The first rule of Bujinkan is simple: something is coming at you, get out of the way.
Always take yourself off the angle of attack using footwork and body postures- kamae.
An example of this used with new students is an excellent starting point.
You and a training partner stand in shizen (natural posture) and they begin with a right punch.
As the strike enters your space, move off the line of attack at 45 degrees and shift to ichimonji no kamae to protect yourself and control this distance.
We also practice this concept with the sword- stand in shizen and a training partner cuts down with a sword- padded and safe training of course.
As the cut enters the space, use footwork to move to the side and out of the way.
With this exercise we start BIG- move really long and far out of the way. Don’t worry about the next cut or attack right now. The point is to learn the movement so we start with big movements so one can see them and train the body/muscles.
Over time and with more proficiency the distance and space closes and gets smaller and smaller, tighter and tighter, so another attack has no space to manifest.
Rule number one: get out of the way.
Rule number one point five: always be moving.