What is Aiki (Part 01)
The application of Aiki in the technique demonstrated by Katsuyuki Kondo is analysed below.
Analysis
At a time of 4.15 Uke attacks with shomenuchi. Uke is unbalanced in the bottom right picture using Aikijujutsu and in the top left picture using Jujutsu.
In the case of Aikijujutsu, Tori induces Uke to apply Aiki by applying an atemi to Uke's face with his right hand as he blocks the shomenuchi with his left hand at the beginning of its forward movement. To minimise the impact of the atemi, Uke reverses the muscle torque about the ankle joint of his rear leg causing him to become unbalanced to the rear by the contact reaction force due to the block.
In the case of Jujutsu, Tori blocks the shomenuchi towards the end of the forward movement where Uke's forward momentum is the dominant factor determining his balance and not the muscle torques of his rear leg. Once Uke's momentum has been dissipated by the block, pressure is applied to Uke's nerve above the elbow joint. Uke then responds to the pain from the pressure point by going on the defensive by relaxing his body so as to minimise the pain whilst doing his best to keep his balance. Because Uke is having to stretch his body this makes it easier for Tori to unbalance Uke with a small amount of force.
