Before we can perform techniques, first we must be able to move. Movement is
rarely backwards in Aiki-Jujitsu. Instead we will nearly always move to the inside or outside of an attack. In doing so, we learn to move our midline. But what do these terms mean? This illustration should help.
The midline is an imaginary line that runs down the centre of the body. All important body structures of which we have only have only one lie down the midline. These include the brain, nose, trachea ("windpipe,") heart, liver and aorta (the largest blood vessel of the body.)
Structures of which there are two lie either side of the midline. For example the eyes, lungs and kidneys. We can manage without one kidney but not without our one heart.
When in defence, move your midline.
When striking, aim through the midline.
When moving the attacker, move their midline.