The first thing you will be taught when you start practicing Aikido is the “hanmi” stance.
Hanmi literally means “half-body”. From a practical standpoint this means that only half of ones body is presented to an adversary. The importance of the hanmi stance cannot be overemphasised. In fact, the founder of Aikido adopted hanmi as a founding principle around which his entire art is organised!
It can often be heard in dojos that Aikido begins and ends with Hanmi, an important aspect of daily practice! Saito Sensei mentions that Aikido is the only martial art that is built upon this Hanmi position, and that when one maintains Hanmi there are no mistakes. In partner practice with the ken (sword) for example, it is possible to avoid an ai-uchi, or mutual kill situation, when one maintains hanmi.
Master the Hamni Position and Unbalance the opponent
A correct hanmi stance is characteristic of Aikido. SAITO Morihiro Sensei always said that the founder was very particular about this point.
A Good Hanmi
Good hanmi allows the hips to be placed correctly (without tension in the body), which leads to correct positioning of the whole body.
There are several types of hanmi (Ken no hanmi, Jo no hanmi, Hitoemi). Hanmi is a necessary prerequisite when starting to learn techniques. It must also be used when actually executing techniques.
To Be Stable & Unbalance the Adversary
The notions of hanmi and balance are inseparable. Good hanmi gives the stability needed to unbalance an adversary. This is particularly true when practicing in kihon (static training) but it is often neglected when practicing in ki-no-nagare (fluid training). No mater how big your opponent is, he can be controlled if you take their balance.
Hanmi allows movements in any direction and hence makes it possible to respond to attacks from anywhere.