Info about "Sankyo video"
Sankyo (third teaching) is an Aikido technique, a rotational wristlock that directs upward-spiraling tension throughout the arm, elbow and shoulder. It contains a wrist twist that can be quite painful, if done with too much force.
For regular training in the dojo, it is important not to overdo the sankyo, or members of the dojo will soon get their wrists damaged. To improve your sankyo, work on how you control the whole of uke’s body, instead of just twisting uke’s wrist to induce pain.