Receiving A Technique
Ukemi (受身, Receiving With Body) is a vital aspect of aikido, a person will spend at least half their time taking ukemi. It is the art of surviving and receiving technique.
On its most basic level it is positioning and moving the body this includes rolling and falling exercises. The practices allow a person to become confident about receiving techniques allowing them to be projected with vigour and speed without fear of harm. Receiving ukemi requires a person to be able to follow a technique and adjust to any change in speed and direction.
The Uke may rotate or fall in any direction as if a sphere, which means they must train to be able to roll or fall in any direction. The only safe way to take ukemi is to remain relaxed and not resist the technique.
Beyond this as ukemi is matching the partners movement it then becomes possible to counteract or reverse the technique this is called kaeshi waza (返し技).