If no fall occurs, the referee stops the match at the end of the first period, gives one of the wrestlers the choice of position, and starts the second period. If no fall occurs in the second period, the referee again stops the match, gives the other wrestler the choice of position, and starts the third period. If no fall occurs in a match, the referee names the winner on the basis of points scored for skill and aggressiveness. Three points is the most that a contestant can win for any single hold or position. During a match the referee must watch closely to make sure that there are no infractions of the rules and that the holds used by the wrestlers are legal.
Some holds are legal only if used in specific ways.
For example, the hammerlock, in which a wrestler's hand is held behind the back, is a legal hold only so long as the held hand is not forced above the small of the back or forced away from the back, which makes it a twisting hammerlock. Illegal holds often involve forcing the head or a limb beyond its normal limits of motion or covering the mouth, nose, or eyes. Holds that do not gain a scoring advantage and hence are used for punishment only are also illegal. Officials in addition to the referee are a timekeeper and scorers. For some matches there may also be an assistant referee and assistant timekeepers.