Maruyama Sensei has often kidded me about all the notes I take when I go to Kokikai camps. I'm usually the last one in the gym after class, writing my notes long after everyone else (save my patient brother) has changed and gone to dinner.
One time, Sensei asked me what I wrote in my notebooks. Without really meaning it, I said, "Everything you say, Sensei." He said, "No, write everything I do." When I thought about it, I realized that really was what I was doing: Seeing in my mind what Sensei did, and then describing it in words.
Those words, themselves, really do me no good. But when I read them - days, weeks, or even months later - they trigger in my mind an image of Sensei doing a particular technique. Once I see him, in my mind, I can copy what I see. This visualization practice has allowed me to continually learn from Sensei, though I only see him a few times a year.
The parents of one of our young students have an amazing book written by an autistic woman. She has a very unusual job - designing facilities for cattle, creating the spaces where they walk, eat, get bathed, and so forth. She has been very successful at designing facilities that work better, run smoother, and make the cattle feel more comfortable. She is able to do this because of one of the gifts her autism has given her: The ability to play a mental videotape of virtually anything she has seen in her entire life. She has seen scores of these cattle facilities, and she has witnessed how well (or how poorly) each one works. When she creates a new design, she reviews her mental videotapes, takes the best elements, then combines them - and even tests them - in her head.
This is visualization (although at perhaps a higher level than most people can ever experience it). It's reviewing and constructing videos in your head. So how do you start accumulating videos that can help you in Aikido? Watch the best instructor you can, then later on, try closing your eyes and replaying, in your mind, the images of what he or she did. You can help yourself by saying what you saw ("Let's see, she stepped back with her right foot and raised her right wrist, keeping her elbow down. . .") as the words may help to create the video in your mind. Practice. The images may be faint at first, but keep practicing and they will get clearer.
It's a good idea to keep some record of the videos you've got stored in your head. That's the purpose my notes serve. If you don't have some kind of written record, you may forget you have the video, so you won't think to try playing it.
Once you get the hang of playing a video of Sensei, or some other instructor, it's time to change the actors in your production. If you have a mental video of Tsuki Kotegaeshi, run it a few times, then try putting yourself in Sensei's place. Only now, try seeing everything from his point of view. Watch as you put your hands where Sensei had put his. Though you are sitting still, feel your own body moving as you mentally do the technique. Go slowly at first - you're directing your own video here. But once it's completed, and you can see and feel every movement as you think Sensei saw and felt it, you've created an amazing learning tool. Run that video over and over again in your head to train both your body and your mind.
By practicing in this way, you can change your habits more effectively. While we often find our bodies doing strange things in the dojo, it may be hard to convince them to change. But the mind leads the body. So if you can see yourself doing something a new way in your mind, your body will soon change, too. When you next practice that technique, you will find new habits in place. Then you can see how uke responds, and use that feedback to improve further.
One more point. You have already begun to learn some skills that are absolutely crucial for effective visualization practice: Relaxing, being calm, feeling positive. So keep one- point while you run your mental videos. The images will be clearer, and the effect will be stronger. (Of course, this also works the other way around. Sometimes when I feel stiff or tense, I will simply visualize myself practicing an Aikido technique. As a result, I will feel more relaxed and gain a stronger feeling of one-point.)
Before I tested for 2nd Dan, I thought, "I don't need to visualize my test. I should be beyond needing that by now." It was, by far, my least satisfying test. So in the days prior to my 3rd Dan test, I practiced visualizing the entire exam. I saw myself doing every technique; I practiced my entire freestyle in my mind. I think it was no mere coincidence that it ended up being one of the most satisfying experiences of my life.