the engagement. Imho martial Aikido has a lot to do with domination by skillfull manipulation of the opponent's mind/body well before physical contact is made.
A little story to illustrate what I mean:
I was asked to spar/randori with a Judoka once since the folks in that area knew that I instructed Aikido. As we closed distance I walked up to him but left my right hand dangling tantalizingly just outside his grasping range, it would be easy for him to shoot in and take the arm while controlling some other part of my body to start a throw or takedown. As he reached for the arm I relaxed, waiting for the last second and then pivoted. The next thing he saw was the ceiling after being thrown with kotegaeshi. He could not understand what happened, he was sure he had the grab and then the hand was not there and he was on his back.
The thing that he did not realize is that I controlled the engagement from the time I started walking towards him using body language, drawing his attention to something I know he would want to take control of, based on his tactical paradigm as a close range grappler. I offered him the bait to place his mind and body where I wanted him to, resulting in an attack that I expected, giving me the initiative and the time to select the best technique for the attack. A more skillful or experienced person may not have taken the bait at first so modifications will have to be made. Feigning unawareness also had a part to play since I acted as if I was not even aware that the hand was so far away from my body and so close to him.
This is a simple example of "setting up the play". Others do it by using atemi that will require a block and then working a technique based on the block. For Aikido to operate properly within its own realm of power the opponent must be defeated mentally before the actual engagement is made. Whenever your opponent strikes, grabs or attacks it must always be on your terms.
Hope this helps some.