Vulcan nerve pinch
A Vulcan technique that applies pressure to the base of the neck, immediately rendering the subject unconscious but ultimately unharmed.
The technique seems to work on most humanoid species, however few non-Vulcans have been able to master the pinch with the same effect. Spock tried unsuccessfully to teach the technique to Captain Kirk a number of times. Only the android Commander Data was able to perfect it to escape a Romulan hostage situation.