At the 2019 summer seminar in Bosco Gurin (Report) Yoshigasaki Sensei derived the technique Tenchinage Irimi from Katatedori Sumi Otoshi. He clarified that these techniques don't just fall from the sky.
"...Well, that's how it becomes a technique. In fact, like that, someone invented this technique. It wasn't God who invented Aikido. It was human beings who invented Aikido. Not God."
"So how human beings did invent it? By understanding the basic mathematics and applying that mathematics to different situations.
This here (beginning of sumi otoshi) is already a bit of mathematics, but she can come to this (with her hand to my face). So... (sweeps his right hand over her head, protecting himself from her hand and throwing her)."
Who did invent it ?
Aikido
