Kubi shime is a stranglehold.
Strangulation is most often performed from behind (ushiro kubi shime), but here it is performed from the front. This attack can be called ryo muna dori kubi shime.
This exercise verifies the rule that no Aikido action can be performed without tori's irimi-tenkan rotation, as the video shows:
The first part of the rotational movement (irimi) allows you to enter while bringing an atemi to uke's face. The second part (tenkan) completes the rotation by bringing out the rear hip, and enables uke to be thrown.
Caution : the rotation must be carried out in the way that undoes the grip. To do this, you must rotate by cutting on uke's lower arm:
Cutting on uke's upper arm is a mistake that has the effect of locking uke's grip even more tightly, and thus increasing the power of his stranglehold.
The logic of the movement is therefore perfect: to undo the grip, you have to cut on uke's lower arm, and to cut on the lower arm, you have to deliver the atemi under the upper arm, which is “just right” because it's easy to strike under the upper arm, whereas it's difficult to strike under the lower arm. The natural movement is the right movement.
Once again, irimi-tenkan rotation creates all the combined and harmonious conditions for an ideal and effective technical execution. As at the same time it makes tori safe from attacks from all four directions, we see that a single action is capable of achieving perfection in two different areas: efficiency and safety. The perfect conjunction - within a single action - of two seemingly unrelated effects is a coincidence whose systematic nature questions the mind, so difficult can it be to conceive the reason for this permanent connection.
Genuine martial art is not a pugilism, that must be understood. An action that is only effective against one opponent is useless. What's the point of a man defeating an opponent if at the same time another opponent coming from a different direction can take his life? The battlefields of the past were strewn with the corpses of warriors whose techniques were probably effective with a single opponent, but that was not enough.
