* 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.[1]
* Head dives are not permitted.[2]
* The technique known as kawazu gake is not permitted.[3]
* 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).[4] This includes wedding rings,
earrings, hard-plastic protective gear, hair-ties with metal
parts, wristwatches, and even press-studs on underpants.
Etiquette
* Contestants must bow before stepping onto the mat.
* Contestants must bow to each other before and after practice
or competition.
* Inappropriate behaviour, such as foul language and bodily
gestures, is not tolerated.
In competition only
* 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.
* Disregarding the orders of the judge is prohibited.
Scoring
* Awarding of ippon (一本) 'One full point'. Award of ippon
decides the winner and ends the match.
* Awarding of waza-ari (技あり). 'One half point'. When Two
waza-ari are awarded in the same match, it is considered to be
same as ippon and the match ends (the judge exclaims 'Waza-ari,
awasete ippon')
* Awarding of yuko (有効). One score of waza-ari is considered
greater than any number of yuko scores. Yuko is currently the
smallest score that can be awarded.
* Awarding of koka (効果). Was introduced in 1975 and removed
from IJF competition at the end of 2008. Any number of koka
scores does not add up to a yuko score.[5][6]
Penalties
Two types of penalties may be awarded. A shido (指導) is awarded
for minor rule infringements. A shido can also be awarded for
a prolonged period of non-aggression. Each time a contestant
is awarded a shido, the other contestant gets points according
to how many shidos the opponent has, as if he had scored them
himself. For the first shido a warning is given to the
offending party (this replaces the previous practice of
awarding a Koka), after that the opponent will yoko, wazaro
and ipon respectively for each shido attained (if the opponent
has a wazari, and receives another from the opponent's shidos,
he wins the match). After four 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) 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.[7]
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.[8]
Grips
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.
* Deliberately avoiding gripping is not permitted.[9]
* In a standing position, it is not permitted to take any grip
other than a "normal" grip for more than three to five seconds
without attacking. A "normal" grip is one where the right hand
grips some part of the left hand side of the opponent's jacket
(and the left hand grips some part of the right hand side of
the opponent's jacket.) A non-normal grip may involve grabbing
the belt, or the trousers, or the wrong side of the
jacket.[10] (A non-"standard" grip is one that does not
involve the traditional sleeve/collar grip. There are no
time-limits related to non-"standard" grips as long as they
are not non-"normal".)
* A "pistol grip" on the opponent's sleeve is not
permitted.[11]
* It is not permitted to insert the fingers inside the
opponent's sleeve opening or trousers opening at any time. You
are permitted to insert your fingers inside your own gi
openings.
* Biting the opponent's gi is prohibited, as it grants another
gripping point.
Age
Judo competitions typically have some safety-related rules
related to age: chokes are prohibited under a certain age
(typically 13[12]), 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).
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.
* 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.[13]
* The legs of the trousers are not allowed to be too short:
they must extend down to no more than 5 cm above the
ankle.[14]
* Excessive advertising on the gi must be avoided, and may
result in a forced loss if an appropriate gi can't be found.
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. 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,
f.ex. can not be treated by the medical team, the contestant
must fix it himself 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
forfeits the match automatically. A contestant can of course
ignore any injuries he has, and keep fighting. This requries
that it's not of any discomfort to the opponent, f.ex.
bleeding over your opponent can cause penalties. If the
bleeding is tried stopped three times, with no effect, the
match is forfeited.
