Ideally Aikido has no stance: a natural body posture called shizen-tai is best.  For training purposes, however, we usually employ a stance based on that use in Japanese swordsmanship.  There are both right and left basic stances in a few variations.  There are also two possible relationships between your stance and that of your partner.

There are several forms of HANMI stance.

The three most commonly used in Aikido are shown at the right.  All embody the principle of triangularity call "Sankaku ho".  Stance 3 is known as "Ura Sankaku".

All examples are shown in

     Right Oblique Stance, known as

     MIGI-HANMI or MIGI-GAMAE.

All are mirrored by corresponding

     Left Oblique Stance, known as

     HADARI-HANMI or HIDARI-GAMAE.

1. Matching stances, known as:
AI-HANMI or AI-GAMAE
Both partners assume the same HANMI-GAMAE,
i.e. both in HIDARI-HANMI or both in MIGI-HANMI.

In this case, their stances are the same and fit together.

This relationship is basic to OMOTE-WAZA, which are "frontal techniques" that enter toward the front of your AITE (training partner).  HANMI NO KAMAE are basic to all Aikido movements.

OMOTE WAZA

2. Opposing Stances, known as:
GYAKU-HANMI or GYAKU-GAMAE
Each training partner assumes a different HANMI-GAMAE,
i.e. you are in HIDARI-HANMI while your AITE takes up MIGI-HANMI.

In this case, the points of your triangular stances oppose each other.

This relationship is basic to URA-WAZA; "rear techniques" that enter into the SHIKAKU, or "BLIND SPOT", behind the shoulder of your training partner.

URA WAZA

Note:  The principle of Irimi-Isshoku implies that you must reach the blind spot behind your partner in a single motion.  In these diagrams, foot movements are numbered; 1, 2, 3....  However, each type of stepping illustrated is nonetheless a single step.  For example, ayumi-ashi is considered one step wherein both feet move.  This principle is important for getting off the line of attack.  This long, straight arrows in the following diagrams represents this attacking movement of your aite.

In Aikido, the hand is often referred to as the "te-gatana" (literally the "hand sword").  We form this "hand-blade" by holding our fingers open and extended so that the heel of the palm and bottom of the arm are elongated while the top of the arm remains relatively relaxed.  In this manner the natural curve of the arm resembles the shape of a Japanese sword, the katana.  Sometimes the basicte-sabaki are referred to as the te-gatana no sosa, or "the use of the hand-blade".