Kahless technique
A Kahless technique was a martial arts skill attributed to Kahless the Unforgettable, founder of the Klingon Empire.
Worf had mastered a Kahless technique allowing one to regulate their heartbeat to near-imperceptibility. In 2401, he used this technique to feign his demise at the hands of Raffi Musiker, during a fight to the death forced on them by the Vulcan kingpin Krinn. This allowed him to then ambush Krinn's bodyguards and take Krinn captive. (PIC: "Imposters")