Judo

Judo has the most interesting officiating arrangement on this site, because the official on the mat is not the final authority.

One referee runs the contest. Video review officials sit at the side with access to replay, and they can and routinely do correct the mat referee's score — not on appeal, not on challenge, but on their own initiative and within seconds. The referee's call is provisional by design.

No other sport here works this way. Football's VAR advises a referee who remains the decision-maker. Gymnastics splits its judgement across two panels that each own their part. Judo simply has a second layer that outranks the first, and the sport has largely accepted it, because what a score depends on — whether a throw landed largely on the back, with control, with force — is almost impossible to see correctly once from mat level and quite easy to see correctly twice from a camera.

That is the underlying reason the technology fits here and fits badly elsewhere. Judo's central judgement is about the geometry of a body at a moment in time, which is a question of fact even though it sounds like an opinion. Football's handball law asks about intent and football's cameras cannot help.

What review cannot settle is the penalty. Shido for passivity, for a false attack, for defensive gripping — these are judgements about a pattern of behaviour over time rather than about a moment, and they remain the most disputed calls in the sport. Since 2018 they can no longer win a contest for the opponent, only lose it for the offender, which reduced how much rests on them.

Judo is the most widely practised martial art in the world and one of the most evenly distributed sports on this site. Its medal table is genuinely global in a way that badminton's and table tennis's are not: Japan, France, Georgia, Brazil, Russia, South Korea, Cuba, the Netherlands, Mongolia and Kosovo have all produced Olympic champions, and several of those are small countries where judo is a national sport.

The evenness has a cause. Judo needs a mat, a jacket and a coach, and nothing else — no facility on the scale gymnastics needs, no pool, no bicycle, no grass. It travelled through the twentieth century on the back of Japanese emigration and military instruction, and it embedded in school and club systems rather than in expensive institutions.

France is the case worth recording. It has more registered judoka than Japan, by a wide margin, built on a club structure that treats judo as a children's activity first and a combat sport second. That is a participation strategy rather than an elite one, and it has nonetheless produced sustained elite success.

The rule consequence is the one running through this whole page. Because the sport is genuinely global and its strongest competitors increasingly come from outside its founding tradition, the question of what judo should look like has real stakes. The leg grab ban fell hardest on nations with wrestling cultures and lightest on those with classical judo lineages, and whether that was the purpose or the side effect is exactly what the sources disagree about.

Judo is the only sport on this site whose founder wrote down what it was for.

Jigoro Kano established the Kodokan in 1882, taking the throwing and grappling techniques of jujutsu and removing the strikes, the joint attacks the body cannot survive, and the assumption that the goal was to injure. What he built was a martial art reorganised as an educational method, with two stated principles: maximum efficiency with minimum effort, and mutual welfare and benefit.

That origin explains why judo's rule arguments sound different from every other sport's here. When the federation banned leg grabs in 2013 and justified it by saying that judo should look like judo, it was making a claim that only a sport with a written purpose can make. Football cannot say a tackle is wrong because it is not football. Judo can, and does.

The system spread through the Japanese education system and then internationally through demonstration and emigration; the International Judo Federation formed in 1951. Judo entered the Olympic programme at Tokyo in 1964, was dropped for 1968, and has been permanent since 1972. The women's competition arrived in 1992, twenty-eight years after the men's.

Kano's other invention was the coloured belt, which is now so universal across martial arts that its origin is invisible. It was a nineteenth-century administrative idea about how to grade a syllabus.

Judo has almost no equipment, and the one thing it does have is contested in a way that only makes sense once you realise the judogi is not clothing.

Both contestants grip the jacket. It is therefore the interface through which the entire sport happens, and its specification is a performance rule rather than a uniform rule. The IJF regulates weave, thickness, sleeve length, the gap at the wrist and the width of the lapel, and enforces those tolerances with a gauge at weigh-in — because a jacket cut slightly tighter is genuinely harder to grip, and a competitor wearing one is harder to fight.

The visible change is colour. Until the late 1990s both contestants wore white and were distinguished by a coloured sash, which on television was two indistinguishable figures on a pale mat. The blue judogi was adopted for major competition from 1998 after sustained resistance, particularly from Japan, where the objection was that white was part of what judo was and changing it for a camera got the priority backwards.

That argument is worth holding onto, because it is the same argument the sport had about leg grabs fifteen years later and about yuko twenty years later. Judo's equipment history is short, but the dispute inside it — whether the sport exists for its practitioners or for its audience — runs through everything else on this page.

The mat is the other piece of equipment, and its evolution is a safety story: progressively better shock absorption, which is what allows throws to be practised thousands of times.

Judo's politics is a long negotiation between the country that invented it and the federation that runs it, and almost every modern rule change is legible as a move in that negotiation.

Japan holds a position no other nation holds in any sport on this site: it is not merely the strongest competitor but the source of the sport's definition of itself. The Kodokan is a separate institution from the IJF and retains authority over judo as a practice rather than as a competition. When the two disagree — over the blue judogi, over scoring, over which techniques belong — the disagreement is not about who wins but about what the thing is.

The IJF's direction for thirty years has been towards spectacle and legibility: distinguishable colours, fewer scores, no draws, no referees' decisions, contests that end with something visible happening. Each step is defensible on its own and the cumulative direction is unmistakable, and it is the direction the Kodokan tradition has resisted at every stage.

The leg grab ban is where those two forces produced something unusual. The federation did not claim safety or fairness. It said judo was starting to look like wrestling, and legislated on the basis of identity — the only governing body on this site to give that as a stated reason, and it could only do so because Kano wrote down what the sport was supposed to be.

Weight categories are the other governance issue, and it is a health one. The sport is contested at a made weight and the practice of cutting to it remains inadequately regulated.

The white-on-white problem. Not an incident but a broadcast fact: two contestants in identical white judogi gripping each other on a pale mat could not be told apart on television, which made the sport unwatchable and made refereeing decisions impossible for a viewer to follow. The blue judogi arrived in 1998 over sustained objection from within the sport.

Wrestling in a judogi. Through the 2000s, techniques that attacked the legs directly with the hands — morote-gari and its relatives — became increasingly effective at the highest level, particularly among competitors from wrestling cultures. They were legal, they worked, and to the federation they looked wrong. Restricted in 2010, banned outright from 2013.

This is the clearest case on the site of a governing body legislating on aesthetics and saying so. There is a competing reading, recorded in the entry, that the ban advantaged the classical throwing styles of the sport's traditional powers over approaches that had beaten them. The sources do not settle it, and the federation's own reason — identity — is unusually honest about not being a sporting one.

Winning by not losing. By the mid-2010s a contest could be won by taking a minimal score or drawing a penalty and then defending for four minutes. Three separate changes closed that off: yuko abolished in 2017, unlimited golden score in the same year, and in 2018 the removal of penalties from the score altogether. A judoka can now only win by doing something.

Necks and shoulders. The one uncontested area. Throws taken onto the head, or finished with the opponent's arm trapped, produced a documented pattern of serious cervical and shoulder injuries, and the 2022 restrictions attracted none of the argument that surrounds everything else here.

Recorded as unsettled.

The leg grab ban, twelve years on. It has not settled. The argument for reinstatement is that the sport removed a legitimate and effective family of techniques on aesthetic grounds and narrowed itself doing so; the argument against is that judo is a defined thing and a governing body is entitled to defend the definition. This site records that the federation gave identity as its reason, which is rare enough to be the interesting fact regardless of who is right.

Rule churn. Judo has changed what wins a contest three times in a decade. There is a real argument inside the sport that this is too much: that athletes build careers on techniques and tactics that the rulebook then removes, and that the accumulated effect is a sport whose eras cannot be compared. Judo has no comparability break in the sense this site usually means, because it keeps no quantitative series — but it may have the most severe continuity problem here, and no chart can show it.

Weight cutting. The sport is contested at a made weight and the practice of extreme dehydration before weigh-in is a documented health risk that the federation regulates lightly. Same-day weigh-ins and tighter tolerances are proposed periodically.

Passivity. Every combat sport with a clock has to decide what to do about a contestant who does not engage, and judo's answer — shido for passivity — asks a referee to judge intent over time. It is the most disputed call left in the sport, and unlike a score it cannot be settled by looking again.