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 does not use only one. Preparation therefore starts with asking whose regulations 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: the yuko score was removed, leaving ippon and waza-ari; the hold-down needed for waza-ari was shortened from 15 seconds to 10; the number of shido causing a loss by penalty dropped from four to three; and the contest time was set at four minutes for both men and women.

Open the All Japan Judo Federation's own rules page, though, and yuko is still there in the scoring used domestically — awarded for a throw landing the opponent on the side, shoulder or hip, and for a hold-down of five seconds to under ten. That is why a competitor can be puzzled to find that a short hold scored at one tournament and not at another.

What deserves emphasis is that the hold-down times for ippon and waza-ari are identical on both sides: twenty seconds, and ten seconds to under twenty. The difference is whether a third tier of score exists at all. If you have read somewhere that the two systems use different hold-down timings, go back to the source — that particular error is widespread in Thai-language material online.

The IJF began restricting leg grabs in 2010 and banned them outright in 2013, on the reasoning that judo should look distinct from wrestling. The Kodokan, the institute where the art originates, never removed this family of techniques from its system, treating them as a long-established way of breaking an opponent's balance.

The interesting turn came in 2025, when the All Japan Championships announced that leg grabs would be permitted again, by decision of the tournament's organising committee with the Kodokan among its members. The condition is that a competitor must already be gripping the opponent's jacket before touching below the belt; if the jacket grip and the leg grab happen at the same moment, it remains a shido. This is a rule specific to that tournament, not an international one.

Worth knowing alongside it: the International Judo Federation had been moving towards reinstating leg grabs for the Los Angeles 2028 Olympics and then reversed course and shelved it. So the two sides are currently heading in opposite directions — Japan opening the door at its own championship, the international stage keeping it shut.

This table is deliberately short, with every cell traceable to a source, rather than long and padded with numbers whose origin cannot be found. Several rows are identical on both sides, which is itself a useful answer.

On 24 January 2022 the All Japan Judo Federation resolved to revise its special regulations for youth competition, banning chokes entirely at junior high school level with effect from 1 April 2022 — the first review of that rule set in forty-five years. The reason was that competitors of that age were being rendered unconscious by chokes even at national-level events. At elementary level, both chokes and joint locks were already prohibited.

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 refereeing rules specify that a standing bow is made at the waist at roughly thirty degrees. The All Japan Judo Federation's page on etiquette explains that keirei, at about thirty degrees, is distinct from hairei at about forty-five, and describes the convention known as 左座右起 — sitting down starting from the left, and rising starting from the right.

On celebrating a win, I would rather state this accurately: it is a matter of etiquette that referees and senior figures in the sport do notice, not a clause that strips a victory on the spot. Raising a fist or leaping in front of a beaten opponent will not lose you the match outright, but it runs against the principle of jita kyoei that the sport holds to, and it costs a competitor goodwill for nothing.

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.