I'm a Swedish writer and aikido instructor, 6 dan Aikikai Shihan, former Vice Chairman of the International Aikido Federation. I've practiced aikido since 1972. I also teach the sword art iaido. Here's my budo bio.
by Stefan Stenudd. The aikibatto sword and staff exercises for aikido students explained, with practical and spiritual aspects of the sword arts, equipment for training, and more. Click the image to see the book at Amazon.
Increase your life energy, by Stefan Stenudd. The life energy qi (also chi or ki), with exercises on how to awaken, increase, and use it. Click the image to see the book at Amazon.
Kotegaeshi in Tantodori
The Aikido Technique Kotegaeshi on Knife Attack
When taking the knife from the attacker in the kotegaeshi technique, first make sure that you have applied the hold properly, according to the picture above. It is best to do the pinning standing up, not to get the knife to close to your face. The hand with which you hold uke in this pinning, is holding on, with the same grip, all through the technique.
In the case of a tsuki attack the knife should normally be positioned as on these pictures, but it is not certain. If the attack had been done from a knife grip where the edge of it was initially upward, it would be in a reverse position here, and removing it would have to be done slightly differently from what is shown below.
The knife here is single-edge, which is more easy to handle than a double edge one. This too must be carefully observed before taking it from uke.
Now it is time to take the knife. Form your free hand into a fork shape, like the letter U, as shown on the picture above. Do not bend your fingers, neither the thumb nor the others. This shape of the hand should be kept until the knife is safely removed from uke's grip.
To avoid the knife falling out of your reach, pinch it a little at the base of your fork grip. If you do this already when you apply the fork hand to the knife, you will be sure to get hold of it whenever uke drops it.
Move your hand in a horizontal semi-circle, allowing the backside of the knife blade to press against the bottom of the U, that is the area between the thumb and the index finger.
The semi-circle should be done with uke's hand as the center - fixed at the same spot all through. It is very important not to let uke's arm or hand move, or uke may very well get a better grip on the knife.
Already when you applied the pinning, uke lost control of the knife. It is actually you who are keeping it in uke's grip, with the hold you have on uke's fist. The semi-circle is still the safe way to take the knife, so do not try to pull it off before this movement is completed.
Apply a good grip on the knife, before moving away from your position or releasing uke's arm.
My Aikido Books
Basic Concepts of the Peaceful Martial Art, by Stefan Stenudd. Aikido principles, philosophy, and basic ideas. Click the image to see the book at Amazon.
How to do kogeki, the attack techniques, by Stefan Stenudd. All the attack techniques in aikido explained, and how to do them correctly. Click the image to see the book at Amazon.