There are of course more than 8 sotai dosa exercises. These are the most basic and can be studied by beginners after some bodywork skills (kyokotsu, tenshikei,….)

Ai gamae ude hineri

Ai gamae ude hineri with bodywork application. See also tenshikei.

There is a similar body movement in relationship with tenshikei, when doing iaido nukitsuke/kirioroshi, a horizontal and vertical cut with the sword. By doing sayabiki a tenshikei action (twisting) is produced, the potential energy of the twist can be used to proceed with furikaburi (lifting the sword) by untwisting. In sotai dosa ai gamae ude hineri, the same actions will direct the tegatana.

The nukitsuke movement in iaido is a rotation movement of the arm and the sword. As such, it follows the laws of conservation of angular momentum. From that perspective, sayabiki has the following positive effects:

1. By providing rotation in the opposite direction, it allows for greater speed of the sword arm and the sword tip.
2. At the end of the movement, the slowing down of the tip (and control to avoid over-extension of the movement) is helped by the associated movement of slowing down at the end of sayabiki.

Gyaku gamae ude hineri

Gyaku gamae ude hineri with bodywork application. See also tenshikei.
The untwisting of the tenshikei starts with turning the feet. Body turns with the feet have many applications in koryu no kata.

In iaido we have a similar body movement, the feet is stepping forward to release the twisting of tenshikei. The untwisting will be facilitated the lifting of the sword.

Ai gamae ude gaeshi

Gyaku gamae ude gaeshi

Ai gamae tenkai ude hineri

Gyaku gamae tenkai ude hineri

Ai gamae tenkai ude gaeshi

Gyaku gamae tenkai ude gaeshi

8 sotai dosa Aikido Sotai Renshu Tomiki