Continuing with our introduction into techniques and the applied anatomy at work…
Nikyo is the second teaching of Aikido (ni-two, kyo-teaching). It is a joint-lock technique that results in extreme pain. Nikyo allows one to control an opponent by effectively destroying his will to continue fighting.
Nikyo is accomplished by flexing and adducting an opponent’s wrist producing an instantaneous sharp pain that causes him to fall to his knees involuntarily to alleviate the pressure. The exact etiology of the pain elicited by this technique has been obscure to many practitioners. Explanation of the anatomy and mechanics of Nikyo have been published in medical literature. What is clear, from actual studies of cadavers (yes, that’s dead people), is that Nikyo forcibly compresses the pisiform bone against the ulna (two bones that do not normally articulate) overstimulating the periosteal nerves.
Why cadavers? Because it really hurts! That and it’s probably unethical to repeatedly subject one to Nikyo for science. On the mat however, you will practice Nikyo at least one thousand times.