Movement

When somebody attacks, they attack you with movement. Without movement, there can be no attack.
It is the movement they use to strike you and it is the movement that you must respond to.

This led to the exercise we call 'yielding'.
Yielding is all about incoming force. The line of force.

Yielding represents the foundation exercise for melee. It applies to punches, kicks and grapples.
Once you can sense and continue the line of force, your scope for response is increased.

As you proceed through the syllabus, yielding is attached to other drills in order to extend their scope.