Rules
The traditional rules of judo are intended to avoid injuries to the participants and ensure proper etiquette. Some later additions to the rules were motivated by a desire to make the sport more interesting to observers.
Penalties may be given for being inactive during the match, or for using illegal techniques. Fighting must be stopped if a participant is outside the designated area on the mat (tatami). If the referee and judges need to discuss something during groundwork, the referee will call sonomama (which means "do not move") and both fighters must stop in the position they are in. When they are done, the referee says yoshi (which continues the match.)
All scores and penalties are given by the referee. The judges can make a decision that changes the score or penalty given by the referee. There are slight differences to IJF rules to accommodate blind judo.
Competition Scoring
The object in a judo match is to throw the opponent to the ground on his shoulder; to pin him to the ground principally on his back; or to force him to submit to a choke, strangle or an armlock.
Judo has four grades of score: Ippon, Waza-Ari, Yuko, and Koka. An ippon literally means "one point" and if one where to get that score they will win the match immediately. An ippon is awarded for:
A throw that lands the opponent largely on their back in a controlled manner with speed and force.
For a mat hold of sufficient duration (twenty five seconds) or for opponent submission.
A waza-ari is a half-point, and, if two are scored, they constitute the full point needed for a win. A waza-ari is awarded for a throw that does not quite have enough power or control to be considered ippon; or for a hold of twenty seconds.
Yuko and koka are lower grades of score, and only count as tie-breakers; they are not cumulative with one another. Scoring is lexicographic; a waza-ari beats any number of yuko, but a waza-ari and a yuko beat a waza-ari with no yuko. It is not uncommon for a match to be decided based on koka.
A fifteen-second hold down scores yuko and a ten-second hold down scores koka. If the person who secured the hold down already has a waza-ari, they only need to hold the hold down for twenty seconds to score ippon by way of two waza-ari (waza-ari-awasete-ippon). Throws further lacking the requirements of an ippon or a waza-ari might score a yuko or a koka. So-called 'skillful takedowns' are also permitted but do not score.
If the scores are identical at the end of the match, the contest is resolved by the Golden Score rule. Golden Score is a sudden death situation where the clock is reset to match-time, and the first contestant to achieve any score wins. If there is no score during this period, then the winner is decided by Hantei, the majority opinion of the referee and the two corner judges.
The scoring system may seem complicated at first, but with practice and memorization. It becomes second nature to know what will gain you a win, and what will not.
Representation of scores
Judo scoreboards show the number of waza-ari, yuko and koka scores scored by each player. Often an ippon is not represented on the scoreboard, because upon award of an ippon the match is immediately terminated. Some computerised scoreboards will briefly indicate that an ippon has been scored.
Scoreboards normally also show the number of penalties imposed on each player, and sometimes the number of medical visits for each. Only two 'medical' attentions are allowed for each competitor during a match; This is most often for minor bleeds, and despite popular belief there is not many matchs that end up with broken bones; Though it does and can occur if one is not trained to fall properly, are not careful, or just out of random just like in any other sport.
It is best to consult and learn how a scoring board will display the score. For example a match with the first player scoring one waza-ari, two yuko, and two koka, beating his opponent who scored one fewer kokas would be displayed on the scoreboard as: "122" vs. "121;" While in print such a result would often be represented as: "1W2Y2K" vs. "1W2Y1K."
New rules?
There are currently experimental new rules at the World Junior Championships 2008 in Bangkok state that scores Yuko, Waza-ari and Ippon that are in use. This is without Koka.
First penalty given will be a warning which is noted on scoreboard. Second penalty will be Yuko and so on until Hansoku Make is given.
Practice
In practice and competition every Judoka needs to know::
- Safety:
- Intentionally injuring an opponent is not permitted.
- Punching, kicking, and other strikes are not allowed.
- Touching the opponent's face is not allowed.
- Attacking joints other than the elbow is not allowed.
- Head dives are not permitted.
- The technique known as kawazu gake is not permitted.
- The technique known as kani basami is not permitted.
- Wearing any hard or metallic object during competition is not permitted.
- The penalty for violating this rule is hansoku make (see Penalties, below.)
- Etiquette
- Contestants must bow before stepping onto the mat.
- Contestants must bow to each other before and after practice or competition.
- In competition only Judokas are:
- Stalling is not permitted.
- Adopting a defensive posture is not permitted.
- It is required to bow to the competition area.
- False attacks are not permitted. They are considered attempts to circumvent
the prohibition against noncombativity.
Penalties
Two types of penalties may be awarded: A 'Shido' and a 'Hansoku Make.' A shido is awarded for minor rule infringements. The penalty of hansoku make is awarded for major rule infringements, or for accumulating four 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 entirely. If there is anything a Judoka must know are what is allowed and not allowed in a competition, as well as in Judo itself.
Competition area
The competition area must be padded with tatami. The minimum allowable size is 14 x 14 meters. The match takes place in an 8 x 8 meter to 10 x 10 meter 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 safety zone between them. This is only during competitions, during training and pratice it is not as enforced. Though there it is best to have at least a 3 meter safety zone between others to avoid injury.
Age
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.) Though those of these age groups can practice such techniques it is highly recommended that they do so under the guidance of their instructor 'sensei.'
The duration of matches is also dependent on the age of the competitiors. Match length is typically three minutes for children, five minutes for teenagers and young adults, and three minutes for 'masters' which is a term for adults thirty years of age or older.
Gi
Rules related to the gi are primarily related either to safety or to preventing contestants from wearing gis that prevent their opponent from being able to get a grip on them. It is important that the sleeves of the jacket are not allowed to be too short: they must extend down to no more than 5 cm above the wrists with the arms extended in front of the body. The legs of the trousers are not allowed to be too short either: they must also extend down to no more than 5 cm above the ankle.
Medical treatment, Illness, and Injury
The official 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 themselves 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.