Yann Golanski wrote:
Ask you sensei and do what he does. .
Its just a tool to learn Aikido. As Yann says do what the instructor does since he's doing it that way to teach something.
Looking at 1st Ken suburi I've been taught 3 versions of this.
Firstly a vertical ken. This is a form of ki misubi. A 'mental' preparation perhaps. Like a lightening conductor the ken and man are a single join between the heavens and the earth. Ten chi nage concepts spring to mind.
2nd version where the ken is lowered down the spine is a more physical preparation. It opens the lungs promoting effective breathing for instance.
Finally there is the martial version where the ken is drawn back covering the head at an angle of approximately 45 degrees.
This provides protection but also enables swift counter strikes.
So you have metal preparation, physical preparation and the martial form itself. In most dojos I've been in this is the same structure as the tai jutsu lessons.