Standing phase

n the standing phase, which has primacy according to the contest rules, the opponents attempt to throw each other. Although standing joint-lock and choke/strangulation submission techniques are legal in the standing phase,[8] they are quite rare due to the fact that they are much harder to apply standing than throws are. Some jūdōka, however, are very skilled in combining takedowns with submissions, where a submission technique is begun standing and finished on the ground. However throwing with a joint-lock is strictly prohibited.
Strikes (i.e. punches, kicks, etc...) are not allowed due to their certainty of injury, but an athlete is supposed to "take them into consideration" while training by, for example, not fighting in a bent-over position for long, since this position is vulnerable to knee-strikes and other striking attacks.
The main purpose of the throwing techniques (nage waza) is to take an opponent who is standing on his feet, mobile and dangerous, down onto his back where he cannot move as effectively. Thus, the main reason for throwing the opponent is to control the opponent and to put oneself in a dominant position. In this way the practitioner has more potential to render a decisive outcome. Another reason to throw the opponent is to shock his body through smashing him forcefully onto the ground. If an opponent executes a powerful yet fully controlled throw, he can win a match outright (by ippon) on the basis that he has displayed sufficient superiority. A lower score is given for lesser throws. A score for a throw is only given when executed starting from a standing position.
In keeping with Kano's emphasis on scientific analysis and reasoning, the standard Kodokan judo pedagogy dictates that any throwing technique is theoretically a four phased event: off-balancing (kuzushi); body positioning (作り tsukuri?); execution (掛け kake?); and finally the finish or coup de grâce (極め kime?). Each phase follows the previous one with great rapidity — ideally they happen almost simultaneously.

Standing phase

n the standing phase, which has primacy according to the contest rules, the opponents attempt to throw each other. Although standing joint-lock and choke/strangulation submission techniques are legal in the standing phase,[8] they are quite rare due to the fact that they are much harder to apply standing than throws are. Some jūdōka, however, are very skilled in combining takedowns with submissions, where a submission technique is begun standing and finished on the ground. However throwing with a joint-lock is strictly prohibited.
Strikes (i.e. punches, kicks, etc...) are not allowed due to their certainty of injury, but an athlete is supposed to "take them into consideration" while training by, for example, not fighting in a bent-over position for long, since this position is vulnerable to knee-strikes and other striking attacks.
The main purpose of the throwing techniques (nage waza) is to take an opponent who is standing on his feet, mobile and dangerous, down onto his back where he cannot move as effectively. Thus, the main reason for throwing the opponent is to control the opponent and to put oneself in a dominant position. In this way the practitioner has more potential to render a decisive outcome. Another reason to throw the opponent is to shock his body through smashing him forcefully onto the ground. If an opponent executes a powerful yet fully controlled throw, he can win a match outright (by ippon) on the basis that he has displayed sufficient superiority. A lower score is given for lesser throws. A score for a throw is only given when executed starting from a standing position.
In keeping with Kano's emphasis on scientific analysis and reasoning, the standard Kodokan judo pedagogy dictates that any throwing technique is theoretically a four phased event: off-balancing (kuzushi); body positioning (作り tsukuri?); execution (掛け kake?); and finally the finish or coup de grâce (極め kime?). Each phase follows the previous one with great rapidity — ideally they happen almost simultaneously.

Combat phases

n judo, there are two main phases of combat: the standing (tachi-waza) and the ground (ne-waza) phase. Each phase requires its own (mostly separate) techniques, strategies, randori, conditioning and so on. Special training is also devoted to "transitional" techniques to bridge the gap. Jūdōka may become quite skilled in one phase and be rather weak in the other, depending on where their interests most lie, although most are balanced between the two.
Judo's balance between both the standing and ground phases of combat gives judoka the ability to take down opponents who are standing up and then pin and submit them on the ground. This balanced theory of combat has made judo a popular choice of martial art or combat sport.

Randori (sparring)

Judo emphasizes a free-style sparring, called randori, as one of its main forms of training. Part of the combat time is spent sparring standing up, called tachi-waza, and the other part on the ground, called ne-waza. Sparring, even subject to safety rules, is much more practically effective than only practicing techniques on their own, which is what jujutsuka were used to doing. Using full strength develops the muscles and cardio-vascular system on the physical side of things, and it develops strategy and reaction time on the mental side of things, and helps the practitioner learn to use techniques against a resisting opponent. A common saying among judoka is "The best training for judo is judo."
There are several types of sparring exercises, such as ju renshu (both judoka attack in a very gentle way where no resistance is applied); and kakari geiko (only one judoka attacks while the other one relies solely on defensive and evasive techniques, but without the use of sheer strength.)

Kata (forms)

Forms (kata) are pre-arranged patterns of attack and defence, which in judo are practised with a partner for the purpose of perfecting judo techniques. More specifically, their purposes include illustrating the basic principles of judo, demonstrating the correct execution of a technique, teaching the philosophical tenets upon which judo is based, allowing for the practice of techniques that are not allowed in competition, and to preserve ancient techniques that are historically important but are no longer used in contemporary judo.
Knowledge of various kata is a requirement for the attainment of a higher rank.
There are seven kata that are recognised by the Kodokan today:
Free practice forms (Randori), comprising two kata:
Throwing forms (Nage no Kata)
Grappling forms (Katame no Kata)
Old style self-defence forms (Kime no Kata)
Modern self-defence forms (Kodokan Goshin Jutsu)
Forms of "gentleness" (Ju no Kata)
The five forms (Itsutsu no Kata)
Ancient forms (Koshiki no Kata) [8]
Maximum-efficiency national physical education kata (Seiryoku Zen'yō Kokumin Taiiku no Kata)
There are also other kata that are not officially recognised by the Kodokan but that continue to be practised. The most prominent example of these is the Go no sen no kata, a kata that focuses on counter-attacks to attempted throws.

Techniques & practice

While judo includes a variety of rolls, falls, throws, hold downs, chokes, joint-locks, and strikes, the primary focus is on throwing (投げ技 nage-waza?), and groundwork (ne-waza). Throws are divided in two groups of techniques, standing techniques (tachi-waza), and sacrifice techniques (捨身技 sutemi-waza?). Standing techniques are further divided into hand techniques (手技 te-waza?), hip techniques (腰技 koshi-waza?), and foot and leg techniques (足技 ashi-waza?). Sacrifice techniques are divided into those in which the thrower falls directly backwards (真捨身技 ma-sutemi-waza?), and those in which he falls onto his side (橫捨身技 yoko-sutemi-waza?).
The ground fighting techniques (ne-waza) are divided into attacks against the joints or joint locks (関節技 kansetsu-waza?), strangleholds or chokeholds (絞技 shime-waza?), and holding or pinning techniques (押込技 osaekomi-waza?).
A kind of sparring is practiced in judo, known as randori (乱取り?), meaning "free practice". In randori, two adversaries may attack each other with any judo throw or grappling technique. Striking techniques (atemi-waza) such as kicking and punching, along with knife and sword techniques are retained in the kata. This form of pedagogy is usually reserved for higher ranking practitioners (for instance, in the kime-no-kata), but are forbidden in contest, and usually prohibited in randori for reasons of safety. Also for reasons of safety, chokeholds, joint locking, and the sacrifice techniques are subject to age or rank restrictions. For example, in the United States one must be 13 or older to use chokeholds, and 16 or older to use armlocks.
In randori and tournament (shiai) practice, when an opponent successfully executes a chokehold or joint lock, one submits, or "taps out", by tapping the mat or one's opponent at least twice in a manner that clearly indicates the submission. When this occurs the match is over, the tapping player has lost, and the chokehold or joint lock ceases.

Judogi (uniform)

Judo practitioners traditionally wear white uniforms called jūdōgi, which simply means "judo uniform", for practicing judo. Sometimes the word is seen shortened simply to gi (uniform). The jūdōgi was created by Kano in 1907, and similar uniforms were later adopted by many other martial arts.[citation needed] The modern jūdōgi consists of white or blue cotton drawstring pants and a matching white or blue quilted cotton jacket, fastened by a belt (obi). The belt is usually coloured to indicate rank. The jacket is intended to withstand the stresses of grappling, and as a result, is much thicker than that of a karate uniform (karategi).
The modern use of the blue judogi was first suggested by Anton Geesink at the 1986 Maastricht IJF DC Meeting.[7] For competition, a blue jūdōgi is worn by one of the two competitors for ease of distinction by judges, referees, and spectators. In Japan, both judoka still use a white judogi and the traditional red sash (based on the colours of the Japanese flag) is affixed to the belt of one competitor. Outside Japan, a coloured sash may also be used for convenience in minor competitions, the blue jūdōgi only being mandatory at the regional or higher levels. Japanese practitioners and purists tend to look down on the use of blue jūdōgi.[7]