A nelson hold is a grappling hold which is executed from behind the opponent, generally when both are on the mat face down with the opponent under the aggressor. One or both arms are used to encircle the opponent's arm under the armpit, and secured at the opponent's neck. Several different nelson holds exist, and they can be separated according to the positioning of the encircling arm(s). A nelson is used to control an opponent or to turn him over on his back and execute a pin.