Ikkyo- the First Teaching

Ikkyo -  the first teaching. In Aikido, the first technique is described as Ude osae  which is translated to arm pin which is the final position of the technique.

Ikkyo - ude osae 

Another (deeper) translation of ude osae however states - to control uke's center through his arm. I believe that this is the principle of ikkyo.  Originally ikkyo is called ik-kajo or first control.

Surely, the technique usually ends up with nage pinning uke  on the ground through the latter's arm, However, before uke could be successfully pinned by nage, nage must first control uke's center, and that is done by controlling uke's arm

Ikkyo is the first technique taught to the beginners, and I believe the most important one in all of Aikido techniques and principles. The series of illustrations below shows how the technique is executed. However, in order for an Aikidoka to execute the technique properly, he must understand the underlying principle(s) behind the technique.

Principles behind Ikkyo

1.  Keep Your Center. You as nage should move from your center (or one-point)-, thus his movement should start from your hips not just your arms. Throughout the execution of the technique, you should keep your center at all times. Meaning,  your body weight should be evenly distributed between your legs to maintain your balance. 
2. Unbendable Arm - your arms should be extended but not straight that the elbows are locked. Slightly curved but not bent on the elbow. Once you bend your elbow you will be using more physical strength than your inner strength.
3. Extend Ki -  I mentioned above "inner strength" in Aikido (and some other Japanese martial arts), it refers to your KI.
   Unfortunately, for the under-trained, this is quite difficult to grasp, and the concept of 'ki', I must admit is not easy to explain, but once you understand it, you will realize it's nothing mystical.
   For now, I will simplify this principle by saying that when executing Aikido techniques, you breathing and movements should be properly coordinated. Before executing the technique, you must breath in and when you extend your arm to execute, you exhale slowly.

Executing Ikkyo

1. Lead uke's arm toward his face. 

After the initial attack (either grab or strike)  you as nage, will lead uke's arm towards his face as shown in the image below (Figure 2). In the process you should take not of the following as you execute the technique

1. Uke's palm and elbow turned upward). His elbow may be almost fully bent or from half to fully extended; his arm may be turned at shoulder height or higher.
2. Your left hand should be on the elbow and the other hand holding the wrist.
3. As you extend your arm, pushing uke's arm in a circular motion towards his face,  
4. Your strength must come from your hips or center.
5. Uke should be slightly off balanced.

Figure 2. Lead uke's arm to his face

2. A : Omote (Front)

1. Do the Irimi movement

1. To go to uke's front or omote, you must do the irimi (entering) movement .
2. As you enter you continue leading uke's arm  down in a big circular motion.

Note:

1. You as nage should be close to the side of uke
2. Uke's arm should be in front of your center. You do this by keeping your arm extended right in front of you as you move. 
3. You should maintain the unbendable arm.
4. Uke's shoulder should be lower than his elbow and elbow is lower than the wrist.
5. Your posture should be upright, you must not stoop or you may loose your balance, uke could bring you down with him.
6. Uke should be slightly off balanced.

Fig. 3:  Omote

3. Bring Uke Down and Pin his arm

1.  Take advantage of uke's unstable position and move quickly forward and lead him down by lowering your hips. Keep your undendable arm extended as you lower your hips. This will push uke down, the force will not be coming from your arms but from your hips.
2. Kneel to uke's side. Keep your left knee close to his armpit. pressing the side of his rib-cage. 
3. Once uke is down on the mat, your  right knee should be placed touching his forearm, but do not kneel on his arm.
4.  Extend your left arm over his elbow and your right arm over his forearm. You may apply pressure by pushing his arm forward, his arm making more than 90 degree angle with respect to his body.
   

   

   Figure 4. Ude Osae

Note:

1. Uke should be brought down first before kneeling to his side. A common mistake made by beginners is they go down the mat first before their uke.

2.B Ura (Behind Uke)

1. In this variation, as you lead uke's arm toward his face, you will step with your left foot behind him.
   
   
2.  Using your left foot as the pivot point, do a tenkan movement. To do this,  turn your hips to your back as in the image below, As you turn your hips, your withdraw your foot to your back, making a circular motion. At the same time, keep your arms extended in front of your center, leading uke down in a circular motion.
   

   

Note:

1. To successfully do the tenkan,  the movement should start from your center, thus the hips. Initiating the movement from your hips, will move your foot and arms with it.
2.  Common mistake in executing the tenkan is, ether nage would move the foot first, leaving the arms on the other side which makes it very hard to pull uke afterwards,  or they would move the arms first, which can only be done by using physical force. However, this may enable uke to regain his balance.

3. Bring Uke down for the pin. 

1. Continue the circular and downward motion until uke is down on the mat. (See Figure 4.)
2. Pin uke as described in Step 2 of  Omote.

The Importance of Ikkyo in the Study of Aikido

Ikkyo is the first technique taught to beginners. In my years of experience in practicing Aikido, I realized that almost all subsequent pinning techniques are based on the principles of Ikkyo. Thus, in mastering the princples of ikkyo, all other techniques can be learned easily.

Japanese Terms Used:

Ikkyo - first teaching, first technique

Ude Osae - arm pin

Ik-kajo (or Ikkajo) - first control

Nage -  the one who applies the technique (also called tori )

Uke - the one who receives the technique

Ki - spirit, inner strength (these are just rough translations)

Omote - front / to the front of uke

Irimi - entering

Ura -  back / to the back or uke

tenkan - 180 degree pivot  on the lead foot.

Reference and Image souirce: Aikido and the Dynamic Sphere by A. Westbrook and O. Ratti