The rear naked choke (RNC), also known as "hadaka jime" in Judo and "lion killer choke (Mata Leão)" in BJJ, is a chokehold in martial arts applied from an opponent's back. The word naked in this context suggests that, unlike other strangulation techniques found in jujutsu/judo, this hold does not require the use of a keikogi ("gi") or training uniform.
The choke has two variations:[1] in one version, the attacker's arm encircles the opponent's neck and then grabs their own biceps/shoulder on the other arm (see below for details); in the second version, the attacker clasps their hands together instead after encircling the opponent's neck.[2] Recent studies have shown that the rear-naked choke takes an average of 8.9 seconds to render an opponent unconscious regardless of the grip that is used.[3]