A chokehold, choke, stranglehold or, in Judo, shime-waza (絞技) is a general term for a grappling hold that critically reduces or prevents either air (choking) or blood (strangling) from passing through the neck of an opponent. The restriction may be of one or both and depends on the hold used and the reaction of the victim. While the time it takes for the choke to render an opponent unconscious varies depending on the type of choke, the average across all has been recorded as 9 seconds.
The lack of blood or air often leads to unconsciousness or even death if the hold is maintained. Chokeholds are used in martial arts, combat sports, self-defense, law enforcement and in military hand to hand combat applications. They are considered superior to brute-force manual strangling, which generally requires a large disparity in physical strength to be effective. Rather than using the fingers or arms to attempt to crush the neck, chokeholds effectively use leverage such as figure-four holds or collar holds that use the clothes to assist in the constriction.
The terminology used varies; in most martial arts, the term "chokehold" or "choke" is used for all types of grappling holds that strangle. This can be misleading as most holds aim to strangle not choke with the exception of "air chokes" (choking means "to have severe difficulty in breathing because of a constricted or obstructed throat or a lack of air"). In Judo terminology, "blood chokes" are referred to as "strangleholds" or "strangles" while "air chokes" are called "chokeholds" or "chokes". In forensics, the terms "strangle" and "stranglehold" designate any type of neck compression, while in law-enforcement they are referred to as "neck holds".
An air choke (or tracheal choke) specifically refers to a "true" choke that compresses the upper airway (trachea, larynx or laryngopharynx), hence interfering with breathing and leading to asphyxia. Although less effective at inducing unconsciousness than its vascular counterpart, the air choke causes excruciating pain and air hunger, and in combat sports a fighter will usually yield to such a submission hold.