Students learn many traditional aikido stances to protect themselves and their attacker. he postures are referred to as shizentai gamae, which is a basic, relaxed posture. The feet are shoulder width apart making the posture balanced. There are two aikido stances that are used: migi (right) gamae and hidari (left) gamae. In each, the named side's foot is forward, but the body remains relaxed, balanced and centered.
Hammi, the basic aikido stance, is also broken up into left and right stances. When both the uke (defender) and the nage (attacker) are assuming the same hammi positioning, but are facing one another, it is referred to as ai-hammi, or mutual stance. When they are facing each other using opposite hammi positioning, it is referred to as gyaku hammi.
The hand positioning is where you will see the biggest difference in the stances. There are three categories or hand positions: Jodan, Chudan, and Gedan. Jodan hand positioning has the hands at eye-level. Chudan positioning has the hands at mid-body. Gedan has the hands at a low level, close to hip level. Each position has its own merits. The Jodan positioning may prepare for upper body combat tactics in defense and attack, while Chudan prepares for mid body and Gedan concentrates on lower body combat.
Nearly all aikido practitioners agree that having one hand at eye level and the other at chudan or gedan level is the most practical and best defensive position. This protects the upper and lower body and allows the combatant the most opportune hand positioning in case there is a need to use hand attacks. Here, either hand has an equal chance to strike or defend.