The spiral of an Aikido movement first rises towards the sky and then descends towards the earth.
This is a principle known as tenchi: from heaven to earth.
This principle is particularly evident in the tenchi nage movement. This is why tenchi nage bears this name, because it illustrates the tenchi principle particularly well.
But the tenchi principle is present in every Aikido technique, and it is obviously present in the yonkyo technique, as we can see in the video:
If this principle is not respected in the execution, no Aikido technique can work, and yonkyo even less so than any other.
The painful point on yonkyo is a detail, it is the tree that hides the forest. It is not the painful point that brings uke to the ground, it is tenchi. It is tenchi and it is also another principle associated with tenchi: kaiten, the rotation.
Without kaiten, without rotation, tenchi is ineffective; without tenchi, rotation is ineffective.
These are two of the four principles required to perform irimi.
