Ikkajo or ikkyo (as referred to in some Aikido styles) is one of the most effective pinning techniques
in the aikido repertoire.

You will recognize ikkajo by the position into which the arm of uke (attacker) will be led (palm and elbow turned upward). Nage (defender) will extend outwards and sweep uke's arm back toward his face, nage's right hand guiding uke's

right wrist while nage's left hand palms uke's elbow. Nage's left hand then rotates uke's arm in a circular arc away from himself.

In the irimi variation, nage will then step forward and pin uke down using his hip power and stable stance. In the tenkan variation, nage will pivot on his left leg and swing uke around in an arc and finally pin him down.