How Do Judo Competition Rules Differ Between Japan and Thailand? What to Know Before Competing There

Entering a tournament in Japan sounds like a change of country. It can also be a change of rulebook, because Japan layers three sets of rules: the IJF rules, which the All Japan Judo Federation applies to domestic competition; the extra agreed rules that some events write for themselves; and the youth regulation for competitors of junior-high age and below. Preparation therefore starts with asking which layer the event runs under, rather than simply training harder.

Our four judo instructors carry dan grades from the Judo Association of Thailand: Ryu and Rain at 2nd Dan, Ken and Michelle at 1st Dan, with Ken separately certified by the Kodokan in Japan. The programme and the team are set out on the IMAC Dojo judo course page.

In 2017 the IJF made a substantial revision ahead of the Tokyo Olympics: it removed the yuko score, leaving only ippon and waza-ari, set the hold-down times at 10 seconds for waza-ari and 20 seconds for ippon, cut the number of shido that cost the contest from four to three, and set contest time at four minutes for men and women alike.

The rules the IJF announced in December 2024 brought yuko back as a third score, and international use began at the Paris Grand Slam in February 2025. Yuko is given for a throw that lands the opponent on the side, the buttocks or the upper back, and for a hold-down of 5 to 9 seconds; waza-ari takes 10 to 19 seconds and ippon 20 seconds. However many yuko you score, they never add up to a waza-ari.

Japan did not keep the old rules for itself. The All Japan Judo Federation's summary of the new rules says they were introduced domestically from the All Japan Selected Judo Championships (全日本選抜体重別選手権大会) in April 2025, and the federation's own rules page now describes the same system: four-minute contests, yuko, disqualification on the third shido, and, if there is still no winner, golden score with no time limit.

An earlier version of this article said yuko was the biggest difference between Japan and Thailand. That stopped being true in 2025. If you read the same claim elsewhere, check which year's rules it quotes. In January 2026 the IJF said these rules remain largely unchanged, and that they will be fixed from the Ulaanbaatar Grand Slam until the Los Angeles 2028 Olympic Games.

Current IJF rules allow gripping below the belt down to the level of the top of the inner thigh, but leg grabbing, hooking the legs with the hand or arm, gripping the trousers and touching the leg from that level down are still penalised with shido. Meanwhile the Kodokan's list of technique names, kept by the institute where judo began, still includes leg-grab throws such as morote-gari (双手刈) and kuchiki-taoshi (朽木倒), and the IJF's Sport and Organisation Rules name a further set of Kodokan techniques that are not allowed in IJF events, among them kawazu-gake and kani-basami.

In Japan, the organising committee of the All Japan Judo Championships (全日本柔道選手権大会) and the women's Empress's Cup announced on 10 October 2024 a new agreed rule from the 2025 editions. The rules for the 2025 edition say that in standing, once you are gripping your opponent, grabbing or touching below the belt to attack or defend is not penalised, but going below the belt directly while not yet gripping is still a shido. The event is co-organised by the Kodokan and the All Japan Judo Federation, and the rule belongs to that event, not to international judo.

The other half of the picture is that the IJF rules still ban leg grabs. The All Japan Judo Federation's summary records that a major relaxation of leg grabs was one of the items a meeting considered in October 2024, before the new rules were announced, but the rules that came out still penalise them with shido, and the IJF will keep its rules fixed until the 2028 Olympics. So for now Japan has opened the door in its own event while the international stage keeps it shut.

This table compares the current IJF rules, which Thailand mainly follows and Japan applies to domestic competition, with the agreed rules of the All Japan Judo Championships and the women's Empress's Cup, as published on the event pages for 2025 and 2026. Every cell can be checked against its source. If you are entering any other event in Japan, open that event's own regulations, because the federation says some events may adjust how the rules are applied.

Japan has a competition regulation for youth events that covers domestic contests for competitors of junior-high age and below. It runs those contests under IJF rules with added safety bans. The one parents should know is that using chokes or joint locks is a shido, and that intentionally choking an opponent or locking a joint is an immediate disqualification (hansoku-make).

The 2015 version of the regulation still let junior-high students use chokes, except sankaku-jime (三角絞); the current version has no such exception. The closing notes list several amendments in between, including one made on 24 January 2022 that took effect on 1 April 2022. Japanese press reported the same day that this amendment banned chokes completely at junior-high level, because competitors of that age had been rendered unconscious by chokes even at national events. The latest version, in force from 1 April 2026, renamed the regulation and added a ban on elementary-school pupils throwing from one knee.

That differs from IJF cadet events, the under-18 category, where chokes are still allowed. The IJF rules only state that a cadet who loses consciousness from a choke cannot continue in that competition. The two systems' age bands do not line up exactly, so a parent taking a child to compete needs to know whether the event uses Japan's youth regulation or the IJF cadet rules.

Japan's youth reform did not stop at technique restrictions; it extended to abolishing the national elementary school championship itself, which I have written about in judo and jujitsu in Japan. For a parent weighing this up, I think news like that reads as a good sign rather than an alarming one: it means the country where the art began was willing to change its own system once it found children were at risk.

The IJF rules require the athletes to bow to each other before the contest begins and after it ends; if they do not bow, or bow incorrectly, the referee directs them to do so, and they must not shake hands before the start. In the dojo, the Kodokan's page on bowing explains that the two bows mainly taught are zarei (座礼), the seated bow, and ritsurei (立礼), the standing bow.

On celebrating a win, the IJF rules have no clause that bans celebrating as such. They do state that at IJF events an athlete who disrespects the opponent at the end of a contest risks disqualification and the loss of prize money and world ranking points, and they count insulting an opponent by word or gesture as an act against the spirit of judo. Punching the air or leaping in front of a beaten opponent is therefore not only a matter of image: if the referees read it as disrespect, there are penalties for it, and it runs against jita kyoei, a value the IJF writes into its own rules.

If you have read this far and are considering judo for your child: the judo class at IMAC Dojo takes students from age 8, and always begins with ukemi, the skill of falling safely. There is a fuller piece on that in what ukemi is, and on where the art itself comes from in what judo is.