Kyoichi Inoue

Aikido Inoue sensei teaching mysterious waza

The application of Aiki in the technique demonstrated by Kyoichi Inoue is analysed below. 
Mechanics of Unbalancing Uke using Aiki

Analysis

As Uke advances to push Tori by his shoulders, Tori moves towards Uke to oppose his push. On contact, Uke experiences a contact reaction force on each hand of UCRF.  To resist/balance the torque due UCRF about his rear knee joint, Uke applies muscle torque about his knee joint in the opposite direction. However, Tori induces Uke to apply Aiki by rotating his shoulders forward to exert pressure on Uke's fingers and wrists. This causes Uke to reverse the muscle torque about his knee joint in the same direction as the torque due to UCRF so as to relieve the pressure on the fingers and wrists and, by doing so, becomes unbalanced to the rear.