Judo rules

This article describes the rules of judo. The main sections of the article describe the rules that apply to any situation in which judo is practiced, and those rules which apply only in judo competitions.
The scoring rules in use starting in 2017 are as follows:
The following rules are no longer in use:
Two types of penalties may be awarded. A shido (指導; literally "guidance" or "instruction") is awarded for minor rule infringements. A shido can also be awarded for a prolonged period of non-aggression. Recent rule changes allow for the first shidos to result in only warnings. If there is a tie, the number of shidos for each player are not used to determine the winner. After three shidos are given, the victory is given to the opponent. This is an indirect hansoku-make, and does not result in expulsion from the tournament. The penalty of hansoku make (反則負け; literally "foul-play loss") is awarded for major rule infringements, or for accumulating three shidos. If hansoku make is awarded for a major rule infringement, it results not just in loss of the match, but in expulsion from the tournament. Prior to 2017, the 4th shido was hansoku make.
The competition area must be padded with tatami. The minimum allowable size is 14 m × 14 m (46 ft × 46 ft). The match takes place in an 8 m × 8 m (26 ft × 26 ft) to 10 m × 10 m (33 ft × 33 ft) zone within this larger area. The surrounding space acts as a safety zone. When two competition areas are side by side, there must be at least a 3-meter (10-foot) safety zone between them.
Rules related to grips are primarily motivated by the desire to avoid stalling, to avoid providing undue advantage, or to reduce the chance of injury.
Judo competitions typically have some safety-related rules related to age: chokes are prohibited under a certain age (typically 13), and arm bars are prohibited under a certain age (typically 16).
The duration of matches is also dependent on the age of the competitors. Match length is typically three minutes for children, five minutes for teenagers and young adults, and three minutes for 'masters' (adults thirty years of age or older).
Rules related to the judogi are primarily related either to safety or to preventing contestants from wearing judogi that prevent their opponent from being able to get a grip on them.
The official International Judo Federation (IJF) rules related to the provision of medical treatment and to the proper handling of situations involving illness or injury are relatively long and involved, since the exact nature and cause of an injury may itself affect the awarding of the match, and since receiving some types of medical treatment, but not others, automatically ends the match. The latter fact makes it necessary for medical attendants at judo matches to have some understanding of this rather complex aspect of the rules of judo. The medical team is not allowed to enter the fighting area without permission from the mat judge, and if a contestant receives medical treatment he automatically forfeits the match. Nosebleeds, for example cannot be treated by the medical team; the contestant must fix it him or herself with materials provided by the medical team. Proper procedure is stuffing cotton balls up the nostrils, while applying tape around the head. If a contestant is rendered unconscious without a choking technique, and is unable to wake up, the medical team has to take immediate action and they can't wait for the contestant's consent; he or she forfeits the match automatically. A contestant can ignore any injuries he or she has, and keep fighting. This requires that it is not of any discomfort to the opponent, e.g. bleeding over an opponent can cause penalties. If the bleeding has been tried to be stopped three times, with no effect, the match is forfeited.