Re: Zazen necessary for training
I practiced Sitting meditation every day for fifteen years and have attended several extended silent retreats. Since I started training I have became more stable, and better able to communicate, nore responsive in ways that continue to develop even when I do not Sit for weeks or months. Currently I am doing more sitting practice than I have been, however I do not see that one is necessary for the other.
I know plenty of lovely people who don't practice as a Spiritual exercise and they seem just as enlightened as those I know who use aikido specifically as a tool for self-transformation.