it is said the this world is created through the two actions of the twin gods Takami-Musubi and Kami-Musubi winding up in a spiral on the right and winding down in a spiral on the left. Fire ("Ka") and Water ("mi") become "Kami", the source of this "Kami" (Fire and Water) returns to the one, but the one becomes the source of the physical and the spiritual.
The crossing spirals are the image of torsional stress.Tension (expansion)(Fire) in one spiral (arrows tail to tail). Compression (contraction)(Water) in the other spiral (arrows head to head, always at right angles to the first spiral (juuji).
The "Kami" in their interaction in a free body, cause precession because torsional stress is the equivalent of rotation, and interacting with such a poised stress -- like pushing a rotating gyroscope -- results in a force seemingly coming from a direction in which no overt action is occurring at all = Aiki.
I contend that the Floating Bridge of Heaven (from which the gods stirred the brine with the divine spear) is the image of this mechanism in the form of a waterspout dropping out of a squall line --
The hot air from below in the tornado rises in the outer spiral wind sheath. The cold air from above descends in the core spiral wind sheath whose spiral flow lines are at right angles to the outer sheath. A vortex tube uses the same principle to dynamically separate ordinary air into very hot and very cold fractions using spiral separation with a similar flow structure: